----- Original Message -----
From: "W7RY" <w7ry@centurytel.net>
To: "'Steve Thompson'" <g8gsq@eltac.co.uk>; <amps@contesting.com>
Sent: Friday, July 14, 2006 11:29 AM
Subject: Re: [Amps] High frequency heater supplies
> We have been finding issues using switching power supplies on commercial
> 2-way radio base stations and repeaters.
> The spurs are spread up and down the band at the intervals of the
> switching frequency. This causes lots of interference. Although the
> spurs are low, (40-50dB down), they are still a problem when you are
> trying to receive close to an affected transmitter.
>
> After replacing the switching supply with a linear regulation supply
> (Astron) the problems go away.
>
> I wonder how many problems that switching power supplies are causing on
> the HF bands?
>
> 73
> Jim W7RY
>
>
Hi Jim,
I just tossed the one that came with my Alvarion Breeze ACCESS 900 mhz
wireless internet transciever. A 5 volt dc , 2 amp wall wart with a 3 prong
plug.
It was S9 50 feet away from the shack all the way up to 8 mhz.
I autopsied the thing. It was so full of components I decided to not waste
my
time drawing it out. There was a pretty good investment in parts there. I don't
see the savings other than weight.
The transciever now runs on a dedicated HP 6433B.
Mike k1ern
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
> On Behalf Of Steve Thompson
> Sent: Thursday, July 13, 2006 7:38 AM
> To: amps@contesting.com
> Subject: [Amps] High frequency heater supplies
>
> Does anyone know if there are problems using high frequency (say 30kHz)
> ac to run the heater in a valve with a cathode? For that matter, the
> filament in a valve without a cathode?
>
> Thanks,
>
> Steve
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