[R-390] The Saga Pt 6 (Antenna Balun

[rbethman]

  Bernie - I don't know what "improvement" will be seen.  It begins to 
get into what specific Signal Generator is used, how its impedance is 
effected, and other things.

Roger R. will tell you that they spent their career(s) using 
AN/URM-25(X) sig gens.  By their nature, they were issued with a 50 ohm 
Z "phantom/dummy" antenna.

Therefore you either use it into the "balanced" input - therefore 
tweaking and peaking for a 50 ohm match, or you used the "C" connector, 
and flipped the internal cables.

The net result was a VERY sensitive receiver, but it really wasn't 
"peaked and tweaked" for the "balanced impedance" input.

I've yet to locate or discover an AN/URM-25(X) with the adapter for the 
balanced input.  I use an AN/URM-25(D) and the TS-585D/U for the audio 
output readings.

I'm extremely happy with the results!

I even use the same lash-up for my Northern Radio SP-600.

Shake them and bake them with what you have - AND - you can make work!

Nothing wrong with Tisha's method!

Bob - N0DGN

On 9/21/2010 11:49 AM, Bernie Doran wrote:
> what improvement is actually shown by the balun, vs the coax flipover or
> grounding one pin of the balanced input?  Bernie W8RPW
> ----- Original Message -----
> From: "Tisha Hayes"<tisha.hayes at gmail.com>
> To:<r-390 at mailman.qth.net>
> Sent: Tuesday, September 21, 2010 9:55 AM
> Subject: [R-390] The Saga Pt 6 (Antenna Balun
>
>
>> "Has anybody tried a balun of the proper ratio to couple the coax to the
>> balanced input?"
>>
>> Yes, I have, that is the way to go. I hand wound a 2.5:1 un-bal, put it in
>> a
>> metal box with a coax connector on one end and a twinax pigtail on the
>> other. It works just great.
>>
>> If I recall correctly, using the C connector there is a mini coax flipover
>> you need to do at the RF deck to get the best sensitivity.
>>
>>
>> -- 
>> Ms. Tisha Hayes/ AA4HA