--- courir26 <[EMAIL PROTECTED]> wrote:
> I have an academic question for the group (point me
> to a manual or
> online reference if needed).
>
> If one was to build a VHF repeater, say 10W
> transmit, two antennas
> and no duplexer, what is the minimum frequency
> separation needed?
>
> I know it depends on a lot of things, such as power,
> receiver front
> end, vertical and horizontal ant sep, etc.
>
> Any rule of thumb?
>
> 73 tom
>
>
The minimum freq separation would be one channel, but
you'd have to have lots of antenna separation to make
that work effectively (like a mile horizontal). Are
you not wanting to use a 600 KHz split?
We had a commercial repeater operating on a 150 KHz
split in the 160MHz band, with about 60 ft of vertical
separation, it worked OK.
If you're talking about antenna separation, at 600 KHz
of freq separation, 50 ft vertical will give you about
65 dB of isolation. This would probably be a minimum
figure, with a good clean TX and a good tight RX
without a pre-amp. Adding a notch or BP/BR cavity to
the TX and RX line would improve things also, if it
doesn't perform well without them.
Joe
__________________________________
Do you Yahoo!?
Yahoo! Photos: High-quality 4x6 digital prints for 25¢
http://photos.yahoo.com/ph/print_splash
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/Repeater-Builder/
<*> To unsubscribe from this group, send an email to:
[EMAIL PROTECTED]
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
