Re: [Repeater-Builder] 220 link equipment

[Mike Morris WA6ILQ]

At 08:16 AM 04/12/10, you wrote:
I'm making plans to link my 2-meter repeater to a 220 mhz hub 
repeater. What type of transceiver, radios, etc is best for a 220 
link ? Thanks !

One big question is what's your duty cycle going to be?

Another is what is your potential desense going to be?
Back before we lost 220-222 one system in an area that
used in-high and out-low on UHF was going to use a couple
of low end channels as inbound link frequencies until he did
the math...  There was no way he could make a 250w
system near 441.750 live with a receiver near 220.800. He
ended up using 900 Mhz for the links.  After we lost 220-221
he was happy he had gone that route.

It would be interesting to do a survey of 220-222 and see
just how used it is.  It might be worth filing the FCC paperwork
to get it back.

Mike

Re: [Repeater-Builder] 220 link equipment

[no6b]

At 4/12/2010 08:34 AM, you wrote:
At 08:16 AM 04/12/10, you wrote:
 I'm making plans to link my 2-meter repeater to a 220 mhz hub
 repeater. What type of transceiver, radios, etc is best for a 220
 link ? Thanks !

One big question is what's your duty cycle going to be?

Another is what is your potential desense going to be?
Back before we lost 220-222 one system in an area that
used in-high and out-low on UHF was going to use a couple
of low end channels as inbound link frequencies until he did
the math...  There was no way he could make a 250w
system near 441.750 live with a receiver near 220.800.

Why not?  If the TX were 220.80 I could possibly see an unresolvable 2nd 
harmonic issue, but subharmonics from the 441.750 TX can always be 
suppressed.  A long time ago we had such a problem with 1/2 the TX freq. of 
a UHF MVP equal to the input freq. of a 220 repeater at the same site.  Had 
to pull the exciter out of the MVP  put it in an RF-tight box, but there 
were no problems after that.

Bob NO6B