Re: Transmit audio level for FM VHF?


Harry Bloomberg
 

You're right...it's been a while since I've done NBEMS on VHF/UHF FM.  Slightly lower audio level than voice is indeed the best.  And a deviation meter is just not needed.

73,
Harry W3YJ


On Mon, Oct 26, 2020 at 1:10 PM KL4YFD ham <kl4yfd@...> wrote:

Hi All,

To adjust audio-levels for FM you can listen to your own voice-signal through a scanner and adjust your digital-Tx-audio to be slightly quieter than voice (to prevent overdriving).
Better to have a too-quiet signal than a too-loud one.

The modes in Fldigi, even the 8PSK modes, are designed to be adjusted by ear without a deviation meter needed.
This is very handy in an emergency situation, hihi.

Since people are using Fldigi more for FM, the manual should have some kind of FM adjustment procedure or info added.
Here is a link for adjusting audio for 8PSK:   
Can apply the same procedure for all Fldigi modes on FM. 

73,
John Phelps
KL4YFD

On Mon, Oct 26, 2020 at 9:18 AM Harry Bloomberg <hbloomb@...> wrote:
My opinion as somebody who used to conduct a ton of NBEMS training...

Getting the modulation perfectly set on VHF/UHF FM isn't worth the time and trouble.  Adjust so that the transmitted NBEMS audio is close to that of a spoken voice.  Sometimes "Good Enough" is good enough.

73,
Harry Bloomberg W3YJ

On Mon, Oct 26, 2020 at 12:15 PM Jim <jamesgood@...> wrote:

A few years ago, I had an IC706MK2G and also made two installations of Fldigi with one for the HF side and the other for VHF/UHF. The interface between the radio and computer was (is still) a SignaLink USB with the cable from Tiger Tronics getting the signals to and from the radio. The settings I used for the SL USB were to have both the TX and RX (the transmit and receive) settings at mid-point or about 12:00 and the DLY set at full counter clockwise (CCW). The power TO the radio (from computer to radio) was set so that the radio would transmit a clean signal at not over half power for whatever band had been selected.

James Good kd5vxh

On 10/26/20 1:04 AM, Randy Allen wrote:

Oh, and forgot to mention in my previous reply, it turns out the optimum settings on VHF/UHF for my set up (IC-706MKIIG on low power and SignaLink) was setting all three knobs at about the 11 O'Clock position when using FLDIGI (usually MT-63 2KL) and setting the DLY to almost minimum when using WinLink. YMMV.

Hope this helps

73

Randy KA0AZS

On 10/26/2020 01:13, Neil Preston W0NRP via groups.io wrote:

The operating manual explains how to set the transmit audio for an HF transceiver, but seems to give no guidance for setting up the audio for VHF FM.
We have the (unverified) information that the recommended deviation level is approximately 3 KHz.

We have been struggling with this in our training nets, and most of us do not have deviation measurement capability.
What methods might allow us to make some kind of reasonable estimate of our audio level when using a SignaLink?

Thanks....


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