[time-nuts] 6CW4 Nuvistors on eBay...
paulswedb at gmail.com
Sun May 2 21:34:41 UTC 2010
Indeed there are.
And even 7587s thats the TRF frontend. In one of the units V3 appears bad
all Rs are good voltage high on plate, 0 cathode current. But oddly when I
swap v1 into position same effect so somethings odd. Or my methods not
The other units working. Had to replace a shorted 6.2 V zener.
The 100 kc vco /lock osc is awful touchy.
Pretty amazing the units pretty hot sensitivity wise -80 dbm.
Interesting afternoon. Way in the deep corner of the basement I think I may
have a nuvistor or two. Time to see what they are.
On Sun, May 2, 2010 at 4:14 PM, Burt I. Weiner <biwa at att.net> wrote:
> For what it's worth, I just took a look and found a bunch of 6CW4's on
> eBay. See:
> Burt, K6OQK
> From: paul swed <paulswedb at gmail.com>
>> Subject: Re: [time-nuts] schematics for a HP117a please
>> Thanks everyone.
>> Indeed the nuvistors will be a challenge.
>> Don't know if between the 2 recvrs I have enough or if they are good or
>> But if need be a bit o redesign may be in order.
>> I am currently using a fair size copper tune loop/preamp on a tracor 599H.
>> So thats a good start. But I will dig in and see whats cooking (Or not)
>> Noticed one has the creeping ground lug oxidation. Time for a drill.
>> On Sat, May 1, 2010 at 1:02 PM, J. Forster <jfor at quik.com> wrote:
>> > Have you tried Dave at Artek Media?
>> > A couple of things on the 117A:
>> > The antenna is a roughly 1 meter diameter loop, but has a very frequency
>> > selective pre-amp built in. Early versions used two Nuvistors and a 60
>> > mechanical filter. Later versions used FETs I think. The amp in the unit
>> > also uses three Nuvistors. These devices are getting scarce and
>> > The coax between thr receiver and antenna has DC on it to power the loop
>> > preamp.
>> > The paper for the stripchart is getting hard to find also.
>> > FWIW,
>> > -John
> Burt I. Weiner Associates
> Broadcast Technical Services
> Glendale, California U.S.A.
> biwa at att.net
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> and follow the instructions there.
More information about the time-nuts