[HBR] Looking for that three section variable

Mon Sep 13 15:13:55 EDT 2010

At the time of the HBR... one thing that set it above and beyond the other simpler homebrew receivers, was 3-section tracking aligned nicely on all the bands.

In today's homebrewing, such tracking is often not considered an important goal. But back in the 50's, it was a goal.

What sets the HBR-14/16/etc. above and beyond the other simpler homebrew receivers at the time, was that it had every bell and whistle that any commercial ham-band receiver had. Including multistage tracking from a single front panel tuning control.

When the tracking is set up correctly, the RF padder doesn't have to be tweaked much for excursions in the same band, in fact the RF padder is thought of as compensating for stray antenna capacitance.

You can see this aspiration for single control tuning in other QST/ARRL projects too, the aspiration seems to have started in the TRF days:

e.g. April 1926 QST p. 17: "All of us have known for a good many years that the difficulties encountered in laying out a receiver with only one tuning control to manipulate several tuned circuits are not to be treated lightly nor easily disposed of".

Feb 1926 QST p. 47, 1DQ: "It is often possible to combine the controls so that all the tuning condesners can be handled through the manipulation of one knob."

Feb 1928 QST p. 54: "That there is a popular demand for single control is generally recognized".

Dec 1929 QST p. 25, W1DF: "One of the great drawbacks of amateur transmission for the beginner is the multiplicity of controls and adjustments which seems to be necessarily attendant"

May 1929 QST p. 23: "Single control in a radio receiver means greater convenience and a better usefulness"

And so on.

Tim N3QE

-----Original Message-----
From: hbr-bounces at mailman.qth.net [mailto:hbr-bounces at mailman.qth.net] On Behalf Of Bill Fizette
Sent: Monday, September 13, 2010 2:49 PM
To: HBR Receiver List
Subject: Re: [HBR] Looking for that three section variable

I must be missing something here, and would appreciate being corrected... 
But:

Why not use a 2-section variable for the mixer and osc stages, and tune the 
RF stage separately with an appropriate variable.  The "antenna" peaking 
control is already in the circuit, and it should be a simple matter to 
adjust the size to tune the various bands, since the main variable is a 
small capacity anyway. Two-section variables are easy to come by, as 
compared to the three-section types.  As I say, what am I missing?

Best to all,

Bill  w2dgb

----- Original Message ----- 
From: "Kees & Sandy" <windy10605 at juno.com>
To: <hbr at mailman.qth.net>
Sent: Monday, September 13, 2010 11:55 AM
Subject: Re: [HBR] Looking for that three section variable

> Sure, I think I have 5 of them .....but we're in the process of moving 
> back into the house after remodeling and I have not come across the box 
> yet.
> 73 Kees K5BCQ
>
> ---------- Original Message ----------
> From: John Landrigan  <jlandrigan at pol.net>
> To: HBR Receiver List <hbr at mailman.qth.net>
> Subject: Re: [HBR] Looking for that three section variable
> Date: Mon, 13 Sep 2010 11:42:47 -0400 (EDT)
>
> Kees,
> If you've got any more please save one for me.
>
> John KA4RXP and Jody KG4VES
>
>
> ----- Original Message -----
> From: "Kees & Sandy" <windy10605 at juno.com>
> To: hbr at mailman.qth.net
> Sent: Monday, September 13, 2010 10:40:06 AM GMT -06:00 US/Canada Central
> Subject: Re: [HBR] Looking for that three section variable
>
> If you can't find an original variable, several of us bought 3 section FM 
> variables from Ocean State Electronics when they were in business. I can 
> probably dig up a few of those.
> 73 Kees K5BCQ
>
> ---------- Original Message ----------
> From: William Wood <ke9xq at charter.net>
> To: HBR Receiver List <hbr at mailman.qth.net>
> Subject: [HBR] Looking for that three section variable
> Date: Mon, 13 Sep 2010 10:11:23 -0500
>
> Greetings Earthlings
>  Anyone have an extra three gang variable for the HBR 13?
> I found one but it goes to 140 pF  not the 25 or so...   Did
> some shopping in the internet, but did not see one yet.  Found
> a bunch of variables, but not the size I'd want.
> Found a beauty Saturday at a local HamFest from an old
> national (I believe)  GREAT gearing set up, 36 to one half
> rotation so I guess that would be 72:1 drive, but it only has
> two variable caps in it.  Think that might make a good project
> some day : )
>  I've not started to put anything together yet as I'm waiting for
> the heart of the matter before I start.  In case I need to move
> things up or down a smidge or two  : )  Would like the cap
> before I drill the first hole...
> 73
> Bill
>
>
>
>
> If the grass is greener on the
> other side of the fence, then
> maybe you ain't watering
> your own lawn...
>
> Favorite Yahoo Groups...
>
> http://groups.yahoo.com/group/OTR_and_Music/
>
> http://groups.yahoo.com/group/Radio_Library/
>
> And check out Tennessee Bill's site at:
>
> http://otrshareandtrade.com/in.php?ID=12
> and his personal site at:
>
> http://TennesseeBillsOTR.com
>
> Don't forget
>
> http://www.archive.org/index.php
>
> and one or two that maybe don't
> want to be listed : )
> And two dozen or more others
> I won't tell you about unless you ask.
>
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