[CQ-Contest] Skimmer ultimate setup?

Joe Subich, W4TV w4tv at subich.com
Fri Mar 21 09:12:30 EDT 2008



> There are two more options worth mentioning:
> 
> -- the SoftRock guys have just come out with a 
> frequency-agile SoftRock Lite.  

  and 

> -- RFSpace makes a little SDR called the SDR-IQ that will 
> sample a swath of spectrum up to 190 KHz wide from 500 Hz 
> (that's right, Hz) to 30 MHz. 

One of these receivers could be coupled with its own antenna 
- either an active receive antenna or multi-band vertical (e.g., 
HyGain AV-640).  If Alex added a "scanning" function to moved 
Skimmer from band to band on a regular schedule (every five 
minutes?) a single user would have an up to date record of 
everything audible at his QTH.   

For improved performance, the software for a  self contained 
front end could also include external CAT data emulating a 
"known protocol."  This would allow using a controller like 
microHAM's Band Decoder to select any unused antenna with a 
six or ten by two switch for improved performance within the 
receiver (mixer) dynamic range.

73, 

   ... Joe, W4TV 
 
 


> -----Original Message-----
> From: cq-contest-bounces at contesting.com 
> [mailto:cq-contest-bounces at contesting.com] On Behalf Of Pete Smith
> Sent: Friday, March 21, 2008 6:49 AM
> To: Joe Subich, W4TV; 'Dave Hachadorian'; 'cq-contest reflector'
> Subject: Re: [CQ-Contest] Skimmer ultimate setup?
> 
> 
> LP-PAN looks very nice, but I'd expect nothing less from N8LP 
> - his stuff 
> is great!  The big advantage of the SoftRock approach is the 
> trivial pricetag.
> 
> There are two more options worth mentioning:
> 
> -- the SoftRock guys have just come out with a 
> frequency-agile SoftRock 
> Lite.  Another guy makes a 6-band bandpass filter board.  It 
> would not be 
> difficult to homebrew a 6-band receiver that could be tapped into the 
> receive antenna loop on the second radio and switched by software (or 
> manually).  The big advantage there is that neither Skimmer 
> nor logging 
> software would require any modifications.  In a single-band 
> form, this is 
> what is currently in use here for the Skimmer reverse beacon 
> experiment.
> 
> -- RFSpace makes a little SDR called the SDR-IQ that will 
> sample a swath of 
> spectrum up to 190 KHz wide from 500 Hz (that's right, Hz) to 30 
> MHz.  VE3NEA is developing Skimmer control of the SDR-IQ.  
> This could be 
> used in the same way as the lash-up described above.  The 
> only drawback is 
> the cost, (~$500), but when not contesting it could be used 
> for lots of 
> other things, such as a spectrum analyzer or swl receiver.
> 
> 73, Pete N4ZR
> 
> At 05:58 PM 3/20/2008, Joe Subich, W4TV wrote:
> 
> >Some additional comments ...
> >
> > > >3. The output of the Z10000 goes to a "Softrock Lite" receiver 
> > > >tuned for 8.215 Mhz. Maybe that frequency needs to be 
> offset from 
> > > >the 8.215 IF to prevent the softrock Lite oscillator 
> from getting 
> > > >into the K3 IF?
> > >
> > > You may not feel the need of the buffer amp (Clifton 
> Laboratories, 
> > > K8ZOA, www.cliftonlaboratories.com) if you offset the 
> Softrock local 
> > > oscillator so that it falls outside the roofing filter bandwidth, 
> > > but it would be a good precaution.  On the radio to which my 
> > > SoftRock is connected, the local oscillator is S9+40.
> >
> >Keep your eye on the LP-Pan project by N8LP (www.telepostinc.com). 
> >LPPAN would replace the buffer/filter and softrock lite.
> >
> > > >6. CW Skimmer outputs spots to the logging program and 
> puts them on 
> > > >the bandmap. I'm a little fuzzy on how CW Skimmer knows the 
> > > >frequency of these spots. Does it look at the rig 
> control frequency 
> > > >of the S&P Radio, or is some other connection required 
> for Skimmer 
> > > >to know the frequency?
> > >
> > > Ah, here's the rub -- Skimmer needs to know what frequency your 
> > > radio is tuned to, so that it can display the waterfall with real 
> > > frequencies rather than frequencies relative to the 
> Softrock local 
> > > oscillator; that, in turn, means that Skimmer needs to be 
> > > communicating with your radio.
> >
> >N8LP's software suite will include a multi-port server that will 
> >allowed multiple programs (PowerSDR, CW SKimmer, logging 
> program, etc.) 
> >to access the radio simultaneously.  Other testing indicates the 
> >important thing is that no program poll constantly at 100% 
> of the radio 
> >interface capability. Icom radios will have significant issues with 
> >split status (as expected).
> >
> >73,
> >
> >    ... Joe, W4TV
> >
> >
> >
> > > -----Original Message-----
> > > From: cq-contest-bounces at contesting.com 
> > > [mailto:cq-contest-bounces at contesting.com] On Behalf Of Pete Smith
> > > Sent: Thursday, March 20, 2008 4:52 PM
> > > To: Dave Hachadorian; cq-contest reflector
> > > Subject: Re: [CQ-Contest] Skimmer ultimate setup?
> > >
> > >
> > > Hi Dave - I think you are very close.  A few comments below.
> > >
> > > At 03:57 PM 3/20/2008, Dave Hachadorian wrote:
> > > >I'm trying to figure out how CW Skimmer will ultimately 
> physically 
> > > >tie in to an so2r contest setup. Let me propose a straw man, and 
> > > >then you smart guys can whip it into shape.
> > > >
> > > >1. We use the IF output of the so2r S&P receiver as the 
> source of 
> > > >wideband RF.
> > >
> > > Yes
> > >
> > >
> > > >2. Using an Elecraft K3 as an example, the IF output is at 8.215 
> > > >Mhz. I hear you need a buffer amp on that output. 
> Somebody makes a 
> > > >"Z10000" that fills the bill.
> > > >
> > > >3. The output of the Z10000 goes to a "Softrock Lite" receiver 
> > > >tuned for 8.215 Mhz. Maybe that frequency needs to be 
> offset from 
> > > >the 8.215 IF to prevent the softrock Lite oscillator 
> from getting 
> > > >into the K3 IF?
> > >
> > > You may not feel the need of the buffer amp (Clifton 
> Laboratories, 
> > > K8ZOA,
> > > www.cliftonlaboratories.com) if you offset the Softrock local 
> > > oscillator so that it falls outside the roofing filter bandwidth, 
> > > but it would be a good
> > > precaution.  On the radio to which my SoftRock is connected,
> > > the local
> > > oscillator is S9+40.
> > >
> > >
> > > >4. The stereo audio output of the Softrock Lite goes into a good 
> > > >quality soundcard with a high sampling rate, since we will be 
> > > >dealing with up to 50(?) KHz audio? This soundcard can 
> be the one 
> > > >in the contest computer, since the soundcard is not 
> normally used 
> > > >in CW contesting. If you want to do an audio recording of the 
> > > >entire contest, maybe you need another computer networked to the 
> > > >logging program and do the recording there?
> > >
> > > The soundcard I am currently using is a M-Audio 
> Revolution 5.1 PCU, 
> > > which cost me about $50.  It records 96 KHz stereo audio, which
> > > translates into I
> > > and Q channels that the Skimmer software will display as a
> > > 96-khz swath of
> > > IF bandwidth centered around the center frequency of your
> > > SoftRock.  You
> > > can get sound cards that go up to 192 KHz, for quite a bit more
> > > money.  Look out, though, for cards that have shared mic and
> > > line input.
> > >
> > > I use the audio CODEC in my MK2R+ to record contests. 
> Depending on 
> > > the BIOS in your computer, you may be able to run both a PCI
> > > sound card and
> > > your original on-board sound.  I can't, but that's Dell for you...
> > >
> > >
> > > >5. Whichever computer gets the audio, it needs to be running the 
> > > >$70 version of CW Skimmer, and that computer also needs to be 
> > > >running the logging program.
> > >
> > > Yes, although the spots can be passed to the logging 
> program over a 
> > > local area network, so in theory you could have Skimmer on one PC
> > > and the logger
> > > on another.  It is worth mentioning here that the CPU 
> demands of the
> > > Skimmer, especially in contest circumstances are quite high;
> > > this could be
> > > disruptive to LPT or COM port CW, depending on your computer
> > > and logging
> > > software.  I run N1MM and Winkey CW, and experienced absolutely no
> > > disruption with Skimmer running on a 2.2 GHz Celeron, 
> even though CPU
> > > utilization occasionally hit 100 percent.
> > >
> > >
> > > >6. CW Skimmer outputs spots to the logging program and 
> puts them on 
> > > >the bandmap. I'm a little fuzzy on how CW Skimmer knows the 
> > > >frequency of these spots. Does it look at the rig 
> control frequency 
> > > >of the S&P Radio, or is some other connection required 
> for Skimmer 
> > > >to know the frequency?
> > >
> > >
> > > Ah, here's the rub -- Skimmer needs to know what frequency your 
> > > radio is tuned to, so that it can display the waterfall with real
> > > frequencies rather
> > > than frequencies relative to the Softrock local oscillator;
> > > that, in turn,
> > > means that Skimmer needs to be communicating with your radio.
> > >  The only
> > > means Skimmer currently has for doing this is through
> > > VE3NEA's OmniRig
> > > interface, which works with many of his programs.
> > >
> > > Unfortunately, Omnirig is not compatible with the rig 
> control used 
> > > by any of the leading contest logging programs.  I have 
> heard rumors
> > > that Writelog
> > > can be adapted to permit exchanging frequency data with
> > > Skimmer - it may
> > > well be that other logging programs can be readily modified
> > > to supply radio
> > > frequency data through UDP or other means, and that Skimmer
> > > will evolve to
> > > support such adaptations as they develop - but all of this
> > > depends on the
> > > software authors.
> > >
> > > I'd suggest reading the section of the Skimmer help file 
> that deals 
> > > with the "SoftRock with IF" option for further details.
> > >
> > >
> > > >7. Since Skimmer will be connected to the S&P Radio, that radio 
> > > >pretty much has to be dedicated for S&P for the duration of the 
> > > >contest, otherwise Skimmer won't get much listening time 
> because of 
> > > >all the cq-ing if it's connected to the run radio radio?
> > >
> > > Probably right, though I used Skimmer briefly during the 
> Russian DX 
> > > contest on my run radio - it would simply stop while I was CQing, 
> > > and then resume
> > > copying calls as soon as I started to listen for callers.
> > >
> > > The way I visualize using Skimmer on Sunday in SS is that 
> you would 
> > > switch the S&P radio to a new band, pause a minute or so while
> > > Skimmer works, and
> > > then look on your S&P bandmap for Skimmer spots to call.  At
> > > that point you
> > > would just run up or down the band picking off any fresh
> > > meat, and then go
> > > on to another band and repeat the process.
> > >
> > > 73, Pete N4ZR
> > >
> > > _______________________________________________
> > > CQ-Contest mailing list
> > > CQ-Contest at contesting.com 
> > > http://lists.contesting.com/mailman/listinfo/cq-contest
> 
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