View Single Post
  #17   Report Post  
Old August 30th 11, 08:13 PM posted to rec.radio.amateur.antenna
Jim Lux Jim Lux is offline
external usenet poster
 
First recorded activity by RadioBanter: Mar 2007
Posts: 801
Default Chinese duplexers

On 8/30/2011 11:14 AM, Rob wrote:
Jim wrote:
Any reason why you're using a split of 600kHz? Why not go to a
non-standard split to make life easier. Pick two frequencies 3 MHz apart
(assuming you can get them coordinated, which is more a political than a
technical issue)


Don't forget that in Region 1, the 2M band is only 2 MHz wide, the
bottom 500 kHz is dedicated to SSB and the top 200 kHz is for satellite.


Sure, that does make it harder. The OP is in region 2, though, where
there's 4 MHz theoretically available)

flame protective suit on And of course, a lot of the band plans are
basically gentlemen's agreements and have no force of law. As long as
you don't interfere with someone (challenging in some geographical
locations), you can pretty much do what you want.flame suit off

I wouldn't want to put input or output on 144.2, for instance.

But looking at the ARRL band plan, you could put your input up at
147.6-147.99 and put your output at 145.5-145.8 (Misc and experimental,
per ARRL).. not quite 3 MHz, but close, and a whole lot better than 600kHz.

Here in the Los Angeles area, either TASMA or the anti-TASMA folks would
probably round up people to have you tarred, feathered and run out of
town on a rail, no matter what you do. In any case, things move so
slowly that unless you were hideously inconsiderate and egregiously
interfering, you could probably run for a year or more before it would
get too nasty.

There is a 147.585/144.930 pair labeled for "portable repeater" in the
TASMA plan (max 72 hrs/month).. that's 2.5 MHz apart (to make filtering
easier). They also say 144.310-144.375 is for simplex unchannelized,
but I've not heard much on the air there..for an experiment, it would
probably work.