SDC Skimmer for Flex Radios

Erik Carling EI4KF

For anyone interested in trying the Skimmer that I prefer over the Afreet CW Skimmer, a PDF with instructions for setting it up is in my Dropbox:

As it is free, there is nothing to lose if you do not like it. It does require you to obtain by email a registration code from its author, as explained in the document.

Erik EI4KF.

updated link: https://www.dropbox.com/s/rhxfnkqy9hdb1oa/SDC%20SKIMMER%20WITH%20FLEX%20RADIO.pdf?dl=0

Russ Ravella

Thanks Erik

Why do you prefer it to CWSkimmer ?

Russ KR6W

Erik Carling EI4KF

Hi Russ,

Mostly because it is more accurate in its decoding, has configurable parameters to maintain that efficiency depending on the use to which it is being put, and is part of the SDC program that has other services that I use every day.

For those who want a Skimmer for the first time, it does not cost them $70.

Russ Ravella

Thanks Erik

Those are some pretty good reasons !

Ben Morris

Erik,

Thank you for posting these instructions. Pavlov got me set up with a registration for SmartSDR and I have it up and running and sending spots to N1MM. I’m looking forward to using it in the next CW contest! 😁

Ben Morris KT4O

Erik Carling EI4KF

Excellent! If any part of the instructions you think need amending or clarifying, please email me with details (ei4kf page, qrz.com). 73 de Erik.

Ron K2RAS

The only thing I don't see is the ability for the software to decode messages (not just the callsigns) across the entire IQ stream like CW Skimmer. Am I missing something?

Thanks, Ron K2RAS

Erik Carling EI4KF

It will decode as much or as little as you like, depending on the settings in Skimmer Global Setup, Band Plan tab. As you tune over callsigns, the messages will appear in the decoding window(s). Or should do anyway, just double checked and seems to working ok.

Erik Carling EI4KF

I have received some feedback, mostly on two themes: multiple skimmers for split and tracking a pile up / additional Slices + N1MM integration. So I have updated the PDF to cover these two features.

https://www.dropbox.com/s/k7ko6nbptv63qb5/SDC%20SKIMMER%20WITH%20FLEX%20RADIO.pdf?dl=0

Erik

WK2Y

I'm trying to get SDC up and running and not having much luck. One very frustrating issue as I try and work my way through the settings is that if I exit SDC and then try and restart it, nothing happens. Anyone else encountering in this and have a solution?

73,

Bob, WK2Y

Erik Carling EI4KF

If you close the GUI, SDC is still running and you will see its icon in the system tray. This is probably where the confusion is.

If you really want to close it, right click the icon to see the menu:

If you are already really closing it then of course it should restart but I have never in 5 years known it not to. But I suppose there is always a first time. Check in Task Manager that the program has exited when you think it has.

WK2Y

Ah ha! We have met the enemy and he is me!! Thank you.

Joe N3HEE

Erik,

I was able to get SDC to work with my Flex and N1MM however the spots would seem to randomly appear and then disappear after a short period of time ? This happened both on the Flex panadapter and in N1MM band map.

Can you please explain how the Interval settings work in SDC. I would think that a spot would stay active as long as the station is calling CQ ? I think I need to adjust the interval settings but not sure what they do ?

These are my settings...

Thanks,

Joe

N3HEE

WK2Y

I am up and running which leads me to another question:

One of my favorite activities is looking get cards from special event stations. They have odd calls like SX200ME, CQ750RSI, VE2SPEED, HO100CANAL. I am looking at the manual's verify section and I am wondering if I would see calls like that when using SDC? Would I need to know about the calls and program them in ahead of time using the Special Calls Format option? Is there a way to not verify calls and display anything that looks like a call? Or am I miss understanding how the verify function works altogether?

Thanks for your help.

73

Bob, WK2Y

Erik Carling EI4KF

Hello Bob: Yes, you should see all odd callsigns such as those you listed without any intervention on your part. The Skimmer does need to know from you those special calls which are ones with non-standard amateur format. So, that does not include those with several characters in the prefix or suffix but does include unusual prefixes. An example of which is 9LY1JM, which if not added to Special Calls Format would be deliberately ignored. As to your last question: a combination of SDC's normal decoding function + any special calls should mean that anything that looks like a callsign is displayed.

Hello Joe: I have just started the Skimmer on 20m and there is some kind of CW contest going on. The Skimmer Spot count is high, over 300 were posted to the panorama in 4 minutes. After 10 minutes a few of the earliest disappeared which equates to 'Delete call after last decode' = 600 seconds. Some disappear more quickly because if the Skimmer decodes a callsign again and it is more than 1kHz from the last Spot, the earlier Spot is deleted. In a contest S&P stations are tuning up and down the band so you do not want to see multiple Spots for the same callsign all over the place. Other than that, I do not see random disappearances.

I do wonder whether Flex has a limit to the number of Spots. I cannot find any reference to this in the SSDR manual. If it does, this would have an effect I suppose.

Nevertheless, you are correct: a station sending CQ (on the same frequency) should not disappear. If you are seeing this I can check it with Yuri. I see no evidence of it myself but who knows, maybe there is an issue.

Erik.

Joe N3HEE

Erik

I found there is a setting in SDR Bridge that limits the spot lifetime. It was set to 100. I believe that was killing spots in 100 seconds. I increased that to 300 seconds.

I will spend some more time with SDC to make sure I have everything set properly before getting Yuri involved.

I have also noticed some other strange behaviors such as random crashes, skimmer decoding stopping and multiple spots of the same stations showing up on opposite ends of the CW band ?

Thanks,

Joe

N3HEE

Erik Carling EI4KF

Ok Joe, my SDR Bridge setting was 600 so that accounts for the difference between us in what was disappearing. I have never experienced the Skimmer stopping or SDC crashing or even strange Spots on band edges. If you do identify any cause(s) please let me know, or Yuri of course.

Erik.

Joe N3HEE

Here is example of the same spot showing up on different ends of the band. You can see NG3R calling CQ in the lower part of the band and he is also spotted higher in the band. Same for N9NA. Both of those stations where operating on the lower end of the band.

Below we see an image signal of K1IMI around 14.063 but he is really transmitting on 14.015. Both are being decoded and spotted.

It appears this is only happening for very strong signals ?

Erik Carling EI4KF

Yuri wrote to me: This occurs if the DAX properties of the device in Windows (DAX IQ1) is incorrectly selected.

Example: if DAX is using a 96KHZ sample rate, then in the Windows Sound properties you need specify 96 KHz / 24 Bit.

However, even with this change I am seeing it as well. I will have to discuss it with him.

Erik.

Erik Carling EI4KF

Joe, if you would like to do it please change the Windows Sound setting to 24 bit / 96 KHz to match the DAX sample rate of 96000 Hz. This has to be done with no devices active. Then recheck the issue with the same stations at each end of the band. Please tell me the result. Yuri says he has rechecked the operation of the Skimmer and the problem does not occur. It is happening here so I'd like to know if it does for you too after the settings change.

Erik.

Erik Carling EI4KF

I have solved it. For some reason I have to set 24 bit / 96 KHz in Windows Sound for both IQ1 and Audio RX 1.

No problem now.

Erik.

Joe N3HEE

Thanks Erik ! That solved the issue for me as well. Make sure to document this setting. -Joe

Erik Carling EI4KF

Yes, thank you Joe. This is now documented along with the Spot Lifetime settings in SDC & SDR-Bridge.

https://www.dropbox.com/s/k7ko6nbptv63qb5/SDC%20SKIMMER%20WITH%20FLEX%20RADIO.pdf?dl=0

Joe N3HEE

Erik,

I figured out why my skimmer was randomly stopping. If using the SDC Telnet server features make sure to uncheck "Connect and Start SKM server" box located in the Telnet Server tab. If this box is checked it will cause the skimmer to stop running when connections are made to the Telnet server because the Spotters are automatically started when a Telnet connection is made. In order to get the skimmer running again you must manually restart SDR Bridge while the skimmer is "Waiting TCP start ... ".

NOTE: There is also another setting for Spot LifeTime located here.

In my case I was sending SDC skimmer spots to DX Labs SpotCollector using the SDC Telnet server. That telnet connection can sometimes get disconnected. When it reconnects it was stopping the skimmer because the "Connect and Start SKM server" box was checked.

Thanks,

Joe

Erik Carling EI4KF

Ah ha, interesting Joe so thank you for that. I never have those disconnections so did not experience the Skimmer stopping. I'll add this point into the instructions.

Not that I have actually timed it but the Spot Lifetime setting there is for those DXCluster clients or 'Spotters'. I expect you know already but just so nobody is confused, it is supposed to have no effect on Skimmer Spots.

Erik

WK2Y

I am enjoying SDC, Two related questions: What settings on the Flex or SDC do I need to tweak to get more accurate decoding? I have Remove Noise Letters checked, the filter set to 50, my Flex AGC on slow and low, but I'm still getting a lot of excess characters. Is it just my noisy QTH?

I presume not, but I want to make sure I am not missing anything: Is there a way to decode multiple transmissions at the same time a la CW Skimmer?

Thanks.

Bob, WK2Y

Erik Carling EI4KF

Hi Bob. I am not an expert on Flex as I've had my 6400M only 7 weeks and 5 of those it was away. I do have AGC on Fast for CW to allow the RX a quick recovery time. I use a 100Hz filter on CW but that is very much a matter of preference, lots of CW guys use a wider filter.

The SDC Skimmer should be very accurate but I do have a noiseless QTH. In the Setup Skimmer 1 window there is a Signal/Noise Detect parameter which I have at 2dB but you might need to increase it for a noisy environment. Maybe test different levels. Else, you can increase the numbers in Global Setup, Verify Call so that a more rigorous test is made on decodes before posting them as Spots. That will reduce decodes overall though. But you could test it.

The Skimmer is decoding multiple transmissions, there are actually a huge number of skimmers working simultaneously. But I have forgotten CW Skimmer, 5 years since I last used it, and cannot think of what you are specifically referring to. If you could explain in greater detail.

Erik.

Joe N3HEE

I think Bob is referring to the ability to see all of the decoded text at the same time scrolling on the right side of the skimmer window. That's how CW Skimmer works. I don't think this is available in SDC skimmer. Although SDC skimmer is decoding every signal on the band you can only view one decode at a time.

I have found that the signal strength has to be pretty high and QSB pretty low to get good text decoding. Call sign decoding works pretty good even with low signals. The skimmer seems to be able to piece together partial decodes and figure out call signs.

I used SDC skimmer last night for the Slow Speed Test and it was decoding call signs accurately and sending them to N1MM and the Flex panadapter. It would sometimes take it a few tries to decode the call sign which can be problematic in contests.

SDC skimmer has the ability to aggregate it's output with other telnet clusters. This is probably the best way for contesting so you don't miss any spots.

Here is a sample of a text decode with a strong signal with no QSB. Flex set for 400 HZ filter, AGC=MED, AGCT=35. Signal strength was S9 to S9+10.

Joe

N3HEE

WK2Y

Joe had it right. Thanks both of you.

Erik Carling EI4KF

Yes Joe, I remember now and you are quite right in that SDC doesn't display in that format. I do remember Yuri, the SDC author, commenting that decoding messages was not its priority. He's a top CW op in UT-land, bit of a purist I think! Spots are good but doing what your brain is supposed to do is not hi. He may well work on that part of it later, SDC versions are released quite frequently. And you you can always email him and ask - he is a really nice guy and very amenable.

Erik.

Mr Radio

Is it essential to run SDC Skimmer on slice 1 or it can be run on any one slice available?

Tom