Monday, November 11, 2013

ANAN-10 Signal Overload

 While looking at signals on 474.2kHz using the ANAN-10 and the Clifton Labs Active antenna I noted that the A/D overload warning in PowerSDR would come on often. I hooked up the ANAN-10 and used the KISS wideband view to see where the big signal was. The answer was "in the medium wave broadcast band. The loudest station peaked -27dBm into the transceiver in the daytime. Looking on the Spectrum Analyser one can see the lots of broadcast stations below 1MHz (nightime view)

I then remembered,  that to protect my K3 from a very local broadcast station on 1.7MHz, I had built a 1.7MHz Highpass filter. It didnt take long to find it in the storage unit, so I put it in front of the ANAN-10. Overloading went away. I also looked on the spectrum analyser:-


Everything below 1.8MHz has gone.

Curious,  I went to the Apache-labs web site and looked at the specification of the ANAN-10. Whereas it has LPF after the PA to comply with spurious emissions, it has NO filtering in front of the receiver which is broadband 10kHz-55MHz. May be time to look at some BPF for it! The only good thing about the lack of filtering is that this is fine for running the DL3HVH CUSDR32 software which allows same time monitoring of 5 bands (160 thro 10m) off a sngle antenna.

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