开云体育

Hi Bob

please see comments below...

On 08/12/2019 15:28, Robert D. Bowers wrote:
> I'm transmitting into a load (the softrock output is about 2mw), and
> using the dongle antenna, a few feet away.

That's +3dBm.? What happens if you drive the softrock at it's rated
power output i.e. 1W mean, +30dBm?

> If needed, I
> can set that up - I've got a good 50 ohm step attenuator for doing
> measurements.

I use a 20dB attenuator rated at over 2W followed by a 120dB step
attenuator for those sort of tests.? I would use coax cables to connect
rather than rely on the stray signal pickup.? NB: Take care not to blow
up the receiver.? Start with max attenuation and work down.

> I adjusted the gain, and it does appear to be the transmitted signal
> itself.? The signal would be (FM mode) a flat-topped curve, with the
> flat portion about 5khz wide, and the sides slowly sloping down to
> around 20khz (each direction), where they start dropping more steeply.

Try it in CW mode or Spot i.e. single tone.? Can you put a 'scope on the
IQ outputs from the sound card?? On CW you should see a sine wave on
each channel, with 90 deg phase shift between the two channels.

Measure the level of these signals for 1W output.

> It appears to be noise of some kind - a high-pitched static (when in FM
> mode, listening to the output of the dongle audio).? For most of my
> tests, the gain on the audio out to the softrock didn't affect the shape
> of that signal.? (In SSB mode, it was differently shaped - two or three
> peaks, with the highest peak rather broad.)
> ...

I suggest that you forget FM and SSB until CW is working properly.

> I may be onto something.? Somehow the computer audio is picking up a
> high-pitched static - but I can't figure out where.? It's not coming
> from the softrock (or as feedback from softrock audio).? When I set the
> mike gain low enough, when I speak the mike audio over-rides the static,
> which vanishes for a second or so then fades back in.? I've been playing
> with turning off and on various audio devices, but without luck so far.
> (Laugh!) It would be my luck to have acquired a computer with bad audio,
> but the evidence goes against that (the sound only appears with Quisk).
> Even then, recording and playing back the audio from the mike under
> Quisk doesn't show the noise.

Are you using the motherboard sound card?? Do you have another sound
card you could try?

> I'm also picking up a strong AC buzz in receive using the softrock, but
> only when I am connected to my main antenna (fan dipole at 50ft -
> hanging off my tower).

Sounds like a grounding problem.

> The audio itself being put out (by my dongle) is strange - a high
> pitched hiss or buzz that I've not encountered before (not plasma TV -
> haven't heard that buzz in a while).

Do you have another receiver you could use to monitor the signal from
the softrock?

> My wife reported a strong buzz from her computer when I used my main 2m
> radio (on .52)... the shack and everything here is grounded and there
> should be nothing there as well.? The P/S for the radio is not connected
> to the softrock, and turning it off doesn't seem to make a difference
> with the problems I'm having.? Still, I'm going to scope that to make
> sure I'm not getting anything there!

Sounds like a separate problem!? In fact there may be several problems
there.

> It's a tough one... but I should be used to those by now!? (GRIN!) Next
> test - try a laptop (I think I have one with Quisk on it).

Good idea.

73
Nick