doc kd4e at VERIZON.NET
Sun May 28 19:04:28 EDT 2006

> Achieving the necessary couple-of-Hz accuracy needed by SSB at VHF/UHF 
> would be a real challenge (see below about 'installed base')

Those requirements are silly, likely invented by some
bureaucrat at the behest of manufacturers.

What is the possible need for couple-of-Hz accuracy?

There is a Federal standard for emergency communications
gear stability & accuracy that has not been a big deal
to implement.

> FM would work well, but it suffers from capture effect. If two stations 
> transmit simultaneoulsy, one could cover up the other and it might not 
> be realized. AM will give a heterodyne under many conditions where FM won't.
> Advantage: AM

If every airplane listened to every other one they'd
be terribly confused.

When I am in an airport monitoring traffic I observe
multiple frequencies with multiple conversations.

When I listen to emergency nets on 2M FM things are
quite orderly as are other services that use narrow
band FM.

I fail to see any requirement for AM for this app
at all.

As for the existing technology?  The FAA forced them
to dump a whole series of old gear that was used for
location a few years back with little regard for cost.
It was for every size of planes.

> At the same time, things should not be tossed out just because they're old.

That would explain the Variable Master Oscillators
sitting outside the shack, the United Electronics
10MHz scope on the shelf, and my wife continuing to
keep me around even after the half-century age mark!


Thanks! & 73, doc kd4e
Florida Home w/Rohn 45 in concrete base & 10 acres for sale:

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