The AM Forum

I put the solderless crimp-on connectors on the cable.....my cable is thicker than what these connectors are meant for (and the braid in this cable cannot be soldered, it just will not flow so it really depends on a mechanical connection).

I put the SWR meter in line (my friend VE3AWA loaned me his SWR meter for a while until I can get my own), fired up the Xmitr, tuned it into the tungsten dummy load, then carefully made a controlled switch over to the antenna, gradually bringing up the plate voltage on the PA keeping the voltage levels low so I don't radiate much power while testing the antenna setup.

I ran tests at both 40 and 80 meters to see where the best SWR can be found. It's rather disappointing to me....40 meter SWR seemed to remain at infinity no matter what I tried.

80 meter SWR came in a little better but it's still far from perfect. The best reading I could get was 3 units forward to 2 units reflected.

Because the braid in this Coax will not accept solder, I know I had some difficulty in fastening it to the Dipole. I may need to mechanically clamp the braid to the antenna wire. The middle conductor is copper plated, I had no difficulty in soldering it to the antenna.

Ironically I may have had better results when I was still using the twinlead...it's rather frustrating I must admit since I have no practical experience in setting up antennas (only in building and designing the electronics) and certainly no money to toss at it, so I'm trying to make do with what I have within the confines of the back yard.

Perhaps I should try using a loop antenna for transmitting and just leave the dipole up for the receiver?

Oh well, anyway, it's late now, I've had a long day driving all over looking for what I can afford in terms of a replacement car (my Hyundai was hit by a pickup truck in late May, the insurance is writing it off so my main focus has to be on finding a suitable replacement....hoping for a Suzuki Swift if possible, took one for a test drive today) and I'll continue to fiddle with things towards a satisfactory SWR.

73s
geo

Geo,

I'm off to K4KYV's  to rescue a pair of 4-400's n a 48" black rack.

I'll be rounding up yer stuff and sending it when the wife is not working next week but it may not be until next Saturday morning, she is going at it 5 days a week at the moment. (I dont drive)

I think the coax is a bad deal. you need open wire line. not plastic coated twin lead either. the swr meter and the rf ammeters will point you in the right direction. i got 25 Birnbach porcelain spreaders NIB for open wire feeders, little ones, 300 ohms. i gave a buck for them, I'll throw them in the box too.

You're going off on a million tangents, just like I do, when things are sucking. Coax sucks for HF anything other than a resonant cut to length center fed dipole. if you havent got that, dont use coax.

just wait a bit until you get my box. It will help.

Wow, yea it's so frustrating...other hams I've discussed this with swear by Coax....others will swear by twisted lead.....now that money has been spent on Coax, it's an awful thing to see it wasted.

I repeated tests this morning, I'm still able to peak the SWR at 3 forward units to 2 reflected units as I approach 3.5 Mhz. Going higher in frequency just causes the reflected units to equal forward units.

I looked closely at the SWR meter, it's rated for 52 Ohms! I didn't realize that! I know my Coax is 72 Ohms and who knows what my antenna is!

But now that I have the Coax, I have to make it work. My wife will make me sleep in the garage if I fail to make this work, she hates to see money spent on things and then it's disassembled and wasted.

If twisted pair didn't work then I have to make the Coax work - it fits in with the general layout since the path to feed the middle of the antenna isn't direct, I have to take a path under the deck diagonally (the feedline is supported by wooden blocks drilled out so it doesn't lay on the ground).

This antenna stuff is so frustrating there are times I'm tempted to just throw in the towel and give up on trying. And my wife isn't happy about me putting holes in the wall, in the siding, or making the backyard look like a lab freak. I love building and designing the electronics part of it, that's where I do best, but in a limited size lot and with constraints, no decent antenna can be set up it seems.

73s
geo
VE3GZB

What type of coax did you buy? Is it TV stuff like RG6? Most coax shielding is copper or tinted copper if it is for transmitting service.  If you stay with open wire line then you can build an antenna tuner and use you existing antenna for all the ham bands on HF. Perhaps you'll not need an antenna tuner for a given ham band depending on the length of your lead in and if the dipole is cut to resonance on a band you wish to operate on.   

They had it on clearance, 72 Ohm (Correction, 75 Ohm!) RG6/U, double shielded, indoor/outdoor Coax, they rate it for digital satellite service. Normally up here it's at least $100 but it was on clearance so it was much less.

Nobody carries RF stuff here anymore, it's pathetic! Even the radio shack went belly up, now it's The Source and it's all crap gadgets for people who wouldn't know the hot end of a soldering iron if one was placed in their hands. What's a ham to do!

The thing is that my wife won't tolerate me putting any more holes (or making any of the current holes bigger) in the wall or the siding. I can't blame her either, it looks like crap. So making clearance for anything that's wider than Coax just won't fly with her, she'll hit the roof.

EDIT: What about any military spy or battlefield transmitter designs? Those small transmitters had to work into random wire lengths and still had to transmit a signal effectively under primitive conditions and had to be durable and portable in the field, so they had to be relatively uncomplicated. Does anybody know anything about military HF antennas and matching for 80 and 40m?

Attached is a crude drawing of our rectangular lot and how things are laid out. The only mount points on the property for any kind of antenna are from the old TV antenna tower to the far clothesline pole, that's about 50 feet. Immediately next to our lot is a high voltage 3 phase power line that runs through town so I don't want to run anything close to it.

The feedline runs from the middle of the dipole, diagonally under the deck to a point near the TV tower where it enters our house and into our bedroom, that's where my stuff, my bench, my tools, everything are set up.

The backyard is about 80 feet N-S by 40 feet E-W and very uneven, the house is built on a bit of a mound. This is what I have to work with.

73s
geo
VE3GZB

You can still use your 52 ohm SWR bridge with 75 ohm coax. At resonance, you will see a differential of 1.5:1 or at resonance,  a 1.5:1 SWR.     

Coax is only good with resonant antennas.  75 ohm coax WANTS to see a 75 om load. Losses start to multiply when you have a high VSWR.  A loss of 9dB or greater is not unusual with mis-matched coax.

My yard is similar to yours. I ran an End-Fed Zepp from the TV tower to the near clothes-line pole then out to the far clothes-line pole, thence to the tree at the corner of the lot and out to another far tree (so to speak - I had different supports, but the idea is the same).  It ran 133 feet.  You have no choice but to convince your wife.  Bribe her.  Either that, or take up model railroading.

52 Ohm SWR meter on 75 Ohm Coax giving SWR of 1.5:1.....well if the best I was seeing was a forward power of 3 and a reflected power of 2, doesn't that translate to 1.5:1?

3:2 = 1.5:1 ? Makes me wonder now, doesn't it? Could my antenna system actually then be functioning properly but it's just my loaned SWR meter that's mixing me up?

Your thoughts?

73s
geo
VE3GZB

On virtually every SWR meter I have ever seen, the SWR can be read directly off the meter scale.  Be absolutely sure of what you are reading, and that that your are reading the meter correctly.

Typical SWR meter scale:
(http://www.eriecb.com/images/SWRE%20Meter.jpg)

Don't forget to set the reference ("set" point).


What kind of SWR meter is it?

Geo,

If you're going to stick with coax, then the only way to get a low swr on 40 or 80 meters is to use a flat top that's 65' long for 40M or 123' long for 75M.  Otherwise the swr will be very high with huge losses - just like what you're seeing now.  You see, the flattop becomes a ~70 ohm load at those lengths for those frequencies. At other lengths, the flattop presents a load that is very different with added reactance and a poor match for 50/75 ohm coax.. (Capacitive or inductive reactance creating high swr)

Since you want to use coax, not open wire, try this:  Concentrate on 40M only for now. Since you have up only 50' of flat top,  add another 7.5' to each end and let the extra wire droop straight down on the ends. This will give you about 65' total and shud be a good match on 40M. Measure it to be sure it's ~65' total. Now, to fine tune the swr, simply adjust the length of these drooping ends (equally) a few inches. Ideally, you shud have an electrical 1/2 wave of coax to get a true swr reading, but let's not worry about that now. Using about 65' of center fed flattop wire should get you in the ball park on 40M with a good swr and you will start making contacts.

This 65' wire coax fed antenna will NOT work on 75M, nor will your present 50' coax fed antenna due to the very high swr and mismatch. It is also too short for 40M at present. Add the extra 7.5' to the ends and you shud be OK on 40M.   Openwire with a tuner is the best way to get a multiband antenna to work, since swr is not important with openwire.  (Other than using traps or other gimmicks for coax fed ants)

73,

Tom, K1JJ

No. The SWR using forward and reflected power is calculated by

SWR = (1 + SQRT(Reflected Power/Forward Power)) / (1- SQRT(Reflected Power/Forward Power))

So, in your case it boils down to 1 + SQRT (2/3) / 1- SQRT(2/3) or 9.9, if I did the math correctly.

It's not clear to me that you are actually measuring power, so your SWR could be something different.

The SWR meter I have on loan is a QualiComp Model 120. Lou Vermond, VE3AWA, loaned it to me until I can get my own. It used to be his mom's (she was also a ham).

I tried using it the "right" way...but all of my reflected readings stayed in the Red zone where there are no numbers.

If I leave it like that, how can I possibly quantify anything I'm seeing except by scaling things down to remain in the black zone where there are numbers.

That's what I did to arrive at figures such as forward level 3, reflected level 2. Otherwise I'd just be saying "It's all in the red". Not useful information at all.

I took photos of the antenna and the general layout of the place, tried to make things a bit brighter.

More pics...

Still more pics...to mention about the feedpoint at the antenna....the coax doesn't have much mechanical strength at all and we get good winds at times (we had a tornado rip up the town back in 85 too!). So I had to tape the coax to the insulator to prevent the coax from breaking loose. No choice in the matter. The tape helps to prevent moisture/rain from creeping into the open coax.

It's probably not the right way, but it's what I have available to me.

K1JJ - The distance from the old TV tower to the far clothesline pole is about 50-55 feet, it's hard to measure it quite right because the darned Rubbermaid plastic toolshed is in the way, it's very heavy, slippery and we can't move it (we already tried, it's impossible to budge).

Neighbours have trees all over, branches overhang and trees absorb RF. So I can't run pure antenna all the way up to the clothesline pole, nor to the tower.

My radiating element is 45 feet long, loaded in the middle of each "arm" with (if I remember correctly) 67uH homebrew loading coil made from a pair of insulators, empty plastic solder spools and 16ga. speaker wire I scavenged, all taped up to keep direct exposure to rain lessened until I can figure out this whole thing and turn it into something better. It's ugly and I know my wife isn't nuts about it....she'd be much happier if they weren't there.

In the bottom picture "loaded_dipole" you can see the high voltage power lines that run right by our lot, we get a lot of interference from those power lines.

I don't have a lot of space to put up an antenna, and the only mount points I have are the TV tower and the far clothesline. No other.

Oddly enough, when I was still running the ugly twisted line to the feedpoint, I seemed to be able to get somewhat better SWR readings (less reflected power) after I added the loading coils. Now with Coax, it seems to be quite different.

My transmitter isn't stable enough to try to run to 20m, so I need to try to stay in 80 and hopefully 40m with what I have right now, even though I clearly don't have a long enough antenna.

Geo,

OK on using loaded coils.  That's fine.

Now, when using coax you must prune the coils to come up with a good match to the coax for a particular band.  This antenna will NOT work efficiently on more than one band at a time with coax.  Pick your favorite band and add or subtract turns on the coils until the swr is close to 1:1.   Only ONE band at a time - all the other bands will have a high swr and be UNUSABLE with coax. (except maybe 15M)

The only other solution is to use that antenna with openwire and the antenna tuner will match the transmitter to the line on ALL bands. The high swr is still there, but will not matter due to the low loss openwire.

Without adjusting the coils or flat-top length, you are spinning your wheels and will never get a good match with coax.


BTW, to support the coax, make a "pipe hitch" knot using rope around the coax and tie it to the center insulator. This uses about eight turns around the coax for a good, distributed, uniform grip.  Look up "pipe hitch knot" on Google.

T

Hmmm.....adjusting the coils when they're already mounted would take a great deal of effort and time, so perhaps that's not the best path...I'm already tied up for time on so many other things at this time, including searching for a car, managing production at work, maintaining electronics at the farm. I was fortunate to have this much time to devote to my hobby so far but it's getting tight.

I don't have enough unmolested antenna wire left, I used everything I had up on getting this far and this antenna I have set up now, well the wire is pretty molested, spliced, just plain messy at this point (I had it set up as a Zepp before and got nowhere with it, now running it as a dipole hasn't proven to be a good choice either).

I'm not sure what you mean by using this antenna with openwire? Do you mean an untuned feedline, like a random length feedline? Or do you mean to change the whole antenna to something other than a Dipole?

Can you link to some image on the internet to show me what you refer to, so I can understand?

What about any kind of military portable transmitting antennas? I'm sure the military must have had some neat ideas back then to allow HF transmission with a piece of damp string or something? How can I begin to research this without wasting so much time chasing info I can't use?

Thanks and 73s
geo

Pipe hitch knot?? Gee!!  :o I never heard of that, it looks very interesting!! I'll look into it!

But how would I protect the coax against the elements of the weather where the casing is open (to allow me to connect)?

Would RTV Silicone work if I gooped it all over the open end of the Coax?

Look up "openwire" on Google.

It's two parallel wires spaced a few inches apart that are held separated by thin ceramic, plastic, Lexan, Teflon, etc, spacers.  You can make it or buy it - the heavier wire the better. #10 wire would be ideal - #14 wire is accepatable.  You will need an antenna tuner to use it. Remember the K1JJ tuner I suggested before?

We've been thru this a few times in past threads. Please reread them.

Bottom line is unless you can adjust those loading coils for a particular band, you will never get a good match to the coax.  The openwire solution is better if you want to put it up and forget about it. I realize the XYL doesn't like openwire, but those are your only options for feeding a 45' long dipole.

T

You mean something like this:

(http://www.qsl.net/vk5br/Fig3MeritsOWLines.jpg)

Well, my wife wouldn't stand for that, having some ugly transmission line draped down the middle of the antenna. She'd probably rip it down out of embarrassment to what it would do to the appearance of the yard (she loves to have a nice tidy appearance).

The appearance matters a great deal, my wife won't tolerate an ugly back yard.

Are there any other alternatives I can look at in terms of transmitting antennas which won't look like a science experiment in the backyard and which will work with Coax (since that's what I am stuck with now)?

73s
geo

Yes, tape the coax real well with electrical tape so no water can enter. Then cover it well with RTV. The RTV will last for about 5 years and eventually blow off, but will keep it dry for the duration.  To keep water that DOES enter the connection  from flowing down the coax, let the last foot of coax circle up and over the center insulator and look towards the ground.  Tie the pipe hitch below the insulator with a 3" rope lead holding the coax to the insulator for support for the run to the ground.

T

Interesting!! I'll look into it and try it when I get more time (this week and the next couple of weeks will be impossible for me, just too much work and insurance and car stuff going on, that's why I tried to get as much done today as possible, but without any success, just spun my wheels).

Yes, that will work - looks like a G5RV.  But might as well get rid of the 75 ohm feedline and run the openwire to the shack with an antenna tuner.



As I said, don't waste any more time playing with the swr readings for a 50' dipole fed with coax without having the ability to adjust your loading coils for a particular band match. It will not work.

Gotta hit the sack - good luck!

T

What about loop antennas? Does anyone here use loop antennas for transmitting? At least if a loop antenna were usable here, then I could simplify so much by keeping the loop indoors, I could tidy up the antenna I have erected now just for receiving signals and that would make my wife very happy too!

Does anyone have loop antenna transmitting experience at medium power levels on 80m?

73s
geo

I've experimented a little bit with loop antennas. Are you talking about a small transmitting loop for things in the 100 watt power level? Indoors? I'm not sure that's practical.

For a small transmitting loop to work well, it typically has to be in the range of .1-.25 wavelength circumference. For 75 meters, that's pretty large. Check out w2bri's site shown below.

Loops have strong fields close in, I'd be very wary of running 100 watts into a loop I was in the same room with. Maybe in the same house with.  ;D  100 watts is also going to require a serious capacitor, probably a vacuum variable or a homemade trombone style.

Small transmitting loops are very hi Q devices, which means they can be twitchy to tune. They also require a lot of attention to reducing any resistance, including choice of materials (copper pipe, large diameter is better) and soldering/welding to make good low resistance connections.

All in all, they are very much harder antennas to make work successfully than the dipole you are working with now. I've gotten some to work reasonably on 10 mhz and up, and have toyed with the idea of one for 75 or 40 meter mobile but the costs and complexities have stalled that project for now.

Check out the following web sites for some info on loops. w2bri has some good ideas on getting started inexpensively on 20 meters, and has an 80 meter loop that will give you a good feel for what it takes to make antenna work on that band.

http://www.standpipe.com/w2bri/
http://www.standpipe.com/w2bri/80meter.htm
http://www.aa5tb.com/loop.html
http://www.iw5edi.com/ham-radio/11/a-magnetic-loop-antenna-for-hf

Good luck in your antenna endeavors.

There's nothing wrong with a Loop (Skywire) Use heavy enough wire an get-r-done heck I ran one with 213 coax feed on 80 and It worked with No Balun...Whoo Hoo....Put one one 40 Vetical man that thing was touchy direction wise  :) werked great....again heavy wire was used...build it heavy it'll work for ya...Heck I even Like the Double Bazooka, especially for receiving...of my location helps alot.

73
Jack.

Hi Geo,  

Seems like a pretty frustrating situation for antennas at your location!  Something that hasn't been mentioned, but might work with your limited space is an inverted L antenna. (END FED 1/4 wave) This is a simple antenna and it is very easy to build.  Just run a total of a quarter wave length of wire (approx 60-65 Ft) up your TV tower, through an insulator and then out to the clothes pole with an insulator at the end.  Feed the ant with the center conductor of the coax to the end of the wire and the shield to a ground rod.  Install some radials to improve your ground system by laying out some 30'-60' lengths of wire on the ground and bury them by slitting the ground with a spade or edging tool, then push the wire into the ground an inch or two.  Tie one end of the radials to your ground rod.  The more radials the better, but it will work if you just have a few to start.  You can use any kind of wire for the radials, whatever you have on hand, or can salvage.  Your 72 ohm coax will work, but if you have some 52 ohm coax (enough to reach the feed point), that would be better.  You could also add a loading coil in series with the antenna at the feedpoint, with a tapped coil arrangement and find taps that would work for other bands.  Or....you already have the makings of an L or Pi antenna tuner...that would work great with this antenna.  On 40M, this would be an end fed 1/2 wave antenna and no coil would be necessary.  This antenna might also be considered by the XYL as a little less unsightly, since you wouldn't have the center feedline hanging down to contend with.  Where there's a will, there's a way!

73,  Jack, W9GT

I'll say that this is the most frustrating part of it...

Initially my antenna was sort of an inverted L where I had the uncut radiating wire strung from TV tower to the clothesline, then the radiating wire bent down 90 degrees to terminate at an insulator just outside my window.

When I coupled my (then) 2W transmitter to it, my friend VE3AWA who lives 150km south of me gave me an S9 signal strength report.

Other hams said to me "No no no, its all wrong, it will never work, change it to a Zepp so I can keep my wife happy and keep the transmission line (450Ohm twinlead) close to the house and not be an eyesore."

I did that. And it became worse.

Then I asked again, and hams told me "No no no, change it to a dipole". So I did that. But then I didn't have enough feedline, so my boss gave me a few hundred feet for free, 14ga insulated wire. I made a twisted pair feedline just like they illustrate in the old ham books and magazines.

Then hams told me "No no no, change it to Coax". So at still MORE expense, I got 500ft of Coax and replaced the feedline.

And still NOTHING WORKS!! SWR is still lousy.

Can you see why I'm so frustrated? I'm getting advice but nothing is working within the physical limits of the lot I live on. And I'm not made of money, I'm doing this all just from out of pocket money, I have no credit cards, I'm the sole breadwinner here...I'm at the point where I'm ready to chuck it all. I can make the receiver and the transmitter from scratch but if I can't get straight experienced advice on the antenna, what's the point? It seems to be only a rich man's game.

73s
geo

Not to sound flip or make this sound like a flame, but....
Do you happen to have a handbook from say the 50's? It would describe every antenna you mentioned. Even with the monetary and/or XYL constraints, this isn't rocket science. You sound like a pretty smart guy who has built some excellent HB rigs. I guess I don't understand what the problem is: that random wire you first described with a simple T network tuner would have worked gang busters. My OM and I used one at our old lake residence for years. nothing hard, about 250 ft of wire tossed up in several trees, to a feed thru insulator, to the tuner. fed the tuner with coax, one coax to my OM's op position, and another to my novice station in my room.
if you need a handbook, PM me, i'll send you one.

Mike, W2ZE

Hi Geo,

Whoa......the advice you have received from many guys here is very good....you just have to choose the best solution for you and your situation.  Dipoles are great if you have room for them.  Balanced line feeding the antenna is great, if you don't have a problem with space or aesthetics or the XYL's disapproval.  Using a tuner and an end-fed wire of some sort is not necessarily the ideal solution, but it will work and might fit your situation and limitations.

Whenever you ask for advice and suggestions from a group like this, you're going to get many different ideas and approaches.  We are just trying to help.  Only you can decide which scheme will work best for you.

73,  Jack, W9GT

Wire antennas held up with pre-exisisting structures is not a rich man's game.

After reading through this thread, I got to agree. And the random wire would be fitting for that buzzardly breadboard TX.

"Hamcalc" does not run properly under Linux Windows emulation "Wine". It is completely unresponsive to keyboard input.

I have a 1942 WWII Radio Handbook which has many fine examples of transmitters, receivers, etc....and I've been referring to it frequently as well as other QSTs, other text books and whatnot.....so when I've seen that twisted pair worked then but today Coax is what Hams are supposed to use, you can see the conflict?

So I go ahead taking all advice, spend pocket money which I shouldn't, hope my wife is patient with me and all the while I still can't get a signal out.

I do work in RFID for my dayjob (our transceivers cover 1.5 to 8.7MHz, very low power) so the electronics part is natural to me. But the kind of antennas used in RFID are very different than outdoor Ham use. I have no practical experience in constructing and troubleshooting outdoor HF Amateur antenna systems for transmitting, see?

I'm not flaming anyone, please don't misunderstand my vent....it's just built-up frustration at an ever declining return on the work I'm putting into this (I've also been very stressed about my car and the collision, the insurance company, etc....they're nothing but parasites, it's been since May 27 that I've still been driving my now-written off condemned car and only just yesterday the insurance decided to rent me a car, all the while my hearing rings from an inner ear concussion from the collision).

The transmitter clearly does deliver - I can light a pair of 100W incandescent lamps with it. And my receiver is the finest I've ever had. And I've constructed the dipole as per textbook....yet my SWR remains stubbornly high and nothing I've tried seems to help it.

Who would not feel upset at this? So I'm not upset at anyone, I'm just upset at spinning my wheels for no good reason. I'm sorry if I injured anyone's feelings. It was truly not intended.

73s
geo
VE3GZB

Yes, I see the conflict; but you went out and bought RG6 without asking anyone if this was OK (correct impedance, power handling, etc...). You spent money on something that isn't going to work. You ask questions about how to read a vswr meter. Tom, K1JJ tells you exactly how to cut a dipole. This is rudimentery stuff. Directly coupling a random wire, as shown in the WW2 book, won't work very well. It was intended to display what to do in an emergency. That random wire, and a T network (which by the way would cost you about a whopping 10 bucks at a hamfest to build), would have worked just fine to put a respectible signal with a 100 watt tx.
Not to sound like I'm blasting off on you, but it sounds like you really need to sit down with a handbook from any era, and read it cover to cover, especially on antenna theory. Once you have a good comprehension of what is in the handbook, then start firing away with questions. There are a lot of talented people on this board, but just because someone tells you something, don't swallow it hook, line and sinker. Ask more questions, do some Google searches.
By the way, just my personal opinion: If you have that much going on in your life, and money is really that tight; now may be a good time to shelf all of this, and focus on family and security. I have been off the air now for about 2 years after taking a new job and uprooting my whole life. Amateur radio isn't a big priority for me right now. I get the urge to start doing new projects, then when I get to doing them, I always seem to ask myself, is it really worth it? 100% of time the answer is no.
Take it for what its worth, sorry you have had this much trouble.

Mike

Judging by what I've seen so far, since jumping into this (and bear in my that I've been studying for a ham license since I was a teenager, I'm in my 40s now and electronics is my profession), today's definition of a Ham seem to operate by the size of one's bank account, the amount of land he/she can afford and how much they can spend on factory built rigs, antennas, etc...

This leaves folks like me, with very small lot, very small money but intense curiousity out in the cold. Can't afford a lot that will support a full size dipole or a fancy rig? Too bad for me then, sucks to be me.

Just telling it like I see it and it's a sad state of affairs. No wonder kids today have no chance to enjoy electronics too.

Maybe a long time ago hams, young boys, could get on the air by raiding the neighbour's trash or the family radio, salvaging parts from broken radios, stringing up lamp cord and making a radio system that way, no SWR measurements, it just worked. Except for harmonics, I see nothing fundamentally wrong with that system and wish to employ it.

I have to use whatever I can get my hands on. And if that just happens to be different, I'm not in a position to afford what "everybody else" can get or use....the Coax I got was what I could afford, period. And I only got it becauase everyone else was saying that twisted lead was not good (forget about the fact that it's used in just about every vintage ham publication).

Advice is nice but when it involved spending gobs of $$, then it's not employable at my budget.

73s
geo

I never said that, quite the contrary. This hobby can be had at the cheap. My point I'm trying to make is don't take everything said here as gospel.

If 10 bux is gobs of money, ham radio should be the least of your worries.

I'm not going to get into an argument, only trying to help ultimetely; but trying to lay the cards on the table with realistic goals here.

I wish you well.

Mike

Mike is right. If money is that tight, you should consider putting amateur radio aside. You seem to be causing yourself much consternation and stress over something as relatively unimportant as amateur radio. I also understand amateur radio can be also be a relaxing and enjoyable activity that is a nice break from the real world.

That said, if you wish to continue, it seems to me that you need to build an antenna tuner. No matter what sort of antenna you install at your location, it will likely be short/small for 80 meters. This indicates a tuner is needed.

How about a loop around the house?  If you have plastic raingutters, all the better.

Seems the first problem you have is the wife, you need STEALTH.  OK, a hidden in the eaves loop is pretty hard to see.  Otherwise, you already have your dipole.

BUT, with all the dollars you've spent now, you have coax that's designed for 75 ohms, and an antenna that should be close to that, and a transmitter that has variable matching in it (pi net or something similiar, not a solid state broadbanded type), and you have an SWR meter that's designed for 50 ohms.

Sounds like your problem is now the SWR meter is incompatible with everything else.

Here's a simple thing you can do, try winding a coaxial balun choke at the feedpoint of the antenna.  It sounds like you have enough coax to do so, and it doesn't have to be large.  http://www.k1ttt.net/technote/airbalun.html is your friend.  That will HELP you, but not eliminate ANY of your problems.

I'd say it's time to learn how to either prune your antenna for resonance, or it's time to sell everything and take up fishing for flys.

Your coaxial cable doesn't like a mismatch, so pruning the antenna for resonance and a 1 to 1 is what you need to do.  This is BEST done at the feedpoint, as the coax will act as a transformer if it is NOT terminated in it's characteristic impedance (in your case, 75 ohms).  Using the SWR meter at the feedpoint means this effect is unable to happen, and when you have it 1:1 at the feedpoint, it BETTER be 1:1 at the transmitter end.

If that isn't possible, it's still possible to get a 1:1 through your coax, but it might take a bit more trial and error, and you MIGHT end up using the coaxial cable as a transformer.  OK at a couple hundred watts, NOT OK at a couple of kilowatts (with the coax I believe you have)...  Keep that in mind, once you get this all working and decide to upgrade your final(s).

Without having a choke balun (or other style balun) at the feedpoint of the antenna, your coax will also have RF on the shield.  This usually pisses the wife off by screwing with her non RF friendly devices (TV's, radios, toasters (extreme case), etc).  HOWEVER, if you don't get any interferience, this can actually ENHANCE your signal.  There are antennas DESIGNED around this phenomenon....  I prefer my ANTENNA to do the radiating, and the transmission line to transmit the signal from connector to connector...  BUT, as Mr.  Varney (G5RV) proved, it does work, and it makes a decent antenna.

You are at the point where you're dangerous.  You know enough to get into trouble spending dollars, which you admit are tight (same here, I'm STILL scrounging my caps and inductors to make my link tuna...  It's been a couple months now.  I took a motorcycle into a wall at 130 mph, and am raising my 2 sons by myself.  100 percent disabled, blah blah blah...  I found CB linears with sweep tubes to be a PLETHORA of parts, if you happen to have old CBers around that can't afford to retube their amps anymore..  A Palomar 350Z netted me 3 caps all the same as well as 2 inductors the same and another slightly larger...  Cost was diesel to go get it, no power supply, no boards, nothing, just a couple output networks in it), but have ALMOST enough knowlege to get it right on your own.  And PLEASE don't think I'm talking down or slamming you, because that is the farthest from the truth.

See if you can find a newer copy of a handbook, or get on google and research.  Your handbook is a bit dated, probably doesn't discuss coax and the inherent problems with it, and that's why you're in trouble now.  Bill Orr also has a great book, The Radio Handbook.  I've a copy of it, and hundreds of copies of books I've downloaded off the internet for free, including some out of print that are FULL of info...  Even on here, I've read about things (Collins Coupler) and someone else chimes in about it (Don) being a Pi, that led me on a half day research about it, a trip to India someone made back in the imperialistic days, etc.  And now I'm rambling.

Anyway, don't give up.  Yes, this IS an appliance operator hobby today, and because of that, it's getting harder to junk box stuff.  You CAN'T go pick up a tubed TV on a street corner anymore, and because of that, you can't get a tubed rig going for nothing.  BUT, guys are using the transistors that have replaced the 6LF6 and other tubes in the horizontal outputs, and using them now in transmitters...  SO YOU CAN JUNKBOX THINGS!! (but, you can't go scrounging at the dump anymore, and people get pissy when you dig through their neighborhood trash, yes, times have CHANGED)

Get your antenna resonant, bud.  Try 468/Freq.  Then half that, and that's the length each side of your dipole should be.  Add a foot, and then cut equal lengths off each side until you get the SWR down.  If you do this at the feedpoint, try to get a 1.3 to 1.5 SWR, and you <<should>> be near 75 ohms at the feedpoint.  Run the choke balun in your coax, down to the transmitter, and load it up, see what you get!

You also might want to try building a field strength meter.  An untuned one can be built REALLY inexpensively, and could REALLY help you with the antennna tuning.  Or a current meter, but I think a FS meter would cost you literally, a couple bucks at most.

Hope this helps.  Don't get too discouraged.  No, this isn't ham radio of the 40s.  This is the ham radio of the new century, where we hear about people making contacts by plugging in a headset to their PC, and no radio is involved.  I don't get it, I'm like you, I want my stuff to glow and reverberate (mod iron) when I talk!!!  (this coming from a guy who runs a Yeasu the size of a CB radio!!!)

--Shane

Every time someone tells you to spend money a bell should go off.
Any idiot can give you bogus advice. Get a couple inductors and a couple variable caps and I guarantee you it would be easy to match a hunk of wire of any configuration to act as an antenna. AS an RF ID guy you should know this.
This is how many of us started in ham radio as kids with no money.
Coax balun will not eliminate near field radiated emissions from the antenna so don't waste your time with it.
Drive a ground rod in the ground or bury some wire and build a little T or L tuner.
Run coax between the tuner and rig. Put up some antenna wire where ever you can and play with the tuner to get a match. I worked a lot of DX with a random wire antenna using a L network and 100 watts.

I'm sending him some stuff. swr meter, 2 rf ammeters, a UTC S20 mod transformer. I understand what he's going through, I was at that point with the Gonset Amp and just had to do something else to keep my morale up. I'll go back and hit it.

MY biggest problem is I dont have anymore balls. I used to just fire up an if it smoked, it smoked. Now I go through all kind of machinations and excuses about what MIGHT happen.  :-X

Geo, just put it aside for 1 week and then go back to it. You'll feel 10 times better.

personally, I much prefer the pre war handbooks. For one thing, there's little or no crap in the rigs about audio clipping, limiting frequency response, etc. etc.  The handbooks after WW2 are polluted with what the Signal Corp.
taught them makes good communications for the military.

geo, the one thing I can say is that nobody on this board gives a damn about if your wife is happy.

That's your business.

Sometimes you have to envoke Murphy's golden rule  ;D ;D "He who has the gold makes the rules!!"

Frank, if I get the deposit slips, do I wear the pants?

EZ Dipole tuning:

Build your dipole/inverted V so that the ends are held up via ropes.

A pulley is nice if you can manage that, but not necessary.
(Note: if you are going over trees you will need to move that rope at least twice a growing season to prevent it from being grown over...)

Polypropylene (dacron) is best, Nylon second. Avoid all other materials and blends. They will UV rot and die fast. Anything is good if you have it on hand to get it up... always use what is on hand!  ;D  Fix it later!

Now build your dipole in length to about 3 feet or so longer on each end than needed according to the formula for the frequency of interest (3885?).

Attach the dipole to the end ropes at a point about 4 feet from the end of the wire by making an appropriate loop in the wire, letting the remaining wire hand down.

Now you pull the ant up, and check ur SWR from one end of the band to the other, noting where it seems to get lower. Probably on one end of the band or another, although sometimes you get a null in band.

If the lower SWR is at the high frequency end (or out of band) then you need to lengthen the wire (add wire to the ends). If it is at the LF end (3500) then you need to shorten the wire. That is what we're hoping for actually... so take the end and bend up a foot or so and tie it around itself! Go check the SWR again. The resonant point ought to have moved up in frequency... continue until you get it at the center freq of interest. This requires a few up/down trips of the ropes.

I've always been able to get my dipoles working in band very quickly by this method. The only thing that may screw it up is if there is other "stuff" interacting with the dipole causing it to resonate somewhere way off the nominal frequency it is cut for.

Sometimes you'll only need to adjust a few inches.

There is likely a way to find out-of-band resonance using a receiver, but I can't think of what that might be at the moment... a grid dip meter might be handy for this... anyone want to comment on how to couple a grid dip meter to the ant??

              _-_-WBear2GCR