[Amps] Audio/RF compression

[Mark - G4FPH]

We're very lucky in my part of UK to have access to a number of WebSDR receivers (ref. www.websdr.org) that cover the 160 and 80 metre bands that I most often use.

When ragchewing on SSB, I have moved from headphone monitoring my transmitted signal picked up locally on a separate receiver to headphone monitoring my signal on a WebSDR at 30, or 40, miles distant. Forget QSK, this is full 'listen through' A kind of single-frequency duplex working!

Working another station, who has a similar strength of signal into the WebSDR, it's possible for me and the other station to jam our transmitters on and hold a conversation similar to you would do on the telephone. Of course, the 'sidetone' level coming back off the remote receiver is louder than desirable, but it's perfectly possible to tell when you are doubling and shut up promptly.

Latency is certainly an issue. The feed coming back from the remote WebSDR is probably 300 ms delayed wrt local mic. audio. After some practice, I've trained myself to work with this, with only the occasional stumble over words.

When I use my SDR TX,  there's some more latency to account for, which increases the risk of doubling, especially in a break-in style net. My brain can still cope though.

For those here on Amps. that have not yet discovered the joys of WebSDR, I strongly suggest you take a look. Forget the 'TX Monitor' function on your transceiver and toss your monitor scope in the bin. If you've ever wondered what your signal really sounds like in another persons shack, well, it's as good as being there and hearing and seeing 'live', for yourself. Yes, your transmit audio really is that muddy, your RF feedback is severe and your signal is splattering like a cows behind! Of course, none of that has and would ever apply to the carefully designed and operated stations of Amps. members'.

Have fun!

Regards,

Mark.

⁣---------------------------- 
Mark Hill - G4FPH 
www.g4fph.net 
www.160m.net 
Sent from my mobile 
--------------------------------- ​

On 12 Jan 2017, 20:59, at 20:59, "Joe Subich, W4TV" <lists at subich.com> wrote:
>
>
>On 1/12/2017 2:13 PM, Jim Brown wrote:
> >
>> Latency becomes an issue when main loudspeakers are 30+ feet over a
>> stage and further displaced side to side, and spill sound to the
>> stage, often in the range of 30-40 msec. This drives musicians nuts,
>> and is part of the reason large and complex stage monitor systems are
>> used. Performers hear themselves undelayed (or minimally delayed) at
>> levels higher than the leaked sound from the main system. Originally
>> this was done with big speakers on the stage floor; now it is far
>> more commonly done with miniature in-ear headphones connected to
>> stereo UHF receivers.
>
>It's particularly acute with vocalists who need to sing *in time*
>with the instrumentalists. Unfortunately, it is impossible when
>using electronic instruments (guitars, keyboards, etc.) that have
>no acoustic output!  It is even worse for keyboard players, etc.
>to press the key and hear no sound for 100 ms or more (think about
>a CW keyer with the sidetone delayed by one dit time or more).  Thus
>the need for either "foldback" speakers on the stage or "in ear"
>monitors.
>
>For another worst case situation, consider the amateur vocalist asked
>to sing the National Anthem at a NFL or MLB game.  Without practice
>and proper local monitor (foldback), it is totally impossible as the
>spillover from the stands will completely kill the performance.
>
>DSP can do some great things but it can often be like trying to keep
>a symphony orchestra together when the members are spread from the 50
>yard line around to the opposite 50 yard line and the percussion is
>in the opposite end zone.
>
>73,
>
>    ... Joe, W4TV
>
>
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