[RFI] New Astron Switching PS RFI?

[K9MA]

I've been using a Samlex SEC-1235M for years. I've never detected any 
RFI from it.

Linear supplies, while they generate no RFI, have a particularly nasty, 
and common, failure mode. When the series pass transistor shorts, you 
get 35 V or so coming into your radio. Unless you have a crowbar. And 
that transistor is under a lot of stress. While it's possible for a 
switching supply to fail in overvoltage mode, it's not as likely, as the 
components which could cause that to happen are not under stress. If the 
switching device shorts, the output goes to zero. A fuse may blow, but 
it won't fry your radio.

73,
Scott K9MA

On 5/18/2020 13:45, Kim Elmore wrote:
> I have an Astron SS-30 (no meters) switching supply. It’s RF silent; the fan makes some noise but it’s quite tolerable.
>
> I also have an old Astron RS-35 (no meters) linear supply. I tossed the Astron regulator board that came with it (very prone to RF) and put in an “RF Proof” regulator board from the 1988 ARRL Handbook. It’s built like a tank and is still doing fine.
>
> Kim N5OP
>
> "People that make music together cannot be enemies, at least as long as the music lasts." -- Paul Hindemith
>
>> On May 18, 2020, at 12:37 PM, Gary Smith <wa6fgi at steeltrails.net> wrote:
>>
>> Imo, linear power supplies are still the best. Case in point, my Astron RS-35m has not missed a beat, it was the first purchase I made when I passed the technician(c) exam in 1968.
>>
>> To this day, it continues to power all of my 12 to 13.8v needs.
>>
>> Nuff said here about that.
>>
>> Gary...wa6fgi
>>
>>> On 5/17/2020 2:33 PM, Bob Turner wrote:
>>> I had the SS-30 (no meters) in the '90s.   No formal testing, just observations.   It was RF quiet, I mostly used it on VHF but at least once on HF.  It had a regulation problem if RF was in the shack, such as a nearby 2m mag mount in a hotel room on a marginal ground plane.  The RF/regulation problem went away when I bolted my 2m rig bracket to the top of the PS case.
>>>
>>> The PS lasted about 15-20 years.  There was no collateral damage to my rig when it died.
>>>
>>> 7 3    Bob
>>> N2SCJ
>>>
>>> -----Original Message-----
>>> From: RFI [mailto:rfi-bounces+n2scj-lists=outlook.com at contesting.com] On Behalf Of Tony
>>> Sent: Sunday, May 17, 2020 5:00 PM
>>> To: Rfi List <rfi at contesting.com>
>>> Subject: [RFI] New Astron Switching PS RFI?
>>>
>>> All:
>>>
>>> Has anyone tested the latest Astron switching power supplies for noise?
>>> I read a few reviews that said the new units produce no noise on HF.
>>>
>>> https://www.dxengineering.com/parts/asr-ss-30m
>>>
>>> Tony
>>>
>>>

-- 
Scott  K9MA

k9ma at sdellington.us