Send MRCA mailing list submissions to

    [email protected]

To subscribe or unsubscribe via the World Wide Web, visit

    http://mailman.qth.net/mailman/listinfo/mrca

or, via email, send a message with subject or body 'help' to

    [email protected]

You can reach the person managing the list at

    [email protected]

When replying, please edit your Subject line so it is more specific

than "Re: Contents of MRCA digest..."

Today's Topics:

  1. Re: ART-13 Junque Box Power Supply (Ray Fantini)

----------------------------------------------------------------------

Message: 1

Date: Mon, 4 Apr 2022 13:08:33 +0000

From: Ray Fantini <[email protected]>

To: "B. Smith" <[email protected]>, Military Radio Collectors

    Association    <[email protected]>

Subject: Re: [MRCA] ART-13 Junque Box Power Supply

Message-ID:

    <DM8P220MB0472B177400A7C1768DD8C3DB8E59@DM8P220MB0472.NAMP220.PROD.OUTLOOK.COM>

   

Content-Type: text/plain; charset="utf-8"

It was a common practice in a lot of the last generation of Harris Broadcast tube transmitters to install the plate current meter in the negative side of the plate supply. They would install a ten or fifteen volt Zener Diode across the shunt so if the resistor opened the diode would short and protect the plate current meter. After a bad lightning strike it was not uncommon to find the transmitter on the air, putting out full power with no issue but the plate current meter reading zero.

Ray F/KA3EKH

From: [email protected] <[email protected]> On Behalf Of B. Smith

Sent: Sunday, April 3, 2022 7:40 PM

To: Military Radio Collectors Association <[email protected]>

Subject: [MRCA] ART-13 Junque Box Power Supply

CAUTION: This email originated from outside of Salisbury University. Please exercise caution when clicking links or opening attachments from external sources.

The ART-13 plate current meter circuit requires a meter "shunt" to be installed in your power supply and the voltage taken from this shunt is used to drive the  meter.  Usual this is a resistor around 12 to 15 ohms.

When constructing this "shunt" try using two or more  resistors in parallel and avoid just using a single resistor. By using a pair of resistors if one fails you will still have a DC return to chassis ground and your meter in this case will not be accurate but the power supply will be safe and still function. BTW the meter scale is not very accurate anyway in the plate current function. Full scale is around 300 ma.

Z

[cid:[email protected]][cid:[email protected]]

-------------- next part --------------

An HTML attachment was scrubbed...

URL: <http://mailman.qth.net/pipermail/mrca/attachments/20220404/91ddded6/attachment.html>

-------------- next part --------------

A non-text attachment was scrubbed...

Name: image001.gif

Type: image/gif

Size: 9511 bytes

Desc: image001.gif

URL: <http://mailman.qth.net/pipermail/mrca/attachments/20220404/91ddded6/attachment.gif>

-------------- next part --------------

A non-text attachment was scrubbed...

Name: image002.jpg

Type: image/jpeg

Size: 77893 bytes

Desc: image002.jpg

URL: <http://mailman.qth.net/pipermail/mrca/attachments/20220404/91ddded6/attachment.jpg>

------------------------------

_______________________________________________

MRCA mailing list

End of MRCA Digest, Vol 216, Issue 6

************************************