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                           xtalfind 2.0
                     by Paolo Cravero, IK1ZYW
                    <ik1zyw at yahoo! dot com>

            See COPYING file for license information.

This software is a very simple bunch of Perl code that allows you to verify whether a XTAL (quartz crystal, used in electronic applications) is suitable for building (HAM) radio equipment.

Various tests are performed, some of them check if the quartz fits into one of amateur bands (80 to 10m WARC included, 6m and 2m, according to Italian frequency allocations). An additional test for a custom IF value is available as well, and latest additions verify your XTALs for Software Defined Radios and DRM receivers/downconverters.

1. CW TX or direct-conversion RX: if you see some output in this section, your XTAL is, on some harmonic, resonating on a HAM band
2. RX with 455kHz IF: this is successfull if n*XTAL+455kHz (or -455kHz) fits the HAM bands allocation, where n is between 1 and the maximum harmonic level you have chosen
3. RX with 10.7MHz IF: this is successfull if n*XTAL+10.7MHz (or -10.7MHz) fits the HAM bands allocation
4. TX with a 12kHz IF: this is successfull if n*XTAL+12kHz (or -12kHz) falls into HAM bands allocation
5. RX with a custom IF: this is successfull if n*XTAL+IF (or -IF) fits the HAM bands allocation
6. SDR for HAM bands using a Johnson counter (LO = 4x): positive when the supplied XTAL is 4 times a HAM band allocation. This allows the use as L.O. for producing I/Q signals of a HAM SDR RX
7. DRM 455-12kHz Converter: this test is successfull if the XTAL can be used as a downconverter for equipment with 455 kHz IF to receive Digital Radio Mondiale
8. DRM 9011-12kHz Converter: this test is successfull if the XTAL can be used as a downconverter for equipment with 9.01 MHz IF to receive Digital Radio Mondiale. Typically for ICOM receivers
9. DC DRM RX: given a list of DRM broadcasts (file DRMfreq.txt), tests show if the XTAL works as a 12 kHz IF receiver for each broadcast

NOTE: altought some sub/harmonics are hard/impossible to achieve without a PLL, xtalfind shows them anyhow as long as they match a test.

You can launch the software on any system that has a Perl interpreter.

Usage

xtalfind.pl [-quartz <n>|-file <filename>] [-arm <n>] [-if <n>] [-sample <n>]

Valid options:

-help                           Get (this) help
-quartz=<number>                XTAL frequency in Hz (default 10000000 Hz)
-file=<filename>                Read XTAL list from file
-arm=<number>                   Check matches up to -arm harmonic (default 10)
-if=<number>                    Also check against a custom IF value, in Hz
-sample=<number>                Soundcard sample rate for SDR (default 48000 Hz)

If no option is given, the program runs with a sample 10MHz XTAL, up to 10 sub/harmonics, and a soundcard sample rate of 48kHz.

Examples

> xtalfind -q 2580000

checks whether a quartz on 2.58 MHz is useful till the default harmonic level (10).

> xtalfind -q 4567000 -a 100

checks usefulness of 4.567 MHz quartz until its 100th harmonic.

> xtalfind -q 22533000 -i 4433619

checks whether a 22.533 MHz XTAL can work in a receiver with 4.433619 MHz IF. Useful if you want to build crystal filters with cheap XTALs.

Feel free to modify the frequency allocations found within the code to better suits your needs. I wrote this software for my own needs, when I decided to build a QRP RX/TX for HF bands.

I would appreciate an email to know you have found this software useful (or not), or a QSL via the buro :)

Have fun de
IK1ZYW Paolo

19 July 2005