[MRCA] BC-654 Antenna challenge

[Al Klase]

Mark,

*Commo wire!!!*

NVIS antennas are generally what half-assed hams had been doing since 
being banned to 200-meter and down.  A low half-wave wire will get you a 
lot of high angle radiation.

The vertical antennas on WWII HF gear were really only appropriate for 
"direct wave" communication, say 10-20 miles.  And, they were woefully 
inefficient, being only a small fraction of a wavelength in height.   
When you were sitting still, you threw some wire in a tree for better 
results.

http://www.mrca.ar88.net/Old%20Pages/Net/Images/Dipole%20vs.%20Whip.png

So, What's Wrong with My Whip?
Your signal is shown in red.  (Low half-wave in blue.)

The SCR-284 TM shows a "T-Shaped Antenna." (That's a Windom)



Of course, one of the big problems for useful, 24-hour NVIS is that the 
early portable sets were all stuck on one band around 5000KHz.  This 
explains why the the SCR-694 / BC-1306 (3.8-6.5 MHz) was being replace 
by the AN/GRC-9 (2-12 MHZ) as the war drew to a close.  Both radios came 
with end-fed half wave antennas in addition to whips.

Enough from me!
Al

On 1/21/2018 11:35 AM, WW2RDO via MRCA wrote:
> I know that the American, British and German Army first started using 
> NVIS antennas for some of their HF radios during World War Two.  So 
> far, I'm having trouble finding much information about how far each 
> military went as far as NVIS antenna use, or any photos of any WW2 
> vintage antenna.
>
> So here's what I'm trying to build.  I'm looking to build an NVIS 
> antenna for the BC-654 using only material available during WW2.  That 
> would include any balun or any additional antenna tuner to be used 
> with the radio, if they are needed.  I am unaware of any issue NVIS 
> antenna issued for the BC-654.   Particularly concerning is the fact 
> that the BC-654 did not use coaxial feed line for the antenna.  I know 
> the AN/GRC106 had an NVIS antenna, the AS-2259GR ,  but I see that the 
> AN/GRC106 used a coax antenna feed line.  I am not sure that the 
> AS-2259GR  antenna, even if I could find one, would work with a BC-654.
>
>
> Mark D.
>
>
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-- 
Al Klase – N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/

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