SDR# Bandplan should respect offset of starting frequency

[AM909]

In SDR# 1.0.0.1807, I have the following line in Bandplan.xml:

  <RangeEntry minFrequency="769006250" maxFrequency="774993750" color="50AAAAAA" mode="NFM" step="12500">All</RangeEntry>

That is, the 770 band here uses 12.5 kHz channels, but they start at 769.00625, 6.25 kHz above 769 MHz. Unfortunately, the snap-to-step logic in SDR# doesn't allow for this, and assumes that all channels start at 0 offset from a MHz, and will snap to 769.0125, 769.0250, etc. It should, instead, use the minFrequency in the relevant bandplan entry to make this calculation.

 

[thewraith2008]

While that would be handy for those who see channel plans that start from odd offsets, I couldn't see SDR# taking instruction from an external plug-in for an internal function (Snap). (even though it's bundled in to SDR# now)
BandPlan would be good for this as it would allow the user to defined the spectrum for themselves.

If you like getting your head bitten off, you could try and suggest it at your own peril on the SDR#/Airspy forum.

 

[Dirk_SDR]

In SDR# 1.0.0.1807, I have the following line in Bandplan.xml:

  <RangeEntry minFrequency="769006250" maxFrequency="774993750" color="50AAAAAA" mode="NFM" step="12500">All</RangeEntry>

That is, the 770 band here uses 12.5 kHz channels, but they start at 769.00625, 6.25 kHz above 769 MHz. Unfortunately, the snap-to-step logic in SDR# doesn't allow for this, and assumes that all channels start at 0 offset from a MHz, and will snap to 769.0125, 769.0250, etc. It should, instead, use the minFrequency in the relevant bandplan entry to make this calculation.

Yes, but you can step through the channels in SDR# also with manual start:
If I want to scan the MW band here (526,5..1606,5 kHz) in Europe with 9 kHz stepping, then I select the 1st channel at 531 kHz manually and set the stepping to 9 kHz.
Then I can step through all channels up to 1602 kHz.

 

[AM909]

I couldn't see SDR# taking instruction from an external plug-in for an internal function (Snap).

If the SDR# snap were set to 1 Hz, could a plugin tuner then be made to substitute for the one in SDR#, allowing freq entry, capture clicks on the spectrum display, and capture the scroll wheel events? Seems like I've seen a plugin that might have this as a side-effect of its main function, like maybe a scanner/freq manager. I'll do some more digging.

Just to document the perhaps obvious, if I turn off snap, it almost does what I want; I can set a starting freq of 769.00625 MHz, step of 12.5 kHz, and scroll wheel up will change freq to 769.01875 MHz. Clicking on the spectrum display, though, sets freqs in 1 Hz increments (e.g., 769187113).

If you like getting your head bitten off, you could try and suggest it at your own peril on the SDR#/Airspy forum.

I don't think I've been there before. I get confused about where to go for what. Link please?
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Yes, but you can step through the channels in SDR# also with manual start:
If I want to scan the MW band here (526,5..1606,5 kHz) in Europe with 9 kHz stepping, then I select the 1st channel at 531 kHz manually and set the stepping to 9 kHz.
Then I can step through all channels up to 1602 kHz.

I'm not sure I understand "526,5..1606,5 kHz". Are the channels offset down by 4.5 kHz, because that is exactly the situation I'm describing.

531 is an integral multiple of 9, so it snaps to it (if snap is enabled). If you type in 532 and then set the step to 9k, it jumps immediately to 531k. If you then type in 532 again and wheel down once, it goes to 522k (jumping by 10k to the nearest integral multiple of 9k), not 523k.