[Milsurplus] Milsurplus Digest, Vol 242, Issue 53

[51 Ops]

Dribble away...
If it works, and gets that vintage gear well into its second life on the
air then who are we to judge. BTW: the sense of pride you get when it
lights up and makes pretty noises will put a smile on your face especially
if you build it. $$ ?- Priceless

On Tue, Jun 25, 2024 at 11:11 AM <milsurplus-request at mailman.qth.net> wrote:

> Send Milsurplus mailing list submissions to
>         milsurplus at mailman.qth.net
>
> To subscribe or unsubscribe via the World Wide Web, visit
>         http://mailman.qth.net/mailman/listinfo/milsurplus
> or, via email, send a message with subject or body 'help' to
>         milsurplus-request at mailman.qth.net
>
> You can reach the person managing the list at
>         milsurplus-owner at mailman.qth.net
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Milsurplus digest..."
>
>
> Today's Topics:
>
>    1. Easy DC to DC inverter (Ray Fantini)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 25 Jun 2024 15:11:36 +0000
> From: Ray Fantini <RAFANTINI at salisbury.edu>
> To: "MMRCG at groups.io" <MMRCG at groups.io>, "mrca at mailman.qth.net"
>         <mrca at mailman.qth.net>
> Cc: "milsurplus at mailman.qth.net" <milsurplus at mailman.qth.net>
> Subject: [Milsurplus] Easy DC to DC inverter
> Message-ID:
>         <
> DM8P220MB04724673D14F35C5B5B146A5B8D52 at DM8P220MB0472.NAMP220.PROD.OUTLOOK.COM
> >
>
> Content-Type: text/plain; charset="us-ascii"
>
> Some ideas work so well and are so simple is hard to wrap your head around
> them. Last couple years have been playing around with solid state inverters
> for powering tube equipment in the field. Recently Craig, N3TPM turned me
> on to this simple circuit, have also seen this several places on the
> internet so decided it was time to try it for myself. Near as I can figure
> it's a multivibrator or at least that's how I drew it. I have put together
> a couple of these on the bench and have to say that due to its low parts
> count and simplicity find it hard to beat. Uses a regular transformer and,
> in this case, using a center taped twenty-five-volt two-amp transformer and
> it develops 120 volts on the secondary all day long. The transistors are
> nothing special, just 2N3055 or the like from the junk box. Unloaded
> current drain is only around six hundred mills and with Rx being 680 ohms
> the running frequency is around sixty cycles, increasing Rx raises the
> frequency and lowering Rx decreases
>   the frequency. When Rx is 250 ohms was running around fifty cycles and
> at 1.2 K was just above seventy cycles.
> Have not tried it yet but would like to see what this will do to
> substitute a mechanical vibrator, going to assume that it will work but
> have not gotten that far yet myself.
>
> Additional comments are commentary: Do not read if easily offended!
> Ok, so I know that there is a plethora of cheap Chinees crap out there
> that you can buy for nothing all day long but screw that stuff. Why buy
> when you can build? The advantage of this circuit is its low frequency so
> there are no big noise issues, it uses cheap junk parts and can be
> understood and repaired by anyone with minimal understanding of
> electronics, just try repairing or replacing something on one of those
> small micro inverters.
> Basic assumption: We do this because this is what we want to do, not
> because it's easy, or cheap. If we were only interested in getting on the
> air and racking up contacts there are way better things then playing around
> with this stuff. Don't know, maybe some feel they may not be up to the task
> of understanding or building their own but what better way to learn? Big
> advantage to working with a lot of this old military stuff or any vintage
> hardware is its bigger, easy to work on and easy to understand where as
> modern equipment that's microprocessor driven or using LSI devices and
> surface mount technology are way more difficult to deal with.
> Least that's how I see it, or perhaps I am just a victim of my own
> prejudices along with my own personal history and preferences, maybe in
> twenty years people will look back and regard these as the "Golden Days"
> when cheap Chinee's junk freed us from having to use soldering guns?
> As you can tell it's a slow day at work, and I have time to sit around and
> write up such dribble.
>
> Ray F/KA3EKH
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> http://mailman.qth.net/pipermail/milsurplus/attachments/20240625/d068ecbc/attachment.html
> >
> -------------- next part --------------
> A non-text attachment was scrubbed...
> Name: Multiverter.jpg
> Type: image/jpeg
> Size: 171466 bytes
> Desc: Multiverter.jpg
> URL: <
> http://mailman.qth.net/pipermail/milsurplus/attachments/20240625/d068ecbc/attachment.jpg
> >
>
> ------------------------------
>
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
>
>
> End of Milsurplus Digest, Vol 242, Issue 53
> *******************************************
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/milsurplus/attachments/20240629/64ae45e6/attachment-0001.html>