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THE AM BULLETIN BOARD => Technical Forum => Topic started by: kk6noh on February 22, 2016, 10:05:11 PM



Title: instructions to build the k1jj tuner
Post by: kk6noh on February 22, 2016, 10:05:11 PM
Hello
I created an account here specifically for this subject. I have been researching the k1jj style tuner for several days now. I have been on countless forums, spent hours reading posts on the subject. What I cannot find is either step by step instructions on how to build this tuner, or any videos of any kind. I have tried to figure out how to build it from pictures, but not a single one of them has the detail I need. I have run into this problem before with other projects I have wanted to do. Some vague text and nothing else. I am pretty good at following clear and concise instructions, not at just winging it.

I understand what materials I need, however I cannot seem to figure out what is connected to what.
Here is the link to the project. http://amfone.net/ECSound/K1JJ13.htm

what exactly does the capacitor connect to? What taps and where do they come from/where do they go? What does floating above ground mean? are there 2 sets of taps one set from the cap and another from the output? What is the optional input cap for and how can it connect to a ground that is floating???????

I am trying to keep this cheap, because it doesn't make much sense to pay 1000 dollars to tune a 400 dollar radio. I will likely never use more than 100 watts. If I do buy an amp it will absolutely never reach past 500 watts much less 1.5kw. The antenna is a loop skywire designed for 160 on up.

Thanks


Title: Re: instructions to build the k1jj tuner
Post by: K7LYF on February 22, 2016, 10:55:21 PM
Follow this link. Hand drawing is down the page aways.

http://amfone.net/Amforum/index.php?topic=5931.0


Title: Re: instructions to build the k1jj tuner
Post by: kk6noh on February 23, 2016, 12:02:55 AM
I had already found that picture in my search. I cannot read half the handwriting because of pixelation. As I look at that picture several questions come to mind

1. I see an input on the left. One is connected to the center pin of the so239. according to the drawing the other half is ground. Where is the ground? it certainly isnt the wood or plastic box that most people use to make these things. What exactly do I connect this to or does it matter.

2. I have no desire to put an swr meter in the tuner itself, but ill have one inbetween the radio and tuner. I see one side of the smaller coil is connected there, but in other diagrams, that side of the small coil goes to ground. Is that correct? If so, read 1..... what and where is the ground.

3. On the right side of the drawing is the bannana plugs for the output and the variable capacitor. It appears that the variable capacitor is connected to both ends of the bigger coil. it also appears that the output plugs bypass over the capacitor and go straight to the large coil. if the outputs bypasses the capacitor, then what is its purpose? How does the capacitor affect the tune if its not in line with the output? does adjusting the capacitor have some form of electrical interaction to the large coil thus affecting it?

4. those connections coming from the variable capacitor to the large coil.... are they permanent on the very ends or are they alligator clips meant to be moved?

on to materials
seeing as how I have no intention of using more than 500-600 watts and thats a stretch.... what materials should I use for the coils? Any suggestions on variable capacitors? How about the connecting wires(teflon coated of what gauge)?

On the coils
the instructions say 40 turns on a 5 inch form... does it matter what the spacing is between the coils? Do I have to worry about arching? Does the spacing affect the tune?

On some designs I see the small coil on the outside of the large coil and sometimes its inside. Which is the correct way? what distance should I have between the small coil and the large coil?



thanks


Title: Re: instructions to build the k1jj tuner
Post by: Todd, KA1KAQ on February 23, 2016, 10:00:44 AM
Well, you're in luck - Tom/K1JJ is a regular here. Pull up a chair and relax, he's bound to wander in at some point. He's good at deciphering hieroglyphics, especially his own. He's pretty sharp technically as well.  ;D


Title: Re: instructions to build the k1jj tuner
Post by: K1JJ on February 23, 2016, 01:29:46 PM
Hi Tom,

Greetings to you in New Mexico and welcome to the AM forum!

There has never been formal instructions or a computer schematic done up on the tuner.  The enclosed handwritten schematic is all there is for now. I will try to answer your questions below...  BTW, this is a simple tuner and was designed so that a single vacuum variable (or ONE single section air variable) could be used as the main capacitor. The more complicated tuner designs with dual split capacitors will have better harmonic suppression, but most transmitters do not need the additional suppression and this design is usually adequate and very simple to build and use.



I had already found that picture in my search. I cannot read half the handwriting because of pixelation. As I look at that picture several questions come to mind

1. I see an input on the left. One is connected to the center pin of the so239. according to the drawing the other half is ground. Where is the ground? it certainly isnt the wood or plastic box that most people use to make these things. What exactly do I connect this to or does it matter.

ANS:  The ground is your coax shield that is used to connect the transmitter to the tuner. There is no other ground connection within the tuner.  The tuner input is unbalanced, thus a connection to ground. The rest of the tuner is floating above ground, thus no ground connection.   This picture should be clear enough to use. If not, then something needs to be adjusted in your picture reader software.  BTW, the input cap is not always needed. It simply adds more tuning range to the tuner. Some guys just ground the other end of the input coil to the coax shield  and eliminate the input cap. They then need to use the alligator clips more aggressively to increase the range lost by the missing input cap. Experiment and you will see.   Remember that the main capacitor will be floating and hot to RF, so you need a big knob and/ or insulated shaft/ coupling to tune this cap. Otherwise you will get an RF burn.  Again, this simple design allows you to use a single section vacuum variable where you otherwise could not.



2. I have no desire to put an swr meter in the tuner itself, but will have one inbetween the radio and tuner. I see one side of the smaller coil is connected there, but in other diagrams, that side of the small coil goes to ground. Is that correct? If so, read 1..... what and where is the ground.

ANS:

As before, the coax ground connects to the transmitter / swr meter and the other end goes tot he tuner. The inner connector connects to the input coil and the coax shield connects to the bottom of the input cap (ground) that we call "ground." This point can also be connected to your station ground. It should already be connected anyway via your transmitter chassis and  coax connector.


3. On the right side of the drawing is the bannana plugs for the output and the variable capacitor. It appears that the variable capacitor is connected to both ends of the bigger coil. it also appears that the output plugs bypass over the capacitor and go straight to the large coil. if the outputs bypasses the capacitor, then what is its purpose? How does the capacitor affect the tune if its not in line with the output? does adjusting the capacitor have some form of electrical interaction to the large coil thus affecting it?

ANS:

The main capacitor  or vacuum variable has two connections. They are connected across the coil. These connections are routinely moved to find the best 1:1 match as shown on the swr meter.  The main cap is also tuned to change its capacitance.  In addition, the antenna feeders are moved along the coil to find the best swr. These three changes are what's need to find a good match.  The tabs on the main big coil are used with alligator clips for easy movement. See the pictures and write ups of the various threads to better understand the adjustments.  Once the proper match is found for a band or frequency, they can be pre-marked on the coil using a marker of whatever for fast band changes. The large cap resonates with the coil and is always connected to the coil using the alligator clips.


4. those connections coming from the variable capacitor to the large coil.... are they permanent on the very ends or are they alligator clips meant to be moved?

Ans:  

Alligator clips get moved to help find a 1:1 swr match..

on to materials
seeing as how I have no intention of using more than 500-600 watts and thats a stretch.... what materials should I use for the coils? Any suggestions on variable capacitors? How about the connecting wires(teflon coated of what gauge)?

Ans:

"Floating above ground"  means there is no connection to the station ground or coax shield.  The input is unbalanced, connected to ground -- and the output has no ground connection and is connected to the balanced antenna feeders. (floated above ground)
 
The coil needs to be mounted on ceramic insulators, PVC blocks or whatever is a good RF insulator.  The main cap is hot and floating with the coil so also needs insulators. The input cap does not float above ground, so can get mounted on aluminum or whatever, as long as the coax shield is connected to the stator or frame of the input cap.

The coil can be whatever is convenient for the alligator clips to get a hold of and not short the adjacent coil turn.  Many guys use 1/4" copper tubing as found at Home Depot, etc. Some use larger  3/8" tubing. Many wind it on PVC pipe or simply support it any way they can. Remember that there is RF HV there and it needs to be mounted above ground with no arcing.   #10  to #14 Teflon wire is fine. You can use regular wire if it is insulated from the main coil well. You can use mylar or any kind of plastic sheet to wrap first and then wind the 5 turns on. Not critical. Use your imagination and whatever you have available for parts.

The input cap should be a standard 2000pf  or whatever variable commonly found. The output cap should be a wide spaced unit of 300 to 500 pf. If you can find a vacuum variable cap, that is best for power and ease using a turns counter.  160M demands 500 pf sometimes. If 75M or higher, then 300 pf may work fie. Much depends on your open wire feedline length and dipole length. That's why everything is adjustable. You can match anything.



On the coils
the instructions say 40 turns on a 5 inch form... does it matter what the spacing is between the coils? Do I have to worry about arching? Does the spacing affect the tune?

ANS:
The coil winding and spacing is not critical. That's what the alligator clips are for. Just make the coil so it is easy to clip to without shorting turns. Look at some of the pics of past projects. They are all different and work well.  As long as you have enough coil for the job, you can clip in what you need for a given match. The rest goes along for the ride and is not used towards the outer ends of the alligator clip positions.

On some designs I see the small coil on the outside of the large coil and sometimes its inside. Which is the correct way? what distance should I have between the small coil and the large coil?

Ans:   Insulated wire can be wound on the outside of the main coil or mounted inside. It does not matter. As long as it does not arc through it should work OK.  Both methods will give you plenty of coupling.

Build it, and experiment with the taps and you will get good 1:1 matches on all bands.


thanks


Hope this helps!

Tom, K1JJ


Title: Re: instructions to build the k1jj tuner
Post by: kk6noh on February 23, 2016, 01:46:32 PM
Hello

Thanks that actually clarifies a lot. However one thing is still unclear. Is the input cap absolutely necessary? According to your original design I thought it could be optional if you are not getting the match you need. The antenna I am tuning is resonate, and only has around 600 ohms impedance. Could it be possible to skip the input cap and connect one end of the small coil to the center pin and the other to the shield?


EDIT EDIT EDIT
Derp
It would help if I would stop confusicating myself and read it again :D . I see the answer in the top of your reply.


Thanks for all your help. When I get to building it I will post another topic with extensive pictures.


Title: Re: instructions to build the k1jj tuner
Post by: K1JJ on February 23, 2016, 01:51:22 PM
Hello

Thanks that actually clarifies a lot. However one thing is still unclear. Is the input cap absolutely necessary? According to your original design I thought it could be optional if you are not getting the match you need. The antenna I am tuning is resonate, and only has around 600 ohms impedance. Could it be possible to skip the input cap and connect one end of the small coil to the center pin and the other to the shield?

Hi Tom,

Yes, you can skip the input cap. You may or may not need it. You can always add it later. It simply adds more range if needed for weird antennas, bands and matches.   

Reread my post above since I added some things about this subject as well as others in edit.

T


Title: Re: instructions to build the k1jj tuner
Post by: KA2DZT on February 23, 2016, 02:08:18 PM
Hello

Thanks that actually clarifies a lot. However one thing is still unclear. Is the input cap absolutely necessary? According to your original design I thought it could be optional if you are not getting the match you need. The antenna I am tuning is resonate, and only has around 600 ohms impedance. Could it be possible to skip the input cap and connect one end of the small coil to the center pin and the other to the shield?


EDIT EDIT EDIT
Derp
It would help if I would stop confusicating myself and read it again :D . I see the answer in the top of your reply.


Thanks for all your help. When I get to building it I will post another topic with extensive pictures.

OK FB,  I didn't read all of Tom's comments, but that input cap may be needed to help match your xmtr to the input coil of the tuner.  The fact that your antenna is resonant isn't a factor in that, other antennas may not be.  You can put the input cap in series with the coax center to the coil, or you can put in it from the cold end (ground end) of the coil to the coax shield.  Either way should work.  You don't need a high voltage type tuning cap for the input cap because it is a low impedance (50 ohm output from your xmtr) high current part of the tuner's circuit.

Start building, post pictures and if something doesn't look correct the folks here will see it


Add another comment,  the ground that is shown in the drawing is your coax shield from the xmtr, the coax shield is grounded at the xmtr.  So, if you build on a wooden frame there is no real ground connection on the wood.  But, you can add a extra ground wire from the coax shield (at the tuner) if you want but it's not needed.

Fred

PS, I'm glad that Tom took the time to answer all your questions instead of me.


Title: Re: instructions to build the k1jj tuner
Post by: kk6noh on February 23, 2016, 02:28:24 PM


OK FB,  I didn't read all of Tom's comments, but that input cap may be needed to help match your xmtr to the input coil of the tuner.  The fact that your antenna is resonant isn't a factor in that, other antennas may not be.  You can put the input cap in series with the coax center to the coil, or you can put in it from the cold end (ground end) of the coil to the coax shield.  Either way should work.  You don't need a high voltage type tuning cap for the input cap because it is a low impedance (50 ohm output from your xmtr) high current part of the tuner's circuit.

Start building, post pictures and if something doesn't look correct the folks here will see it.

Fred

PS, I'm glad that Tom took the time to answer all your questions instead of me.

Do you  have any recommendations for an input capacitor? If it turns out to be cheap enough I might just go ahead and put it in from the get go. As it is the output cap costs a ton of money and I am trying to keep costs down. After all this is for an icom 735.... not the new fangled top of the line radio of today. Tom recommended a 2000pf..... what voltage rating should I be looking at?


Title: Re: instructions to build the k1jj tuner
Post by: KA2DZT on February 23, 2016, 02:40:28 PM


OK FB,  I didn't read all of Tom's comments, but that input cap may be needed to help match your xmtr to the input coil of the tuner.  The fact that your antenna is resonant isn't a factor in that, other antennas may not be.  You can put the input cap in series with the coax center to the coil, or you can put in it from the cold end (ground end) of the coil to the coax shield.  Either way should work.  You don't need a high voltage type tuning cap for the input cap because it is a low impedance (50 ohm output from your xmtr) high current part of the tuner's circuit.

Start building, post pictures and if something doesn't look correct the folks here will see it.

Fred

PS, I'm glad that Tom took the time to answer all your questions instead of me.

Do you  have any recommendations for an input capacitor? If it turns out to be cheap enough I might just go ahead and put it in from the get go. As it is the output cap costs a ton of money and I am trying to keep costs down. After all this is for an icom 735.... not the new fangled top of the line radio of today. Tom recommended a 2000pf..... what voltage rating should I be looking at?


Tom is correct about the 2000pf but you can use less if that's all you have.  You can use a broadcast type cap, close spacing.  Next question, what's a broadcast cap?  Ans, the kind you would find in an old AM radio.  You should be able to find someone that has one you can have for little or no cost.

Fred


Title: Re: instructions to build the k1jj tuner
Post by: K1JJ on February 23, 2016, 03:00:42 PM
Do you  have any recommendations for an input capacitor? If it turns out to be cheap enough I might just go ahead and put it in from the get go. As it is the output cap costs a ton of money and I am trying to keep costs down. After all this is for an icom 735.... not the new fangled top of the line radio of today. Tom recommended a 2000pf..... what voltage rating should I be looking at?





http://www.ebay.com/itm/Pioneer-QX-9900-Quad-Receiver-TUNING-CAPACITOR-/291691305027?hash=item43ea281843:g:JoMAAOSwUuFWy3F4


Tom,

A common receiver tuning capacitor is what you want.  Look on eBay and I know flea markets and some of the guys here have them. Ask around.

Here's a sample from eBay, but look for 4-5 sections for 1500 to 2000 pF minimum if possible. Under $25 is a good price. I think Fair Radio used to have them, but too expensive there. You can always pad a smaller cap (<1500 pF)  with a 500 pF fixed cap if need be for 160M.

Glad to help!   This tuner project activity runs in cycles and I'll bet some others see the thread and build up a few too.

T


Title: Re: instructions to build the k1jj tuner
Post by: kk6noh on February 23, 2016, 03:17:57 PM
OH
Now I Understand!

I was looking all over for a capacitor in that range... little did I know that they rate those things by section. So all those 3 to 4 or 5 section capacitors I kept finding are actually much better suited that I had thought.

Thanks for clearing that up.


Title: Re: instructions to build the k1jj tuner
Post by: kk6noh on February 23, 2016, 09:41:32 PM
another question... approx how many feet of tubing/wire will I need for the large coil... and how much teflon wire for the small coil?


Title: Re: instructions to build the k1jj tuner
Post by: Steve - K4HX on February 23, 2016, 09:59:19 PM
Circumference = pi x diameter

You do the rest.


Title: Re: instructions to build the k1jj tuner
Post by: flintstone mop on February 24, 2016, 05:59:23 PM
The tuner was a nice build just using the pictures. Ya buy a 25??? .... foot roll of 1/8 copper tubing for the big coil and wrap it on something round about 6 inches diameter. I wound 40 turns for the big coil.....The inner coil could be a few feet of 1/8 tubing about 6 or 8 turns..it is wound to fit inside the big coil. I picked a 40M freq and diddled with the tuning, experimenting with the taps,  and then I moved the little coil, inside the big coil for the lowest SWR, using the MFJ 259..I hope you have some sort of analyzer....this project will turn ugly if you do not have the MFJ or similar type of antenna analyzer...
I connected coax from the transmitter to this coil that sits inside the big coil and soldered taps on the big coil for connecting the antenna/ladder line. On the ends of the big coil is a huge vacuum variable cap. I forget the value. I know it was a Russian type rated for 25KV. No cheating here with a bread slicer...vacuum variable cap. I did not use a tuner cap for the input.
Antenna system is 240 feet of dipole about 65 feet in the air fed by 150 feet of ladder line, 600 ohms.
Antenna system is good from 160 M - 20M. Using a dipole this long on the upper bands would probably be a lot of pattern distortion. It would work, but I have other antennas that are better suited for the upper bands.
If you are researching this project in the Forum, you will see many nice pictures from others, and me on the construction.

Here's an old link when the tuner was first introduced here....further down the page I posted pictures of my tuner

http://amfone.net/Amforum/index.php?topic=11466.0


Fred


Title: Re: instructions to build the k1jj tuner
Post by: W4EWH on February 24, 2016, 08:41:44 PM
This tuner project activity runs in cycles and I'll bet some others see the thread and build up a few too.

Glad to oblige!  ;)

I have a number of commercial tuners, varying in size from tiny to ginormous, and I've always wondered why their designs vary so much. Ergo, some questions, es TIA.

  • Carl Smith taught me that two capacitors and two inductors could match any load to any source, but also that either side might have to have the capacitor and inductor in series. Your design makes me wonder if all common antenna loads can be matched with a parallel-resonant circuit. Does that always work?
  • Does having the tuner "ground" supplied through the coax shield connection back to the source risk punching through the coax when there is an unusually high load impedance?
  • If the load is fed via coax, is it advisable to ground one side of the parallel-resonant output circuit?
  • Some tuner manufacturers use rolling inductors instead of variable caps. Does this change the output circuit's Q enough to be a factor?
  • Speaking of rolling inductors, I have a Heathkit tuner which uses one, along with a mechanical counter. It seems to take forever to change bands, but do I get some added functionality in return?
  • What are the advantages and disadvantages of clip leads? Are they unimportant at Amateur power levels?
  • Is there any electrical benefit to putting the tuner in an enclosure, or would that be only for cosmetic reasons?
  • I've heard some hams who say that an open wire line "must" terminate in a 4-1 or 6-1 balun. What do you think?

Bill, W4EWH


Title: Re: instructions to build the k1jj tuner
Post by: K1JJ on February 24, 2016, 09:38:50 PM
    Hi Bill-

    See answers below:




Glad to oblige!  ;)

I have a number of commercial tuners, varying in size from tiny to ginormous, and I've always wondered why their designs vary so much. Ergo, some questions, es TIA.

  • Carl Smith taught me that two capacitors and two inductors could match any load to any source, but also that either side might have to have the capacitor and inductor in series. Your design makes me wonder if all common antenna loads can be matched with a parallel-resonant circuit. Does that always work?

ANS: Low impedance antennas may need a series configuration. It is easy to change this tuner to series with clip leads.  Does anyone have the series / parallel circuit diagram that K4HX drew up?   It's on this site somewhere..


  • Does having the tuner "ground" supplied through the coax shield connection back to the source risk punching through the coax when there is an unusually high load impedance?


ANS:   The coax to the tuner is low impedance at 50 ohms and no danger of arcing internally. The input is isolated from the high voltage output due to the input coil that is isolated.



  • If the load is fed via coax, is it advisable to ground one side of the parallel-resonant output circuit?

ANS:    I suppose that would work. Though for 50 0hms to 50 ohms I would recommend an unbalanced  T or Pi tuner that works best for low impedance.


  • Some tuner manufacturers use rolling inductors instead of variable caps. Does this change the output circuit's Q enough to be a factor?

ANS:   It would depend your preference and on the particular design.    Compared to a roller,  a fixed coil can be tapped or switched easily. It will need to change inductance to match loads on different bands. A roller inductor is nice for ease of use and finer tuning, but a fixed coil should work just as well..


  • Speaking of rolling inductors, I have a Heathkit tuner which uses one, along with a mechanical counter. It seems to take forever to change bands, but do I get some added functionality in return?

ANS:    Again, depends compared to switching or clip leads.  Changing inductance is changing inductance.



  • What are the advantages and disadvantages of clip leads? Are they unimportant at Amateur power levels?

 ANS:   Over 1KW may cause hot spots using clip leads. It is best to get clips that make fat contact to the coil.  12V battery clip leads of solid copper work well... the  2" size or so.


  • Is there any electrical benefit to putting the tuner in an enclosure, or would that be only for cosmetic reasons?

ANS:   Only if your shack is prone to RF getting into things like audio, etc.  I see many guys mount them on the wall where the OWL comes in and leave them open for ease of changing bands.


  • I've heard some hams who say that an open wire line "must" terminate in a 4-1 or 6-1 balun. What do you think?

 ANS:   No.  Open wire directly to the balanced tuner is the most effiecent way.   Who's to say what the OWL impedance at the balun input will be on different bands? It could be 100 ohms on one band and 800 ohms on another band with Xc and Xl all over the place. Why put a fixed impedance balan in line to muck things up?  No reason I can see IF the tuner is balanced and the OWL is balanced.


[/list]

Bill, W4EWH


73,

T


Title: Re: instructions to build the k1jj tuner
Post by: aa5wg on February 28, 2016, 10:23:26 PM
Hi everyone.

Here is the link to the K1JJ Link Antenna Tuner schematics.

http://www.amwindow.org/tech/htm/160smallants.htm

73,

Chuck


Title: Re: instructions to build the k1jj tuner
Post by: N7ZDR on March 03, 2016, 04:14:30 PM
I thought I would post a picture of the one I use all the time.
The primary coil is 5 turns of copper tubing-- This is suspended on the inside of the secondary. You can see the coax coming from the radio with the center clipped to one side of the primary. The shield side of the coax connects to one side of the broadcast cap, then from the cap back to the other side of the primary.
I have added 3 500 Pf single caps if needed to the broadcast ( Most of the time I am sitting about 2000 PF).
The big variable is clipped on the secondary at equal spots. You can see the open line clipped out a couple turns from the Cap.

Hope this helps.

Cheers
Larry


Title: Re: instructions to build the k1jj tuner
Post by: KD6VXI on March 03, 2016, 09:34:53 PM
Questuon:  If one used dual indicators,  would you not be able to also use a clip lead style tuna to force balance in an unbalanced antenna?

I'm not thinking OCF style (maybe it would),  but more akin to having a vertical.   I've OWL my vertical.   Works great,  as long as the radials are resonant.   Could you not tap this style tuna (I only have the pair of Johnson boxes)  to give equal currents in a case like mine (using a 40 me ground plane on 20, for instance)?

U could see this becoming an autotransformer quickly.

--Shane
KD6VXI


Title: Re: instructions to build the k1jj tuner
Post by: flintstone mop on March 04, 2016, 09:02:07 AM
I hope the OP returns with some good news...It was a couple of days of getting ideas and supplies and actually mounting the tuner on a nice plywood platform... Waiting for the Russian vac variable was a while.

Fred


Title: Re: instructions to build the k1jj tuner
Post by: kk6noh on March 07, 2016, 12:10:07 AM
I hope the OP returns with some good news...It was a couple of days of getting ideas and supplies and actually mounting the tuner on a nice plywood platform... Waiting for the Russian vac variable was a while.

Fred

Its likely going to be a long time before I save up enough money for the vacuum variable capacitor. That is a LOT of money.


Title: Re: instructions to build the k1jj tuner
Post by: KD6VXI on March 07, 2016, 03:23:32 AM
Ebay and the fall of communism.   Hundred to two hundred bucks.

Or,  an air variable for lower power.

--Shane
KD6VXI


Title: Re: instructions to build the k1jj tuner
Post by: flintstone mop on March 07, 2016, 10:48:51 AM
Ebay and the fall of communism.   Hundred to two hundred bucks.

Or,  an air variable for lower power.

--Shane
KD6VXI

SAVE the money for a vac variable!!!! You'll be disappointed with and air variable. Low power is no fun!!! It's worth the money and don't worry about communism. The Russian caps are way overrated and you'll love it!!
Don't rush into this with less than QRO power...Always have that as a necessary option when the bands are messy.

Fred


Title: Re: instructions to build the k1jj tuner
Post by: N7ZDR on March 07, 2016, 10:51:15 AM
I actually like the large air variable better for my cardboard toner. I find myself never happy with anything I do in the shack, this being said-- a nice big vacuum capacitor works great but for me it takes too long to rotate it where I need it to be. On the other hand, one quick look at the big air variable and I can rotate it where it needs to be positioned in less than a seconded (Wham Bam done)

Flea- Bay is your friend for this stuff.

Cheers
Larry


Title: Re: instructions to build the k1jj tuner
Post by: N7ZDR on March 07, 2016, 10:58:40 AM
Looks like we posted at the same time Fred-----Don't get me wrong-- I love any big Vacuum cap as there all but bullet proof. I just found myself spending too much time looking at the turns counter and wondering when the dip was coming.

Cheers,

Larry


Title: Re: instructions to build the k1jj tuner
Post by: kk6noh on March 07, 2016, 04:40:10 PM
lol talking about 100-200 dollars like its nothing. That will likely take me months to save up for.


not to mention the copper wire... that will cost a good 30 dollars.


and now people are telling me I need an antenna analyzer? Well the cheapest I could find was over 50 dollars. I can safely say this project will not happen for at least 6 months, when hopefully I am finished paying off this years auto insurance.


Title: Re: instructions to build the k1jj tuner
Post by: KA2DZT on March 07, 2016, 07:53:47 PM
lol talking about 100-200 dollars like its nothing. That will likely take me months to save up for.


not to mention the copper wire... that will cost a good 30 dollars.


and now people are telling me I need an antenna analyzer? Well the cheapest I could find was over 50 dollars. I can safely say this project will not happen for at least 6 months, when hopefully I am finished paying off this years auto insurance.

Take your time with the antenna tuner.  No rush, I've been licensed for 55 years and I haven't used an antenna tuner yet and I have all the parts to make one.

Fred


Title: Re: instructions to build the k1jj tuner
Post by: KD6VXI on March 07, 2016, 07:59:25 PM
You don't need an antenna analyzer.   It just makes it a LOT easier.

An antenna noise bridge can often be found for ten to fifteen dollars.   Work just as good,  and you'll learn how to use it very quickly.

A bread slicer cap will work just fine.   Yes,  a vac variable from the commies looks nicer  handles more V (and usually I),  but if you can't make more than a couple hundred watts pep,  you don't have a need for a kw level tuner.

Yes,  power makes it easy to have long distance QSOs a lot more easily.   But,  if you don't have the capabilities today,  throw a ten dollar bread slicer in your project tuner,  and when you can afford a vac cap,  replace the bread slicer.

Or,  use coax cable and resonant dipoles.  No need for a tuna.

--Shane
KD6VXI


Title: Re: instructions to build the k1jj tuner
Post by: Steve - K4HX on March 07, 2016, 08:54:31 PM
You may want to consider no tuner.

http://www.w5dxp.com/notuner/notuner.HTM


Title: Re: instructions to build the k1jj tuner
Post by: kk6noh on March 09, 2016, 09:50:49 PM
I am afraid that the antenna design I have decided on requires a tuner. I have no desire to get a 100+ foot tower and pay thousands of dollars to get onto 160 meters. This is the antenna I am going to use this tuner on. http://home.4x4wire.com/deddleman/photos/WireLoop.pdf
EDIT
Noise bridge huh? I like it! Thanks for pointing that out!


Title: Re: instructions to build the k1jj tuner
Post by: Steve - K4HX on March 09, 2016, 09:55:23 PM
Where did you get the idea that a 100 foot tower is required? The subject antenna at the link I provided was only 37 feet in the air. It requires only 137 feet of wire and two supports. The antenna at the link you posted requires over 500 feet of wire and 4 supports. The loop is a more expensive antenna.


Title: Re: instructions to build the k1jj tuner
Post by: kk6noh on March 09, 2016, 09:57:54 PM
Where did you get the idea that a 100 foot tower is required? The subject antenna at the link I provided was only 37 feet in the air. It requires only 137 feet of wire and two supports. The antenna at the link you posted requires over 500 feet of wire and 4 supports. The loop is a more expensive antenna.

1000 feet of wire and 3 supports actually. However from what I can tell using a dipole too close to the ground results in all kinds of problems. I am using the one resource I have plenty of....... acreage.


Title: Re: instructions to build the k1jj tuner
Post by: Steve - K4HX on March 09, 2016, 09:59:14 PM
All kinds of problems? Such as?

You claim you don't have money to spend. Why waste it needlessly wire and a tuner?


Title: Re: instructions to build the k1jj tuner
Post by: kk6noh on March 09, 2016, 10:07:15 PM
All kinds of problems? Such as?

You claim you don't have money to spend. Why waste it needlessly wire and a tuner?

problems with feedpoint impedance, radiation pattern and elevation, and ground losses. I learned that from several ARRl publications including their antenna book and this--> https://www.arrl.org/files/file/antplnr.pdf


Title: Re: instructions to build the k1jj tuner
Post by: Steve - K4HX on March 09, 2016, 10:26:36 PM
Those are so general statements as to be nearly useless. For example, let's take radiation pattern. This cannot be called a problem unless some specifics are known. Frequency and desired radiation pattern would be two very important ones. Type of operating or coverage area (local or DX) would be another very important one.

You really cannot pick an antenna or make judgements on any given antenna without some specifics. Example: too low (whatever that means) on one band is high enough on a higher frequency band. Saying an antenna is too low without any other info is  just about meaningless.

Is this your first home-brew antenna?
How high will your loop (or any other antenna) be?
What bands will you use? In priority order?
What sort of coverage is desired, local versus DX.

Yes, the antenna at the link I posted was at 37 feet above ground. However, the concept will work with the dipole at greater heights. It is simpler and less costly than the loop and a tuner.


Title: Re: instructions to build the k1jj tuner
Post by: KD6VXI on March 09, 2016, 11:27:46 PM
I'll play Devils advocate here.

You might want to listen to what Steve says.   

You're going to find a wealth of knowledge here.   There are government spooks (three letter agencies with way better radios than we have),  commercial shortwave engineers,  antenna engineers,  etc.   Then,  you have guys with money that can throw up multiple hundred plus foot towers and can listen to gnats fart in Brussels.   When the band's are closed.

But you have to want to learn.   

Don't settle on any antenna you read about.   Ask around.   Post something here about what you want to accomplish,  and how much you have to spend.   Someone here,  somewhere on the face of the earth,  on this forum,  probably has the answer.

Don't approach it with the 'I stayed in a holiday in express and read three ARRL books,  so I already know what I want'  attitude,  or you really will miss out....   Simply because no matter what,  someone has a different take on it.

Or,  as Carl,  KM1H,  told me when he saw me opening my yap here a few years ago...   "Shane,  shut up.   The people on amfone are the real deal.   Ham for them is a hobby.   Real life was spent doing it for a living,  and there are real experts there'.

He was right.   I've learned more here in a few years here than I did devouring every book I could find.   Because the guys here will help,  within whatever constraints you have (practically of course).

Before you poo poo Steves idea.   Scrapped 75 ohm cable TV coax for feedline.   Dipole will resonate around this value at heights you and I have available (I have a 37 foot tower and a 32 foot pole.   And a pair of 80 foot towers laying in my back yard I can't use).   So your swr will be 1.5 at resonance (or thereabouts).   Use your radios internal tuna.

Since your coass feeding it,  a 40 dipole will work for 15 as well.   Has limits,  but hey,  you just saved a feedline and another 50 feet of wire on the dipole. Add a 20 meter dipole to the feed point,  and you have three bands covered by two dipole and coass you can get for free.  (Make friends with cable or satellite TV installers.   They usually have extra coax on 'roll ends'  that get tossed.   Ymmv.

--Shane
KD6VXI



Title: Re: instructions to build the k1jj tuner
Post by: K1JJ on March 09, 2016, 11:28:10 PM
1000 feet of wire and 3 supports actually. However from what I can tell using a dipole too close to the ground results in all kinds of problems. I am using the one resource I have plenty of....... acreage.


There is a misconception that the more wire in the air, the better the antenna.

For local work, for 160 or 75M, a simple flat 1/2 wave dipole  as high a practical (60'-100' high)  is the most efficient antenna you can use.  Use open wire for multi-band - coax for single band. It does not really matter.

The problem with bigger wire antennas, like full wave loops or larger, 2-half waves-in phase, double extended Zepps, etc., is that the take off angle starts to get higher and the ground losses start to build. More wire coupling to the Earth becomes a problem.  

For example, on 75M, you need to put the double extended Zepp up 20' higher than a standard 1/2 wave dipole to get the same take off angle. So with limited support height, use a standard 1/2 wave dipole for lowest take off angle and efficiency.  If you have the height available, then use whatever length you desire.  I have a 190' self supporter tower and have full wave loops .. works great only because I have the height to work with. If lower, I would opt for 1/2 wave dipoles.

An extreme example would be putting up a 2 mile long wire, either end or center fed for 160M and the higher bands -  fed with OWL. Some would think that is the ultimate antenna. But it would have lobes like an octopus, exhibit sharp long wire directivity, with deep nulls due to random phasing - heavy ground losses -  and perform more poorly than a standard 1/2 wave dipole at the same height.


Stick with a 1/2 wave dipole for the lowest frequency (1.8 MHz) and the pattern will be a nice broadside figure-eight for both 160 and 75M when using OWL.

For lower DX angles, Steve's suggestion to use an end fed inverted L is excellent.


Hope this helps.

Tom, K1JJ




Title: Re: instructions to build the k1jj tuner
Post by: kk6noh on March 10, 2016, 12:18:45 AM
this isn't my first antenna project. I have spent literally years in planning this station. I have experimented with several different antenna designs trying to find one I like.

my goals are
80m, 40 and 20, 160m, and 10m in that order of desire.
it needs to cover all those bands, be cheap, be low to the ground, Omni directional, be quiet(low noise level), and not be some sort of compromise. I have a half mile square of acreage to deal with. Despite all the room I want to avoid anything resembling a tower because of high winds and hostile neighbors with high power optics. I found that dipoles work, but are not truly omni-directional and have to be mounted very high to be at the right takeoff angle. Inverted L's work ok on the longer bands but are very noisy. Yagis are completely out of the question. Vertical antennas are also out.

so that is what lead me to the long loop skywire. I plotted the antenna in software and it seems to check out.

It covers all ham bands with a tuner to match the impedence. It has a low noise floor. It is omni-directional. It is practically invisible. It has a nice low dx takeoff angle with an overhead null. I can get the wire for rather cheap, the mast poles for practically nothing, and the twin lead for a lot cheaper than coax. The only thing holding the project back was a lack of a tuner... which has been solved.

I guess my main issue with dipoles is pretty much every single ham on the planet either uses them or recommends them. I hate being mainstream. :D


Title: Re: instructions to build the k1jj tuner
Post by: K1JJ on March 10, 2016, 10:58:29 AM
my goals are
80m, 40 and 20, 160m, and 10m in that order of desire.
it needs to cover all those bands, be cheap, be low to the ground, Omni directional, be quiet(low noise level), and not be some sort of compromise.

It's hard to beat a 1/2 wave dipole for pattern and efficiency.

To satisfy your objectives:

1) I would put up a 1/2 wave dipole for 75M fed with open wire and use it on both 40M and 75M.  This will give a nice figure 8 pattern, but because it will not be that high, it will exhibit a quasi-omni-directional horizontal pattern on 75M, which you desire.

2) For 10M - 20 M put up another 1/2 wave dipole fed with OWL -  this time for 20M and it will have reasonable patterns on 10M and 15M.

3) Put up an inverted L for 160M.  A 160M horizontal dipole, if not very high, is inefficient on 160M -   thus use an inv L vertical which does very well for 160M.

In contrast, if you put up a big 160M / 75M loop or dipole and use it on 10M - 40M, it exhibits  a cloverleaf or octopus pattern with yuge nulls.

The next step up would be a Yagi, which you said you do not want.

T



Title: Re: instructions to build the k1jj tuner
Post by: Steve - K4HX on March 10, 2016, 06:49:26 PM
Nothing wrong with being out of the main steam. :) That's pretty much what AM is all about.

Just a couple of thoughts.

1. A low loop will work no better than a low dipole (maybe worse) in most scenarios.
2. A horizontal loop will NOT produce any more low angle radiation than a dipole at a similar height.
3. A loop is not necessarily any "quieter" on receiver than a dipole. If you have a bunch of acreage, you may already be in a quiet receive location.
4. A low dipole is omni-directional for all but the lowest takeoff angles.
5. There is no "right" takeoff angle. It depends on what coverage or distance you need.
6. Low is relative. A dipole at 30 feet above the ground could be considered low on 80 meters. But, for example, on 15 meters, it is more than a half-wave above ground and will produce plenty of low-angle radiation (assuming that's what you want).
7. If you really want to hear well on the lower HF bands (160, 80 and 40 meters), put up a specialized receive antenna like a Beverage, K9AY, etc. These are easy and cheap.

Good luck with the loop. I have nothing against them. I've had as many as four up at the current station and still have two.


Title: Re: instructions to build the k1jj tuner
Post by: kc1gtk on April 11, 2021, 09:24:41 PM
Greetings--- I know this is an old thread, but relevant to my project, maybe I should have started a new one, I'm a newby here.
Anyhow attached is my working but not mounted up version of K1jj's tuner.
50-1000pF vac cap, and 2000pF Air var/cap. and an 8 turn link.

 Tuners fascinate me in my short ham career so I wanted to make one for my open fed doublet. Thanks to info here and some emails to a few members, I ended up with this. Fired it up morning after tuning it with a nanoVNA smith chart and it's almost flat on 80 thru 20m.

My doublet is only 125' long, I know it should be longer for 160m. This tuner won't tune 160, ( nor will my palstar BT1500A).

I wonder if I put the vac cap in series with the big coil's center like I've seen in some info here, it would tune a short antenna???

My wife thought I was building a still when she saw the coil!

It was a blast making this beast, I'll neaten it up and make it presentable.

And thanks to all who posted about this cool tuner
73
 Paul KC1GKT


Title: Re: instructions to build the k1jj tuner
Post by: kc1gtk on April 18, 2021, 11:29:52 PM
Okjust to report, I did split the coil and put the feed line on the split, so now it's series connected. It tunes up fine now and I can run the amp with it, low swr at the amp and the radio. putting out 500w I got over nine reports into VA. not real effecient on a 1/4wave double but am happy with it


Title: Re: instructions to build the k1jj tuner
Post by: K1JJ on April 19, 2021, 12:15:16 PM
Ok just to report, I did split the coil and put the feed line on the split, so now it's series connected. It tunes up fine now and I can run the amp with it, low swr at the amp and the radio. putting out 500w I got over nine reports into VA. not real efficient on a 1/4wave double but am happy with it

Glad you got it running well, Paul.

Yes, usually a 1/4 wavelength dipole like a 75M dipole tuned up on 160M (low impedance feed) may require series tuning, whereas the same 75M dipole tuned up on 75M or 40M (higher impedance feed) may require parallel tuning. So having a way to quickly jumper back and forth from series to parallel tuning is desirable.  You will find you can match any reasonable, balanced antenna on the planet to a perfect 1:1 with enuff playing around.  Mark the taps and tuning positions for later and you're all set.

There was a time when I had five separate dedicated tuners using OWL dipoles, each serving one band. Quick band selections. But it was more practical to run separate coaxial feedlines in the end, so that these days I have a total of  5,000' of 75 ohm hardline run underground in 4" PVC pipes. Each antenna is a click of a switch.

Just to make one last point... if you listen long enough on 75M AM, you will find that the biggest signals on the air, the big guns, are mostly running coaxial feedlines. This includes the biggest contest stations.  My point is that there is really little difference between open wire feed and coax when it comes to losses and signal strength of a properly tuned antenna. Remember that the tuner has losses too... and we lose control of our clean bi-directional dipole radiation pattern on the higher bands. Open wire is more for convenience and more bandwidth when separate antennas are impractical, (or feeding balanced arrays) despite its increased physical complexity for installation.

But I must admit, saying you are running open wire feeders is MUCH cooler than coax...  ;)

T



Title: Re: instructions to build the k1jj tuner
Post by: kc1gtk on April 19, 2021, 09:13:06 PM
Thanks for the reply Tom.

In the process of neatening the lay out now that I know it works.  I put 2 banana sockets on the split which is at 12Oclock. I can grab them with the clips on the feedline for series, and shunt them out with the banana plugs when going to parallel.
input cap is needed on 160m, not needed on 80-20. so I'll make up a quick shunting switch for the cap on 80 up.

 Waiting for a turns counter  to arrive for the vac cap.
 here is how it looks at the moment, with taps for 160m

My new homebrew Elmer, W1IA who lives nearby, pointed me in this direction and your version.
 The 8 turn link gets to about body temp when running 700w on 160, but not on 80 - 20

 I'll post another pic when it is mounted and pretty

Thanks again, I found many of your variants online, which helped me understand and make this
73 kc1gtk


Title: Re: instructions to build the k1jj tuner
Post by: K1JJ on April 19, 2021, 11:57:49 PM
Looks like yours will work very FB, Paul.  The turns counter makes a huge difference in ease of use.  That 50 ohm input tuning cap with the link gives you good control of the input  --  and with combined output control, there are virtually infinite combinations of taps and adjustments. Not to mention your new series/parallel modification. That's the objective - wide range impedance control.  I have used this design up to 10M when feeding a large wire array in the field. It was a custom made tuner with 10M optimized coils, etc.

Just to set the record straight:  This tuner is not my original design, but a circuit that has been used for many purposes going back to the 1920s. Back in 1987 I needed a cheap antenna tuner design that could use a simple single section tuning cap (like a vacuum variable) and a minimum of parts and be able to run 2KW+, etc. Everything out there was either too expensive, needed multi-ganged caps, dual rotary inductors or whatever. One day looking thru the 1930s handbook I came across a similar circuit that was being used as a 500 watt plate tank matching circuit. I adapted it for antenna tuner use and built five as I mentioned. The copper tubing was real cheap then as well as vacuum caps and input 365 pF X4 receiver tuning caps.

I have talked about this design since the late 80s and the name "K1JJ Tuner" eventually stuck and became a convenient way to quickly identify the simple design. Some call it a "link coupled tuner with a one section [vacuum] capacitor and coil,"... but it's all the same thing.  

BTW, the 2nd harmonic suppression (additional attenuation) of this tuner design is less than a more complex split stator of grounded capacitor design.  If your transmitter is already of good design (pi-network) with a reasonable Q with standard harmonic suppression numbers, all will be fine.  I know of only one guy over the years who had an RFI problem (when using this tuner and OWL) possibly due to harmonics. It was later fixed by replacing some (rectifying) oxidized CATV connectors at his neighbor's house.

FB on Brentina being your Elmer. You can't find a better one.  Tell him I said hi and I listen in quite often. I need to get back on the air with youse guys soon.  I have finished all my rig building for the time being.

T


Title: Re: instructions to build the k1jj tuner
Post by: WA4WAX on April 20, 2021, 03:03:25 PM
BC-610 coils are FB for this application.

Run a 2.5 mH choke in series with a 3K 1 watt carbon from the neutral point of the BC-610 coil to chassis ground. Mod this a bit if you use a split stator, as the rotor must float in such a cap.

Put a 500 to 1500 pF variable in series with the link and chassis ground.


Title: Re: instructions to build the k1jj tuner
Post by: Chuck...K1KW on April 22, 2021, 03:22:41 AM
Just saw this thread after building another balanced tuner for a new open wire line fed antenna going up this year here.

These balanced tuners need a RF center tapped return to ground on the "secondary" side driving the open wire line to ensure a true balanced drive.  Otherwise any small imbalance will create a significant common current which will cause the open wire line to radiate.  This means that 1) the tuning cap on the secondary needs to be a balanced split one with the rotor grounded or 2) with a single isolated cap tuning on the secondary the coil center needs to be grounded directly.  Think of this like driving a pair of modulator tubes in push pull using a driver transformer with no center tap return as an analogy. What would happen?

You should not do both (split stator, rotor grounded, and ground the CT of the secondary coil) since this will now give you two separate resonant circuits forcing an imbalance unless they are exactly identical and there are no antenna induced imbalances.

I have always opted for grounding the secondary coil center since this provides a "DC" ground return for any static build up on the antenna.  It makes a quiet antenna especially during "rain" static.  It also protects the receiver front end from static build up which will cause arcing and could jump to the the primary turns  blowing up the receiver front end!  Experience speaks here!!!!

In the case of a low impedance current feed driving from the split center of the coil, you should use a balanced tuning cap with the rotor grounded to ensure a decent balance.  No short cuts on this one since current feed is more susceptible to common mode currents.  However, on these low bands feed line radiation may not be an issue unless it gets into your audio or your neighbors!  


Chuck K1KW



Title: Re: instructions to build the k1jj tuner
Post by: K1JJ on April 22, 2021, 11:59:21 AM
Yep, for parallel feed a center tap to ground off the main coil is a great idea for the reasons described.   I notice adding one usually has no effect on the general matching operation of the tuner when it is centered perfectly which is a good thing.   Those CT points and features have been asked from time to time and should be edited / added into past postings for future builders to implement with any of these tuners.

Another point to ponder:  Since most OWL antennas, or any large wire antenna in the real world, are usually physically unbalanced due to one dipole leg being higher than the other or the feedline coming closer to metal objects on one side or another...   is it beneficial to tap one side of the feedline connections either out or in farther on the main coil than the other leg to achieve a better feedline current balance?  A current balance could be indicated by the relative brightness of two light bulbs, one on each feeder or an RF current meter indication on each leg, looking for balance...

T



Title: Re: instructions to build the k1jj tuner
Post by: Steve - K4HX on April 24, 2021, 12:34:43 PM
I would not recommend using transmitter plug in coils for a tuner, especially in a high power application. The conductor size of these coils is often too small for the amount of current involved because of the higher Qs involved. Remember, these coils were designed for use in an output tank with a Q lower than 10 or so.


Title: Re: instructions to build the k1jj tuner
Post by: kc1gtk on April 24, 2021, 11:59:14 PM
Ok She's about finished and works well!

BE interested in info about how to put 2 bulbs on the feed wires to see if any noticeable imbalance?

I have taps now on the link, before the taps I could tune 160 to 20m, 80 to 20 works with the big cap parallel. never tried above 20 yet.

Works well with the amp too.

That's about a compact as i could make it.

There are 2 high resistance resistors shunting to a ground rod behind the wall where the feed comes in.

Any comments or suggestions welcome!
thanks
KC1GTK
Paul
73



Title: Re: instructions to build the k1jj tuner
Post by: K1JJ on April 25, 2021, 12:22:14 PM
OK Paul -

For the light bulb feedline indicators:  You can use  most any flashlight bulb, 1.5 to 6V with two wires soldered on each bulb.  Start with one feeder leg and attach a bulb  a few inches spaced onto ONE leg. This will pick up a voltage drop. Tune the rig up to say, 1/4 power output and adjust the two wires spacing until the bulb JUST starts to light. The eye is most sensitive to light intensity changes when the bulb is barely lit. Do the same for the other side, making it the same spacing as the first bulb. Compare the bulbs for brightness.

Just to be sure, you are not going across the feeder line but each bulb goes onto one feeder leg.   When dimly lit you will see the difference in RF voltage drop quite easily. If the bulbs are too bright, the eye cannot see the difference as easily.    Also, a more expensive but effective way is to find a pair of RF current meters to put in series with each leg.


As for the center tap using high value resistors to ground, let's get some more opinions on that. Maybe it would be better to make a hard DC connection to the coil CT then run to it the station ground as well as the copper rod outside.   I also received an email from someone who showed a variable cap from CT to ground with a balance "0" meter used.

T



Title: Re: instructions to build the k1jj tuner
Post by: W1NJC on May 04, 2023, 05:20:49 PM
Hey guys, long time lurker around these parts.

Two things:

1) I've been using this method to check balance with good results.  Take a FT240 core (any kind) and wind a couple turns of small wire around it.  Connect the ends of this wire to a scope probe/gnd clip.  Then pass both balanced lines through the core.  Using low RF drive, tweak your taps for the lowest displayed signal on your scope.

2) I've built this tuner and I've been modifying and playing with it for over a year now.  My main changes have been varying degrees of coupling by winding the primary on a section of cardboard tube which is slid over the secondary, and changing that diameter by adding foam and/or the number of turns.  Of course this also changes the L of the primary. 
I can get it to work quite well on 160-80-40.  That is to say, good match and good balance.  What I would like to do is get it to be able to work well on 20-17-15-10.  There are a lot of variables going on when trying to find the sweet spot(s): Co tuning, Co taps, Ci tuning, Feedline taps.  When in "discovery mode" after a change, I hook up a VNA and watch the Smith chart.  To try to do it any other way would result in lots of profanity and possibly lost tools!  In the cases where I have gotten a match on the higher bands, the taps are very close to the middle, and I get poor balance (and thus RFI in the shack, speakers buzzing, etc.). 
So I could use a little guidance on what to try next.  I realize I might not be able to get a one-size-fits-all 160-10 configuration.  That's ok, but I'd like to better understand the variables that need to change and I could rig something up to try it.  Have any of you guys gotten a design like this to play well on the upper bands?

I should mention that my antenna is a 700+ft loop, so in general the impedances presented in the shack are not low.  This is from a while ago, but should still be close (attached file).
(https://photos.google.com/share/AF1QipNlQA1W3DH1-SB0kHUudPRfU2xu8xYJ0B3sHWMrHH16mYDS8-K__NoTQUzDiV1-pw/photo/AF1QipMkltqbIwuI0dr8vdhCXSAK4vWdtxLoZ9Hwpx2n?key=cFFzc1hQV3pjajA3eUZSSkg0d1dIdXZwUWh6NTh3)

Thanks in advance,
Nick W1NJC


Title: Re: instructions to build the k1jj tuner
Post by: Tom WA3KLR on May 05, 2023, 05:25:07 PM
Hi Nick,

I would think that the 800-foot loop is not a good antenna for the higher bands, pattern-wise and I do wonder about the ac resistance of the 800 foot loop of wire. I recommend a trap vertical for 20 meters and higher with a good ground plane or trap yagis. I have my 20-15-10 trap vertical on the ridge of my pole barn and the roof is sheet steel, works well.

I do like your home-brew antenna tuner I saw in your QRZ photos. So you have a good set-up for the lower bands and I think you should draw the line there on that system. I have a friend with a 75 meter dipole that works well up to 10 meters. You could have a separate dipole that is a 20 meter half-wave dipole and I found on simulations in the past if the dipole is not all horizontal but the ends come straight down on the outer 1/3 of total length, that the nulls of the lobing are reduced on 17, 15 and 10. And a separate tuner for these bands.

My 2 cents worth.


Title: Re: instructions to build the k1jj tuner
Post by: W3SLK on May 05, 2023, 06:12:00 PM
Tom, I had fantastic results with my 510' 160M loop on 10M when I was at the other QTH and that was during a sunspot null.


Title: Re: instructions to build the k1jj tuner
Post by: Tom WA3KLR on May 05, 2023, 06:48:41 PM
Hi Mike,

What kind of wire were you using in your loop? As Vortex Joe would say, inquiring minds want to know.


Title: Re: instructions to build the k1jj tuner
Post by: W1NJC on May 05, 2023, 07:57:54 PM
Yes, I have excellent results on the higher bands with this loop.  It's a real pileup buster on 40 and above, sometimes with just 100W on SSB.  On the upper bands it has lots of low-angle gain (9-12dB at 10-25).  Sure it's not 100% coverage in the azimuth (nulls) but so what? 

The wire is 13AWG Davis WM516 which now seems to be unobtanium.  It's good wire.  Feedline is 4-inch spaced open wire.

Honestly I've been fairly satisfied using this LCT for 40 and below (maybe 20) and just using a MFJ T-match on the upper bands...but it's like unfinished business in my mind.  I took off some turns on my primary and it makes 20m possible while still being able to use 160, though the Q seems to be even higher on 160 so I'm guessing there's going to be a point where 160 will be tough to match - but I'm not sure, which is why I'm asking the brain trust here!

Nick


Title: Re: instructions to build the k1jj tuner
Post by: W3SLK on May 05, 2023, 10:41:52 PM
WA3KLR said:
Quote
Tom WA3KLR
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Hi Mike,

What kind of wire were you using in your loop? As Vortex Joe would say, inquiring minds want to know.
Tom it was nothing more than a pseudo parallelogram with about 512 feet of #14 gauge. Maybe up 30' at the highest. Nothing fancy really.
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