melting coils...

[K3ZS]

Yes, I am well aware that the best performing antenna is one that is as long as possible fed with good open wire line and a good balanced tuner.

The downside of that is you need to tune the antenna any time you change frequency.
You cant even listen unless you tune.

Not exactly true.    I am using a T tuner with a very good external balun.    Using a 135 ft doublet on 160M with balanced window line, is very sharp and you must retune if you change frequency.  But, on 80M you can go +/- about 50 Khz and still not have to change anything.    On the higher bands you can go over the whole phone band and not have to retune.    As far as listening, I just bypass the tuner and just use the balun, and listen to all the bands with the same signal to noise ratio, even though a few S units lower as compared to the having the tuner in place and tuned.   Except for the shortened use on 160M, and from the signal reports I get on the other bands, I am not sure you would notice the difference as compare to a real balanced tuner.

[N2DTS]

What balun?
What tuner?
Do they get hot at 350 watts carrier?

From what I hear about balun's, they do not like SWR at all.

I figured I could use open wire line into a balun and no tuner on receive fine, but you need a tuner on transmit, then a way to switch the tuner in and out.

When I ran the G5RV into the big heathkit tuner, it got quite hot....lost energy...

I like the resonant dipoles I have up now, nothing gets hot at full power which should be a good sign.

For the last 25 years, I have mostly run coax fed dipoles cut for the AM windows, and every time I try something else, it catches fire/shorts out/melts....

Brett
N2DTS

[WA1HZK]

Yup
Hot Spots on the roof, dead birds, squirrels mutated in the back yard.

[K3ZS]

What balun?
What tuner?
Do they get hot at 350 watts carrier?

From what I hear about balun's, they do not like SWR at all.

I figured I could use open wire line into a balun and no tuner on receive fine, but you need a tuner on transmit, then a way to switch the tuner in and out.

When I ran the G5RV into the big heathkit tuner, it got quite hot....lost energy...

I like the resonant dipoles I have up now, nothing gets hot at full power which should be a good sign.

For the last 25 years, I have mostly run coax fed dipoles cut for the AM windows, and every time I try something else, it catches fire/shorts out/melts....

Brett
N2DTS

I use an MFJ 989 tuner, but don't use the crappy balun that these have.   I am using a external DX Engineering balun rated at 5KW continuous power derated at 3:1 SWR.    They make one for use with tuners that use high voltage wire.  No heating at all on 80M and above.    No perceptible heating on 160M with short dipole,  but I am sure there is some.   The real test is to transmit  about 900W of continuous carrier on 160M, with everything tuned for 1:1 and watch the SWR.  If it rises, your balun will not last long.   I have done this with a so called W2DU 1kw balun and it doesn't take long to see the rise and feel the warmth of the balun.   A real balance tuner is the best for 160M, but at 80M and higher, my setup is fine.    I only have one antenna, 135ft doublet, with a 16 ft in parallel, to give a better antenna pattern on 10M.

[N2DTS]

That is very interesting!
I would never have believed anything mfj makes would take any sort of power at all.

I know you can buy big baluns, and can make them out of coax, which I thought about.
That might be a way to go for future experiments, it might have advantages over a balanced balanced tuner, since with a balun you could receive all over, the tuner could be in the transmitter path only.

Brett
N2DTS

[Steve - WB3HUZ]

Can't say as I ever experienced and receiving problems when using a tuner. On most of HF, most especially 160, 80 and 40, the ability to hear someone is completely based on the SNR of the incoming signal. As long as the signal is above the noise floor of your receiver, you will hear it the same, tuner in or tuner out. Most receiver have a noise floor well below the noise floor coming in from the antenna.

[KD6VXI]

What balun?
What tuner?
Do they get hot at 350 watts carrier?

From what I hear about balun's, they do not like SWR at all.

Use the coaxial choke method.  No mo problems.  I've run QRO into them, and not had to worry.

As long as you use QUALITY coax, it shouldn't heat up, as you are choking the currents off the outside of the feedline, and NOT making a BALanced to UNbalanced transition.

If you use hardling, then the W2DU style is about the best you can get, unless you get some LMR at the feedpoint...  I've heard of people making chokes out of 5 gallon buckets and hardline, but I find it hard to believe it doesn't distort the inside of the cable.

--Shane

[KD6VXI]

Can't say as I ever experienced and receiving problems when using a tuner. On most of HF, most especially 160, 80 and 40, the ability to hear someone is completely based on the SNR of the incoming signal. As long as the signal is above the noise floor of your receiver, you will hear it the same, tuner in or tuner out. Most receiver have a noise floor well below the noise floor coming in from the antenna.

I believe what he is talking about is the loss from the mismatch, or the loss from within the tuner itself.

I've experienced it, it can make the difference from S9 to S3 or so, depending on the mismatch, type of line, type of tuner, etc.

--Shane

[Steve - WB3HUZ]

For sure. But other than S-meter readings, it will make no real difference in what you can hear.

[N2DTS]

On my setup, with the heathket tuner and say the G5RV, I cant hear much of anything if the tuner is set for 80 meters and I want to listen on 40.
My setup has coax all the way from the antenna to the tuner and radios.

Also, if I try and receive on 80 meters with the 40 meter dipole, I dont hear much at all, only very strong signals.
I was on 3835 this morning, and someone was weak, so I tried the 40 meter dipole and the vert ant, to try and pull them through, and heard nothing at all.

For weak signal work, a resonant ant seems to work best here.

Now I notice on some rigs with built in tuners, it does not seem to make much difference, I dont know if the tuner is only in line with the transmitter or not.

Very often, the noise level is VERY low, say an s1 or s2 on the meter, and I work stations giving a 3 to 6, though the tuner that is not tuned, the noise level drops to zero and I dont hear the weak ones.

I have not tried it with any sort of balanced tuner and open wire line though, it might be much different.

Brett
N2DTS
 

[K3ZS]

That is very interesting!
I would never have believed anything mfj makes would take any sort of power at all.

It was poor balance that led me to initially get another balun, and not use the MFJ balun.    The coil and capacitors seem to handle the power OK.    I had problems picking up all kinds of interference from my house.     I put an antenna up far from the house,  and used balanced line as the best way to feed it over that distance.   I was still picking up interference from the house on 80 and 40, and on 160 it was as bad as not having a feedline at all.    I read an article that tested the losses of various baluns and read reviews before getting the one I did.  If I had a stock of high power capacitors, I would have built my own balanced tuner.    By the way, it was a W2AU balun that craps out at 100W on 160M with the short antenna, not a W2DU type, which are pretty good choke baluns.   Sorry W2DU.

[K1JJ]

I've been impressed when using large ferrite beads over cable as an RF choke, in general.

For all my linear amp filament chokes, I've switched from the standard ferrite rod with fil leads coiled on -  to a stack of large ferrite sleeves with the fil leads going through the hole just once.  Just slip the cores over the two wires - done.  Make sure you use the proper permabilty cores for the freq and power, or saturation may occur. (OR they may not generate enuff inductance for the job)

I ran some measurements on 160M (the lowest operating freq) using a sig gen, scope and load. I found they worked very well in blocking RF flow.

So, bottom line, the ferrite sleeves on the coax shud do just as well reducing shield unbalanced currents, assuming you reach the critical  amount of inductance needed for the given freq.   A rule of thumb is the generated ferrite impedance shud be at least 10 times the coax impedance.  (500 ohms, for example at the lowest freq)

Here's some more info on using coax baluns and dividers:

http://amfone.net/index.php?pid=12
http://amfone.net/ECSound/K1JJ23.htm

T