Crystal problem - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

sentinel040 · 20th Jul 2023, 7:21 pm

Once again, sorry for the delay.

As an undergraduate I had a friend who synthethised a Pye Vanguard, somehow, whilst interesting I doubt I would do that; I am probably not clever enough anyway. The DDS route also seems to have too many potential problems, so it will be time to go fossil hunting and see what old rocks I can find. I was starting to form a list of things that use 44Mhz HC25U and the Daiwa and Trio rigs are all I had managed to remember from my dubious past. Time for some more digging through the historical mag pdf's on line then look up the radios in question, it all keeps me out of mischief.

Thank you for the offer of a crystal loan Jon, I think I am convinced enough of it being the crystal and my partners current health means I doubt I will be wandering off onto any high spots this summer.

I had heard of krystaly, and whilst they do not list HC25U, along with the others it offers another avenue, so thank you both. There is also Vincent to try as well.

73

Ian

Bazz4CQJ · 21st Jul 2023, 12:00 am

Quote:

Originally Posted by sentinel040

As an undergraduate I had a friend who synthethised a Pye Vanguard,

Ian

As an undergraduate, I put an 11MHz VFO in to the receiver of the Vanguard. Took me a while to get it 'acceptable', but I learned a lot in the process. Sadly, it was pretty deaf, but that was just about the time that 2m AM went down the plug hole, so it all came to nought.

B

Jon_G4MDC · 21st Jul 2023, 8:54 am

By accident I also came across David RW's suggestion that you could short out the crystal socket of a Pye Cambridge and run it as a VFO with the pulling coil.

My 4m one heard quite a few fire brigade channels that way.

Good luck on the search for 44MHz crystals. I don't think you will find from Icom (IC22 & IC215 etc were 15MHz fundamental) or Yaesu ( I only know FT202 which also used fundamental) and I suspect Standard were the same. Kenpro KP202 maybe?

Bazz4CQJ · 21st Jul 2023, 9:28 am

Quote:

Originally Posted by Jon_G4MDC

By accident I also came across David RW's suggestion that you could short out the crystal socket of a Pye Cambridge and run it as a VFO with the pulling coil.

My 4m one heard quite a few fire brigade channels that way.

I'm not sure about doing it that simply. The design I used had been published in SWM and used a FET oscillator and two buffer stages. In the Vanguard or the Cambridge the big problem was achieving thermal stability. As long as the set is just on receive, things are not too bad, but when the Tx is switched on, temperatures rise! I think the SWM design had the VFO as an external unit but mine was located internally.

B

Jon_G4MDC · 21st Jul 2023, 10:17 am

Yes Bazz- I didn't mean to imply that it was good enough to use for the long term. Actually it was hellishly tweaky but by keeping up the adjustments you could follow what was going on.

sentinel040 · 17th Sep 2023, 8:48 am

Rather than leave this as a cliff hanger, I finally tracked down a suitable crystal, which arrived last week and it is now fitted and the old rig working again.

Thank you all.

Ian

Jon_G4MDC · 17th Sep 2023, 9:09 am

Well done Ian. Patience paid off!

20th Jul 2023, 7:21 pm	#21
sentinel040 Hexode Join Date: Feb 2007 Location: Near Lichfield, Staffordshire, UK, most of the time and Crystal Palace, S London, some of the time.. Posts: 326	Re: Crystal problem Once again, sorry for the delay. As an undergraduate I had a friend who synthethised a Pye Vanguard, somehow, whilst interesting I doubt I would do that; I am probably not clever enough anyway. The DDS route also seems to have too many potential problems, so it will be time to go fossil hunting and see what old rocks I can find. I was starting to form a list of things that use 44Mhz HC25U and the Daiwa and Trio rigs are all I had managed to remember from my dubious past. Time for some more digging through the historical mag pdf's on line then look up the radios in question, it all keeps me out of mischief. Thank you for the offer of a crystal loan Jon, I think I am convinced enough of it being the crystal and my partners current health means I doubt I will be wandering off onto any high spots this summer. I had heard of krystaly, and whilst they do not list HC25U, along with the others it offers another avenue, so thank you both. There is also Vincent to try as well. 73 Ian

21st Jul 2023, 8:54 am	#23
Jon_G4MDC Octode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 1,984	Re: Crystal problem By accident I also came across David RW's suggestion that you could short out the crystal socket of a Pye Cambridge and run it as a VFO with the pulling coil. My 4m one heard quite a few fire brigade channels that way. Good luck on the search for 44MHz crystals. I don't think you will find from Icom (IC22 & IC215 etc were 15MHz fundamental) or Yaesu ( I only know FT202 which also used fundamental) and I suspect Standard were the same. Kenpro KP202 maybe? Last edited by Jon_G4MDC; 21st Jul 2023 at 9:01 am.

21st Jul 2023, 10:17 am	#25
Jon_G4MDC Octode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 1,984	Re: Crystal problem Yes Bazz- I didn't mean to imply that it was good enough to use for the long term. Actually it was hellishly tweaky but by keeping up the adjustments you could follow what was going on.

17th Sep 2023, 8:48 am	#26
sentinel040 Hexode Join Date: Feb 2007 Location: Near Lichfield, Staffordshire, UK, most of the time and Crystal Palace, S London, some of the time.. Posts: 326	Re: Crystal problem Rather than leave this as a cliff hanger, I finally tracked down a suitable crystal, which arrived last week and it is now fitted and the old rig working again. Thank you all. Ian

17th Sep 2023, 9:09 am	#27
Jon_G4MDC Octode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 1,984	Re: Crystal problem Well done Ian. Patience paid off! Last edited by Jon_G4MDC; 17th Sep 2023 at 9:39 am.