[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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