[ARDF] Question about 2m frequencies for ARDF

[Dale Hunt WB6BYU]

The official range used by Region 1 (Europe and Africa) is 144.5 to  
144.9 MHz,
which is not particularly convenient to our repeater band plan.  (I  
have, however,
used a 2m repeater pair for a competition before, with permission of  
the owner
and/or after ensuring that it would not cause interference.)

While there may be some homemade receivers that only tune a restricted  
range
of frequencies for various reasons, you can generally expect receivers  
to cover
144 - 146 MHz.  The 145.8 - 146 range is discouraged because it is  
used for
satellite operation.  As long as you publish the frequency in advance,  
those
with narrow-tuning receivers can adjust them accordingly.

The biggest issue is strong signals near the frequencies - the older  
European
Sets have a pretty wide IF bandwidth and will respond to signals several
hundred kHz off frequency if they are strong.  Here in Oregon we have a
number of packet radio links operating in the 145.5 - 145.8 MHz band  
that
sometimes cause problems.


	- Dale  	WB6BYU




On 16 Nov 2009, at 14:51, Matthew Robbins wrote:

> I know there are some 2m receivers that don't receive in the upper  
> part of
> the 2m band.  What is a safe range for a transmitter frequency that  
> would
> include as many of these receivers as possible?  Is there any  
> problem with
> 145.565?
>
> Matthew
> AA9YH
> Cincinnati
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