How high off the ground are the radials.
Do you tie radials together at their ends inside the square where they
cross each other?
Thanks
Gary K4FMX
Paul Playford wrote:
> per W1XT:
>
> Use 8 elevated radials for each vertical element, and the whole system has
> got to be isolated from ground.
>
> The drive points of the vertical elements are 1/4 wavelength apart, on a
> square.
>
> Install the element support structures.
>
> Install two radials in the form of a dipole and trim to length at desired
> operating frequency. Resonance is 0 ohms reactance on the MFJ.
>
> Cut the rest of the radials to this length and install.
>
> Install the identical vertical elements (slightly long to allow trimming to
> length)
>
> Install feed lines to each element, consisting of 3/8 wavelength
> (electrical) of RG-213 (or equal) - measure this with your MFJ 259B as the
> real velocity factor is not always as published. Once you determine the VF
> of a roll of coax it will be the same for the whole roll.
>
> Fabricate a relay box: one DPST relay for each element. Wire the relays
> such that when one relay is operated it will connect the center conductor
> and the shield of the transmission line (from the transmitter) to the center
> conductor and shield of the feed line to one element - the center conductors
> and shields of the other 3 feed lines will remain open from each other and
> the transmission line. The fed element is the driven element and the other
> 3 will be reflectors.
>
> Observe the resonant frequency of each driven element by switching the
> direction relays.
>
> Allow a little 'Kentucky windage' (the resonant frequencies will probably
> not be the same) and trim each vertical element the same amount to your
> desired operating frequency.
>
> When completed all radials will be of equal length and all vertical elements
> will be identical. The vertical elements will be a little bit longer than
> the radials.
>
> Have fun!
>
> FWIW, the handbook parasitic sloping dipole array was installed on W1XT's
> tower - his old call, can't remember what it was.
>
> Bob had an array installed about 1 mile from my QTH. We are both weak
> signal Dxers and if I could hear/work a station with my 4 square phased
> array he could also, and vice versa. So we rated the arrays as equal.
>
> I modeled both arrays with EZNEC 3.0, which really cannot handle that many
> segments, but my conclusion is that the parasitic array is narrower in
> bandwidth than the phased array. EZNEC 3.0 shows 40m as not a problem but
> 75m and 80m cannot be done parasitically.
>
> de Paul, W8AEF
>
>
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Ron Feutz
> Sent: Monday, February 21, 2005 4:29 AM
> To: towertalk@contesting.com
> Subject: [TowerTalk] parasitic 4-square for 40 meters
>
>
>
>>TT'ers
>>
>>I have everything I need for a parasitic 40 meter 4-square but can't
>>find design info.
>>
>>I want to try this antenna as my marginal cost will be zero. I have 4 33'
>>verticals, an Ameritron RSC 8-V switch and plenty of radial wire and
>>coax on hand.
>>
>>Any info on design and tuning will be appreciated. I believe the
>>design has 3 "reflectors" that use the inductive reactance of the open
>>feedline to make them "reflectors," right. How long should the
>>feedlines be? I can tune with the MFJ 259B.
>>
>>Any models out there to tell me what to expect?
>>
>>Archive and google search turned up nothing.
>>
>>73,
>>
>>Ron KK9K
>
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
> questions and ask for Sherman, W2FLA.
>
> _______________________________________________
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_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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