[Milsurplus] TBW Transmitter power-ON/Generating high voltage(mobile/portable)

[Bill Pileggi]

Dear Mike,
Good comment about the computer UPS's. I commonly pick up one, or am at least offered one, at EVERY hamfest. For FREE. With a dead battery. The last one was on May 3, I picked up a 900 watt unit. Very heavy. Most seem to be in the 300-400 watt range.

I test them by removing the gel-cell batteries and hooking to a high-current 12V source (some run from 24vdc). If the unit starts working, putting out 110vac, we have a winner. (Don't plug in the line cord.) Sometimes you have to turn "ON" the front panel switch or throw a dip-switch in the rear. If it still doesn't operate, it's scrap, and of little use for us.

You can rectify the 110 vac output directly, or install voltage-multiplier chains to get the desired high-voltage output. You could also simply build a stock power supply to run from the UPS, your choice. Bill/KA3AIS.

Message: 11
Date: Thu, 04 Jun 2009 18:35:54 -0400
From: Mike Hanz <AAF-Radio-1 at aafradio.org>
Subject: Re: [Milsurplus] TBW Transmitter power-ON
To: milsurplus <milsurplus at mailman.qth.net>
Message-ID: <4A284C4A.2060106 at aafradio.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Occasionally, you can find variable frequency lab inverters on ebay that 
will do the job, if you're patient.  
http://aafradio.org/sidebar/Behlman_100-C.jpg is one example - winning 
bid for this one was only $16.  The only sound is a quiet fan.  The 
400Hz oscillator drawer has a phase shift oscillator that's easy to 
modify for 800~.  Perhaps a computer UPS could be modified in a similar 
way - they seem to bring fairly low prices, especially without 
batteries, and the power capabilities are about right.  The older lab 
inverters with analog meters are normally fairly reasonable, but be sure 
you can get a manual...they aren't as common as radio manuals seem to be.

73,
Mike


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