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Reviews Categories | Ham radio kits | QRP-ME X-CHECKer Help


Reviews Summary for QRP-ME X-CHECKer
QRP-ME  X-CHECKer Reviews: 1 Average rating: 5.0/5 MSRP: $50.00 plus shipping
Description: FT-243 Crystal Grinding Station. A quartz crystal testing oscillator with built in frequency counter
Product is in production.
More info: http://qrpme.com/?p=product&id=Q17
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K1WHS Rating: 5/5 Mar 3, 2019 18:33 Send this review to a friend
A very neat little tool.  Time owned: 0 to 3 months
The QRP-ME crystal grinding tester fills the bill for a simple and easy way to check FT-243 quartz crystals as you grind them to your favorite frequency. I had done some crystal grinding when I was a kid and have fond memories trying to grind crystals to 8.0 MHz to get down on the bottom of the two meter band. I had a homemade oscillator that I would plug the crystal in and then I would listen on a receiver and guess what the new frequency was! W1REX has simplified the process for QRPers and those who still have fun grinding their own crystals. The kit consists of a circuit board and parts to make an oscillator, a frequency counter and an LCD display to indicate frequency. A neat trick is the flat circuit board pad where you can place the raw crystal blank and put a copper pipe cap on it to read the frequency of the crystal blank without putting it back in the holder! In operation, you can check crystal activity by placing the FT-243 pins down on the two big crystal pads on the PCB. A green LED will light up when it oscillates, and the oscillating frequency will appear on the LCD readout. You can monitor your actual crystal frequency while you grind away! Just remove the grinding debris from the crystal and dry it before testing.
You must download the assembly instructions and schematics from the QRP-ME website, but construction was simple and pretty much fool proof. The counter works from about 400 kHz up to about 50 MHz with about a + 10 dBm rf power input from an external source. In the midrange frequency area of 5-15 MHz, where your fundamental crystals will operate, the counter is quite sensitive at about -15 dBm. W1REX provides a small trimmer cap to align the frequency counter. I had no trouble zeroing in the crystal timebase to match my big lab counter.The X CHECKer counter will indicate crystal frequencies down to 10 Hz resolution.
Now, granted, an FT-243 crystal grinding station is not for everyone, but there are so many little QRP kits around these days that use old fashioned crystals, so it is a great fun enhancer to actually get into the crystal grinding business and roll your own!! I won't go into details, but there was a QST article on crystal grinding within the last year or so. All you need to start is a working FT-243 crystal on a frequency slightly below the desired frequency. You can simply move a crystal about 200 kHz as a rule. I am now going out looking for some 1000 grit sandpaper and assorted grinding compounds. I need to make a crystal on 3.045 MHz so I can make a transceive adaptor to match up a 75A4 with a Central Electronics 100V transmitter. I cannot wait to start grinding! Rex's kit is so much fun to use.
 


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