We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissible in your locale.

Author Topic: Crystal question  (Read 2527 times)

Offline JimIO

  • Sr. Member
  • ****
  • Posts: 491
  • QTH I.O. MA
    • View Profile
Crystal question
« on: June 25, 2018, 0309 UTC »
Will an HC-49S crystal work in a tube rig?

Offline Brian

  • Hero Member
  • *****
  • Posts: 522
  • Ireland
    • View Profile
    • Email
Re: Crystal question
« Reply #1 on: June 25, 2018, 1252 UTC »
Probably.
I think one or 2 of my crystals are HC 49. Not sure about the 495 though.

One way of finding out.........

Offline Stretchyman

  • Hero Member
  • *****
  • Posts: 657
    • View Profile
Re: Crystal question
« Reply #2 on: June 25, 2018, 1755 UTC »
Will work in any radio, it's a Xtal, a passive like a capacitor...

Str.
'It's better to give than receive' so why Rx when you can Tx!

                                              ;)

Offline JimIO

  • Sr. Member
  • ****
  • Posts: 491
  • QTH I.O. MA
    • View Profile
Re: Crystal question
« Reply #3 on: June 25, 2018, 2318 UTC »
Reason I ask is I just got a Heathkit DX-35. The original power transformer had been replaced and it was a real rats nest. I've ripped out all of the non original parts and will build an external power supply/modulator for it. I only have some HC-49S crystals for testing now. I see they  are rated 100uW drive (whatever that means) and I don't have any data on the old style crystals. When I'm ready to test it I will see what happens and post it here.
« Last Edit: June 25, 2018, 2328 UTC by JimIO »

Offline Stretchyman

  • Hero Member
  • *****
  • Posts: 657
    • View Profile
Re: Crystal question
« Reply #4 on: June 27, 2018, 1002 UTC »
You can put a resistor in series to limit the current if needed.

Check for circuits in th'Net.

Str.
'It's better to give than receive' so why Rx when you can Tx!

                                              ;)

Offline syfr

  • Hero Member
  • *****
  • Posts: 687
    • View Profile
Re: Crystal question
« Reply #5 on: June 27, 2018, 1611 UTC »
Typical protection scheme of the day was a miniature bulb in series with the crystal.
Kiwsdr x 2. TenTec Paragon/NRD535

Offline JimIO

  • Sr. Member
  • ****
  • Posts: 491
  • QTH I.O. MA
    • View Profile
Re: Crystal question
« Reply #6 on: June 27, 2018, 1631 UTC »
I just bought a half dozen FT-243 crystals in the 6.3-6.5 Mhz area. Going to try crystal grinding.

Offline Pigmeat

  • Marconi Class DXer
  • ********
  • Posts: 6684
    • View Profile
Re: Crystal question
« Reply #7 on: June 27, 2018, 1829 UTC »
Be careful. Even a few strokes on what seems to be a well oiled fine grained whetstone can send those things off the chart. I was fool enough to try it as was a guy I knew. At least they were cheap then? Some people use toothpaste and mineral oil with success, but it's time consuming.

I'd blame the whetstone thing on youth, but we were both past forty. Live and learn.

Offline Josh

  • DXing Phenomena
  • *******
  • Posts: 4322
    • View Profile
Re: Crystal question
« Reply #8 on: June 27, 2018, 2112 UTC »
You can fine tune xtals by lightly using a lead pencil on the faces, but that can only lower the freq a bit.
We do not encourage any radio operations contrary to regulations.