[GreenKeys] FT-243 Crystals

[Bob Camp]

Hi

Well like all things it's a fairly complicated problem when you get 
into it.

The early FT-243's often were made with X cut blanks rather than AT cut 
blanks. There was a war on and X-ray gear was a bit hard to find. Also 
the technology to use the X-ray gear was a bit complicated. A guy by 
the name of Galvin spent a lot of time trying to get problems like this 
straightened out.

By the end of WWII a lot of the issues had been straightened out. Of 
course then we didn't need any more crystals and roughly 98% of the 
crystal companies went out of business. Mr. Galvin went back to being 
president of Motorola.

I have always wondered if something similar happened in the world of 
Teletype machines. The expansion and collapse of the crystal industry 
is very well documented. I would *think* that the demand for TTY gear 
dropped off pretty significantly at the same time.

Anybody out there with any data?

	Take Care!

		Bob Camp
		KB8TQ



On Nov 10, 2004, at 12:36 PM, George B. Hutchison wrote:

> GreenKeyers - - -
>
> I try and stay pretty much silent, but when I saw FT-243 crystals 
> mentioned,
> I had to say something.
>
> DO NOT USE FT-243 CRYSTALS. The holder uses a spring pressure 
> arrangement
> where the blank is held by the corners between two plates. These older
> styles exhibit more drift than a ocean full of icebergs.
>
> Use HC-6 type crystals. I recommend International Crystals as a good 
> source.
> Crystals are a bit pricey these days, but if one wants to stay in 
> place, a
> cheapie will shoot you in the foot every time.
>
> The International Crystals website offers a number of fact sheets and
> tutorials on crystal oscillators, different crystal cuts and their 
> relative
> stabilities and accuracies, etc. They are past masters at helping 
> people
> select the best type for the application, and their service is 
> relatively
> fast.
>
> Good luck on your quest for genuine FSK.
>
> 73,
>
> George, W7TTY
>
>
>
>
>
> _______________________________________________
> GreenKeys mailing list
> GreenKeys at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/greenkeys
>