Re: [Elecraft] Low antennas in high places

2005-08-11 Thread Stuart Rohre
Mike, consider that the soil on some cliff tops is the same as that at the base, if the cliff is formed as a geologic fault. Then, it would be no better nor worse than the soil down on level ground. That is not the main reflection gain mechanism from the elevated cliff side dipole, as my other

Re: [Elecraft] Low antennas in high places

2005-08-11 Thread Stuart Rohre
No matter what the ground conductivity is at a given hill top located antenna, what is shown in one ARRL Antenna Compendium piece on gains from an antenna near the edge of, and atop a hill, is that you are no longer shadowing say, a dipole parallel to the cliff face from radiating at angles bel

Re: [Elecraft] Low antennas in high places

2005-08-11 Thread Paul Gates
s the program on NVIS antennas and he is writing an article for QST. Paul Gates K1 #0231 KX1 #1186 XG1 [EMAIL PROTECTED] - Original Message - From: "Mike Morrow" <[EMAIL PROTECTED]> To: "'elecraft'" Sent: Thursday, August 11, 2005 1:19 PM Subject: RE: [Elec

RE: [Elecraft] Low antennas in high places

2005-08-11 Thread Ron D'Eau Claire
Mike KK5F wrote: For an HF dipole installed along a stony cliff or bluff, I've always had my doubts that the earth and stone behind the dipole act much like an effective ground reflector. If the height above average terrain of this cliff dipole is, say, 1000 feet, I suspect that the antenna actua

RE: [Elecraft] Low antennas in high places

2005-08-11 Thread Mike Morrow
Ron wrote: >The advantage of low dipoles on slopes for DX noted by Moxon >is that the earth behind the radiator acts as a reflector. For an HF dipole installed along a stony cliff or bluff, I've always had my doubts that the earth and stone behind the dipole act much like an effective ground r

RE: [Elecraft] Low antennas in high places

2005-08-10 Thread Ron D'Eau Claire
Stuart wrote: NVIS (Near Vertical Incidence Skywave) dipoles or antennas are any antenna operated at low elevations above ground from lying on ground to being say 0.1 wave high, and certainly well below conventional heights for that antenna. --- The optimum height i

Re: [Elecraft] Low antennas in high places

2005-08-10 Thread Stuart Rohre
Paul, NVIS (Near Vertical Incidence Skywave) dipoles or antennas are any antenna operated at low elevations above ground from lying on ground to being say 0.1 wave high, and certainly well below conventional heights for that antenna. They are horizontal dipoles usually a half wave type, or tune

[Elecraft] Low antennas in high places

2005-08-10 Thread James R. Duffey
Vic - I often operate QRP field operations from such a location at Gallisteo Dam. It has a long steeply sloping ground to the East and Northeast. I use an inverted vee for 40 M and 20 M at 24 feet in a painters pole. Propagation is great and I do pretty well in the QRP field contests. It is worth l

Re: [Elecraft] Low antennas in high places

2005-08-10 Thread Stuart Rohre
This past Field Day, we used some NVIS dipoles atop a hill in Austin TX. There was a sharp drop to the east and to the West. We not only worked obvious NVIS range signals; but worked a number of skip signals from antennas no more than 7 feet high at the highest. The 40m antenna was only 3 1/2

[Elecraft] Low antennas in high places

2005-08-09 Thread Bill Tippett
K2VCO wrote: >such a location can show excellent gain at low angles. See the HFTA TOA analysis of such a location below: http://users.vnet.net/btippett/w3cra.htm W3CRA (pre-war W8CRA) had legendary propagation. The TOA analysis shows why. The blue line shows 12-15 dB at low angles ove

Re: [Elecraft] Low antennas in high places

2005-08-09 Thread Mike Morrow
Vic wrote: >I would like to correspond with anyone who has tried portable QRP >operation from a high location, using a low horizontal antenna at the >edge of a sharp dropoff. I always got great results operating from a bluff on Arkansas' Mount Magazine and similar locations, by running the end

RE: [Elecraft] Low antennas in high places

2005-08-09 Thread EricJ
If I run across it, I'll send you the URL. Eric KE6US www.ke6us.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Vic K2VCO Sent: Tuesday, August 09, 2005 11:14 AM To: Elecraft Reflector Subject: [Elecraft] Low antennas in high places I would lik

RE: [Elecraft] Low antennas in high places

2005-08-09 Thread James Kern
) 212-807-0575 (fax) 908-451-6801 (cell) 800-209-7438 (pager) [EMAIL PROTECTED] -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Vic K2VCO Sent: Tuesday, August 09, 2005 2:14 PM To: Elecraft Reflector Subject: [Elecraft] Low antennas in high places I would

[Elecraft] Low antennas in high places

2005-08-09 Thread Vic K2VCO
I would like to correspond with anyone who has tried portable QRP operation from a high location, using a low horizontal antenna at the edge of a sharp dropoff. In the Moxon antenna book (chapter 10), he says that a simple dipole or inverted vee at a low height in such a location can show exce