TX latency with HERMES LITE

[jdow]

Max asked: "Approximately how much is the latency (just an estimate)? 100ms, 500ms, more?"
Alessaandro55 answered: ""

Please answer the question. Also, is there RF in the shack? Are you presuming you press PTT briefly to transmit and press it again briefly to stop transmitting. Just what IS your PTT setup. And when you comment about delays, monitoring yourself is a poor model for "to the air" latency. You go through two DSPs for that rather than one for observing the RF directly. (Trigger a storage scope with the PTT signal and monitor with a few inches of wire into the scope input.

If you periodically drop out, the most common problem source is RF in the shack. In particular look for ground loops or long cables. Make these RF path's impedances as high as possible. If you insist on monitoring yourself with the RX output of SDRC, make sure the automatic mute on input overload is not triggering.

And what IS this latency level you are upset about? A USB microphone will have as much as about 7 ms USB latency and an audio packet size delay. Don't fuss with ASIO. If you can set WSAPI parameters to as small a buffer as possible. (In this application ASIO is an extreme pain in the butt when you have two clocks, one driving the RF/DSP and one driving the microphone.)

{^_^}

[Alessandro55]

Hi, I don't have RF, if I use a few watts or many I have no RF I assure you that it is like this!! The transmission stops by always holding down the PTT, when I start to transmit it doesn't go into TX but will take 1 second to go!! I don't know what else to try, it's a real shame I like the software but I can't use it, maybe I'm doing something wrong, but I've been using the SDRS for years..... strangely if I turn on the PA and go into TX with 500 watts the situation improves but there is always a delay, already OM tells me that I go out at times as if a Noise GATE was active, thanks.

the PTT is mechanical but even with the one in the sdr console software it is the same I have the same latency problem

I'd like to try it even better but it seems that with ELAD FDM DUO the latency is lower!!

[jdow]

OK, I am not trying to be snarky. I'm just doing some basics just in case. (Old Just-in is a friend from way back. {^_-})

Under tools select options. Follow the rows of items down to "Auto-Mute". Make sure it is disabled. That can cause cutouts.

Under Transmit menu select Options. Select "TX | Tone | Tune". These delays are for assuring you do not feed TX RF into receiver inputs or burn contacts with RF before they are closed. Adjust carefully according to your system's needs.

What happens when you hit the tune button for a LONG time feeding a dummy load, of course? That might lead to a possible issue somewhere?

Oh, and what is your computer and CPU/Memory/etc? It LOOKS like it's something fairly new with plenty of CPU. The information might lead to something.

If these don't do any good we may have to get Simon involved. (Looks like this time will work. Nvidia drivers blew a fit leading to my windows session being logged out but the system did not reboot, which is both interesting and annoying. It's my bed time though. So it'll be some time tomorrow before I get back at this. If Max has no ideas I'd suggest he flag Simon on it.)

{^_^}

[Alessandro55]

Now I connected ELAD FDM DUO and it works very well, I have no problems.... I followed Simon's configuration... the mystery remains with HERME LITE, perhaps the reason is that the elad has USB connections, but it works fine with this sdr!!!


Sometimes it happens to me that with the console running I suddenly can't access the taskbar and I have to restart....but it did the same sometimes with HERME LITE, but the software works only that it doesn't let you open any app on the taskbar

[Max]

Now I connected ELAD FDM DUO and it works very well, I have no problems.... I followed Simon's configuration... the mystery remains with HERME LITE, perhaps the reason is that the elad has USB connections, but it works fine with this sdr!!! Sometimes it happens to me that with the console running I suddenly can't access the taskbar and I have to restart....but it did the same sometimes with HERME LITE, but the software works only that it doesn't let you open any app on the taskbar

You never did get back with the answer to pretty much any of my questions about the audio latency that you hear on SDRC..... I was trying to understand if the latency is at RF or if it's happening in the audio chain before it even gets to RF? You could have found this out by answering the questions I answered about monitoring the audio at the input to the Audio DSP as I suggested. But because you never answered this then we still do not know. Maybe you do, but you have not told us!

However, the fact you say there is a long delay when you hit the PTT to going in to TX, and you say that the audio is reported as "like a noise gate" that implies missing packets. So now you have confirmed that the FDM Duo works fine via USB. This is all pointing very much to a LAN issue between your network/PC and the HL2.

Please describe EXACTLY how the Hermes Lite 2 LAN/ethernet socket is connected to your PC? Via router? Direct plugged in to PC? What?

I can assure you that the HL2 works extremely well with SDRC when it is set up correctly.

Max

[Alessandro55]

Sorry, but sometimes the translator doesn't write correctly in Italian!! The Hermes is connected directly to the PC's network card. Could it be a bad cable? I definitely don't have RF, but what should I do? Can you explain better? It's my fault, thanks.

[Max]

Do you have any other networking equipment of devices connected to the PC network card? If so, what?

Cable to the network card from the HL2 must be CAT5e or CAT6.

Ci sono altri dispositivi o apparecchiature di rete collegati alla scheda di rete del PC? In caso affermativo, quali?

Il cavo che collega l'HL2 alla scheda di rete deve essere CAT5e o CAT6.

Max

[Alessandro55]

No!! Yes Cat 5e diretto al pc

[jdow]

1) Just for drill, is a wireless connection involved in any of your Hermes Lite setup? That is a sure way to have drop outs. (For example the wireless earphones I have will drop out if it doesn't like the color of the most recent car to pass on the street outside or something else as random and arbitrary. The bluetooth connection to my audio system is within arm's reach of me when this happens. Wireless is poison, pure poison, when drop outs mean more than a momentary annoyance. I switch to a wired connection for ham activity.)

2) I also presume your CAT5e cable is short, 5 meters to 20 meter range. Cables that are called Ethernet cables but are smaller than about 5mm are not usually very good for even modest length runs.

3) I don't remember if you said other SDR programs can transmit with your Hermes Lite. That is an important test.

4) Also, what happens when you use the TUNE button? (Use a dummy load to stay legal and be polite to other hams, please.)

{^_^}

[Alessandro55]

The cable is 1.5m long, I don't use a BT connection or headphones at all!! Yes, the HERMES LITE works fine with the THETIS. When I use the TUNE it works fine, the problem is when I transmit with AUDIO. I wanted to ask something about the elad, but is there a way to make a mechanical PTT so that when I want to talk I have to press the button???