i have seen the video
summarize ... set rf gain to 27db (max sensitivity), if gain to
- 35db (not overdrive next stages) , visual gain to -40 db
(calibrate s-meter)... and your readout should be good to
plusminus 1 db or so ... between -130dbm and -50dbm!!
base noise then is at around -145dbm (from what i could see in
the video) ... so a -140dbm signal is still clearly 5 db over
the base noise
.....
what i do on any sdr... i set the gain (rf gain and if gain)
that the base noise just BARELY lifts up ... to have the max
sensitivity ... and then with visual gain i set it that the s
meter readings are ok (do match the real level) ...
most sdr are quite accurate in readings (as you found out with
your signal generator)
why the rspdx needs a minus 75 db correction downwards (if gain
and visual gain summed up) ... ok that how it is done in THIS
sdr (others sure need different settings)
gedas ... a question ... can you try to set visual gain lower
and increase if gain .. or set if gain lower and increase visual
gain ... and have the same results??
does the rspdx overdrive on a setting?? (sure it does depending
what level you throw at it) ... at what level with what
settings??
means try to find a setup with max sensitivity and high dynamic
range before overdriving ... try different combinations of
visual gain and rf gain to find the best compromize and then let
it there
plus ... you can do that also on vhf and uhf (and maybe find
complete different numbers)
next is ... if you set your receiving a bit sideways from
centre ... do you see "ghost" signals?? (a mirror of the main
signal or mixing products)??
pull the "high" slider in spectrum a bit upwards (to see those
high peaks also with -50dbm or higher without going "out of
sight" at the top)
greetz sigi dg9bfc
Am 04.07.2021 um 19:07 schrieb Gedas:
Have you
watched the video Simon? I ask because the video sorta
shows clearly what happens. I guess if you saw it and
still wanted me to summarize the data I would do that (it
is the least I could do for you after everything you have
done for us). 73
Gedas, W8BYA EN70JT
Gallery at http://w8bya.com (under repair)
Light travels faster than sound....
This is why some people appear bright until you hear them speak.
On 7/4/2021 12:55 PM, Simon Brown
wrote:
Any chance you
could write the details here?
So just for the fun of it yesterday I input different RF
level carriers into my RSPdx while changing some of the RF
gain, IF gain, and Visual Gain settings.
No conclusions are being drawn here, simply noting some
observations. I was always curious to see what different
levels looked like on the s-meter of my receiver. I hope
it is of some value to others.
https://www.youtube.com/watch?v=qHJE6wa9dVw
Gedas, W8BYA EN70JT
Gallery at http://w8bya.com (under repair)
Light travels faster than sound....
This is why some people appear bright until you hear them speak.
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