[HamWAN PSDR] HamWAN over tideflats

Mike Culver mculver at extencia.com
Tue May 6 11:08:10 PDT 2014


So signal strength is clearly correlated to the moon :)
________________________________________
From: PSDR <psdr-bounces at hamwan.org> on behalf of Tom Hayward <esarfl at gmail.com>
Sent: Tuesday, May 6, 2014 10:59 AM
To: Puget Sound Data Ring
Subject: Re: [HamWAN PSDR] HamWAN over tideflats

On Tue, May 6, 2014 at 10:53 AM, Bart Kus <me at bartk.us> wrote:
>
> That's a cool observation.  I would caution against equating correlation with causation though.

Agreed.

> "The effect of tides on signal level" may indeed be an effect of temperature changes (ducting?) or something else.

Temperature didn't change much all day.

> If I recall correctly, you were seeing very large (10dB?) high frequency (1s period?) signal swings.

Nope. I never saw more than 1 dB change during a 10 second period
(never really watched it for longer periods than that). The signal
very smoothly increased as the tide came in from the minimum to the
maximum I shared earlier. As it rose, I never saw it dip again by more
than 1 dB.

> It'd be fun to understand that phenomenon as well as the slower one you're reporting here.  Perhaps you were just being slowly moved through an interference node with the water level, and an antenna mounted +/- 2ft from your antenna's elevation might have reported the opposite power behavior?  I also wonder if there is any polarization rotation happening here.

Maybe I should try the same location with a MIMO modem.

Tom KD7LXL

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