[TowerTalk] Tower and antenna decisions

[Richard Solomon]

Jerry Letvin would agree with you, he used the same term in a
televised broadcast in the early 60's. The FCC did not react.

73, Dick, W1KSZ


On Mon, Oct 28, 2013 at 11:39 AM, Jim Brown <jim at audiosystemsgroup.com>wrote:

> On 10/27/2013 2:26 AM, Jim Thomson wrote:
>
>> #  Lemme rephrase that slightly.  IF the ground is relatively
>> flat....higher
>> is STILL better.   The 1st 45 feet doesn’t count.  You need that just to
>> clear junk +
>> clutter in the surrounding neighbourhood.
>>
>
> I won't dispute that.
>
>  ## While 70 ft may seem high....on 40m + 80m, its not.   70 ft on 40m is
>> like 35 ft up
>> on 20m.
>>
>
> Gee -- from your earlier post, to which I strongly objected, I got the
> distinct impression you were talking about tribanders. But that is is
> exactly my point -- in addition to clearing the clutter, the most important
> contribution of height is forming the vertical radiation pattern of the
> antenna, and for that, height must be thought  on in ELECTRICAL DEGREES,
> not feet or meters. Up to a point, additional height boosts low angle
> radiation, but eventually a height will be reached where it produces nulls
> in the vertical pattern. At lower heights these nulls are at higher angles,
> but when you go higher, they are at lower angles.
>
> I'm currently in the midst of a project to raise my 80/40 fan dipole from
> around 120 ft (155 degrees on 80M) to around 140 ft (182 degrees) to
> improve its low angle radiation on 80M, and to add a reflector to increase
> the gain to the east coast and EU. If it were flat land, NEC predicts 2 dB
> for the increased height and 3.5 - 4.5 dB for the reflector (the lower gain
> number is because the available trees don't allow the reflector to be
> parallel to the driven.  We'll see.
>
>  Take one of these 89 ft crank ups....and run it from 26 ft nested..up to
>> 89 ft extended..and it’s a real eye opener.  I have a  slight uphill rise
>> from N-S...all facing east.   And slightly downhill.... from N-S..all
>> facing west.   I need all the height I can get when pointed at EU, AF, SA,
>> etc.
>>
>
> Right, but you said flat land. I have similar topography here to the north
> and east, and on all bands, higher IS better in those directions, even on
> the higher HF bands.  But it is NOT better to anywhere in the Pacific,
> because I have five miles of down-slope in that direction.
>
> The beauty of N6BV's HFTA software is that it first models the
> contribution of terrain to the vertical pattern along any azimuth that you
> choose, then allows you to superimpose statistical modeled data for the
> vertical propagation to a range of destinations for the non-WARC bands.
> This allows the user to see when those vertical nulls are likely to get us
> in trouble, and when they don't matter. I have two towers, one holding a
> 3-el SteppIR (no trombones) at 120 ft,  another placing monobanders for 20
> and15  at about 45 and 35 ft respectively, and a third push-up holding a
> 10M Yagi at 20 ft. In all cases, HFTA accurately predicts the actual on-air
> performance of these antennas.
>
> As to stacking Yagis -- I've heard W3LPL do an excellent presentation on
> this topic at part of K3LR's Contest University.  I don't know whether this
> material is available on line, but it's well worth seeking out.
>
> Someone objected to my use of  "profanity" to make a point. The late Paul
> Klipsch, was one of the most highly respected of engineers working in pro
> audio as well as some other disciplines (explosives and firearms, as I
> recall), and founder of the loudspeaker company bearing his name. At annual
> meetings of the Audio Engineering Society, Paul made a practice of sitting
> at the back of technical papers sessions wearing a plaid sport shirt (and a
> bola tie, as I recall). When the technical content of a given paper strayed
> from the laws of physics, Paul would stand in the aisle at the back of the
> room and open his shirt to reveal a tee-shirt containing the single epithet
> "BULLSHIT" in large letters.
>
> 73, Jim K9YC
>
>
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