Re: G5RV dipole

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From: Rogerio Gonzaga (gonzaga@med.up.pt)
Date: Fri Jul 05 1996 - 03:54:23 EDT


                Hi, Grover & Doris,

                Thanks for your message. About your request,

>X-POP3-Rcpt: gonzaga@hipocrates
>Date: Wed, 3 Jul 1996 14:43:19 GMT
>X-Sender: SIXPENCE@postoffice.worldnet.att.net
>To: gonzaga@med.up.pt
>From: Grover <SIXPENCE@worldnet.att.net>
>Subject: Re: G5RV dipole
>
>Roger: Would you kindly give me the specifications for your 1/2 size portable
>G5RV?
>
>
> 72 y Paz ..Grover KQ4AL & Doris KE4CYE
>QRP/QSLs WAS = 34 DX= XE VE
>QRO/QSLs WAS = 49(-Hawaii) DXCC = 62 IOTA = 27
><SIXPENCE@worldnet.att.net>
>
>
>

                I am sorry for the delay in answering, but I had to check
locally - it has been done more than a couple of years ago. Indeed, all the
dimensions are half of the full size G5RV, with some corrections according
to the VF (velocity factor).

                My portable G5RV has been done with heavy gauge insulated
multistranded wire, each half had originally 25.5 feet (7.65 meters). I did
not make any VF correction and, when last year the connection to the
matching section has broken, I had to cut some 3 cm in each size to fix it,
without any alteration in performance (it does need an ATU in any situation,
after all).
                My matching section was made with 450 ohm ladder line
canibalized from an old Drake dipole. Initial dimensions should be 17 feet
(of open line), correcting according to VF should gives 14.75 feet for 300
ohm TV line or 15.3 feet for 400 ohm ladder line (which I have done, that
is, 4.59 meters).
                The matching section is conected to the coax (any lenght) by
a female PL socket. I did not use any balun, neither the recomended choke of
a dozen of turns of the coaxial cable in a 5 to 6 inch form, after the
matching section. I know there is some RF back to the shak, but I use low
power and this is a precarious aerial for portable use.
                I have always used it flat-top, and I have never tried to
bend the dipole or to make an inverted V. As I have hanged it from 3 to 8
meters AGL, sometimes I had to bend the matching ladder and put the last 1
to 2 meters horizontally, about 1 meter over the ground, with (obviouslly)
some loss of performance.
                Last winter, during a brief stay on the Northest Portuguese
Mountains, while staying as a guest in a Monastery run by Polish Monks, I
have hanged it between the roof of the main building and the stryke
protector located on a water deposit (as I have mentioned by that time, the
weather was superb, sometimes I like to take some risks, and I am a fan of
Ben Franklin): the results were most rewarding (no strykes, many QSOs).

                I hope the info is usefull, just build one and have fun.

                Best 72/73 de Roger, CT1ETT


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