Hi John,
If you are not using any radials (just the ground rods), then YES it is very
ground lossy!
As per the discussion, ground rods are for DC grounding ONLY! You need an RF
ground (counterpoise) for the vertical. Indeed a vertical antenna (the part
that sticks up vertically) is only HALF of the antenna, the other half is
the radials!
73, Dan Magro W7RF, (President WARC 1999, member SCDXC, SCCC)
Manufacturers Rep & Distributor for HENRY RF Power Amplifiers.
RF Applications Power Measuring equipment, See the VFD!
www.radiodan.com <http://www.radiodan.com> RFpower@radiodan.com
<mailto:RFpower@radiodan.com> A trip to our web site is worth the click!
> -----Original Message-----
> From: owner-amps@contesting.com [mailto:owner-amps@contesting.com]On
> Behalf Of John / NS1Z
> Sent: Thursday, October 07, 1999 10:20 PM
> To: Phil Clements; amps@contesting.com
> Subject: Re: [AMPS] Ground rods?
>
>
>
> Hmmmm???! I just planted a used HyGain HyTower in the backyard. Their
> instructions direct you to use 6 8' ground rods in a pattern at
> the base of
> the antenna, about 24" out, all tied together with #8 or so buss wire. It
> seems to work. Is that because the antenna is so lossy the VSWR only
> appears to be good but the radiation efficiency is really dirt (!) poor? I
> have worked JA's with 100 watts from the Wilds of Maine, which, I realize,
> may be as scientific as the antenna articles found in 73 magazine....
>
> At 10:17 PM 10/7/1999 -0500, you wrote:
> >Rods driven into the ground have absolutely nothing to do with making
> >an RF counterpoise or RF "drain." Ground rods serve only one purpose,
> >and that is to protect your equipment from lightning damage.
> >
> >Polyphaser produces a good book on the subject of grounding, and
> >shows how good engineering practice will pay off when the storms come
> >your way.
> >
> >Ground radials, or a ground screen under an antenna system handle the
> >RF end of things at a radio station. Rich is correct; they may lay on top
> >of the ground, or be buried a few inches, it makes no difference. The
> >reason radials are buried is to make the landscape look better at the
> >antenna farm. Relying on ground rods to serve in place of a proper
> >RF ground sends valuable RF into the lossy earth instead of its intended
> >destination.
> >
> >(((73)))
> >Phil, K5PC
> >
> >
> >
> >
> >--
> >FAQ on WWW: http://www.contesting.com/ampsfaq.html
> >Submissions: amps@contesting.com
> >Administrative requests: amps-REQUEST@contesting.com
> >Problems: owner-amps@contesting.com
> >Search: http://www.contesting.com/km9p/search.htm
> >
> >
>
> 73 from NS1Z, FN44rn
>
> John Wilcox
> 871 Route 120
> Rumford, ME 04276-3836
>
> fon: 207-364-2246
>
> --
> FAQ on WWW: http://www.contesting.com/ampsfaq.html
> Submissions: amps@contesting.com
> Administrative requests: amps-REQUEST@contesting.com
> Problems: owner-amps@contesting.com
> Search: http://www.contesting.com/km9p/search.htm
>
>
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|