Galaxy radio drift

[Larry A McClanahan]

That's just plain cool. Is that tubular stock?

I've been wondering so I'll just throw this out here...

It deals with your issue of finding a good paraffin wax or something like it - that has a relatively high melting point - which usually equates to low levels of VOC (Volatile Organic Compounds) so the melting or drop point goes higher the less VOC's you have. So it's more of a refinement issue.

Found a cute site here, lots of good stuff for anyone to use for their own tuning issues and circuit fabrication....
http://www.zen22142.zen.co.uk/Theory/tunedcct.htm (look around that site, including the upper menu bar to find other parts of the site I have yet to explore but contain a lot of fun stuff for curious mounds of mind - like myself.

But that isn't why I'm posting this, I'm trying to find the stuff that Cobra, Uniden, Midland and even Realistic used back in the days that had a higher melting point than that of typical wax...

Thanks for the site. I've been checking it out and it's really cool. Lots of information. Thanks very much.

 

[Handy Andy]

I think it's awesome that you have that time, patience and resources in thought and capability to fabricate like you do. I think that speaks volumes on ones ability to overcome a lot of different challenges and even make something better than when you got it.

To me - this matters! I got laughed at for the various ideas I've talked about but even with that - I was able to make stuff work in environments that would make other radios fall - flat - I commend you and offer you my congrats at getting this thing this far.

Keep going - like the Energizer Bunny - only in black, blue or (insert favorite color here) - whatever you can do, many a radio maker skipped out on and may have not even thought of as a process to make these things stable - so again, keep going!

:+> Andy <+:

 

[Larry A McClanahan]

Thanks Andy. That means way more than you realize.
Never let them discourage your quest.
Many like to act as a purist, but if man had never thought outside of the box, I'd still be rubbing two sticks together to light my Camel.
I was blessed with Superior analytical skills. Got them from my grandfather.

 

[Larry A McClanahan]

And I would love to hear some of your new ideas.

 

[Larry A McClanahan]

In the end I will offer a kit with the components epoxyed in a three chamber shielded unit with a shield plate for the bottom side of the board. I could even use a varactor with enough capacitance to go 5kc's.
I like to shoot DX at Europe and quite often they will split a channel because in their country that is the frequency that they would normally be on. The cure to getting more slide out of the clarifier is not changing that resistor out like you see in CB Tricks.

 

[Larry A McClanahan]

You can change out R-157 to a 470uh choke.

 

[Larry A McClanahan]

Patient is being fitted for a barrier but it's not necessary to use metal and to risky. So this idea is scrapped.

Just need, and much safer, plastic containment barrier. The three chamber metal can will stop spurious emissions. No need for a metal barrier.
Just need to contain hot glue or wax. It prevents the heat-sensitive components from becoming heat-sensitive.

 

[Martian]

Hot Glue?
Epoxy?
Seriously?

What is the before and after spectrum of the radio after you fixed these "spurious emissions"?
Can you even measure these impurities you say they have?
You realise this are type accepted radios so they already meet emissions standards.

BTW, when you want to stabilise an oscillator you use HEAT to do it.
That's why we have these things called oven controlled crystal oscillators.

People. Instead of filling a can with paraffin wax, epoxy, or my god, hot glue... buy a heater and move on.

Next I guess is the frequency response of the galaxy noise filter..... It's dying for a hack.

 

[Larry A McClanahan]

Next will be the gnf filter. I understand the theory of the crystal heater. However, the drift is mostly caused by heat. The only additional instability are the three parts. If you doubt my troubleshooting abilities, put an RF sniffer down there see what you get. In fact, you don't even need a sniffer. Watch your frequency counter and put your finger in there above the components and around the components and watch your frequency jump all over the place. It's tremendous. The crystal heater raises the temperature of the crystal above the internal temperatures generated by the unit. It's amazing what happens when you eliminate the Heat.

 

[Martian]

However, the drift is mostly caused by heat. The only additional instability are the three parts.

No, No, No!
It's TEMPERATURE CHANGE.

If you doubt my troubleshooting abilities, put an RF sniffer down there see what you get. It's tremendous.

I have, because I have fixed this problem!
It's TRIVIAL to fix!

The crystal heater raises the temperature of the crystal above the internal temperatures generated by the unit. It's amazing what happens when you eliminate the Heat.

YES! that's correct! It will get hotter!
The reason you HEAT the crystal is because it's easier to control the temperature when HEATING the crystal, not cooling it.
What happens when it's colder inside?
Or hotter?

Read:
https://en.wikipedia.org/wiki/Crystal_oven

Please. Then maybe you will understand why we heat crystal oscillators, not cool them.

 

[Larry A McClanahan]

Eliminate the Heat, re-soldered all the oscillator connections on the underside of the board, can or Shield C-130, c-131, and d49. And put a shield on the other side of the board under the oscillator and you have solved your frequency drift.

 

[Larry A McClanahan]

Eliminate the Heat and protect the area from temperature change. Now if you're running a mobile, that's a different story. It would be nice to have a crystal heater in an uncontrolled environment for the winter time that you could turn on and off.

 

[Martian]

I have heard you on the radio. Your off frequency.
How do you think I know about the GNF?

 

[Larry A McClanahan]

As stated by someone previously, the coils in this section are also very susceptible to heat reaction. So is C-130, C-131 and D-49. Old school knew this. That's why many old radios had areas that were boxed in and filled with wax. It protected them from vibration and heat reaction.
The three cans that contain the coils have two vent places on each side. They allow any Rising temperatures to enter and affect the coil. Box them in.

 

[Larry A McClanahan]

I have heard you on the radio. Your off frequency.
How do you think I know about the GNF?

You may very well have heard me off frequency. I probably turn the clarifier trying to clarify folks in. But when I talk to the locals that are all on frequency, and my frequency counters all indicate when I put it at 12 o'clock I am on frequency and it stays there.