[Elecraft] BL-2 Balun Heating

[Don Wilhelm]

Gary,

Those two 80 foot 'counterpoises' are doing you no good at all.
run some wires off the ground and insulate the ends, cut each one to be 
a 1/4 wavelength at a band of interest.  If you have to run them in a 
bundle, keep the ends of the shorter ones separated from the rest of the 
wires by at least 2 feet.
Those wires have a high impedance at the far ends and thus may have a 
high RF voltage.  The near end (in the shack) will be a low impedance 
for RF at the frequency where it is an electrical 1/4 wavelength long.  
In your case, the best place to connect the wires is at the place where 
the coax shield meets the input of the balun.

If your tuner is actually radiating given the current configuration, 
there will be little that you can do other than switching to a balanced 
tuner.  I believe radiation from the tuner is probable since it is an 
unbalanced tuner feeding a balanced line.  Yes, a tuner chassis used 
like you are using it will be hot with RF and adequate protection 
measures to prevent anyone touching the tuner chassis while transmitting 
are necessary.

73,
Don W3FPR

Gary Winkelman wrote:
> Thanks for all the advise!  I've been running  tests all day to which I 
> have a nice Excel spreadsheet.  I've run the tests on 160 thru 10 meters 
> using my trusty MFJ-259B (couldn't live without it).  I ran AT1KM - no 
> balun, BL-2 1:1, BL-2 4:1 and a W2AU bead balun 1:1, all thru the 
> AT1KM.  All SWR, R & X values jived.  I did not try running 125 watts 
> thru the balun during the tests.  If it heated up, I'd have to let it 
> cool to get an accurate reading the next frequency.  The test would take 
> 2 weeks!
>
> Finally, I took the advise to put the balun between the tuner and the 
> transmitter.  Tuned fine so I added power.  It stays cool as the 
> proverbial cucumber!  One slight problem, the tuner is now RF hot. and 
> there's RF getting into my computer.  If I reduce the power to 75 watts, 
> the computer functions.  The transmitter is not bonded to the tuner.  
> Because of my circumstances, I am not able to use an RF ground rod.  I 
> have two  80 foot counterpoises that run next to our house on the ground.
>
> Thanks everybody for all your help!
>
> 73, Gary  N2UM
>   
>