[Milsurplus] Horizontal loop on German vehicles

[Gene Smar]

Gents:

      Thanks for your many suggestions where to find source material for 
my original question:  Did US Hams intercept ca. 30 Mc comms from Erwin 
Rommel's forces in the African campaign in the early 40s?  I now have a 
few hints at sources that I must track down.

      As for NVIS as a possible transmission mode for Rommel's forces 
(yet another subject stirred up by my original email), if his armor 
units relied on ca. 30 Mc radio equipment as I've read, it is not likely 
that such transmissions were heard via NVIS in the States. First of all, 
the freq is too high; my earlier sources on NVIS transmission tell that 
NVIS propagation cannot be supported above the 10-12 Mc range.  
Secondly, NVIS mode provides somewhat reliable communications out to 
under 500 kM from the transmitter, not far enough to be heard along the 
US east coast.

      I had read elsewhere that the "cage" seen above command cars in 
Afrikakorps photos was not an NVIS antenna but, as others have said 
here, a top loading capacitive cap for a short vertical radiating 
element.  I believe that such an antenna could have been used 
successfully for close-in ground wave transmissions, such as on a tank 
battlefield, with, as Hue suggests, the 30WS HF transmitter.

      However, Fiedler, in his 1996 book "Near Vertical Incidence 
Skywave Communication - Theory, Techniques and Validation", discusses 
the Soviet Union's mechanized units as using "zenith radiation", their 
term for NVIS, to maintain comms over large swaths of territory.  He 
includes a photo of a Soviet BTR-60 (to me it looks like four-axled 
armored troop carrier) with a "railing-like antenna array" on the 
horizontal top surface.  He claims this photo supports other Soviet-era 
documentation that suggests, "Ionospheric communication ... during brief 
stops at distances up to 200-300 km is conducted using Zenith radiating 
... antennas arranged on top of the operating vehicle."

BOTTOM LINE:  NVIS for Rommel not likely; for former Soviets, probably.

73 de
Gene Smar  AD3F


On 9/20/2021 1:13 PM, David Stinson wrote:
> Hue is correct.
> The "loop" is not a loop at all.  It is "capacitive top-loading"
> for an electrically-short vertical element.  This is a field I know
> a good deal about.  It will surprise some
> just how well one can communicate with even this tiny bit
> of radiation resistance, especially over ground-wave distances.
> I wonder how many tank drivers got RF burns on the tops
> of their heads, LOL.
> 73 Dave AB5S
>
> On 9/20/2021 8:11 AM, CL in NC via Milsurplus wrote:
>> In reference to the post about military DX during WW II, the July 
>> 1968 QST has  an article about a mobile horizontal loop made out of 
>> gutter down  spot called the 'MABAL'.  Just several years ago the 
>> same author wrote another article called the 'MABAV'.  They were both 
>> broad band tuneable horizontal loops mounted above the roof of his 
>> car.  Perhaps an offshoot of what the Germans had.
>>
>> Charlie, W4MEC in NC
>> ______________________________________________________________
>> Milsurplus mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Milsurplus at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>