I believe this is a 43-foot vertical with some radials.  The antenna tuner 
is required in order to get close to a 1:1 match on any band except 60 
meters, according to some stuff I was reading last night after thinking 
about this message.  I don't know whether the tuner is at the base of the 
antenna or back in the shack; it would be more efficient at the base, but 
you wouldn't know if something was arcing over unless you were constantly 
monitoring reflected power at the shack.
There are no easy answers to this problem; too many variables.  I think I 
would first try to get everything working correctly with the FT102 running 
barefoot.  This includes obtaining a dummy load so that the 102 can be tuned 
up into a 1:1 SWR before the antenna tuner and antenna are connected.  After 
a match is achieved with the ATU and antenna on all the bands of interest 
and reliable operation is guaranteed, start testing the amplifier into a 
dummy load that can handle its output.  After all those tests have passed, 
you can consider hooking the amp through the tuner again.
With the voltages and currents involved, it may not be possible to run high 
power through that setup on all bands.
That's my advice, for whatever it's worth.  I used to run my 600-watt amp 
through a Johnson matchbox (275-watt rating) into an 80-meter dipole fed 
with open-wire line.  It worked well on most frequencies.  But if I tried 
using that tuner into coax at that power level, arcing occured.  Be cautious 
and take the time to isolate the variables that are contributing to your 
problems.  You will have a better relationship and a reliable station at the 
end of the process.
73,
Lloyd Rasmussen, W3IUU, Kensington, MD
http://lras.home.sprynet.com
-----Original Message----- 
From: Kelvin Marsh
Sent: Monday, April 07, 2014 4:05 AM
To: [log in to unmask]
Subject: Re: Unun balen fed vs traps

Hi Mike,

I've not been following this thread, but the first thing I would say is that
your friend probably feels as bad as you do.  Personally, I would count
friendship way above a couple of tubes, or indeed, any equipment <smile>.  I
have amateur friends, and yes, they occasionally suggest things that I know
are wrong, but then, I'm sure I often do the same.  Neither of us are
'idiots', we just have differing experience.

If I was your friend, I too would think the problems must be with your
station, and I too would go looking for issues!

As I said, I've not been following the thread, but I can possibly answer the
differences between your vertical and a trapped vertical.  Basically, you
are relying on the tuner to find a good match, whereas a trapped antenna
will attempt to give you resonance on the bands it covers.

The big question I would be asking, is what is the SWR for each band on your
vertical.  This is the SWR without the ATU.  It could be 2 to 1 on 40,
meaning the ATU is just tweaking the impedance, but it could be 30 to 1 on
75.  I would not personally put high power into this, even if you can get a
1 to 1 match using an ATU.

As I say, check the antenna SWR on each band.

Best wishes, Kelvin Marsh - M0AID

Working to improve accessibility for radio amateurs with disabilities

www.active-elements.org

For accessibility evaluations of amateur equipment and MP3 manuals

-----Original Message-----
From: For blind ham radio operators [mailto:[log in to unmask]]
On Behalf Of Michael Ryan
Sent: 07 April 2014 03:34
To: [log in to unmask]
Subject: Unun balen fed vs traps

Hi all:

I know this discussion has been posted to the list many times but I wanted
to gauge an opinion again.
Does anyone know if an Unun fed antenna, mainly a vertical, induce high
currents and voltages back through a coax feed line?
I'm getting an indication that my 43 foot vertical is now the cause of my
apparent tube failure and if don't stop using it, I'll blow the crap out of
the rest of my station.
My own tuner, after a period of a couple of months of use, started having
trouble tuning out a 75M 6/1SWR spike but behaved perfectly on 40/10,
including the DX contest with my amp running 600W CW with 50W of drive.
The tuner I have now, handles this antenna from 75M to 10, didn't try 160,
with my amps 600W CW no problem. My own tuner, is currently on a wire
antenna, handling the SSB output from a HeathKit SB-220, about 1200W, 75/10M
with no problems.
Put my tuner on my antenna, it will tune perfectly and handle 200W on 75/10M
but put 500W CW through it, the amp hissed. This may have lead to the 20M
issue a couple of weeks ago but I don't think my amp is made of cardboard.
LOL
Now how would a trapped vertical be different?
I'm very confused, discouraged and most of all scared.
I don't know what's to gain by BSing me but its starting to look like the
gentleman who's been a helping friend since I got my license is doing just
that or is simply wrong.

73:
Mike VO1AX