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Re: Prefered AO40 Transmit Antennas ?



The key is EIRP. 150-200w is usually plenty even for SSB.  I generally run
5w into a 14 turn helix which works out to about 125 w EIRP.  Even during
the US Field Day its been enough for solid CW contacts.

Lee-KU4OS

----- Original Message ----- 
From: "Michael Kjorling" <michael@kjorling.com>
To: "Peter Moscatt" <pgmoscatt@optushome.com.au>
Cc: "AMSAT-BB" <amsat-bb@AMSAT.Org>
Sent: Saturday, June 28, 2003 12:07 PM
Subject: Re: [amsat-bb] Prefered AO40 Transmit Antennas ?


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> On Jun 28 2003 10:40 +1000, Peter Moscatt wrote:
>
> > What is generally used for the 70cm uplink and what would the typical
> > gain need to be for a good link into AO40 ?
>
> I don't know if it is the "generally used" uplink antenna, but I am
seriously
> considering a simple 70 cm (RHCP) helical antenna for my station.
According
> to AMSAT-SM, 200 W EIRP "is enough", but they don't state if that is for
SSB
> or CW. That is 10W into a 13-element X-Yagi, or 50W into a 4-turn helical
> antenna, if their web page can be trusted (which I hope!). Of course, the
> exact gain you need will be a function of how much power you can feed to
the
> antenna at 70 cm! I, for one, only have 5 W at 70 cm, minus cable losses,
so
> the four-turn helical won't cut it at all unless I get a 13-17 dB PA
> (reasonable cable losses and some margin figured in).
>
>
> Michael Kjörling
>
> - -- 
> Michael Kjörling :: michael@kjorling.com :: SMØYBY JO89  ^..^
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> Also 95f1 074d 336d f8f0 f297  6a5b 2aa3 7bfd 8a70 e33e (old)
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> ----
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