Hi Jason,
the source encoding of the transmitter power in WSPR messages is
complex. As far as I can see the message type is interleaved with the
dBm power value, this was probably done when type 2 and type 3 WSPR
messages were introduced to support compound callsigns and 6-digit grid
squares. The power values allowed probably once included all integral
values from -30 dBm through to +60 dBm but they have been reduced to
discrete values at roughly 3 dB intervals 0, 3, 7, 10, 13, 17, 20, 23,
27, 30, ... up to +60 dBm. The previous negative values and the missing
intervals 1, 2, 4, 5, 6, 9, 11, 12, ..., 53, 57, 60 have been repurposed
for the newer message types. In summary the new message types 2 and 3
have been shoe-horned into the existing protocol by freeing up some
"unnecessary" transmitter values.
I should note that I am guessing a bit from this after a brief scan of
the source code, Joe or Steve can probably confirm or clarify if necessary.
73
Bill
G4WJS.
On 08/10/2019 20:17, Jason Milldrum wrote:
Thanks Bill, that was my reading of it as well, but since the dropdown
box in WSJT-X had those smaller values, I wasn't sure if I was missing
something. I am still curious why those values were inserted if there
is no plan to implement them. If the devs have any further information
about this, I'd love to hear about it.
Thanks,
Jason NT7S
On Tue, Oct 8, 2019 at 9:12 AM Bill Somerville <[email protected]
<mailto:[email protected]>> wrote:
On 08/10/2019 16:50, Jason Milldrum wrote:
> So my question then is whether there is any support for power
levels
> below 0 dBm in the actual WSPR payload yet?
Hi Jason,
the source encoding of WSPR messages restricts the power value p
to 0 <=
p <= 60 dBm. There is no space in the payload to store values
outside of
that range.
73
Bill
G4WJS.
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