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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

so this should be fast enough.
Thanks again.

Chris
KD4PBJ
----- 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

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

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Hi Guys,

I am working on getting this little receiver up and running but noticed a
few things I wanted to ask of those more experienced.

I connected my generator and set it to 7.040 Mhz at -60 dBm then went to the
General tab and clicked on Calibration. I set the frequency in the field to
the generator frequency and clicked on start and it gave me a Frequency
Calibration Complete message. I did the same thing for amplitude, so now
the peak on the spectrum display is at -60 dBm. However the displayed
reading for the RX meter at the top right says -83.2 dBm. As I tune around
and the peak disappears the reading changes. What causes the discrepancy
between the signal meter reading and the spectrum peak's value- is the
reading an average between the signal and the noise floor?

The clicking was stopped by selecting MME under the Primary Sound Card
setup details field under Audio. Thanks Bruce for this help. I was worried
that I had to get a new soundcard for the computer (which is new, so I hate
to replace something that isn't broken).

I worked more with the Image Reject feature under DSP and I can only null it
by about 10 dB. It is sitting at about -65 dBm right now. The best null
comes with the Phase all the way to 400 at far right and the Gain all the
way to -500 at far left. The controls are at the end of their setting so I
need more range and I don't get the twitchy response that Bill mentioned. I
went back to the General tab and clicked on calibrate Image Null (above
values) and got an message that says "Error calculating image null. Please
try again."

Does this mean that the receiver is bad or is there something in the
software I need to change?

Thanks again for a great little receiver and especially for this forum that
we can get almost real time help from the designers and more experienced
users. It helps tremendously!

Chris
KD4PBJ


----- Original Message -----
From: "Chris Waldrup" <kd4pbj@...>
To: <softrock40@...>
Sent: Thursday, October 06, 2005 6:56 PM
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
----- 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 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

Yahoo! Groups Links

Yahoo! Groups Links

Yahoo! Groups Links

Hello Chris,

My answers in line

At 08:10 PM 10/6/2005, you wrote:

Hi Guys,

I am working on getting this little receiver up and running but noticed a
few things I wanted to ask of those more experienced.

I connected my generator and set it to 7.040 Mhz at -60 dBm then went to

General tab and clicked on Calibration. I set the frequency in the field

the generator frequency and clicked on start and it gave me a Frequency
Calibration Complete message.

Hmm -- not sure the freq calibration will have any effect with the soft
rock as that is used to calibrate the DDS reference osc, and there ain't
one in a SoftRock setup. The way to get the freq calibrated for a

is to set the center frequency on the SoftRock page in setup.

I did the same thing for amplitude, so now
the peak on the spectrum display is at -60 dBm. However the displayed
reading for the RX meter at the top right says -83.2 dBm. As I tune

and the peak disappears the reading changes. What causes the discrepancy
between the signal meter reading and the spectrum peak's value- is the
reading an average between the signal and the noise floor?

It is not the diff between the sig and the noise floor, I think it's the
average power across the bandpass selected or something like that. Try
putting your known signal inside a 500 khz passband and see how the meter
correlates with the panadpater display.

<...deleted...>

I worked more with the Image Reject feature under DSP and I can only null

by about 10 dB. It is sitting at about -65 dBm right now. The best null
comes with the Phase all the way to 400 at far right and the Gain all the
way to -500 at far left. The controls are at the end of their setting so

need more range and I don't get the twitchy response that Bill mentioned.

went back to the General tab and clicked on calibrate Image Null (above
values) and got an message that says "Error calculating image null.

try again."

I do not think the automatic calibrate on the image null will work with

Soft Rock, I've always done it by hand.

Does this mean that the receiver is bad or is there something in the
software I need to change?

This sounds like a hardware issue - one should not need to go to the
extremes to null the image. I don't think I've ever seen a properly
working SoftRock that needed to go the extremes to null the image signal.

First thing to check is that you're using a stereo input, some laptops

have a mic input and it is typically mono. Second thing to try is
reversing the left and right inputs to the sound card. Third thing to
look at is the hardware itself. If you have a scope try feeding a -30 dbm
or so 7.050 MHz signal to the Soft Rock antenna input and look at the I

Q outputs on the scope. They should be a 4-6 khz signal and about 0.8
Vp-p. They should also be of similar amplitude -- within about 20-30% of
each other. The phase relationship should be about 90 degrees between

If the IQ sigs are not of similar amplitude, check the soldering on the
FST3125 bus switch, and check that you see clock inputs on all the control
lines. 99% or soft rock hardware problems seem to be the connection of
the signals on the FST chip.

If that does not get it going, come on back and we'll debug some more.

Cheers,

Bill (kd5tfd)






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That sounds like the problem I had when I didn't have the SR-40 connected

a stereo input on the sound card (seems all of my mic inputs are really
mono). The image should null easily about into the noise level not too far
from the center range. Go to your sound level window on the computer

this is not part of the sr-40 software) and see if you can adjust the
left-right balance on the input you are using. If you can't, its mono. Try
using a line in connection to the sound card.
73/72 - Mike WA8BXN


-------Original Message-------

From: Chris Waldrup


Does this mean that the receiver is bad or is there something in the
software I need to change?




Yahoo! Groups Links

Chris -
A quick way to check to see if you are using a stereo input or not is to
change the display from panadapter to phase 2. If you don't get a display

any moving dots, its mono. Be sure to use line in instead of microphone in
too.
73/72 - Mike WA8BXN












Yahoo! Groups Links

Hi Guys,

I performed some tests tonight- the radio still won't null but here's what I
have so far.

I'm not worried right now about the RX meter, but I shifted to a 500 khz
bandwidth and the display only changes about three tenths of a dBm. It is
still has a 26 dBm difference from the signal peak, but the panadapter is
right so I'll go with that.

Today at work during lunch, I inspected the board under the
stereomicroscope on my bench (I am a SMT soldering/rework technician). All
looks fine. I checked the components and made sure that all were in the
correct locations and that is ok too.

I tried reversing the tip and ring of the audio connector, and that only
made the minimum null be with both sliders to the extreme left (before, one
was far left and one was far right).


Voltage measurements

FST 3126 pin # (Inputs to chip)
1 4.2 V p-p square wave. Wide bottom part of trace with a thin upper
part (maybe 75 % is wide bottom and 25% is top of wave). 2 no measurable
reading on scope
4 4.2 V p-p. Also same characteristic as pin 1
5 no measurable reading on scope
10 4.2 V p-p . Same as pin 1
13 4.2 V p-p. Same as pin 1

FST 3126 pin # (chip outputs)
3,6,8,11 no measurable reading on scope

Out of curiosity I tried putting the scope probe on the output of the signal
generator and there was barely anything detectable at -30 dBm. When I
brought the signal up to around -20 dBm I began to see a signal. My
generator is an HP 8640B and scope is a Tek 465.

Pin 14 (Vcc) of the FST3126 read 4.38 V with my DMM and pin 8 (Vcc) of U8
also read 4.38V.

I can hear the generator when I connect it, and I can hear CW so I am
assuming that I can get RF into the FST3126. I measured the values of L1
and L2 before I installed them so they are correct. I also used red and
green wire when winding T1 so I would not get the colors confused.

What's the next step? Thanks in advance and sorry for the long email.

Chris



----- Original Message -----
From: "Bill Tracey" <kd5tfd@...>
To: <softrock40@...>
Sent: Thursday, October 06, 2005 10:30 PM
Subject: Re: [softrock40] A few more things

Hello Chris,

My answers in line

At 08:10 PM 10/6/2005, you wrote:

Hi Guys,

I am working on getting this little receiver up and running but noticed a
few things I wanted to ask of those more experienced.

I connected my generator and set it to 7.040 Mhz at -60 dBm then went to

the

General tab and clicked on Calibration. I set the frequency in the field

to

the generator frequency and clicked on start and it gave me a Frequency
Calibration Complete message.

Hmm -- not sure the freq calibration will have any effect with the soft
rock as that is used to calibrate the DDS reference osc, and there ain't
one in a SoftRock setup. The way to get the freq calibrated for a

SoftRock

is to set the center frequency on the SoftRock page in setup.

I did the same thing for amplitude, so now
the peak on the spectrum display is at -60 dBm. However the displayed
reading for the RX meter at the top right says -83.2 dBm. As I tune

around

and the peak disappears the reading changes. What causes the discrepancy
between the signal meter reading and the spectrum peak's value- is the
reading an average between the signal and the noise floor?

It is not the diff between the sig and the noise floor, I think it's the
average power across the bandpass selected or something like that. Try
putting your known signal inside a 500 khz passband and see how the meter
correlates with the panadpater display.

<...deleted...>

I worked more with the Image Reject feature under DSP and I can only null

it

by about 10 dB. It is sitting at about -65 dBm right now. The best null
comes with the Phase all the way to 400 at far right and the Gain all the
way to -500 at far left. The controls are at the end of their setting so

I

need more range and I don't get the twitchy response that Bill mentioned.

I

went back to the General tab and clicked on calibrate Image Null (above
values) and got an message that says "Error calculating image null.

Please

try again."

I do not think the automatic calibrate on the image null will work with

the

Soft Rock, I've always done it by hand.

Does this mean that the receiver is bad or is there something in the
software I need to change?

This sounds like a hardware issue - one should not need to go to the
extremes to null the image. I don't think I've ever seen a properly
working SoftRock that needed to go the extremes to null the image signal.

First thing to check is that you're using a stereo input, some laptops

only

have a mic input and it is typically mono. Second thing to try is
reversing the left and right inputs to the sound card. Third thing to
look at is the hardware itself. If you have a scope try feeding a -30 dbm
or so 7.050 MHz signal to the Soft Rock antenna input and look at the I

and

Q outputs on the scope. They should be a 4-6 khz signal and about 0.8
Vp-p. They should also be of similar amplitude -- within about 20-30% of
each other. The phase relationship should be about 90 degrees between

them.

If the IQ sigs are not of similar amplitude, check the soldering on the
FST3125 bus switch, and check that you see clock inputs on all the control
lines. 99% or soft rock hardware problems seem to be the connection of
the signals on the FST chip.

If that does not get it going, come on back and we'll debug some more.

Cheers,

Bill (kd5tfd)






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