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 Post subject: National PW Vernier
PostPosted: Aug Sat 29, 2009 7:30 pm 
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Joined: May Tue 30, 2006 4:46 pm
Posts: 6369
Location: Santa Rosa, CA
I recently acquired a PW dial with right angle drive. Looks to be almost new.

Was this used in HRO receivers or any commercial/MIL equipment?


Rich


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 Post subject:
PostPosted: Aug Sat 29, 2009 10:59 pm 
Member

Joined: Jul Thu 27, 2006 1:57 pm
Posts: 386
Location: Lakeland Fl
Hi Rich,There are two types of National PW verniers.The first version is black and was used in the pre-war versions of the HRO and 1-10.
The post war version is grey and used on the HFS and postwar HROs.Both versions may have been used on other pieces of gear including test equipment.The right angle drive was optional and came in single (L configuration) or dual (T configuration).
73 de Bill


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 Post subject:
PostPosted: Aug Sat 29, 2009 11:37 pm 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
Posts: 34328
Location: Sandpoint, IDAHO 83864
They are the best vernier drives ever concocted by mankind! They have REAL gears in them and good bearings. Carl will probably be showing up in a bit and bragging them up a bit.
Curt

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Curt, N7AH
(Connoisseur of the cold 807) CW forever!


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 Post subject:
PostPosted: Aug Sun 30, 2009 12:06 am 
Member

Joined: May Tue 30, 2006 4:46 pm
Posts: 6369
Location: Santa Rosa, CA
The one I have is black and has only a single shaft, not dual.

It looks like it could serve as the PTO on a garden tractor!

Rich


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 Post subject:
PostPosted: Aug Sun 30, 2009 11:58 am 
Member

Joined: Jul Thu 27, 2006 1:57 pm
Posts: 386
Location: Lakeland Fl
Hi Rich,you have the pre-war version, model PW-0.These units came in five configurations-PW-1 (with a single 150,200,350 or 500 pf variable cap attached to it;you had to specify what cap value you wanted on the drive.)The rotor shaft was not insulated from ground on this or the PW-0 version ("L" configuration).The PW-2,3 or 4 versions had variable caps on each side of the gearbox arranged in 1x1,2x1 or 2x2 in either 150 or 225 pf per section.Once again,you had to specify the values that you wanted.This was the "T" configuration and the rotor shaft WAS insulated from ground.Gearing was 20:1 ratio via a worm gear assy supported by 4 bearings.These boogers weren't cheap!The PW-4 unit went for $24.00 in 1936 dollars.Data taken from 1936 ARRL Handbook,pg 386 (National ad), hope this helps.
73 de Bill


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 Post subject:
PostPosted: Aug Sun 30, 2009 2:28 pm 
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Joined: Oct Sat 20, 2007 3:36 am
Posts: 14393
Location: Southern NH, 03076
If any one has an early HRO German Silver dial assembly Id like to buy it. They were only on the earliest production runs and many were replaced by the black version.

Carl


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 Post subject:
PostPosted: Aug Sun 30, 2009 5:23 pm 
Member

Joined: May Tue 30, 2006 4:46 pm
Posts: 6369
Location: Santa Rosa, CA
Thanks for all the information.

I knew this was a high quality drive, but was surprised by the size and mass of it.

Looks like over-kill for the simple one- and two-tube regen receivers that I build.

Most of my projects use the Bakelite types from Pilot or National. Maybe I will put this one up for sale.

I do have a German Silver National vernier, but it's not an HRO or PW type.

Rich


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