Chris Waldrup

开云体育

Hi All,

?

I finally got my Softrock up tonight after playing with it last night with no luck.? Tonight I can hear stations!!? I had a SDR program operator error last night.

?

I took it into work and during lunch plugged it into a USB port and verified with a scope that the timing signals were present.? A little overshoot and undershoot on the output of the buffer amp U1, but the signal is present.? I did the initial soldering under my microscope but checked over it again today to make sure all was fine.

?

Tonight I hooked it up to my 8640 generator and hear the tone fine, but every few seconds there is a rapid succession of a few clicks where the signal dies and then comes back.? The signal strength goes up from about -140 dBm to mid -50's.? The LED does not flicker at all during this (I had thought that the USB connector may be loose) and I tried connecting the USB connector up to my wife's new laptop and I get the same result.? I also connected the radio up to my antenna to rule out the generator acting funny and I get the same result.?

?

How accurate is the signal strength meter?? I set my generator for 7.040 Mhz at -73 dbm and the signal strength meter read -109 dBm.? I checked the output of my generator last year with a commercial power meter and it was about 2 dBm off, not 36 dBm off.

?

I have one last question.? I was going through the "Configure and Use" section of the assembly manual and?item #4 made me pause. Do I have to null the receiver to below -50 dBm on the?panadapter display ?or am I supposed to have a difference before and after nulling of 50 dBm.? I can get the receiver to null by about 5 dBm on the screen (from -108 dBm to -103 dBm).

?

Thanks in advance for any help that can be provided.

?

Chris Waldrup

KD4PBJ

Alverson, Tom \(Xetron\)

#321

开云体育

Chris:

?

I put my softrock on a calibrated? HP siggen and got a very accurate reading with a -80 dBm input.? You may have a problem with your? input filtering? (got the 2 inductors switched maybe?).? I don't know if the soundcard levels affect the s-meter or not.? I also got the "popping" effect on the PC I used that? was near the signal generator.? (an IBM with built in sound).?? My Dell Dimension 4600 with built in sound does not have this popping problem (every few seconds, there is a popping sound, and the spectrum display jumps at the same time).? Maybe some tweaking of the sound card/drivers would help (or a different sound card).

?

73 de Tom NU8D

From: softrock40@... [mailto:softrock40@...] On Behalf Of Chris Waldrup
Sent: Wednesday, October 05, 2005 10:32 PM
To: softrock40@...
Subject: [softrock40] Softrock up and running but need a little guidance

Hi All,

?

I finally got my Softrock up tonight after playing with it last night with no luck.? Tonight I can hear stations!!? I had a SDR program operator error last night.

?

I took it into work and during lunch plugged it into a USB port and verified with a scope that the timing signals were present.? A little overshoot and undershoot on the output of the buffer amp U1, but the signal is present.? I did the initial soldering under my microscope but checked over it again today to make sure all was fine.

?

Tonight I hooked it up to my 8640 generator and hear the tone fine, but every few seconds there is a rapid succession of a few clicks where the signal dies and then comes back.? The signal strength goes up from about -140 dBm to mid -50's.? The LED does not flicker at all during this (I had thought that the USB connector may be loose) and I tried connecting the USB connector up to my wife's new laptop and I get the same result.? I also connected the radio up to my antenna to rule out the generator acting funny and I get the same result.?

?

How accurate is the signal strength meter?? I set my generator for 7.040 Mhz at -73 dbm and the signal strength meter read -109 dBm.? I checked the output of my generator last year with a commercial power meter and it was about 2 dBm off, not 36 dBm off.

?

I have one last question.? I was going through the "Configure and Use" section of the assembly manual and?item #4 made me pause. Do I have to null the receiver to below -50 dBm on the?panadapter display ?or am I supposed to have a difference before and after nulling of 50 dBm.? I can get the receiver to null by about 5 dBm on the screen (from -108 dBm to -103 dBm).

?

Thanks in advance for any help that can be provided.

?

Chris Waldrup

KD4PBJ

Bill Tracey

#322

Hearing signals -- that's a good sign.

As to the accuracy of the power meter -- it's entirely inaccurate until you calibrate it as it is dependent on the sound card.  Once calibrated it should be quite accurate.    To calibrate it you need to feed it a known signal and use the calibrate settings on the General tab.  Set the freq and the level of the input and then hit the start button next to the Level entry field on the General tab.

Also while you're on the general tab, try setting the process priority to AboveNormal and see if that gets rid of the dropouts every few seconds.  Depending on the sound card and processor speed you may be dropping frames from time to time as the computer goes of and does something it feels is more important.

To null the image you use the phase and gain sliders on the Setup->DSP->Image Reject page.  I usually send in a -60 dbm signal at 7.040 and then set the panadapter display to spectrum, and turn off averaging of the display.  The primary signal will be on the left and the image to the right.  Slide the Phase slider until you find a minimum on the image signal, and then move the gain slider until you find a minimum, and then back to the phase slider to find a minimum,  repeat until you can't get a smaller minimum..  As you close in on the best null you can get the control will get a little twitchy.  Using the keyboard to adjust I can usually get the image signal all the way down into the noise.

Hope this helps.

Regards,

Bill (kd5tfd)

Show quoted text

At 09:32 PM 10/5/2005, you wrote:
Hi All,

I finally got my Softrock up tonight after playing with it last night with no luck.  Tonight I can hear stations!!  I had a SDR program operator error last night.

I took it into work and during lunch plugged it into a USB port and verified with a scope that the timing signals were present.  A little overshoot and undershoot on the output of the buffer amp U1, but the signal is present.  I did the initial soldering under my microscope but checked over it again today to make sure all was fine.

Tonight I hooked it up to my 8640 generator and hear the tone fine, but every few seconds there is a rapid succession of a few clicks where the signal dies and then comes back.  The signal strength goes up from about -140 dBm to mid -50's.  The LED does not flicker at all during this (I had thought that the USB connector may be loose) and I tried connecting the USB connector up to my wife's new laptop and I get the same result.  I also connected the radio up to my antenna to rule out the generator acting funny and I get the same result.

How accurate is the signal strength meter?  I set my generator for 7.040 Mhz at -73 dbm and the signal strength meter read -109 dBm.  I checked the output of my generator last year with a commercial power meter and it was about 2 dBm off, not 36 dBm off.

I have one last question.  I was going through the "Configure and Use" section of the assembly manual and item #4 made me pause. Do I have to null the receiver to below -50 dBm on the panadapter display  or am I supposed to have a difference before and after nulling of 50 dBm.  I can get the receiver to null by about 5 dBm on the screen (from -108 dBm to -103 dBm).

Thanks in advance for any help that can be provided.

Chris Waldrup
KD4PBJ

Bruce Beford

#323

Hi, Chris.

Re: The "popping sound" and shift in signal levels- (when you say 
the signal level goes from -140 dBm to -50 dBm during these jumps, I 
am sure you are talking about the background signal, not the output 
of the signal generator itself.) This sounds like the Windows audio 
driver issue that many of us have seen. Go to the Audio tab of the 
PowerSDR Setup screen. Set the audio driver to MME, instead of 
Windows DirectSound. Hope this helps.

73, -Bruce, N1RX

.--- In softrock40@..., "Chris Waldrup" <kd4pbj@b...> 
wrote:
<snip> 
Tonight I hooked it up to my 8640 generator and hear the tone fine, but every few seconds there is a rapid succession of a few 
clicks where the signal dies and then comes back.  The signal 
strength goes up from about -140 dBm to mid -50's.  The LED does not 
flicker at all during this (I had thought that the USB connector may 
be loose) and I tried connecting the USB connector up to my wife's 
new laptop and I get the same result.  I also connected the radio up 
to my antenna to rule out the generator acting funny and I get the 
same result.  
<snip> 
Chris Waldrup
KD4PBJ

Chris Waldrup

#326

Hi Bruce,

That fixed it!  The background would pop and shift levels even with no
antenna or signal generator connected.  Quite annoying when listening to a
faint signal.  Now that I got that taken care of, tonight I will work on
spur nulling and checking on the amplitude level readings (did not agree
with performance verified HP signal generator when I was testing it last
night).
The computer I am using is a Dell 3.06 Ghz machine with XP and 512 MB of RAM
so this should be fast enough.
Thanks again.

Chris
KD4PBJ

Show quoted text

----- Original Message ----- 
From: "Bruce Beford" <bruce.beford@...>
To: <softrock40@...>
Sent: Thursday, October 06, 2005 6:44 AM
Subject: [softrock40] Re: Softrock up and running but need a little guidance

Hi, Chris.

Re: The "popping sound" and shift in signal levels- (when you say
the signal level goes from -140 dBm to -50 dBm during these jumps, I
am sure you are talking about the background signal, not the output
of the signal generator itself.) This sounds like the Windows audio
driver issue that many of us have seen. Go to the Audio tab of the
PowerSDR Setup screen. Set the audio driver to MME, instead of
Windows DirectSound. Hope this helps.

73, -Bruce, N1RX

.--- In softrock40@..., "Chris Waldrup" <kd4pbj@b...>
wrote:
<snip>
Tonight I hooked it up to my 8640 generator and hear the tonefine, but every few seconds there is a rapid succession of a few
clicks where the signal dies and then comes back.  The signal
strength goes up from about -140 dBm to mid -50's.  The LED does not
flicker at all during this (I had thought that the USB connector may
be loose) and I tried connecting the USB connector up to my wife's
new laptop and I get the same result.  I also connected the radio up
to my antenna to rule out the generator acting funny and I get the
same result.
<snip>
Chris Waldrup
KD4PBJ

Yahoo! Groups Links

Alverson, Tom \(Xetron\)

#331

开云体育

Changing from "DirectSound" to "MME" also fixed the popping problem here.

?

73 de Tom NU8D

From: softrock40@... [mailto:softrock40@...] On Behalf Of Chris Waldrup
Sent: Thursday, October 06, 2005 6:56 PM
To: softrock40@...
Subject: Re: [softrock40] Re: Softrock up and running but need a little guidance

Hi Bruce, That fixed it!? The background would pop and shift levels even with no antenna or signal generator connected.? Quite annoying when listening to a faint signal.? Now that I got that taken care of, tonight I will work on spur nulling and checking on the amplitude level readings (did not agree with performance verified HP signal generator when I was testing it last night). The computer I am using is a Dell 3.06 Ghz machine with XP and 512 MB of RAM so this should be fast enough. Thanks again. Chris KD4PBJ

Show quoted text

----- Original Message -----
From: "Bruce Beford"
To:
Sent: Thursday, October 06, 2005 6:44 AM
Subject: [softrock40] Re: Softrock up and running but need a little guidance

> Hi, Chris.
>
> Re: The "popping sound" and shift in signal levels- (when you say
> the signal level goes from -140 dBm to -50 dBm during these jumps, I
> am sure you are talking about the background signal, not the output
> of the signal generator itself.) This sounds like the Windows audio
> driver issue that many of us have seen. Go to the Audio tab of the
> PowerSDR Setup screen. Set the audio driver to MME, instead of
> Windows DirectSound. Hope this helps.
>
> 73, -Bruce, N1RX
>
> .--- In softrock40@..., "Chris Waldrup"
> wrote:
>
> > Tonight I hooked it up to my 8640 generator and hear the tone
> fine, but every few seconds there is a rapid succession of a few
> clicks where the signal dies and then comes back.? The signal
> strength goes up from about -140 dBm to mid -50's.? The LED does not
> flicker at all during this (I had thought that the USB connector may
> be loose) and I tried connecting the USB connector up to my wife's
> new laptop and I get the same result.? I also connected the radio up
> to my antenna to rule out the generator acting funny and I get the
> same result.
> >
>
> > Chris Waldrup
> > KD4PBJ
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
>