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Author Topic: Need your opinion on a tuner.  (Read 26042 times)
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K5UJ
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« Reply #25 on: October 30, 2009, 06:04:34 PM »

I must say that is a heck of a link coupled tuner in that photo.   I also wondered about the construction technique for getting the coil in the plexiglass holder strip (or is it Teflon?) and guessed he either sliced it in two lengthwise cutting through the holes then seating the coil and gluing the top half down, or drilled out the strip and cork screwed the coil through the strip working from one end using a hot glue gun to cement it in place (making the holes a tad bigger than the o.d. of the copper).

Just as good is the link coil and getting that wound and held in place.  Not sure what the link is made of.

Rob
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Are FETs supposed to glow like that?


« Reply #26 on: October 30, 2009, 06:30:07 PM »

You take a piece of plexi,  and drill all the holes, spaced properly...
The rows are staggered...

You wind the coil on a form...

Remove it from the form, and then screw it into the holes in the plexi.
The hole pattern in the plexi is like a tapped hole, the coil is the screw.

it really is THAT simple to make a nice coil..
Makes it real neat and easy to mount, and the coil won't move.


I see he used 2 strips... I usually just use one wide piece...

But obviously works both ways!
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WQ9E
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« Reply #27 on: October 30, 2009, 07:51:21 PM »

This is the typical AM forum discussion; full of information and civil!  To paraphrase George H.W. Bush this site represents a "kinder, gentler internet".

I agree with the philosophy of putting up the best antenna you can but I also subscribe to the "overkill tuner" because you never know in the dead of winter when you might need to operate on a less than optimal antenna after your desired antenna bites the dust. 

The original poster's MFJ tuner is one of the better ones they have sold but isn't a great choice for a balanced feed line with a mismatched antenna.  I would much prefer a true balanced tuner for this situation and they are easy to homebrew.  If you don't need 160 (or are willing to modify the KW matchbox) it would serve you well.
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Rodger WQ9E
K7NCR
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« Reply #28 on: October 30, 2009, 09:31:12 PM »

This is the typical AM forum discussion; full of information and civil!  To paraphrase George H.W. Bush this site represents a "kinder, gentler internet".

I agree with the philosophy of putting up the best antenna you can but I also subscribe to the "overkill tuner" because you never know in the dead of winter when you might need to operate on a less than optimal antenna after your desired antenna bites the dust. 

The original poster's MFJ tuner is one of the better ones they have sold but isn't a great choice for a balanced feed line with a mismatched antenna.  I would much prefer a true balanced tuner for this situation and they are easy to homebrew.  If you don't need 160 (or are willing to modify the KW matchbox) it would serve you well.
I have set up a swap with the other ham, and will get a hopefully decent matchbox. I think it is a good choice for my antenna.
I can get use of an MFJ antenna analyzer for testing. Do I need a balun to connect it to my open wire feed for a sweep?
In one of the archived posts, I read about a dual roller balanced tuner, with rollers driven in sync with belts. Anyone know who this might be? I'd like to get a photo of that setup, or at least a diagram. I may be able to use some of my junk box parts for one like that.
I wish I had access to antenna modeling software, I'd like to model the SLAB BACON SPECIAL X2 that I built to see how it looks.
Thanks everyone for your posts! Some great info! Keep it coming!!
Norm K7NCR
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Ralph W3GL
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« Reply #29 on: October 30, 2009, 09:43:49 PM »

Norm,

The balanced, balanced tuner info is at Rich Measures, AG6Ks' website:

http://HTTP://WWW.SOMIS.ORG/bbat.html

Was published someplace, I can't recall at the moment but the full information
is there...
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73,  Ralph  W3GL 

"Just because the microphone in front of you amplifies your voice around the world is no reason to think we have any more wisdom than we had when our voices could reach from one end of the bar to the other"     Ed Morrow
K7NCR
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« Reply #30 on: October 30, 2009, 10:09:57 PM »

Norm,

The balanced, balanced tuner info is at Rich Measures, AG6Ks' website:

http://HTTP://WWW.SOMIS.ORG/bbat.html

Was published someplace, I can't recall at the moment but the full information
is there...

Thanks!! I have enough parts in my stash for one of these! (without the motors) I'll start gathering up stuff and keep you posted.
Norm K7NCR


* bbt_pic1.jpg (155.64 KB, 960x1280 - viewed 426 times.)
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ke7trp
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« Reply #31 on: October 30, 2009, 10:41:41 PM »

No balun with Matchbox.  Hook up wire,  Plug in MFJ 259,  Make a chart for  1.0 50 ohms for each band/Freq. Post it on wall.  Smiley 

Some hints about matchbox.  You should need very little change on the dials for the bands if the Open wire line is the correct length.  If you cant tune a band or you need lots of dial changes to tune in,  Remove 6 inches of line at a time and check again.  Or add line.. 

Once correct, Mine needs only a 10 degree change from 80 to 40 on the AM Freqs. 

C
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W2VW
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« Reply #32 on: October 31, 2009, 12:19:25 AM »

Er. There is nothing wrong with use of a BalUn if it is used properly. Don't write off systems which use one until you understand what's happening.

The little matchbox isn't worth as much as the trade tuner in question.

Build your own tuner and sell the MFJ to someone who can't read.

Matchbox doesn't work on 160 and has limited impedance range where it does work. This can be a problem or not. depends on your luck or research.

One guy sez 275 watt matchbox handles 100,000 watts other guy can't get his to work with 200 watts. Maybe the guy with the 200 watt zorch is at a voltage node and can't find a good text.

Antenna couplers bring out the very worst in hammy folklore.
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K7NCR
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« Reply #33 on: October 31, 2009, 12:30:37 AM »

No balun with Matchbox.  Hook up wire,  Plug in MFJ 259,  Make a chart for  1.0 50 ohms for each band/Freq. Post it on wall.  Smiley 

Umm,
I was thinking I would sweep the current antenna setup without the tuner in line to see what I might be up against. That's why I asked if I would need a balun to hook it up to my open line. Am I off track?  Huh
Norm K7NCR
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ke7trp
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« Reply #34 on: October 31, 2009, 01:05:39 AM »

IN one station the Matchbox will take 1500. In another it might take 500 or less.   Also.. They are old.  You might get one that is zorched with carbon marks on the plate. Then it will be more likely to Zorch again.

If you where asking about using the MFJ to sweep the antenna without the tuner, I think its a waste of time. There is no real point. It does not have to be resonant with a balanced tuner and open wire line.  However, You can do this if you want with the correct matching balun. 

C
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W2VW
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« Reply #35 on: October 31, 2009, 10:32:53 AM »

Also don't let anyone know that a Jaw-N-Son (Pittsburgh pronunciation) Matchbox hooked up for 50 ohms in and balanced out IS a Balun.
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K3ZS
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« Reply #36 on: October 31, 2009, 10:49:40 AM »

Put a good balun on the output of the MFJ tuner and don't use the one in the tuner.   You will have a much better combination.   You will have better balance and will have the advantage of being able to receive on all the bands better, with the tuner on bypass.    I use a DX Engineering balun.    Following this you will hear from the balun haters, but it works well for me.    Better yet build a real balanced tuner as others have said.
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Steve - WB3HUZ
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« Reply #37 on: October 31, 2009, 01:52:08 PM »

If yu'uns are gonna do the pronunciation thing, it's Picksburgh.


Also don't let anyone know that a Jaw-N-Son (Pittsburgh pronunciation) Matchbox hooked up for 50 ohms in and balanced out IS a Balun.
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K5UJ
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« Reply #38 on: October 31, 2009, 01:59:12 PM »


If you where asking about using the MFJ to sweep the antenna without the tuner, I think its a waste of time. There is no real point. It does not have to be resonant with a balanced tuner and open wire line.  However, You can do this if you want with the correct matching balun. 


In theory it's not a waste of time for analyzing the feed/antenna over a sweep of frequencies can yield useful information for getting a tuner to work i.e. choosing a range of L and C values for success.  The problem is that ham swr analyzers are normalized for 50 ohms unbalanced so you have a problem there with a 600 ohm balanced line.   You might be better off using a modeling program, maybe TLW (Transmission Line for Windows) along with an antenna modeling program.  The antenna modeling software can give you the feedpoint Z for a given balanced antenna of N wavelength on F frequency and with that you can use TLW to give you the line resistive and reactive values for 600 ohms ladder line on a line of so many feet in length, at the tuner end.   The Matchbox spec's give the Z matching range so then you'll know if it can do the job or not.    TLW comes packaged on a CD ROM that accompanies the ARRL antenna handbook.   You can try modeling different lengths of line for some load Z to find out what the line transforms to at the tuner end and thereby see if lengthing or shortening it X no. of feet will help or hurt.

73

Rob
K5UJ
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ke7trp
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« Reply #39 on: October 31, 2009, 02:45:47 PM »

 I was thinking about building my own Balun in a 4 ft tall Bud case.  I would use Huge Cores. The 2 ft diameter ones with some 00 cable. My only downfall right now is I cant find Gold plated 00 gauge Terminals to connect to the Solid gold Buss bar.   

Anyone know where I can find some solid gold Coax connectors?  I can only find Silver plated, pot metal and thin gold plated ones.  I really want to Get some solid Gold ones. Maybe I will contact a Jeweler to see if they can make some for us.

How many do you guys want?

C
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K7NCR
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« Reply #40 on: October 31, 2009, 02:56:38 PM »

I was thinking about building my own Balun in a 4 ft tall Bud case.  I would use Huge Cores. The 2 ft diameter ones with some 00 cable. My only downfall right now is I cant find Gold plated 00 gauge Terminals to connect to the Solid gold Buss bar.   

Anyone know where I can find some solid gold Coax connectors?  I can only find Silver plated, pot metal and thin gold plated ones.  I really want to Get some solid Gold ones. Maybe I will contact a Jeweler to see if they can make some for us.

How many do you guys want?

C

Now you are just bein' sthilly!
Normie-poo
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ke7trp
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« Reply #41 on: October 31, 2009, 03:00:09 PM »

Yeah... LOL... I am bored..     I think you will like the Matchbox. Small, simple to use and great performance.

I guess I will go wash Toby the dog..

Cya

Clark
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K7NCR
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« Reply #42 on: October 31, 2009, 03:05:04 PM »

OK, here's the plan,,,
I only paid $25 for the 989, so I don't feel too bad about a swap. I think the Junkston will be a good match for my current bands and power (no 160, PW, or nearly so).
I'm going to build a balanced tuner ala AG6K, without the motors, but with switchable C on the input in case of low resistance antennas. (antenni? antenna?) He suggested this in the article.
I don't have access to any antenna or feeder modeling software right now. Maybe Santa can bring some?


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w8khk
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« Reply #43 on: October 31, 2009, 03:08:30 PM »

I was thinking about building my own Balun in a 4 ft tall Bud case.  I would use Huge Cores. The 2 ft diameter ones with some 00 cable. My only downfall right now is I cant find Gold plated 00 gauge Terminals to connect to the Solid gold Buss bar.   

Better watch the oxygen content of that 00 cable, or the tessitura of the sidebands might overcompensate for the sound stage presented by the carrier...... 
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Rick / W8KHK  ex WB2HKX, WB4GNR
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« Reply #44 on: October 31, 2009, 03:23:53 PM »

A Ham once told me " I would not walk across the room for a DB in gain".   

I told him "I will walk across the room 10 times"


Clark
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Steve - WB3HUZ
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« Reply #45 on: October 31, 2009, 03:30:18 PM »

Quote
I don't have access to any antenna or feeder modeling software right now. Maybe Santa can bring some?


Santa doesn't need to bring it. You can get it free.


Antenna Modeling

http://mmhamsoft.amateur-radio.ca/

http://home.ict.nl/~arivoors/


Transmission Line Calculations, etc

http://www.ac6la.com/tldetails.html

http://fermi.la.asu.edu/w9cf/tran/index.html


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W2VW
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« Reply #46 on: October 31, 2009, 04:41:16 PM »

OK, here's the plan,,,
I'm going to build a balanced tuner ala AG6K, without the motors, but with switchable C on the input in case of low resistance antennas. (antenni? antenna?) He suggested this in the article.
I don't have access to any antenna or feeder modeling software right now. Maybe Santa can bring some?




One way is to cornfigure the thing so any combination can be switched like this:

http://w2dtc.com/2009-0818-kc2ifr-photos/W2A28.jpg

This thing can put the C across the output or the juncture of the BalUn and coils or keep it out of the circus altogether. Same with the roller inductor at the top.

Less copper than a linky tooner and it isn't bandpass so you can hear stuff when cruising the bands without retuning.

The tuner was originally whipped up for K3L 2005 where we were stuck with a 60 foot center fed radiator. We did a lot of operating on 75. The Johnson KW matchbox would not load on 20 with our combination of feedline and flattop but this thing would. It can be difficult to setup initially however.

At W2A the antenna feedline combination was exactly resonant on 75 so the tuner didn't have much to do except for the input BalUn. On 40 we were almost exactly at the voltage maximum at the tuner's output. This required moving KG2IR's vehicle away from the tuner and feedline in order to get a measurement! It still manages to deliver power without any problems even with the 30S-1 at legal limit. Try that with a flashbox or a T nutwork with an output BalUn.
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K7NCR
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« Reply #47 on: October 31, 2009, 04:43:03 PM »

Quote
I don't have access to any antenna or feeder modeling software right now. Maybe Santa can bring some?


Santa doesn't need to bring it. You can get it free.


Antenna Modeling

http://mmhamsoft.amateur-radio.ca/



http://home.ict.nl/~arivoors/


Transmission Line Calculations, etc

http://www.ac6la.com/tldetails.html

http://fermi.la.asu.edu/w9cf/tran/index.html




Thank you Santa!!!
My, what a long brown nose you have,,,
 Grin Grin Grin Grin Grin Grin Grin Grin Grin Grin Grin Grin
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W2VW
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« Reply #48 on: November 01, 2009, 12:31:33 PM »

If yu'uns are gonna do the pronunciation thing, it's Picksburgh.


Also don't let anyone know that a Jaw-N-Son (Pittsburgh pronunciation) Matchbox hooked up for 50 ohms in and balanced out IS a Balun.

You may be right. I was using the narrow filder. I replaced it with a capaster.
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WA1GFZ
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« Reply #49 on: November 01, 2009, 12:48:15 PM »

I designed the fugly balanced -balanced tuner in 1983 a few years before Measures invented it.
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