Great information Gene and Dan.
I will file this email for future reference.
I've read lots of good info from many sources including ON4UN books and these
reflectors are a wealth too.
Thanks for all the replies.
73-
W1JCW
John
From: Gene Fuller
Sent: Thursday, September 06, 2012 9:24 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Fw: 4 Sq array Dx or Hi Z
----- Original Message -----
From: "Gene Fuller" <w2lu@rochester.rr.com>
To: "Dan Schaaf" <dan-schaaf@att.net>
Sent: Thursday, September 06, 2012 10:23 PM
Subject: Re: [TowerTalk] 4 Sq array Dx or Hi Z
> Hi John -
>
> Whatever focuses the transmit signal also focuses the receive signal. .
>
> What we're looking for is an antenna with the most tightly focused
> aperture in the desired direction. This brings into play both horizontal
> beamwidth AND vertical beamwidth. An antenna might present a very high F/B
> for a given radiation angle and still have a very large forward vertical
> beamwidth in the desired direction and thus not present a good (S+N)/N.
> From the little computer analysis I have done on vertical arrays my
> impression has been that with short vertical elements and good phasing it
> is possible to get very high F/B but the forward lobe may still be very
> broad in the vertical plan. As the height of the verticals is increased
> thevertical aspect of the lobes shrink down, thus excluding noise that
> you don't want, until it gets down to the point that it also starts
> excluding signals that you do want. East coast guys working into Europe,
> with 80 meter 4 sqrs with 90 foot verticals, have found that they work
> like gangbusters for opening and closing the band when desired radiation
> angles are way low, but as the band becomes really "opened", and the
> desired radiation angle increases they loose out to the guys with arrays
> using 60 foot verticals and a little higher radiation angle. The extra db
> or so that the longer elements offer is soon lost by focusing the energy
> at too low an angle. Some of why beverages work so great is because their
> forward lobe is narrow in both the vertical and horizontal planes, but
> again there are optimum lengths. Because of space limitations, for
> receive, I use two phased four direction pennant systems. Very good F/B,
> but the forward lobe is perhaps 60-80 degrees wide in the vertical plane
> and lets too much high angle noise in. At least two guys I know of, within
> 100 miles of me, using ~ 600 foot beverages that run circles around me
> receiving. Both also have full sized 4 sqrs and I've heard them say that
> the full sized 4 sqr, properly tuned, is nearly as good as the beverage
> for receive.
>
> Bottom line, when someone offers a small receive antenna system, claiming
> great F/B, try to get them to specify the vertical beamwidth.
>
> There may be a silver bullet out there but if there is it's mighty
> illusive.
>
> Gerne / W2LU
>
>
> ----- Original Message -----
> From: "Dan Schaaf" <dan-schaaf@att.net>
> To: "W1JCW" <W1JCW@hotmail.com>; <john@kk9a.com>;
> <TowerTalk@contesting.com>
> Sent: Thursday, September 06, 2012 7:26 PM
> Subject: Re: [TowerTalk] 4 Sq array Dx or Hi Z
>
>
>>I have heard, and I have been in conversation with both suppliers on 4 SQ
>>and 8 circle receive arrays. And I have talked to guys who have owned both
>>receive arrays and beverages.
>> The overall conclusion is that the vertical receive arrays outperform
>> the 4 SQ TX array and are equal to 1,000 ft bevs.
>>
>> The reason that they outperform the 4SQ TX array is that there is no real
>> noise rejection on the 4 SQ TX array. They are just arrays that focus
>> transmit energy.
>>
>> Whereas, the receive arrays use fancy footwork in phasing that actually
>> reduces the noise. It reduces noise from all directions that are not in
>> the direction of reception.
>> So, for example, if you want to copy a weak signal to the northeast, then
>> noise from all other directions is cancelled.
>>
>> Normally, It is the sum of noise from all directions that smothers out
>> the signal of interest. Remove the noise from east , south, west, north
>> and all you have is noise from the northeast + signal.
>>
>> I am embarrassed when my ham friend 300 miles from me hears DX on 160 and
>> I hear nothing but noise on my vertical and on my K9AY Loop and my Mag
>> Loop.
>>
>> Which manufacturer to buy from, you do the research. I bought a 1/4 acre
>> next to my house for the sole purpose of installing a dual 4 SQ RX Array,
>> 45 degrees apart so that I have 8 cardinal points. 80 ft radius for this
>> system. When I have the available cash, I will install the system.
>> I know which one I most likely will buy.
>>
>> Get on the Low Band chat room and ask for opinions. Those guys are the
>> ones to talk to. They live for 160 meters.
>>
>>
>>
>> Best Regards
>> Dan Schaaf
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