[Lowfer] WSPR-15 tonite

Wed Feb 6 14:00:34 EST 2013

Jay,

You mentioned one item that makes be very suspicious, the sound card. It 
is a Dell that came with the new computer. It calibrates very well with 
respect to frequency but it is a "junk" type card. I used to use a Delta 
44, but they don't fit in the new machines so mine is laying in a pile 
of parts somewhere around here. I bought a $125 external Soundblaster 
USB card last year but I think I read that USB cards don't work all that 
well either. Anyone got a solution for a quality soundcard that fits in 
the latest Windows machines. After I bought the computer, I went to the 
Flex Radio site and to my dismay, they were recommending the Delta 44 
card for their products and really didn't recommend much else. I haven't 
looked lately.

I had no noise blanker etc turned on.

Pat
N4LTA

On 2/6/2013 1:46 PM, jrusgrove at comcast.net wrote:
> I've been watching this thread for a while now ... here's my 2 cents. 
> BTW, I've changed the subject line to one more in line with the 
> discussion.
>
> No, Pat, I don't think you have a screw loose ;~) ... don't forget I'm 
> in the 'near field' of this signal and see 'crushing' levels as well 
> ... even with directional antennas pointed the other direction!
>
> First a comment about receiving setups. It really shouldn't make any 
> difference whether one uses the R-75 for direct reception or a setup 
> using the converter ahead of the receiver ... at least as far as WSPR 
> overload is concerned. The 200 Hz WSPR bandwidth is contained within 
> the boundaries of both the R-75 roofing and i-f filters. The overload 
> is occuring within this area. In terms of the likelyhood of what's 
> causing the problem I'd guess ... E probe (not likely), converter (not 
> likely, but not completely ruled out), R75 (not likely especially 
> since the K3 produced similar results), A/D (possible depending on 
> wherther it is a quality external sound card or 'onboard' audio junk) 
> and software (probably the most likely). This assumes that no noise 
> blanking, noise reduction, clipping, compression etc is in use - these 
> are known bad things that cause overload.
>
> If there are visible 'phantom' products in the waterfall (as I 
> sometimes see here) this overload is probably some sort of IM or 
> 'image', and it should be possible to make two tone measurements to 
> determine the offending component by inserting attenuation between 
> each of the major system component and observing the overload level.
>
> Jay W1VD  WD2XNS  WE2XGR/2
>
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> ----- Original Message ----- From: "pbunn" <pbunn at matrixei.com>
> To: "Discussion of the Lowfer (US, European, &amp; UK) and MedFer 
> bands" <lowfer at mailman.qth.net>
> Sent: Wednesday, February 06, 2013 9:57 AM
> Subject: Re: [Lowfer] WSPR-15 tonite
>
>
>> John,
>>
>> There seems to be a problem with strong signals and WSPR.  Eric has 
>> emailed me and seems to think that the problem is with my R75 but I 
>> don't think so. I realize that an R75 has poor strong signal 
>> performance but I have a very strong receive converter ahead of my 
>> R75. I use a mini circuits +17 DBM with a 7 pole filter in front and 
>> a GPS disciplined LO followed by a good diplexer and a Norton 
>> lossless FB post amp. Last night I could clearly hear a weak XSH/6 
>> QRS3 in the background when Bob was transmitting. I made an audio 
>> recording of it. Bobs signal was not blocking.
>>
>> My WSPR panel gain had to be set  to where I had no green bar at all 
>> in order to decode Jay and Eric. The background was jet black.
>>
>> I have a K3 that I could use as a receiver but in tests I see little 
>> difference. Jay asked me this weekend why I was transmitting WSPR -15 
>> at 468 KHz and I responded to "get away from the strong signals"
>>
>> I think he thinks that I have a loose screw, but from my experience, 
>> if you have powerful signals in the band pass or nearby, WSPR does 
>> not perform well.
>>
>> Thanks for the comment. This sure is fun. More fun than I have had in 
>> a long time with radio.
>>
>> Pat
>> N4LTA
>>
>>
>>
>> -----Original Message-----
>> From: lowfer-bounces at mailman.qth.net 
>> [mailto:lowfer-bounces at mailman.qth.net] On Behalf Of John Andrews
>> Sent: Wednesday, February 06, 2013 9:45 AM
>> To: Discussion of the Lowfer (US, European, &amp; UK) and MedFer bands
>> Subject: Re: [Lowfer] WSPR-15 tonite
>>
>> Pat,
>>
>> I had something similar with Jay last evening. Very strong signal, 
>> and several missed decodes. At least one was in a period where XGR/6 
>> was off. Was running AGC on the R75, so it certainly wasn't a 
>> receiver overload issue.
>>
>> John, W1TAG
>>
>>
>>
>> On Feb 5, 2013, at 10:58 PM, <pbunn at patbunn.com> wrote:
>>
>>> I have been running WSPR-15 since last night. When Gary noted that
>>> someone was in the middle with a drifting signal, I went out to the
>>> shop to see if I could see the signa
>>>
>>> What I saw was a surprise. I have not touched any gain setting since
>>> last night and have been getting good decodes until recently.
>>>
>>> The screen shot shows what I found and shows where I reduced gain to
>>> the point that very little noise is showing ( and very likely no weak
>>> signal would be seen)
>>>
>>>
>>> The screen can be seen at
>>> http://i620.photobucket.com/albums/tt286/n4lta/wsprscrn_zps392e4d37.gi
>>> f
>>>
>>> The screen is split between when I first found it first smeared in
>>> red, my first gain reduction and then a further adjustment.
>>>
>>> The far left is Bobs WSPR 2 signal
>>>
>>> There is no noise here tonite to speak of. The S meter on the R75 is
>>> below
>>> S1 (no bars on the S meter) and goes to S4 when Bobs signal comes on.
>>>
>>> The gain setting was initially set last night and worked fine all
>>> night with numerous decodes.
>>>
>>>
>>> Something is unusual with WSPR and strong signals, and I am pretty
>>> certain it is not my receiving equipment. I can hear the WD2XSG/6
>>> beacon in the background at the same time Bob is transmitting. He is
>>> not blocking the radio front end.
>>>
>>> Pat
>>> N4LTA
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