Need weird crystals? Quartslab are still trading!

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Phil_G
Posts: 413
Joined: 15 Feb 2018, 23:32
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Need weird crystals? Quartslab are still trading!

Post by Phil_G » 08 Jun 2020, 20:17

Quartslab were always a favourite with hams, they make radio crystals to any was spec you like.
We all used them a lot for converting police and taxi radios to ham bands, but they seemed to disappear for a long time. Well they are trading and for anyone wanting non-standard crystals its a very realistic option.
Say you have an early Macgregor superhet with the 470k IF. Suitable transmitter crystals are ten a penny but receiver crystals for a 470k IF are rocking horse poop. Quartslab will cut you a brand new one for £12. Actually theres a minimum order of two but thats ok, they dont have to be the same crystal.
Given the price some vendors are asking for standard crystals, I think £12 for an otherwise unobtainable custom made one is great value.
Use the bottom half of their form, specify the exact crystal frequency (eg transmitter frequency minus .47mhz for Macgregor), the holder as HC25/U or HC50/U, series resonant, 3rd overtone:

quartslab.jpg

Pchristy
Posts: 150
Joined: 16 Feb 2018, 13:57
Location: South Devon, UK

Re: Need weird crystals? Quartslab are still trading!

Post by Pchristy » 11 Jun 2020, 19:38

Good spot, Phil! Especially with crystals of any sort becoming harder to obtain!

My "go to" supplier, back in the UHF days, has long since gone, sadly!

--
Pete

Pchristy
Posts: 150
Joined: 16 Feb 2018, 13:57
Location: South Devon, UK

Re: Need weird crystals? Quartslab are still trading!

Post by Pchristy » 11 Jun 2020, 22:34

Phil_G wrote:
11 Jun 2020, 21:03
Cathodeon?
Websters in Chard (near Merryfield, where I did a fair bit of single-channeling, back in the day!).

The boss was a keen RC modeller, and fell over backwards to help us with crystals. Alas, due to the multiplication factor involved (X6), we had to go to military spec to stand even the faintest chance of interchangeable crystals! If anyone wanted more than one pair, I had to sit down and go through all the ones we had trying to find two pairs that would be interchangeable!

Reftec got round it by using a (very!) broadband receiver! I doubt that it would have worked at less than 50 KHz spacing! We were aiming for 25 KHz, and it worked fine at that, but all the sets had to be individually tuned to their specific crystals. I then had to try and find a second set that 1) were in tolerance for the transmitter and 2) were in tolerance for the receiver IF!

Very time consuming!

Not sure how Cotswold managed it, never managed to get my hands on a set! Multiplex was also 50 KHz only, but at least they had a decent receiver - even if it was the size of a house brick! Mine fitted in the same case as the 35 MHz receiver, and Peter Valentine (Lark helicopter designer) shrank it even further!

I assume that Mr Webster (never did find out his first name) retired or passed away, and the company vanished. Mick Wilshere used to do all the dealing with them, so I only got involved second hand.

--
Pete

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