RE: [digitalvoice] Digest for - 2 updates in 1 topic

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David Grove

Jun 25, 2021, 12:36:09 AMJun 25

Hi Viktor


I’ve successfully tested FreeDV (I can’t remember which mode) on 6m FM on an IC7000 connected to a PC interface. That was without using a Hamlib set up.


Two-way transmissions were successful over a ~20 Km path to VK2ZIW. From memory we, initially tried to communicate with FreeDV on 6m SSB but the noise was too high (we’re both on noisy suburban blocks). However, FM cut-through just fine.


You should be able to receive the characteristic tones of FreeDV on a receiver tuned to your FM transmission





David Grove – VK2DWG


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Sent: Friday, 25 June 2021 13:40
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Subject: [digitalvoice] Digest for - 2 updates in 1 topic


·        FreeDV modulation on VHF - 2 Updates

"Víctor José Sánchez Escribano" <>: Jun 24 12:37AM -0700

Hi everyone.
I have a little doubt about FreeDV 2400B mode in VHF band (or another
FreeDV mode in this band) with a Yaesu FT-857. Which modulation should I
use: FM, DIG (SSB-based AFSK) or USB? I've try to receive with a near FM
handheld: if I TX in FM the FM HT hardly or not receive (squelch is open)
but if I TX in DIG or USB I can hear noise in the HT.
I've read the documentation but I only see that in HF bands it should be
LSB for <10 MHz and USB for >10 MHz (as usual) but I cannot find any
information about modulation in VHF band.

Mooneer Salem <>: Jun 24 10:22AM -0700

Hi Victor,
2400B is intended for use with FM. Some radios (like the FT-817) have a
specific "PKT" mode as well that is preferred, but it's definitely not
required. From what I remember, the FreeDV application will detect whether
you're in FM if 2400B is selected and you have Hamlib set up. Note that
volume levels with FM may be different than with SSB, which may also
explain what you're observing.
-Mooneer K6AQ
On Thu, Jun 24, 2021 at 6:14 AM Víctor José Sánchez Escribano <

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Víctor José Sánchez Escribano

Jun 25, 2021, 2:37:45 AMJun 25
to digitalvoice
Hi Dave

Thanks for share your experience. Maybe I should review any setting but as you said FreeDV tones are heard in a simple FM walky to test when I transmit in SSB modes (DIG, PKT, USB) but in FM is hardly heard or no heard. It could be a dumb question but I want to check is all OK.

Thanks, 73
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