G8JNJ

Hi John,

I think you have most of the common modes already covered, perhaps with the exception of ROS.

I agree about the lack of RSID. It is becoming increasingly difficult to identify some digital modes that are being used on the amateur bands. New ones seem to po up all of the time, and unless you are part of the "clique" that use them, up to date information regarding operational frequencies and specific modes, seems to be very hard to find.

Outside of the amateur bands

Winlink and Sailmail seem to be the only others that spring to mind and they use a mixture of Packet, Pactor, ARDOP and VARA, most of which is proprietary

https://www.winlink.org/RMSChannels

Regards,

Martin

Hi Glenn,

I have used WSPR Daemon with good results, but unless you have set aside some KiWi channels to allow it to run, it's not really applicable to the average KiWi installation.

Although not calibrated against a known noise reference, the graphs I have obtained using the standard KiWi SNR stats are almost as detailed as the ones I obtained using KiWi Daemon, in therms of indicating propagation changes. But unlike WSPR Daemon, it's a background process and doesn't require additional resources such as a RasPi (scarce at the moment), or consume precicous receive channels in order to work.

In addition I feel that the use of WSPR is beginning to wane somewhat, and FT8 is now taking over the world of Amateur radio. In fact if FT8 had a mechanism for reporting transmitted power and a full 6 digit locator, as does WSPR, I think WSPR would be in further decline for use as a propagation indicator.

With this in mind, it would be nice if the KiWi could support more of the JT/FT modes as an extension, in addition to WSPR, as I believe the libraries are available, but I guess it's not particularly high on the adgenda for John these days.

Regards,

Martin

Some additional notes on LZ1AQ's pages

http://active-antenna.eu/application-notes/receiver-front-end-protection/

Regards,

Martin - G8JNJ

I should have added.

I think the term AGC threshold may be misleading. I'd expect that if you reduced the AGC threshold level down to say -130dB, it would be operating all the time, but actually the opposite seems true, as you increase the threshold value the gain is reduced.

Try listening to a weak SSB signal and adjust the AGC threshold. There should be a point where the background noise is reduced but the intelligibility remains the same.

Tune to a CW signal and observe the decoder threshold graph whilst adjusting the AGC threshold. You can see the background noise fall away and the CW becomes much more consistant.

Maybe the default AGC threshold value should be in the Admin setup, so that it can be adjusted for the site noise floor.

Regards,

Martin - G8JNJ

Hi John,

I know we have discussed AGC settings and possibly implementing a bandwidth defined threshold in previous threads.

However I've just had to clear the cookies in my browser, and I notice that the default AGC threshold seems to be back at -130dB, which means that for most users of KiWi's the AGC is effectively running disabled and as a consequence the background noise level is higher than it really needs to be.

I'm fairly sure that in the past the default value used to be -90dB.

I've got a fairly low noise floor and -90dB for USB bandwidth is just enough to reduce the background noise level without degrading the sensitivity, so I think this would be OK for most users.

Regards,

Martin - G8JNJ