[Elecraft] Power Supply?

[Dave Ingram]

I use the Powerwerx 30A switching power supply. It is switchable voltage and
takes an IEC lead, so there is no problem using it here in Australia. The 25A
continuous rating is well suited to the K3 with the PA. It takes up almost no
bench space and is only 3lbs. The dimensions are 6.1 x 5 x 2.5 in (154mm long,
127mm wide, 63mm tall).

The powerpole connections on the front really make it easy to use with the K3.

The cooling fans are off by default and it takes a lot of transmitting before
they spin up. Using a UHF/VHF mobile at 10W doesn't get the fans going, but my
old GME (Australian brand) switching radio PSU would fire up the fans with 5W
transmit and was noisy. This PSU is pretty quiet, and will make field
transport a breeze. I haven't found any extra RF interference from it (over
and above a gel cell), but I live in an urban area and so the background noise
is pretty bad.

I don't have any relationship with the supplier, other than being a happy
customer.


Dave.

-- 
David Ingram (VK4TDI)
Brisbane, Queensland, Australia
To avoid spam trap, send email to dave at ingramtech dot com

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On 4/07/2011 9:15, Ron D'Eau Claire wrote:
> Also note that the Astron 20A rating is actually the ICS or "Intermittent
> Commercial Service" rating. OTs recognize this as the former ICAS rating
> when "Amateur" was included in the designation. 
>
> IIRC, ICS is based on five minutes at full current and five minutes on
> standby. 
>
> Running SSB, CW and *some* digital modes, the actual load is much, much
> less. SSB, for example, draws peak current only on voice peaks and, of
> course, CW draws peak current only so long as the key is closed. 
>
> Now, hammering out a digital mode such as RTTY at 100% power for long
> transmission is a different story - and often well beyond the capabilities
> of the transmitter anyway. 
>
> Airflow and environment are important too. In commercial repeater service we
> seldom crowded the specs, especially when the system was in a building full
> of repeater gear where the temps around the power supply might exceed 100F
> in spite of air conditioning. Even so, dozens of Astrons ran year after year
> without a hitch. I cannot recall finding one dead. 
>
> And then there's the Ham station I saw one time where the power supply was
> sitting on the floor - directly on top of a heating vent! 
>
> I've been running the home station from an Astron 20 for about 10 years now
> - a K2/100 and then the K3/100. It handles either rig to full output with
> current to spare. I am a 99.9% brass pounder.  
>
> Ron AC7AC
>
> -----Original Message-----
>
> Another example of "reading the manual" or in this case the "info sheet".
>
> I have run Basecom20 for a 50w VHF-FM radio for up to ten years 
> onboard 200-foot oil field work boats.  I did have one "croak" but 
> that might have been due to the highly regulated (joke) ships 
> generator: 115vac +/- 50vac!  Ten years in continuous duty is not 
> bad.  These look to be re-labeled Astron RS-20 PS and have been 
> supplying multiple radios on a boats.  250w => 18 amps.  A 150w 
> marine SSB will have a dc load of about 250w.
>
> I use a 50A Tait PS (14.1 vdc) to power my home station 12volt 
> needs.  The No. 6 welding wire supply line is fused at 30A at the 
> radio table distribution point.  Been in service for about 9 
> years.  This is a re-labeled Astron VM-50.
>
> So, yes, I derate them about 60% for long-term service.
>
> Ed - KL7UW
>
> At 06:16 AM 7/3/2011, Eugene Balinski wrote:
>> All,
>>
>>    Please be advised that Astron supplies are generally
>> over rated.  The RS-20 is rated at 20A peak and 16A
>> continuous.  It is more like 12 -14 continuous.  I have
>> seen people try to use them at their "continuous" ratings,
>> only to have them fail.  The heat sinking is just not
>> there.  Be careful when using any of the supplies at their
>> top ratings.  If you need to use one at rated, then put a
>> good fan on the heat sink.
>>
>>
>> 73
>> K1NR
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