[Amps] k9yc pdf

[Carl]

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From: "Jim Brown" <jim at audiosystemsgroup.com>
Sent: Tuesday, January 13, 2015 12:45 PM
To: <amps at contesting.com>
Subject: Re: [Amps] k9yc pdf

> On Tue,1/13/2015 4:03 AM, Jim Thomson wrote:
>> This pdf is very well done..and a real eye opener.   It also assumes you
>> are in the middle of a wheat field in Kansas.
>
> Not really -- what I've tried to do is show what matters, the effects of 
> height and ground on both horizontal and vertical antennas. Those graphs 
> showing the value, in dB, of antenna height, on 80, 40, and 20M. Yes, it 
> assumes "flatland", but not infinite real estate. If you have irregular 
> terrain (I do), you'll also need to use HFTA to get a handle on antenna 
> height. But it does answer the question, "If I could somehow rig a 40M 
> dipole between trees or a tree and a building at 60 ft, how much better is 
> that than at 30 ft?"


I thought those basics were well understood and published back in the 
1930's.
 Nothing since has disproved them. Fill ins for in between heights and 
different
grounds has been around since the 70's when commercial/military software was
 "leaked" in ham publications, the YCCC or other contest clubs.

90' has always, since I can remember going back to the mid 60's, been the 
all
around magic height for 20M DX with 80-100' being the general range used.
 Of course higher is often best for some long haul paths and so is lower at 
times.
 When I had HB 4 el monobanders with multiple switching options at 
40/80/120/160'
and all independently rotatable the differences  were very noticable and the 
lower
 pair was often used for Western Eu and the upper pair for the next hop east 
or
deeper into Russia or Asia. The hilltop modified the best heights quite a 
bit but TA
took care of that and about 10 years of ARRL/ CQ, DX and WPX wins were 
pretty
standard (-; Then it got boring and I concentrated on VHF to microwave.
On 10 and 15 similar stacks were used at lower heights and on 10 it was 
possible
 to null G's, F, EA and boost DL, SP, UA, etc just by switching pairs. Oft 
times all 4
are in use became a flamethrower to the target area. This is readily shown 
in Deans
 regular contest predictions and as the band opened or shifted running 2- 4 
different
 directions paid off well.

 HFTA has been a boon to show how real world enviroments affect the theory.

Ive known Dean, N6BV, since he was a fresh minted EE out of Yale and was 
hired
by National Radio back around 1967 or so; He then had XYL problems and moved 
to CA
and in the 80's he moved back East and became an almost neighbor on another 
hill
 in the next town. We were always running antenna tests and the fact I was 
continually
beating him on 10-20M (my 1200W LK500ZC to his 1500W AL-1200) led him to 
develop
 the original Terrain Analyzer which was included in later versions of Brian 
Beezley's, K6STI,
antenna modeling software using my hilltop as a model. My terrain rolloff 
was quite different
 than Deans and showed how well it boosted "gain" at elevation angles most 
important for
 chasing DX and winning contests.

Anybody want a 5A hilltop QTH in Southern NH (Im 2 miles from MA) in 3-6 
years or so let me know.

Carl
KM1H