Making the 403-435 MHz MTR2000 Operate up to 440 MHz

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Operate up to 440 MHz
By Robert W. Meister WA1MIK

The 403-435 MHz station is limited by RSS, but apparently the exciter and power amplifier will operate over a larger range. The range values are all stored as 8-byte double-precision values, easily found and changed using most hex editors.

A Belgian amateur operator needed his station to work up to 440 MHz, the upper range for his country. He contacted me and inquired. I gave him a list of addresses to change. Here's the procedure.

Make a backup copy of MPS.EXE in the MTR2000 folder. Better to have it and not need it than to need it and not have it.

Open the MPS.EXE file. Set your hex editor for "Little Endian / Intel Byte Order".

Search for the 64-bit (8-byte) value 435.000; you should find three locations. The 8-byte value will be:
00 00 00 00 00 30 7B 40
Change all three locations to 440.000 MHz. The 8-byte value will be:
00 00 00 00 00 80 7B 40

It's possible that this change will also raise the lower limit of the 435-470 station up to 440-470, but it got the job done for the person who requested it.

You should also change the ASCII text that describes the frequency range of the station, PA, and RSS. In the same file, search for the text "435"; you should find four such strings that will say:
403-435_MHz_100W_1_Circ
435-470_MHz_100W_1_Circ
403 - 435 MHz 100W 1 Circ
435 - 470 MHz 100W 1 Circ
Two of those strings are for the 435-470 MHz station. DON'T CHANGE THOSE. Just change the "435" to "440" in the two 403-435 strings, where "435" is the upper range limit. Save the file and you're good to go.

I don't have a 403-435 MHz station to try this on but the amateur who requested this made the mods and reported that the station worked fine. You should go through the transmitter alignment and check the station's performance around 439.9 MHz.

It appears that 440 MHz is about as high as you can go with the typical station. Of course, your mileage may vary.

Contact Information:

The author can be contacted at: his-callsign [ at ] comcast [ dot ] net.

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This page originally posted on 17-Feb-2016

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.