[ARC5] T-11 Crystals

[Mike Everette]

If you're serious about this and want to buy new crystals at a reasonable price, try Bomar Crystal Company in Middlesex, NJ.  They probably have a web site.  They not only make crystals, but also many kinds of oscillators and filters.

I have been buying crystals from Bomar for years, to be used in public safety transmitters and receivers.  Granted, those days are passing by; but we still need crystals from time to time when frequencies are changed in our operating areas.  VERY SELDOM (in fact I may recall one instance) have I ever had a problem with one of Bomar's crystals.

I am not affiliated in any way with Bomar, don't own any Bomar stock, and all the other usual legal orbiting circularities.  I just know a good product when I see it, and the prices keep the tightwad-cheapskate-po'mouthin' State of NC happy.

73

Mike
W4DSE


--- On Sun, 2/10/13, David Stinson <arc5 at ix.netcom.com> wrote:

> From: David Stinson <arc5 at ix.netcom.com>
> Subject: Re: [ARC5] T-11 Crystals
> To: arc5 at mailman.qth.net
> Date: Sunday, February 10, 2013, 9:50 AM
> 
> ----- Original Message ----- From: "Robert Eleazer" <releazer at earthlink.net>
> 
> > I have a few ARC T-11 transmitters and in a moment of
> unusually intense insanity last night decided I should try
> to put one on the local Unicom frequency, 122.975 MHZ,
> ...
> > It says that the crystals operate in a Pierce circuit
> at either 1/12 or 1/18 of the operating frequency....
> 
> First:
> Likely more than one person is going to jump on you about
> how using this gear to talk on modern aircraft freqs is
> "illegal"
> because it's not "type-accepted."
> FWIW, I don't think there's an FCC agent with his DF-geared
> SUV in your parking lot, and a few test transmissions at
> 2-watts out to a receiver across the hanger aren't going to
> be heard
> by the nearest monitoring station.
> But there are people who worship rules, even when they
> make no sense at all in this situation.  I wouldn't
> hesitate to
> do such "test" transmission, but I wouldn't be doing
> a bunch of QSOs with passing flyboys, either.
> Well.... maybe one or two.... or three.....  YMMV.
> 
> Crystal freqs you need are either  10248 or 6832.
> I will dig in my stock, but an old original is unlikely
> for that freq, since it's a "new" 5 KC channel.
> 
> If you do manage to find "vintage" crystals for these,
> they will oscillate off that freq to one degree or another.
> Most of the old CR-1 crystals oscillate high.
> This wasn't a big problem in 1946, since the receivers were
> broad by design.  If you're going to talk to modern
> equipment
> with their 5 and 10 KC internal filters, you need to be on
> frequency.
> I did this in my "type-17" A.R.C. set by using a 5-30 pFd
> variable
> across the crystal to "rubber" it onto frequency.
> 
> This brings me to a project which is still in the "noodling"
> stage.
> "New" crystals can be ordered, but the price is
> prohibitive-
> $40 to $50 for one!
> But there is an alternative- custom frequency clock
> oscillators.
> You can order these programmed for any frequency you like
> for just a few dollars each.
> Voltage derived from the filaments will power them.
> May or may not need a little "buffer" stage after the
> output.  This would be easy to build and install
> right at the crystal socket.
> This on my "hot project" list, which means I just
> might get it done this year ;-).
> 
> Now don't write me saying it won't work-
> yes; it will.  Just got to "get it right."
> When I do, I'll write it up.
> 
> GL ES 73 DE Dave AB5S
> 
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