Re: Variable power control

M Garza <mgarza896@...>
 

Jack,
Nothing wrong with that.  It should work fine, as long as it doesn't introduce any RF hash from the switching regulator.  
I would think that you could replace the variable that controls the voltage with a panel mounted one.

Marco - KG5PRT

On Tue, Jan 2, 2018 at 3:47 PM, Jack Purdum via Groups.Io <jjpurdum@...> wrote:
Ok, I'll probably look silly asking this, but you all know I'm a software guy, not EE, so here goes. Why can I have a 24V supply and use this:

ebay # 152837387238

to drop the voltage to 5V? It seems that less power goes up in heat using one of these, so why won't these work?

Jack, W8TEE



From: M Garza <mgarza896@...>
To: BITX20@groups.io
Sent: Tuesday, January 2, 2018 4:32 PM
Subject: Re: [BITX20] Variable power control

Kind of crude, but you could power the entire radio with 24v.  Use a 12v regulator for the receiver and a LM350 for a variable regulator to the PA.  You could set it up to be variable for only a few volts change to vary the output.  You alternately could use a 12 v source and the LM350 to vary the voltage to the PA.  Again, you could design something that would vary by a few watts.
Running from 24v lets you get the higher output but allows you to turn things down, as needed.

Here are a couple of  LM317/350/358 calculator pages:


Hope this helps.

Marco - KG5PRT



On Tue, Jan 2, 2018 at 3:20 PM, N8DAH <Dherron@...> wrote:
On Tue, Jan 2, 2018 at 01:17 pm, N8DAH wrote:
Group has a lot got smart folks I'm sure we will figure out a nice mod.
I am not one of them if you can tell by typing skills hihi




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