[Milsurplus] Garage door openers

[Dick]

The military are the primary users of the 225-400 MHz spectrum.  They use
it for air/air and air/ground communications, along with some channels
dedicated to UHF SATCOM.  The UHF SATCOM XMTRs typically put 100 W on the
air and can be either continuous or burst, depending on the SATCOM mode in
use.  The aircraft UHF voice radios typically put 10-20 W on the air.  Glide
slope XMTRS used in airport instrument landing systems (ILS) also operate in
this band.

Out of curiosity, I fired up a spectrum analyzer and looked at the signal
from the key chain keyless entry XMTR for my Dodge pickup truck.  It was
close to 349 MHz.  Keyless entry and garage door gadgets must meet FCC Rules
Part 15, which says they cannot cause interference and  must accept any
interference they suffer.

So, try changing the codes on your garage door openers.

Dick W1NMZ

----- Original Message ----- 
From: Ralph Cameron
To: milsurplus at mailman.qth.net
Sent: 02 December, 2006 17:57
Subject: [Milsurplus] Garage door openers


This reminds me of the very strong garage door jammer that operated in 
downtown Ottawa last year. With all the government sophisticated DF 
equipment they couldn't locate the source but every garage door opener for 
20 miles radius was knocked out. Even the local embassies had trouble and 
there are quite a few here.

That frequency range has military as primary use in Canada but it is shared 
with other users.

After all the excitement died down it was attributed to a ,"...new U.S. 
military system" but failed to elaborate.

Didn't Pres. Nixon's Air Force One cause similar problems when he flew home 
to Calif.  All the neighbours knew he was coming because their garage doors 
operated. Sort of a distant early warning system.


73

Ralph Cameron
VE3BBM