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  • Idea
  • Updated 5 months ago
MARS net operations require seamless switching from voice to digital.  Members who have the budget for a FlexRadio probably already use hardware modems that need to connect to the radio's accessory port.

Idea/Request:  We need a way to configure the accessory port to bypass filters and equalizers, etc. without the need to duplicate or change slices.  When the mic is keyed the radio should transmit voice normally.  When the accessory PTT is keyed and there is audio from the modem we need a clean unfiltered transmission of the modem audio.  Of course the audio out from the accessory port to the modem must be unfiltered as well.

We really need this to happen on one slice per frequency.  It is common to monitor multiple MARS frequencies at the same time and can't give up slices to support the modem on each frequency.  The accessory port should follow whichever slice is selected for transmission.

If this idea is implemented FlexRadio will become a better option for MARS operators than the single or, at best, dual VFO radios that are predominant now.
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Mike McIntosh

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Posted 2 years ago

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David Salomon

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Mike -

I use my 6600M for MARS every day,  I have Slice A set for digital (DIGIU), which does bypass all signal processing.  My MARS software modem gets sound from that slice via DAX and transmits via that slice.  Slice B is set up as USB, with normal filtering, etc.  This provides good digital capabilities while having voice on a separate slice.

There are 2 issues with this setup.  First, when the rig is switched to Slice A for digital, the TX remains on that slice after the digital transmission is complete.  I have to manually switch the TX back to Slice B.  Second, it's using 2 slices for one channel, thereby limiting me to only 2 usable slices for another channel (assuming I do second channel digital on Slice C and voice on Slice D).

While this is more manual than I'd like, it does work.  I often forget to switch TX back to Slice B after transmit, so I end up transmitting voice on Slice A.  That's also not a big deal as DIGIU works just as well as USB.  The receive audio I listen to is still Slice B.

I do agree that it would be VERY, VERY nice to be able to use a single slice for voice and digital.

I would LOVE to have a hardware modem, but they're fairly expensive.  A hardware solution I've found is the external modem from RapidM, but even that is around $3k.  And if you add on options (M141, etc.) it goes up to about $5k.  There's also the Icom F8101, which is 125 watts and has built in M110A.  However, after investing in my 6600M, there aren't enough pennies left over for one of those.

73 - David, AG4F
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John - WA7UAR

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Hi David, I am a new /T Army Mars volunteer. I’m trying to come up to speed as quickly as possible. Do you have any written tips you can pass along that you have learned? I’m running a 6700. I’m not currently using any hardware modems — I hope to use Dax for all things digital. Thanks for any insights you can share.
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Mike McIntosh

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I think you can obtain the external RapidM RM-2 modem from for less than $2000.  The modem for the F8101 is only about $800 from them but won't work with the Flex.