VARA FM Wide bandwidth

Have you seen VARA FM Wide pass data through a Digirig Mobile at wide speeds? I mean speeds greater than 14,000 bits/second, which are only supported by the wide modes of VARA FM. The VARA display might look like this. VARA FM speeds are listed here.

If you’ve seen this, please tell us about the radio, antenna, computer and software versions you used.

I’m not sure a Digirig Mobile has enough audio bandwidth to do this. Demonstration of such a high data rate would be evidence that it does. I’m not equipped to test it.

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If radio can handle the wider bandwidth, Digirig will not be a bottleneck.
The standard voice band in ham is 2.4K while Digirig’s bandwidth is 24K (48K sampling rate) so there is quite a bit of margin.

That’s a plausible theory, but is there any empirical evidence to support it?

From what I’m reading it looks like Barry K3EUI is well equipped to settle this question. I’ll try to make a connection and post the update.

Jeff WX7OR said he saw VARA FM Wide level 12 going through a Digirig Mobile. That’s good news.

Yep, 47k transfer speeds are reported with Digirig in the same thread.
Thanks to Vara Modem community for running the tests.

I can confirm that using a DigiRig and a FTM-6000 on UHF I have hit 47k transfer speeds.

I believe speeds can get faster and will be trying some speed experiments with a Kenwood TK-8180 as the base station with many other radios including another Kenwood TK-8180. These radios were used in Convention and Trunking setups with many used as 9600 baud data radios for MDTs.

I will also plan to try some of the Motorola series radios including a APX-6500 and APX-8000 handheld over (P-25) with Vara FM and DigiRig.

I have a deviation monitor that I need to breakout to confirm other radios bandwidth vs speed, but that will be in the future when time permits.

By the way you need a high SNR (Signal to Noise Ratio) to hit higher speeds with Vara FM. Try the ping test against a couple of local sites and see how they respond. The differences will amaze you.

I hope future versions of Vara FM for wide will let you set the initial QAM connection speed. Like QAM-16.

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There are some very high speed VARA UHF gateways in Houston. I’ll see how fast I can go.

Testing digirig mobile with a FT-7900, I reached maximum speed level (25 kbps) with VARA FM WIDE for a link across 18 km and line of sight. The S/N was 35 dB.
Depending on your cabling, use of the USB-isolator might be necessary to reach best S/N.
Martin HB9AUR

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