[amsat-bb] Re: Terrestrial QRM to FM satellites

[Tony Langdon]

At 04:36 PM 9/21/2007, Nate Duehr wrote:

>I was on the "stop doing that kids, it's illegal" bandwagon up until
>the rule change, now I'm still on the "please, put your favorite toy
>on 222, UHF or higher, kids!  VHF is kinda "full" in most big cities,
>even if you stick to the bandplan" bandwagon.

That's the case here too now.  I'm glad I decided to do something 
different and make my 2m output SSB, as that and D-STAR are really 
the only options available here, without reading on someone's 
toes.  And as much as I'd like to run a D-STAR gateway, my budget 
will only cover one D-STAR capable radio, not two.

>The manufacturers really make this above-mentioned situation so much
>worse by selling VHF-only radios as "cost" or "loss leader" products
>to entice new hams into buying them.   They really need a better
>marketing plan that doesn't stuff VHF so full to the gills that
>interference can't be helped.  Please support and applaud any
>manufacturer who's UHF single band radios (if they even have any) are
>as inexpensive to purchase as their VHF's.   Right now, I don't think
>a single manufacturer of ham rigs meets that, or has even given a
>thought to what they're doing to VHF.

Dunno if it's the same in the States, but 2m has such a long history 
of club nets and other groups that users have spread right through 
the band.  It's literally very difficult to find a frequency that 
doesn't have some sort of use.  Fortunately, everyone steers clear of 
the satellite allocation.  The only free space now is in the SSB 
segment and now on D-STAR, which can fit in between our FM channels.

>As a major volunteer for IRLP, I would remind folks that if it turns
>out to be something like IRLP, EchoLink etc... please don't taint
>your viewpoint of these technologies, or get overly-emotional about
>the "source" being one of those networks... the networks are just
>linking technologies, but many hams really don't know when and where
>it's appropriate to link things into simplex FM -- especially on 2m
>FM simplex.

The best approach is to play Elmer, calmly explaining what's 
happening and offering advice, and perhaps inviting them to work 
satellites.  I once modified my IRLP node to act as a crossband 
repeater with an output in the satellite band, so I could have more 
power on the uplink of UO-14, to help overcome the severe Asian QRM 
on its input. I used another band besides 70cm, so I didn't desense 
my downlink. :-)

>Also keep in mind that if someone does copy something and reports it
>here to the list, the voices/callsigns they hear might not even be
>the callsigns of the operator of the "incorrectly placed" link/
>Auxiliary Station.

It's not a bad idea to make contact with those people though, they 
may know the node owner and may pass on your concerns.  Sometimes 
that can reap rewards.  In any case, they may know someone that uses 
the offending link, who can pass on the message.  Networking 
sometimes bears fruit.

>The only thing you might know for sure if you listen to 145.85
>locally and hear something that's not a satellite transmission, is
>that the transmitter actually causing the interference is in your
>area... from that point, some knowledgeable and experienced sleuths
>may be required to help figure out what exactly it is... and of
>course, a good DF'ing crew doesn't hurt either!

Dfing certainly helps, that usually yields a location that can be 
used for a callsign lookup and hopefully an email address to make 
contact, assuming the owner isn't able to come up on the air (do that 
between passes! :D ).

73 de VK3JED
http://vkradio.com