----- Original Message ----
From: Dan Evans <dan.evans@insightbb.com>
So how bad do you think the APRS signal is going to be for the 2m SSB
station?
---------------------------
The frequency difference between 144.39 and 144.2 is only 190-kHz. This is
much too narrow for a filter of any sort. There are two general strategies to
employ for APRS use in a rover:
On the SSB side, use a transverter for SSB operation -- one with a high dynamic
range front. I use the SSB Electronics transverter on 2-meters, and the band
is quiet within 5-kHz of a KW station only 8km from my home (when they are
active).
On the APRS side, use low power (really! 300mW may be ok), poor antenna
(really!) and separate the antenna from the SSB antenna by as great of a
distance as possible. Remember, all you need to do is be heard by a digipeater
and you'll be repeated for others to hear. You'll already be on a hilltop or
knoll, so probably LOS to a digipeater. Alternately, consider powering-on the
APRS system only when the QSO rate is low, or while in-transit and not on SSB,
etc.
As with so many other things, there are many variations of these strategies
that can be made to work, but this can give folks a few ideas to digest.
Regards,
Ev, W2EV
PS: The advice for APRS is *opposite* that of HamIM, where high power and good
antennas are the norm. Why the difference? HamIM takes place on 147.585 (over
3-MHz away!), and is simplex in nature. A 70-watt 1/2 second TX is barely
noticed on the 2m SSB transceiver.
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