Radio W4KAZ

Thanks for stopping by the virtual KazShack. Feel free to comment - I often approve them.

2015 Field Day W4KAZ class 1E

Life’s swirl of events led me to be non-committal about FD with the usual suspects this year.  Probably a good thing, given the way brown stuff keeps making sudden contact with the rotary impeller.  Even the minimal home operation in lieu of a real event was in question as days grew shorter.

So 2015 FD was flying solo in the KazShack.   [Some photos here]  The twist to make it FD was to run the station on emergency power, class 1E.  With enough ’round-too-its’ having been previously cashed in to assemble a portion of the battery set up  desired, the battery op seemed feasible.  Accumulated over the past year are a couple of 30w solar panels, a pair of well-matched deep cycle marine batteries, a decent charge controller, and assorted minor peripherals(cables, connections, etc).  The original plan was to be ready for NC-QSOP earlier in the year.  Brown Stuff vs Rotary Impeller.  Brown Stuff won, no Qso party.

In field day spirit, I also hoisted an “emergency” field portable 40m/20m inv-V off of a fiberglass telescoping mast obtained from “The Mast Company” several years back.  After collecting dust for these years, it occurred to me that it could fill a big unused space on the edge of the ‘wire-farm’, backed up very nicely by the 20m/40m reflectors in their permanent positions.  This worked very well on both bands during FD, showing four or five S-units difference depending on conditions and the direction of the signals.

The 2015 FD Station:

For the event, I relocated the solar panels to be within reach of the feeder cables to the shack. The batteries had been connected to the solar panels for over a month, so they were nicely topped off.  The batteries were brought into the shack, and connections were set up to power the K2 as the load off the controller.  Not willing to go whole-hog QRP, all transmitting was done at intermediate-low power levels, 45w overnight, 75w during daylight.  (Based on actual current draws by the K2 as measured in place). Add a laptop and ready to go.  The antennas were the normal wire farm plus the hasty-install dipole on the fiberglass mast.

The Solar Problem:

Expected to have poor results from the solar panels, as their default location for the shack is only in full sun in the afternoon.  Hoped for a sunny afternoon on Saturday.  No. Such. Luck.  In fact, the WX really sucked.  When the WX didn’t suck, there was lightning and rain.  Zero sunlight.   The panels only produced about .3amps in shade under clouds, instead of their full-sun 2.8amps.  90% reduction.

Solar panels, laid out on a conveniently parked truck

Solar panels, laid out on the conveniently parked truck

Charge controler for solar power

Charge controller for solar power

 

 

 

 

 

 

 

The good news is the batteries seemed up to the challenge on their own.  Battery voltage dropped to 12.3v at its lowest.  The K2 drew only about 11 amps in transmit, and just over 1/3 amp when in receive. If the panels had been in a good full-sun location the charging would probably have kept up with the demands during daylight operating.  Success.  The charger says that 24ah were drawn over 12 hours of operating, with transmitter power at 50w for the 6 hours on Saturday, and 75w for the 6 hours on Sunday.  In full sun the solar cells would probably have kept the batteries topped off until sundown.

The current draw at full transmit power on the K2 is in the 15A ballpark.   Rolling the transmit power back to 65 or 75 watts is a good compromise between output power and current demands, as the current draw is closer to 11amps at 70W.

Actual Operating Condx:

WX conditions cut outs a large chunk of Saturday prime time in the late afternoon/early evening.  So after putzing around for the 1800Z-2000Z hours, did not return to the chair until 0150Z.  Then a decent three hour stretch, alternating between 40m and a few sweeps of the other bands.  A nice long nap and the back in the chair well after sunup Sunday morning.  Not terrible Sunday morning, but not fantastic.

Finished with 532 CW contacts logged and 2128 QSO points.  Not terrible for only about 10 hours of butt-in-chair time.

So the emergency power and emergency antenna set up worked well enough.  A bulk of the QSOs were made on the portable antenna. In the shack the charge controller indicated the station drew a total of 24 amp hours.  The solar cell charging put 9 amp hours back in, not bad given the clouds and shade trees.    That was with the solar cells providing only about half an amp.  In full daylight the charging would have been sufficient, and closer to 3 amps.   The power draw had been conservatively estimated/ball-parked/WildAssedGuessed at a need of about 40 amp hours.

The Renogy charge controller is well worth the minor additional expense.  It senses the voltages from both battery and solar panel, and can charge 12v batteries from 24v solar cells if needed.  It also monitors both load and input currents, as well as the battery charge state.  (Seems to be sold under several different name plates, all seem identical based on advertising specs.)

Overall, very happy with the experiment.

 

 

 

W4KAZ Skimmer Station – 05) Si570 Programmable Oscillator for Softrock CWSkimmers – or for “Whatevah”

Note: More links at bottom of page:  This is a simple-to-build programmable oscillator for use with the Softrock Lite kits for CW skimmer and input to the Reverse Beacon Network.  It uses the Si570 chip and an AtTiny85-20 programmed with the PE0FKO firmware used for the Softrock Ensemble kits.

Currently a programmed ATTiny chip is available separately from K5NWA.  The firmware is available for download, so programming the AtTiny is also an option.  The PE0FKO site also provides the required USB device driver, software, and guidance on using them.  (links)  The Si570 is available from Digikey(digikey part#:336-2518-ND,  manufacturer part:570CAC000141DG).(SiLabs 570CAC000141DG part )

The oscillator itself is pretty simple, and is the bare essential hardware required for re-programming the oscillator for a needed single frequency to use with a Softrock Lite II rx.  It is based on what I saw in the the schematic of the Softrock Ensemble RX, nothing original, just pared down and hijacked from the original Ensemble design.  The Si570 part itself is the bulk of the expense of the oscillator, and the cost of the Si570 chip is almost as much as the Softrock Lite kit itself.    The oscillator signal is fed into the divider through a 10K voltage divider as in the Softrock RX.

So why?

The RX Ensemble kit is a viable alternative expense wise.  It really depends on the intended usage.  Using separate Softrock Lites as single band CW skimmers leads to the choice of a programmable oscillator for customizing the center frequencies, especially for the high bands.  The method used for 20m using the third harmonic seems to result in a decrease in dynamic range.  That results in an increase in false mirror images being reported to RBN by the CW skimmer as actual spots.

Using the Si570, the oscillators can be set at the frequencies needed by the Softrocks, i.e. 4 times the center frequency.  (for 96Khz bandwidth the oscillator would need to be: 20m=56.188, 15m=84.188, and 10m=112.16).   A programmable oscillator also allows switching from 96Khz to 192 Khz bandwidth(20m=56.38,15m=84.38, and 10m=112.38).  Keeping just the bottom half of a 192Khz bandwidth CW skimmer would at a minimum eliminate at least 50% of bad mirror image spots.  There are also likely to be fewer stations CQ’ing below the “.096″ section of a band(e.g., most often there is not so much regular CWactivity above 28.096 as there is below).  That is the idea anyway.

The Oscillator Prototype:

The first version is deadbugged on a bit of board scrounged from the parts bin.  Not many parts, but a bit more PCB real estate would have been better.  Functional rather than esthetic.  The USB connection is via the usb cable end clipped from an old computer mouse in the parts bin(unlabeled black coil in left of photo).   “Engineer the possible”.

Si570 oscillator board for 10m Softrock CW skimmer

Si570 oscillator board for 10m Softrock CW skimmer

Testing the original prototype board pictured resulted in three build mistakes to debug:  a missing 5v connection to the ATTiny and the reversal in polarity on both zener diodes across the USB data pins.  These mistakes prevented function without damage to the components.  After correction of the build errors the software was able to function with the Si570 as needed for both programming the oscillator(‘startup’) frequency and running as a stand-alone oscillator.

The Si570 when programmed for 112.36Mc was found to have an actual oscillation at close to 28.090 exactly from the Softrock divider, as measured with TS-590 and Elecraft K2.  This was with the oscillator inserted in-circuit as the Softrock Lite oscillator via a transformer(5 bifilar turns on a type 43 torroid core) and a 2.2k resistor.  The frequency is very consistent and stable when the power is cycled on/off.

Easy measurement of the actual frequency in place is good enough for initial setting up of the skimmer software. A few KC either way will make little difference in a CW skimmer set-up, as final adjustments were done in CW skimmer software to put the skimmer signals ‘on frequency’.  In this case the CW skimmer center frequency is nearly identical to the Si570 programmed frequency.  That has not been the case with the versions using ordinary crystal oscillators, those having a bit more drift.

A new Softrock Lite II is the 10m test bed, with 15m revision to follow.  These two bands suffer the most from poor dynamic range and false mirror images.  The 15m oscillator also has a nasty tendency to drift with temperature changes.  If the modified softrocks perform as desired it will be time to pair these two bands with the best of the sound cards available.  That will be a separate game of trial and error.  The 20m softrock skimmer may also be retrofit, as using the third harmonic for the softrock center frequencies seems to adversely impact the dynamic range.

Photo of 10m Skimmer

Photo of 10m Skimmer at W4KAZ

As an aside, the first 10m center frequency chosen was 28.060 into a 192Kc bandwidth sound card. Horrible choice, as it was close enough to the 15m harmonic that interference spikes were present on both bands every 900hz.  Resetting the Si570 oscillator to place the center Fo for 10m at 28.080 greatly reduced(but not eliminate) the problem.  Currently set on 28.090 as of 20150414.  More tinkering required, and migrating the 15m Softrock over to an Si570 oscillator may help.

The current Skimmer package for 20m, 15m and 10m.  20m and 15m will likely be re-worked to use  Si570 oscillators.

The current Skimmer package for 20m, 15m and 10m. 20m and 15m will likely be re-worked to use Si570 oscillators.

LINK LIST:

  1. W4KAZ Schematic

    Schematic for W4KAZ version of si570 oscillator

    Schematic for W4KAZ version of si570 oscillator

  2. W4KAZ BareBones Parts List (PDF) (HTML with links)
  3. KB9YIG Five Dash softrock products page
  4. K5NWA ATTiny85 page
  5. PE0FKO Firmware page
  6. Document:

 

WPX SSB Prep

The 2011 NR3X Multi Single from N1LN.

And 2014 WW4LL, most local M2 leader.

Skimmer File Extracts Summer of 2014

File extracts for three summer contests from four skimmer stations for May 2014’s CQ WPX and June’s JARL All Asia and ARRL FD.  The files are by skimmer spotting station and are sorted in datetime order.

Spots from K1TTT

Spots from W1NT

Spots from W4KAZ

Spots from KM3T

CW Skimmer Station for WPX CW 2013

Some repairs to the skimmer station set up have been made after losing the 20m and 10m softrocks.  Both were probably damaged due to modifications I made to the voltage regulation circuits.  That appeared to eventually fry the QSD chip, which is the heart of a softrock.

The 20m skimmer was replaced completely with a new softrock lite.  10m is pending re-work, but replacement would probably be the best bet.

So for WPX 2013 there are five bands available, 160m through 15m.  These will be active during WPX intermittently.  I intend to bring them up and down based upon my own operating.  The skimmer will be down when I am operating.

Other changes made to the skimmer station include loading windows XP onto the Optiplex 360 that had been running windows vista.  Vista was able to run one instance of CW skimmer, but was not able to support two instances simultaneously due to sound card conflicts.  Windows XP does not seem to have a problem with the two sound cards, and is an OS supported by CWSkimmer(Vista is NOT supported by skimmer).

 

CW Skimmer Errors and RBN spots

After several contests, monitoring of the softrock skimmers has turned up a bit of a problem with using softrocks as the skimmer platform.  Very strong signals are producing a mirror image that is often reported as a spot to the RBN.  Certain to be annoying for the S&P packet crowd during a contest.  Annoying enough that a few flame mails have arrived.

The volume of the bad spots is relatively low on the lower bands, and more common on the higher bands.  40m is somewhere in the middle, with most of the bad spots being sent for domestic USA stations.

The problem is a combination of the hardware and software, both contributing to the problem.  A software fix could potentially be made to CW skimmer or to the RBN aggregator to correct for the problem.  Will inquire to the authors…..

In the meantime the best solution available is to throttle the RBN aggregator to allow only spots below the center frequency to be reported.  For example, the 15m skimmer is based on a softrock with a center frequency at approximately 21044.5Mc.  So for the duration of the ARRL DX CW contest, an entry in the “Notched Frequencies” will be active to not report 21044.5-21100 to the RBN.

That solution does nothing to correct for half of the possible bad spots(i.e., a strong signal above the center frequency whose mirror image is being spotted below the softrock center frequency).  But it should alleviate many/most of the actual bad spots, since most run stations prefer to operate as low in the band as they are able.

Open to other suggestions short of replacing the softrocks with better (yet unaffordable) hardware.

Update 20130217, 2140Z:  There are new versions of both skimmer and aggregator.  Perhaps upgrade will help.

More on Xonar DX Experiments

A thread over on the softrock user group list spurred the curiosity…..: http://groups.yahoo.com/group/softrock40/message/68324

G4ZFQ has  RightMark test data for a high end Xonar D2X card, as well as several others.  An internet search found other RightMark tests of several other Xonar cards, all of whose test data show curve trends remarkably similar to those of the D2X, albeit with somewhat worse IMD, spurious, and noise figures.

The curiosity is the test data shows a roll off on the frequencies above 50khz.  The nature of the loopback test is an issue, but it also seems likely that using a sound card as the source may be having an effect on the test results at the higher edges of the sound card frequency response.  But signal generators as input to the tests shows the same general trend.  SDR at wider bandwidths pushes at these edges of a ‘sound’ card’s ability….So perhaps the SDR software is compensating for the expected performance drop-off at frequencies above audible levels?

The Test- (Pertinent Excerpt from list post):

Having not yet thought of a better way to do a meaningful real-world test on the sound card with what is available in the KazShack, I fired up the 80m softrock on the xonar DX.

Test condx:
Transmitting a cw signal(a string of dashes at about 18wpm) at 5w into a dummy load on separate radio, noting the SNR readings obtained by CW skimmer from the SoftRock center frequency(353395x) to its upper limit. With the xonar DX set to 192khz scan rate, the actual upper limit on the readings was 3629.60. SoftRock connected to normal antenna system, a NE facing K9AY with W7IUV pre-amp. In summary, a sound card test using the SoftRock system as input source.

fq….—-SNR(dB)
3534.5—-42

3543-3593-42-40

3603——37
3613——35
3623——32
3629.6—-36

After CW skimmer collected a bit of data, the SNR readings above 3600 improved to 37-39.

So the worst case for CW skimmer(as currently configured) using a Xonar DX is being 6db less sensitive at the upper edge of the 192khz bandwidth than it is at the center. That is actually a lot better than I expected for an audio device pressed into service outside normal audio ranges (and I already liked the Xonar DX).

My curiosity is now nagging me to run the same tests on all of the other in-shack cards more methodically at their maximum scan rates(mostly 96khz), and to find a lower level outside signal source. I’ll try to recruit a fellow in the near field who will better be able to generate a low level test signal.  It would be useful to see what happens at the band edges when the best copy close to the center of the SoftRock’s scan range starts out at 20dB, 10dB, or 6dB SNR.

But with the WX here improving, all of that might not happen for several months.
😉

Engineer the Possible…

Xonar DX es SoftRock CW Skimmer

Yesterday, having not yet thought of a better way to do a meaningful real-world test on the sound card with what is available in the KazShack, I fired up the 80m softrock on the ASUS Xonar DX for a bit of putzing around.

Test condx:
Transmitting a cw signal(a string of dashes at about 18wpm) at 5w into a dummy load on separate radio, noting the SNR readings obtained by CW skimmer from the SoftRock center frequency(353395x) to its upper limit. With the xonar DX set to 192khz scan rate, the actual upper limit on the readings was 3629.60. SoftRock connected to normal antenna system, a NE facing K9AY with W7IUV pre-amp. In summary, a sound card test using the SoftRock system as input source.

fq….—-SNR(dB)
3534.5—-42

3543-3593-42-40

3603——37
3613——35
3623——32
3629.6—-36

After CW skimmer collected a bit of data, the SNR readings above 3600 improved to 37-39.

So the worst case for CW skimmer(as currently configured) using a Xonar DX is being 6db less sensitive at the upper edge of the 192khz bandwidth than it is at the center. That is actually a lot better than I expected for an audio device pressed into service outside normal audio ranges (and I already liked the Xonar DX).

My curiosity is now nagging me to run the same tests on all of the other in-shack cards more methodically at their maximum scan rates(mostly 96khz), and to find a lower level outside signal source. I’ll try to recruit a fellow in the near field who will better be able to generate a low level test signal.

But with the WX here improving, all of that might not happen for several months. 😉

engineer the possible….
73 de w4kaz

Upgraded to Ubuntu 12.04 LTS (Precise Pangolin)

My testing sandbox server is running on an ancient Dell Optiplex 280 minitower, which has a P4 processor and 2gb of ram.  Its been chugging along placidly on Ubuntu 10.04LTS.  The 12.04LTS version has been popping up for a bit, and it seemed like it was being reported as a very solid release.

The install running in my VirtualBox partition went smoothly enough, but that was only a leap from 11.x to 12.04.  Upgrading from 10.04 is a couple of levels to jump, so the possibility for problems increases.

So with some amount of trepidation I decided to run the upgrade process on the 10.04 sandbox. If the upgrade should barf completely, its not a tremendous loss.  If it works, the 12.04LTS version is supposed to be good through 2017(if I recall the upgrade notes correctly).

The upgrade seems to have been completely successful, with zero impact on the test bed.  Sweeeeeet….. The 10.04LTS was mostly a plain vanilla install, but its nice that it made the leap with so little intervention.

This upgrade went far more easily than a prior upgrade(from 8.10 to 9.04).  Very happy to see the Ubuntu developers have made the upgrade process so user friendly.

Very.  Nice.  Work.

So now the file server is good to go and can remain stable for the foreseeable future.  Time to get back to hacking up some web apps for graphing the Reverse Beacon network data extracts.

Not so happy with the UNITY desktop, but at least it is easy to revert back to Gnome.  Unity is kinda like the new Windows 8 – ButtHole Ugly.  The very last thing I want is an interface that looks like a tablet.  Bleh.

Never have understood why OS developers seem to think that 30 years of accumulated OS familiarity is so readily cast aside for their own vision of ease-of-use.  Too little customer contact….  Most customers want their interfaces to function the same way they functioned yesterday(providing they actually worked yesterday), and changed only if they were broken.  AKA, “New Coke Syndrome”.

Coke Classic pleeze…..add gold rum and lime….

Skimmer Station

Added a new page to the skimmer station fun facts list.

The new page describes observations from using several different sound cards for both music and as the interface for SoftRock software defined radios and the CW Skimmer software.