Digital Velvet Vernier. Any Suggestions?

Thread Starter

Rory Starkweather

Joined Jan 27, 2015
41
I bought a pair of DIY HAM band receivers several years ago, from Ramsey. Nice kits, but tuning was/is iffy. They both use potentiometers to control tuning and my hands shake so much that I can't lock on to a target frequency, especially since they only have about 300 degrees of a circle to cover the whole tuning range. Kind of frustrating so I'm tryiing to think of a 'workaround'.

I love Velvet Verniers, but they haven't been made for years, and I can't afford $50 per tuning knob on kits that originally cost less than $25.

One thing that came to mind was some kind of digital tumer. (Up button, down button and an LCD readout, of . . . something.) Now I know there are are a lot of things like this in use, but I don't even know what to Google.

I'm thinking of replacing the tuners with some more expensive versions, but, before I go there, I'm wondering if there is a cheaper solution already out there.

The bottom line is that I would like to replace a pair of variable resistors with something with more accuracy, and selectivity.

Does anyone have any suggestions?
 

DNA Robotics

Joined Jun 13, 2014
655
Maybe a more mechanical method with pulleys and a belt. Salvage parts from an old cassette player? If you put a large knob on the motor shaft, you would have a lot of control.

pulley system.jpg
 

Thread Starter

Rory Starkweather

Joined Jan 27, 2015
41
Maybe a more mechanical method with pulleys and a belt. Salvage parts from an old cassette player? If you put a large knob on the motor shaft, you would have a lot of control.

View attachment 79649
I'm not saying "No" but the whole thing is like 6" by 5". (The whole receiver.) I've thought about breaking it out, but I haven't gone there yet.

Your idea is a very good one, but I would have to buy something like the ten turn pot, mentioned below, and then there's the problem with limit switches. I don't want the motor trying to tear off either end of the potentiometer.

Almost forgot. I suk at salvaging. :) I can't salvage a pebble from a rock.
 

Thread Starter

Rory Starkweather

Joined Jan 27, 2015
41
I am radio illiterate.

But, why not two tuners: course and fine?
You have been a constant source of really good suggestions. HOWEVER, this time, I don't have any idea how to build either one, let alone, both. I believe in success through successive approximations.

As usual, your idea is a great one, but I'm not advanced enough for that yet.
 

DNA Robotics

Joined Jun 13, 2014
655
I guess I confused things by using a motor as an axle mount.

When I said If you put a large knob on the motor shaft, you would have a lot of control, I meant to turn it manually with a 50:1 or so gear reduction.
If you turn the knob a lot, it turns your tuner a little bit.
 
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