Re: Numbers station 8992KHz USB, 10/14/2013, 06:33UTC.

BramStoker Wrote:
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> I've logged AFA Andrews AFB on 8992, and heard
> that weird reverb a few times too on other USAF
> xmsns.

That "weird reverb" comes from additional receivers being on (same frequency) in adjacent radio-watch vans. They do their communications from a Comm Watch Van. 1/4 the size of a mobile home but jam packed with radio gear, tuners, amps and speakers etc. They're a lot like the old TRC-75 Vans of the 60's only with modern equipment. They usually put 3 vans packed together right next to an active runway. So the audio from the receivers from the other vans feedback into the one transmitting. They seldom operate with the doors closed because they give you claustrophobia and you can't talk to the people in the other vans with the doors closed. The "vacuum" sound may be the back blast of jets taking off or landing or it may in fact be someone cleaning the van.