[Milsurplus] ARC-1 to ARC-4 QSO

[D C *Mac* Macdonald]

NVIS (Near Vertical Incident Skywave) is basically high vertical 
angle radiation using frequencies 10 MHz and below.  Antennas 
are lower to the ground than "normal" ensuring the high angle 
radiation.  The lower frequencies will penetrate jungle and 
forest canopies whereas higher frequency energy will simply 
be absorbed by the foliage. 
 
The target of NVIS is close-in communication, day or night,
out to two or three hundred  miles.  As such, the desired 
coverage more closely resembles the "upper" half of a
tennis ball.
 
73 - Mac, K2GKK/5 
Oklahoma City, OK 
 



> Date: Wed, 24 Sep 2008 12:17:05 -0400 
> From: jfor at quik.com 
> To: jupete at bigpond.net.au 
> Subject: Re: [Milsurplus] ARC-1 to ARC-4 QSO 
> CC: curator at battleshipcove.com; mrca at mailman.qth.net; robandpj at earthlink.net; cosmoline at netboobie.org; milsurplus at mailman.qth.net 
> 
> It may well be a propagation issue, rather than an equipment issue. The 
> Armyradios Group on Yahoo is very interested in NVIS. As I understand it, at HF, 
> most of the transmitted power goes into space, not to the receiver. Sometimes it 
> bounces off the ionosphere and shows up many hundreds or thousands of miles 
> away, leaving a local "donut' of silence. 
> 
> Best, 
> -John 
> 
> ============== 
> 
> Pete Williams wrote: 
> 
>> G 'day list...I sometimes wonder how, with all current technical knowhow, 
>> it seems so difficult to make WW2 radios establish 2 way comms even over 
>> moderate distances 
>> A couple of struggling guys out our way had great trouble getting out on 80 
>> M over a few miles using ground support field radios and they were the full 
>> bottle on ability. 
>> If such reliability /performance existed in a real sit.one can only hope 
>> the carrier pigeons were well fed and on standby. 
>> 
>> Cheers 
>> Pete VK3IZ 
>