[ARC5] restoring hacked vhf receiver

[George Babits]

Last December I bought a 350 watt (15 amp) 24 volt unit.  It put out a 
strong signal every 90 KC from 2 MC to infinity.  No amount of RF filtering 
on both the input and output helped at all.  If you can live with the hash I 
guess it is OK, but not me. I finally bought an Astron linear regulated 
supply.

73,
George
W7HDL


----- Original Message ----- 
From: "Bob kb8tq" <kb8tq at n1k.org>
To: "David Stinson" <arc5 at ix.netcom.com>
Cc: <arc5 at mailman.qth.net>; "Robert Eleazer" <releazer at earthlink.net>
Sent: Tuesday, March 06, 2018 10:40 AM
Subject: Re: [ARC5] restoring hacked vhf receiver


Hi

Most of what you see runs a square wave at 20 to 60 KHz. Without added 
filtering
on both the input and the output you *will* see RFI out of them. They also 
require
some amount of air flow to cool them. If you are putting out 30W, you should 
count
on getting rid of 6W or so. The cooler you keep them, the longer they will 
last ….

All that said, they are a good way to get the job done. You can’t build 
something
better for the same money.

Bob

> On Mar 6, 2018, at 12:16 PM, David Stinson <arc5 at ix.netcom.com> wrote:
>
>
>
> From: Robert Eleazer
>
> Subject: [ARC5] restoring hacked vhf receiver
>
> By the way, I am wondering about those buck-boost converters you see for 
> sale for a few bucks the ones that can take in around 5 to 30VDC and put 
> out 1.5 V to 35 VDC.  I have been trying to build am LM350 circuit to 
> provide a little over an amp at 28 VDC to power a radio and while it 
> worked at first it's been driving me nuts.  Is the power out of those 
> buck/boost converters fairly clean or are there lots of harmonics?
>  -----------------------
>
> They are very useful, and they are very RF-noisy.  One really needs to 
> build it into an RF-tight enclosure with filtering in and out.  I posted 
> about this a few days ago.
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