|
Hi there, first time poster, but been lurking for many years.
I have a question, though the answer could be more to do with FM, the TX or RX rather than ST. But just in case it is something I have miss-set, I thought I would ask..... (I have a FM Pro licence with declipper & advanced dynamics)
ST is great and put it to good use over the summer with a short term FM licence in the UK to run a scout radio station. I set up ST on a RaspberryPI (4, 8MB) & HiFiBerry in order to generate an MPX. It was to feed a Lucoro TX50, bypassing its built in audio encoder and processing. I think I set the tilt okay on a scope, and all the levels were good and peaks nicely under 75KHz deviation, frequency measured and spot on (I think!). Preset based on Greek 5&7. So I hope I set it up well.
Sounded great to be honest, both in testing TX into a dummy load and once deployed. The only setting that was not the best possible was latency in the Pi. I set this as low as I dare as I needed reporters in the field to use off-air as a cue feed. Was around 25ms, not overly easy to use, but was the compromise between delay and good enough stable audio.
However, the issue being every time the audio level went low (music fades, gaps, overnight carrier on), the background RF noise picked up. Quite a lot. If you were doing speech or had gaps, it would be hard to listen to. With music and fast talking or background sounds, it sounded good, which was the majority of the time.
I didn't notice this in testing, just when on-air. It could be a feature of the TX or the RX I used, or perhaps an FM anomaly, or something in the settings of ST I missed. Has anyone else ever come across this anomaly?
Andrew.
|
Register
Login
FAQ
Search