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Author Topic: ICOM's on the 630 meter band  (Read 8713 times)

AA2UK

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ICOM's on the 630 meter band
« on: September 21, 2017, 10:17:58 AM »

While I wait to either hear back from the UTC or if no response after 30 days start transmitting. Last night I tuned my IC-7410 to the 630 meter WISPR freq and was able to Rx stations in Canada, the US and ZF1EJ (EK99). I'm encouraged since my Rx antenna was my 6 meter Moxon (for real). I do understand building a "short" Tx vertical and base ATU will have it's challenges.

I have read a few articles on converting the ICOM IC-735 for use on the 630 meter band.
I hope to source one soon to do the conversion, this allows the transceiver to well Tx & Rx on 630 meters.
http://alain.st.free.fr/site1/aspicsite/IC-735/500KHZ/735-630m-mod.pdf


I have an IC-7410 that does a good job receiving but it doesn't look like it can directly transmit on 630 unless I go the transverter route. Has anyone seen a 7410 mod(s) that will allow it to Tx?

AA2UK, Bill
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G8YMW

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RE: ICOM's on the 630 meter band
« Reply #1 on: September 21, 2017, 03:46:18 PM »

Hi Bill
Are you receiving on the Moxon or the Moxon's coax outer against ground?

As for a transmit ATU, have you considered a variometer as the RF voltages may flash over any caps
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73 de Tony

AA2UK

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RE: ICOM's on the 630 meter band
« Reply #2 on: September 22, 2017, 02:50:05 AM »

Hi Bill
Are you receiving on the Moxon or the Moxon's coax outer against ground?

As for a transmit ATU, have you considered a variometer as the RF voltages may flash over any caps

The shield of the coax and the center conductor are not shorted in other words the shield is ground. My guess is the Moxon is acting like a small loop.

I have procured a working IC735 from K1JT for the project. I'll modify it to work on 630 meters.

I'll be using a short vertical with a base loaded coil and variometer.

AA2UK
Bill
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KD0YTE

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RE: ICOM's on the 630 meter band
« Reply #3 on: November 02, 2017, 10:02:45 PM »

I saw where someone mars modded a 7300 to transmit on 630M with mixed results. Could the same not be done to the 7410?  Maybe need to run an external filter?
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AA2UK

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RE: ICOM's on the 630 meter band
« Reply #4 on: November 03, 2017, 08:17:21 AM »

I saw where someone mars modded a 7300 to transmit on 630M with mixed results. Could the same not be done to the 7410?  Maybe need to run an external filter?
No the I have not been able to locate a single mod that allows the IC-7410 to transmit below 1.5mHz.
Bill, AA2UK
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