For exchange of information about electronic components.

22 responses total.

What is the inductance of a small inductor (the  size of  a 1/2 watt
resistor) that is marked LQ103?

I'm not familiar with inductor markings, but I do have a digital SCR meter.

Er, "LCR".  

I don't have a LCR meter, but if I have to measure it, I will find the
resonant frequency with a capacitor (I have signal generator). I'm hoping
someone will know that component code. 

You sure about the marks on that?  If so, must be an in-house marking,
as I can't find any reference for it.  (Or could be really new?)

Yup -LQ103. I wonder whether it is like capacitors, which would make it
10,000 ph, but that would be only .01 uh, which is below the range of
chokes available in that package in catalogs. 

I couldn't find anything referencing that, on Google.
Let's see what's going on, using and LCR.

Having made a power supply for my antique homebrewed 80 m CW transceiver,
I went looking for crystals for the oscillator, and discovered that things
have changed a great deal! FT-243 packaged xtals (which my radio takes) 
are also antiques and very scarce. I've done a lot of web searching about
this, but have been unable to find a good source for FT-243 xtals, either
in the surplus market or of new manufacture. In regard to the latter, it
would certainly be OK to use crystals in more modern packages if there
were adapters available for FT-243 sockets, but I find nothing like that
either. Does anyone know of sources of "surplus" FT-243 xtals, or means to
substitute for them? 

Are FT-243 crystals the ones in the big Bakelite cases held together with a
screw?

Yes. Also sometimes denoted Type Z-2. But that is just the packaging -
0.486" between pins, and 0.093" pins. There is another more modern sealed
can standard called HC-6/L that has the same pin dimensions. I know a lot
less about the electrical characteristics of crystals in these different
standards, and what are compatible and what are not. 

You can probably tweak the circuit to work with the modern ones.

It's been a long time, but if I remember right the modern ones have less
capacitance and oscillate more easily.  They can also be 'rubber banded'
more in a VXO.  They may not tolerate quite as much power as the older,
larger ones.

I'd try it and see what happens.  Unless the circuit design is critical,
it may very well work.  If it doesn't work, you can try adding a small
amount of capacitance and see what happens.  I forget if it has to be in
series or parallel.

If you have a Z-2 crystal that's below the frequency you want, it's
possible to grind it by hand to oscillate at a higher frequency.

So they say...I don't think I'll fool with that if I can get crystals
"surplus", or even have some made for me. There are a LOT of shops out
there making crystals, since they are in everything, but mostly surface
mount now.

You said this is an 80M CW transmitter, right?  A cheap way to test its
reaction to newer crystal types might be to hook up a TV colorburst
crystal (3.579545 MHz).  They're widely available and very inexpensive.
 If you have any old TVs around you can scavenge one for nothing.

Worth trying - can't hurt for a short test (now, to find one....).

Purchase Radio.  I've recently bought a colorburst crystal from them, and I
believe they had quite a few FT-243s

I've got a couple FT-243s lying around, but I'd have to check the
frequencies.  I don't know if I have any you'd be interested in.

I have a bunch of the colorburst crystals, Rane.

Klaus - you should come by an ARROW meeting. The club has rebounded. 
Are your colorburst crystals in FT-243 cases? 

Yes, I should.  I'll have to see if I make one soon.  I'm glad that the club
has rebounded!

Boy, I don't know what kind of casses they are in.  All kinds.  I have one
that's inside a little 8-pin vacuum tube!

I have to have FT-243 mounts - the radio is very tightly packed inside and
I want to avoid any rebuilding if possible. What I haven't been able to
find is any fulsome source of FT-243s or suggestions on putting modern
crystals in FT-243 cases. There really has to be a lot around since they
are now obsolete. I've thought it peculiar that vacuum tubes are available
in abundance but the crystals of the same era are not.

I don't think many people use crystal-tuned radios anymore.  Most people
seem to want a VFO.

It's big in QRP circles. QST published an xtal controlled QRP xmitter
plan quite recently. There are numerous web sites for QRP. 

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