[Milsurplus] Strange Sound On Air- Data Burst?

[J. Forster]

Related, yes, but not the same.

Ionosondes look directly at the zenith.

The link sounders I described test the propagation between two,
non-colocated, points.... like Washington to/from London.

-John

==============


> Sounds like a chirpsounder:
>
> http://en.wikipedia.org/wiki/Ionosonde
>
>
> ---- "J. Forster" <jfor at quikus.com> wrote:
>
> =============
> There are sounders used to check propagation between sites. They send a
> bit, measure S/N, skip to a new frequency, and repeat. Most often used for
> things like embassy HF links, I think.
>
> Maybe one of those?
>
> -John
>
> =============
>
>
>
>> For years I've occasionally heard this sound on the bands:
>>
>> http://home.netcom.com/~arc5/pulses.wav
>>
>> It is not swept; it's specific to a frequency.
>> Often, there is only one set of two pulses.
>> Sometimes there are three sets, other times several more.
>>
>> I've been told these are data bursts sent from one RDF site
>> to another, which replies.  These bursts are used to adjust
>> the site calibration vs. real-time propagation, giving a more
>> accurate RDF "fix."   I think this was the person's theory,
>> rather than any certain knowledge.
>>
>> Does anyone have an idea?
>>
>> 73 DE Dave AB5S
>>
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> Jon Oldenburg AB9AH
> "A bicycle can't stand on it's own because it is two tired..."
>
>