If you are looking to improve your receive performance look at the K9AY
loops, flags etc especially on 80m.
What band or bands are you trying to improve?
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of K4SAV
Sent: Saturday, November 11, 2006 9:49 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Shunt fed tower 2
One other item regarding phasing two different type verticals. The phase of
the current in the shunt fed tower will not be what you expect due the
matching network. You have to know the phase of this current to get the two
verticals working properly.
I guess there are a few choices:
1. Analysis the heck out of the tower with NEC (this will be complicated and
not likely to produce an accurate answer unless you include every associated
wire and antenna).
2. Set up the gain and front to back experimentally using field strength
measurements.
3. Build it, then play around with phasing and see if you can get any front
to back, or see what seems to work best. This may take a while, and is
unlikely to produce good results.
It can be done, but it's not going to be easy.
Jerry, K4SAV
K4SAV wrote:
>..."Above the top at 35 feet is a triband. I have a wire spaced 1 foot
>from the tower and attached at the 30 foot point.
>I feed it at the bottom with coax and many radials. On 80 cw with 50
>watts I work into europe. On 40 cw with 50 watts I have worked into
>the Indian Ocean. I am assuming it works on transmit or propagation
>was good. But on receive it is a dog. A real failure.
>
>Compared to an off center fed 33 foot vertical (WD9AHH 73 magazine aug
>1981) the vertical is supperior in signal strength received."....
>--------
>
>I assume you are talking DX here and not local stations. If that
>vertical receives more signal strength that your shunt fed tower, you
>have something wrong with your tower. Then the vertical should also be
>better on transmit. Is it?
>
>For receiving purposes signal to noise ratio is the parameter of
>interest (not signal strength). For transmit purposes the received
>signal strength is the parameter of interest (not the S meter level of
>the noise).
>
>If you have a wide disparity between these two antennas for
>transmitting, I would fix that before trying to phase them.
>
>Jerry, K4SAV
>
>
>p.haire wrote:
>
>
>
>>Thanks for the info on shunt tower.
>>
>>I am 70 and retired.
>>
>>A few years ago I cut my vintage Rohn fold over tower from 50 feet to 30
feet so I could manage it better.
>>
>>Above the top at 35 feet is a triband. I have a wire spaced 1 foot from
the tower and attached at the 30 foot point.
>>I feed it at the bottom with coax and many radials. On 80 cw with 50
watts I work into europe. On 40 cw with 50 watts I have worked into the
Indian Ocean. I am assuming it works on transmit or propagation was good.
But on receive it is a dog. A real failure.
>>
>>Compared to an off center fed 33 foot vertical (WD9AHH 73 magazine aug
1981) the vertical is supperior in signal strength received.
>>
>>I want to use the tower and vertical in a phased array using discimilar
verticals (Yardley Beers W0JF QST oct 1977).
>>
>>Before I go on I want to make sure the tower will not weaken the
performane over the complete array.
>>
>>I am beginning to think it is best to go with some of the suggestions or a
helical end loaded horizontal.
>>
>>Any suggestions or thoughts about the tower?
>>
>>Paul WA5MUE
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>>
>>
>>
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>>
>>
>>
>>
>>
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