Nems-Clark WX2/120 field meter B battery upgrade

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Deep Thought
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Nems-Clark WX2/120 field meter B battery upgrade

Post by Deep Thought » Thu Aug 27, 2015 11:57 am

Anyone interested in an updated replacement for the Eveready 416 67.5 volt B battery used by the Nems-Clark AM field meter line? It runs on 8 AA cells and delivers a regulated 67.5 volts with very low EMI (doesn't register on the meter at the lowest scale and is barely audible). Price should be bit less than two of the current knockoffs available (when you can find them), and it fits in the B battery compartment.

Only one of these power supplies is needed since it can supply both the receiver and calibration oscillator with the necessary operating current.

Let me know below if this is something you think you might use. Thanks!
Mark Mueller • Mueller Broadcast Design • La Grange, IL • http://www.muellerbroadcastdesign.com

Larry Milliken
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Re: Nems-Clark WX2/120 field meter B battery upgrade

Post by Larry Milliken » Thu Aug 27, 2015 2:48 pm

Hi Mark,

Please email Rick and I with your information. KYOS has the last tube production model purchased new in the 70's. I understand it was the last one made. Thanks.

Larry

BingNYEng
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Re: Nems-Clark WX2/120 field meter B battery upgrade

Post by BingNYEng » Thu Aug 27, 2015 2:58 pm

I bought and built a kit to power one of my antique radios that needed 67.5 volts. It was offered for sale by Tony Maher in Australia. It uses 4 AA batteries to fit the original footprint of the B battery and was very quiet.

Details of his circuit are here: http://www.portabletubes.co.uk/sitefiles/ausbatt.htm

kcbooboo
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Re: Nems-Clark WX2/120 field meter B battery upgrade

Post by kcbooboo » Fri Aug 28, 2015 3:16 am

Does this upgrade have two independent and floating outputs? I ask because the negative connection on the RCVR battery does NOT go to ground as it does on the CAL battery.

Is this a cheaper alternative than two banks of seven 9V batteries in series?

Bob M.

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Deep Thought
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Re: Nems-Clark WX2/120 field meter B battery upgrade

Post by Deep Thought » Mon Aug 31, 2015 11:02 am

I've passed the ground lead question on to the person who is working on this. Thanks!
Mark Mueller • Mueller Broadcast Design • La Grange, IL • http://www.muellerbroadcastdesign.com

grich
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Re: Nems-Clark WX2/120 field meter B battery upgrade

Post by grich » Mon Aug 31, 2015 10:01 pm

One of my clients has a 120 ready for new batteries. They may be interested in this.

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Deep Thought
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Re: Nems-Clark WX2/120 field meter B battery upgrade

Post by Deep Thought » Sat Jan 16, 2016 12:24 am

This has progressed to production status. Two of them fit into a WX2/120 perfectly. A meter being run by these supplies has been compared to a recently calibrated FIM-41 and was found to be within spec, and the power supplies do not add any noise to the received signal nor do they radiate any measurable signal from the meter. These are very tightly regulated and will operate down to a AA cell voltage of 1 volt, which makes the usable with 1.2 volt rechargeable as well as alkaline cells. Each unit requires 8 AA cells and should operate from a set for 36 hours or more.
IMG_20160114_132628.jpg
These are designed and are being produced by a former Motorola design engineer.
Price is $99 each. Contact me if you are interested.

By the way, if you have any of the old battery clips for these batteries you'd like to find a home for, let me know.
Mark Mueller • Mueller Broadcast Design • La Grange, IL • http://www.muellerbroadcastdesign.com


Kent T
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Re: Nems-Clark WX2/120 field meter B battery upgrade

Post by Kent T » Thu Apr 28, 2016 7:18 am

Love this sight, makes many an older FIM less expensive to use in the long run, and much easier battery supply.

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