[HBR] Progess report and 50:1 drive idea

[w2dgb]

Not mentioned as yet is the possible use of the early National PW dial
drive/gear box, as used on the original HRO and the NC100/101 series
receivers. These give an effective dial that is 12 feet long, and once
cleaned up and functioning properly can be smooth as silk. Until a couple of
years ago they were readily available at FMs, and while more scarce now can
still be found. The ones from the NC100 receivers may come with the original
National 3-gang capacitor still attached. The micrometer dial reads direct
to one part in 500, and the worm gear gives a 20:1 ratio. If caps are
attached, they can be either 160 or 225 mmf per section.

At an estate sale last year I picked up two HBR receivers, one of which uses
the PW dial. Preliminary tests indicate that the dial works well with the
HBR.  (I need to spend more time with these sets and intend to post them on
the site.)  While 20:1 is not the 50:1 which is the subject here, it still
takes 12 feet to cover the 180 degrees...does that still make it 20:1?

73 de Bill  w2dgb

----- Original Message ----- 
From: <n2ey at aol.com>
To: <hbr at mailman.qth.net>
Sent: Tuesday, April 25, 2006 10:19 AM
Subject: Re: [HBR] Progess report and 50:1 drive idea


>
>
> -----Original Message-----
> From: windy10605 at juno.com
> To: hbr at mailman.qth.net
> Sent: Tue, 25 Apr 2006 08:42:15 -0500
> Subject: Fw: [HBR] Progess report and 50:1 drive idea
>
>
> >One of the best no backlash high ratio drives is still the tuning
> >mechanism out of a BC221 Frequency Meter which always show up at
> >swapmeets.
>
> For my money, they are *the* best. There are at least two different
styles, one used in the LM series and
> one used in the BC-221 series. Slight differences but the same quality.
I've built receivers, VFOs and
> transceivers with them.
>
> >The Command Set anti-backlash gear sets are also great but the gear ratio
> >is higher and you have to get mechanically creative to use it.
>
> The ARC-5 transmitter caps have the same ratio as the BC-221 - 100 to 1.
Fifty turns to make the
> capacitor turn a half revolution. They are second only to the BC-221/LM
caps. The ARC-5 receiver
> caps are good too but not the same.
> Still another option is the tuning gang from the TCS series. But they're
"only" 50:1.
> The trick to using any of these is to use the whole unit - capacitor,
drive, and dial/drum. Simplifies
> things greatly. ARC-5s and BC-221/LMs with usable caps but that are beyond
restoration are neither rare
> nor expensive.
> 73 de Jim, N2EY
>
> ************************************
> Visit the HBR Receiver Web Site with over 100 pictures of receivers and
> construction notes...... via http://www.qsl.net/k5bcq/
> there is also a mirror (faster response)at http://k5bcq.edebris.com/
>
>
> Retrieve reflector archived data via
http://mailman.qth.net/mailman/listinfo/hbr
>
>
>
>
> -- 
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.1.385 / Virus Database: 268.4.6/323 - Release Date: 4/24/06
>
>