[time-nuts] Difference in GPS antennas

Reeves Paul Paul.Reeves at uk.thalesgroup.com
Mon Aug 17 07:38:09 UTC 2009


VHF weather imaging using Automatic Picture Transmission (APT) is still very
much alive and operational both on NOAA and EUMETSAT birds despite the
desire of the weathermen for ever greater bandwidths on 1.6GHz and above. It
doesn't appear to improve their forecasting however.......

Paul Reeves,    G8GJA

-----Original Message-----
From: Lux, Jim (337C) [mailto:james.p.lux at jpl.nasa.gov]
Sent: 15 August 2009 23:34
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Difference in GPS antennas





On 8/15/09 3:25 PM, "Chuck Harris" <cfharris at erols.com> wrote:

> Lux, Jim (337C) wrote:
>> 
>> 
>> On 8/15/09 8:27 AM, "Magnus Danielson" <magnus at rubidium.dyndns.org>
wrote:
>> 
>> 
>>>> If you're near a harbor with fishing boats, you'll see plenty of quad
>>>> helices about a half a meter in overall height, used for VHF Weather
>>>> satellite reception.  They're also used on spacecraft (Mars Science
Lander,
>>>> Mars Reconnaissance Orbiter, and Phoenix all have UHF quad helix
antennas,
>>>> I
>>>> think, for about 400 MHz)
>>> Not used by the fishing vesels near me...
>> 
>> Really?  Practically all the fishing boats (mostly squid) boats going out
>> from Ventura Harbor (in Southern California) have big ol' quad helix
>> antennas up on the cross bar (as well as the usual HF SSB and VHF whips
and
>> the radar).  Maybe it's a regional preference thing (or folks are going
to
>> the 1.6 GHz band or something).
> 
> Haven't all of the VHF weather satellites been decommissioned?

Could be. I suspect that those antennas have been up on those boats for
decades.


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