[Milsurplus] LF & HF Crystal Tester prelim comments

[Hubert Miller]

So I bought online for very little money one of those LF, HF crystal testers with readout.

It arrived remarkably quickly. It is quite a small unit and arrives in a little mailing bag. In fact, when I received the bag,

I thought it only would contain a couple transistors I had ordered elsewhere.

The thing is really only intended for tiny crystals with wire leads.
To test anything else, I think we need to attach the smallest alligator clips to very short leads and wire to the tester's

tiny crystal test socket.

I found:

It does not at all like any test leads to your crystal that are anything long. It will not "read" the crystal.

I think it needs good, strongly active crystals. I seem to recall that some that my dipmeter resonated, when tested on

this machine, did not show anything.
Maybe it has trouble with crystals with a higher than usual series resistance?



It did however measure a couple of those WWII FT-241  LF crystals.



It also proved its worth to me in short order. I had a bunch of crystals marked  453.5 that I bought from some boat - radio

surplus lot. Oh boy, I thought, a bunch of 453.5 kHz rocks I can use either with a mechanical filter or as single - crystal

selectivity near the common IF freq. Well, they all tested on this device as in the 16 MHz range. I don't get the 453.5 marking

and I'm pretty sure they weren't intended for 453.5 MHz use, but I'm not positive. More likely I think they were for 1970s -

1980s crystal controlled SSB boat radios. Now one less thing to save.



However, the ( gradual ) search for the ideal crystal tester goes on.

-Hue








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