Vara HF Console Information
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Hi Mike. Go to? where you downloaded VARA-modem and look for "VARA-HF quick guide" and "VARA documentation" down the page. As usual, reading manuals is not a thing :) 73, Erik OH2LAK On Sat, 4 Jan 2025 at 12:54, Mike via <mwilliams=[email protected]> wrote:
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Mike, when you get familiarized with the terminology and the acronyms, it is quite straightforward. And as the modem console is mostly just an indicator of what's happening, you do not need to have it visible all the time. Most critical things are the VU-meter on the left, which shows that the incoming audio level is OK. I tend to adjust the audio level so that it points directly upwards, so half scale. CPU load is also just for information, with modern computers the load should not be something which would bother the modems operation or other applications. The VARA modem runs with elevated priority so it gets more resources than usual applications. Two rightmost meters tell about the quality of the signal. The AFC meter indicates the frequency error of the received signal. VARA-modem has a AFC window of about 200Hz so it can correct?+-100 Hz offset. This is to do with slightly different clock frequency?of sound cards, or then the actual frequency offset of the radio on the other end. 99% of all the radios are within 20Hz or so of what I have operated. The last S/N meter indicates the Signal-to-Noise ratio of the incoming signal. VARA-HF is able to decode somewhere down to -20 dB SNR, but then there is no margin left at all. Better the signal, the faster speeds the modem negotiates with the other station. You can set the modem to show the diagrams which means you get to see the transfer speed of each transmission & reception,?and also the eye pattern of the modulation received. Waterfall shows the waterfall but it is not very useful, but good for debugging if you don't have audio input at all. The 'lamps' in the middle of the VARA-modem are sometimes the most useful things to watch at. As VARA is an ARQ mode, each transmission is acknowledged meaning that the other end reports back that your transmission has been received OK and your modem reports likewise before sending or receiving the next data batch. When observing the lamps during a connection, they are green when all is good but red when things need to be re-sent or that the modem has not heard an acknowledgement. This is how you can diagnose a stuck QSO for example. I tend to listen to the RX/TX audio while operating and I can already identify the chirping and what they mean :) I run the modem with just the gauges visible, but usually minimized as VARA-modem reports all the important things to the applications using it, for example VarAC. Hope to chat with you over VARA! 73, Erik OH2LAK On Sat, 4 Jan 2025 at 16:59, Mike via <mwilliams=[email protected]> wrote:
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Erik Finskas OH2LAK