Tuner Frequency Response Analysis

[BxS]

BxS


No problem i will test.

Thanks

[rel]

True, some LNBs are off, that'll certainly skew frequency values.

If the cards would/will report signal strength without being locked onto a stream, reporting signal only, spectrum analysis would be possible. That would be a very handy feature. I don't know enough about the drivers and cards to know if that's possible.

The biggest headache with DVBcore was the time taken before it would report no signal and allow another change, blind scan would be virtually impossible.
But with direct hardware support it's certainly more feasible.

Scan for carriers, give software a start and stop range, when a carrier is detected scan until signal falls off again, math determines the signal's bandwidth. Then a symbol rate search based on the bandwidth. Not sure what would work best, top down or bottom up. If bandwidth is approximated at 18Mhz wide we could guess the symbol rate won't be small, scan rates from 30msps down until a lock. Something like that.

Naturally higher symbol rates move along faster.

Feed hunters will tolerate the time it takes. We do now. It can take as long as a half hour to scan one bird.

I think I will try to make a signal scanner (in fact, "lock scanner"!) when i find time later, with the logic you wrote above.

ss2 owners could try BxS's transponder finder app to see how feasible to make a blind scanner on a DVB card is.

[Rockin' Rick]

That would be cool.

Minimize the scan time by approximating bandwidth and possible symbol rate. Not sure if there's any advantage to scanning in one direction or another. Maybe top down always to avoid issues with minimum rates for the cards. Easy to set a maximum scan rate of 45Msps.

Start at 30% numerical value for symbol rate above estimated bandwidth.
So 11Mhz...start at 14.3Msps.

Then after a little testing perhaps narrow the margins.

Using DVBCore this would take days. But with direct support this would work much better.