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RE: Re: Re: QRM ON 2.4 GIG



>From: "Bruce Rahn" <brahn@voyager.net>
**snip**
>In the case of the Siemens, it looks as if both uniques periodically
>interrogate each other.  I had to unplug the base unit before the frequency
>hopping pulses went away.  I've got some more digging to do as I thought the
>Siemens employed both a 900 MHz as well as 2.4 GHz link.  But I saw 2.4 GHz
>activity from both the handset and the base unit.  I didn't take the time to
>look at the 900 MHz band.

My experience with my Panasonic, model KX-TG2570B, 2.4 GHz spread-spectrum
cordless phone is that I have heard no interference from it when it is
"on-hook".  It's been awhile since I tested but I think there was a slight
hash produced when it was ringing or off-hook, but no worse than my
microwave oven (when running).  I do not get the reported clicking.

My phone base and the oven are both in the kitchen about 25-feet from the
AO-40 antenna, which is a 33-inch offset feed dish, 5-turn helix feed,
db6nt preamp to a Drake down converter.  The dish does look away from the
phone unit which is 15 foot north of the antenna location (maybe that
helps).  Frankly, I can't understand why a phone would transmit when it is
on-hook.  The handset should be able to lock on to the base signal quickly
upon incoming ring (or outgoing dialing).  If some units beacon constantly
then obviously the manufacturers care little about compliance with part-15
(wow big surprise!).

The solution has been offered before.  Build a 2.4 GHz 10-20w propagation
beacon and run it continuously when AO-40 is below horizon.  That will
nicely knock out any nearby 2.4 GHz device from operating (can't you see
all the blue-tooth WAN folks returning there "defective" units to the
computer store LOL).  Yes you are legally licensed to beacon...they are not!

Just think the FCC will see all this great ham microwave activity thus
preserving the band for our use.  (OK this was offered somewhat in jest).

Ed
Amsat Coord in Alaska 
Amsat #3212 
50-24,192 MHz 
weak sig/sat/eme


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