Radio W4KAZ

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2018 RSGB IOTA as K4Z from Cape Lookout

Operating IOTA for 2018 solo again.  Once again from the cabins at Cape Lookout, IOTA NA067.  Original plan was to use wire yagi from June 2018 QST article.  Weather changed plans….

As it turns out, lots of things were different.

Original plan:

The original plan was to operate on batteries at 100w using the K2 as the station.  Original antenna plan was to set up wire yagi’s for 40/20/15 using three telescoping fiberglass masts at ~30 feet height.  The wire yagis were to be based on design from 2018 June QST article(ref?).  An additional mast was going to be set up for 10m/80m, using a 10m dipole that I would base load for 80m with a K2AV style folded counterpoise.

Revised Plan:

The weather took a prolonged turn for the wet and nasty about 10 days before the event, and forecasts for IOTA weekend were maybe even a bit worse.  On the drive down to the dock the on Friday I hit light rain a couple of times.  Also a short shower as I exited the ferry onto the Island.   No lightning, but radar showed active storms offshore.  So the original antenna plan was trimmed to bare minimum – a single mast with multiple dipoles.  And a plan for quick disconnects if things got worse.

Time Lapse video, mast deployment–>  https://youtu.be/hy2bE-N47tI

After setting up the antennas and station, quite a bit of time was burned debugging a couple of mistakes, a mixup with the feedlines and a 40m dipole with a bad connection.  Temps were about 30C, with a continuous ocean breeze.  So it was a long hot day, but not as uncomfortable as either 2017 of Field Day 2018.  But tiring, so not much radio play.

Operating Conditions:

1200Z Saturday morning – Scarf up some breakfast after a restless night of broken sleep.  A quick trip outside to tension the dipoles and eyeball local WX conditions.  Lots of cloud cover, brisk wind, but no rain or lightning.  Nice.   Turning on the radio – “OK – what’s wrong?”  Very few signals heard, all very weak.  Spent time checking to see if something was broken.   Eventually worked a few, but not having fun.  This was a real discouragement, as I had a lot of success with essentially the same set up just a month earlier for ARRL Field Day.  Was not counting on not hearing any EU stations in the morning.  Was also not counting on having such difficulty working US stations.

Spent some of the down time scouting some of the other cabins as potential sites for future trips, and a good bit of time on the beach.    Tried a couple of times in the mid/late afternoon to get runs with domestic stations, but zero success.    Starting to seem like a S&P affair.   Tuning the bands at around 1630Z it was starting to seem like there was more activity, so finally settled in for a short run on 20m CW.  WX was starting to look bad so I decided to take a break for a short siesta.  Decided I’d make a decision after getting some rest and food.  Another 20m run from 2030-2130Z and only 30 or so Q’s.  Bleh.  Unable to run on SSB after several attempts over the late afternoon.

2400Z and the WX is OK overhead, but storms over the mainland and radar looking worse.  Forecast is calling for major storms overnight and in morning.  Here is where a bit of bad planning caught up with reality.  The return trip on the ferry was scheduled for 1300z Sunday, which would have been a bit rushed in good weather.

So I decided to pull the mast down and yanked the plug on the operation.   This turned out to be a Very Good Thing.  Sunday morning brought a heavy storm with lots of lightning.  Better to watch it from inside than try to fool with antennas in that.

What Worked:

The plan for setting up the yagi’s would have been workable in this cabin area.  There was enough room for everything needed.  Batteries and station equipment, all FB.  The ‘basic’ food plan was fine.

What Broke:

The trip reservations – not nailed down far enough in advance.  The 40m dipole – must have a break in one of the wire legs.  The operator – Poor CW skills, and not sleeping sucks!

_____________CW          __                     PHONE

BAND      QSOs      Point      Mults  QSOs      Points      Mults

80            0             0               0               0           0            0

40            0             0               0               1           5             0

20           57          415           10             19         155          6

15            4             30             2               1             5             0

10            2             10             0               1             5             0

625          X             18 =          11250

points                     multipliers  score

Red Pitaya SDR as Core of CW Skimmer – Part 2, Notes and Updates

Additional Red Pitaya CW skimmer notes, last update 2018-08-22
Notes and Updates 2018-08-22:

Note 1:  Skimmer station outage in mid July 2018, cause appears to be rx antenna related.

Note 2, Transformer:  N6TV identified a mini circuits 14:1 transformer that is suitable for use with the Red Pitaya on RX.  Expect the transformer to be available from Red Pitaya, or occasionally N6TV.  Available from mini-circuits vendors, but may be expensive in quantity 1.

Note 3, RX antenna:  Some what by accident I discovered that the 160m L I use for transmit seems to make a fine all-band rx antenna for the Red Pitaya skimmer set up.  FWIW, the antenna is about 140 feet of wire.  About 60-70 feet vertical, with the remainder making a dog-leg turn from top of vertical section.  From there it runs horizontally  NW to second support about 40 feet away, and a second sharper turn to the east, horizontally and slightly downward for the remainder which runs west to east.  The radial system is the K2AV type folded counterpoise system described in more detail at link.

Field Day 2018 – 1B NC de W4KAZ

The normal group of Field Day scalawags were in the wind for 2018.  N4GU was uncertain if the QTH from 2016 and 2017 would be available.  N4YDU took up N9NB’s offer for FD at Ted’s QTH in VA foothills.  I was also kindly invited, but decided that I didn’t want to drive quite that far, despite the nearly ideal location.  I do love me some VA mountains.

Photos from FD2018: http://w4kaz.com/images/fd2018/

For 2018 I took exit ramp #3, and went with the backup backup plan.  Operated 1B at a campground near Wilmington NC.  A nice easy drive, with a couple of easy on/off stops along the way to stretch out the body parts complaining loudest.  That made the drive tolerable.   Also made it into a mini-escape, leaving home QTH on Thursday with a return on Monday morning.

Weather conditions[i.e., heat] soon had me thinking I’d have been better off in the VA mountains, but after acclimatizing to “swamp butt” conditions, it was fine.  When I sweat enough to remind me of living on the South coast – its pretty darn sticky.  Usually not quite so bad in NC, but it happens enough to know to be prepared.  Lots of water and gatorade.  Thursday afternoon was the worst of it though.

Friday morning was spent doing a bit of unrelated recon.  Friday afternoon I laid out the antennas and supports, and some more unrelated area wide explorations.  WX on Saturday dryed out some, and there was a nice breeze that picked up from the start of operations though early evening.  Never a drop of rain, just temps and humidity in the 90’s.  Just like being back in good ole Bigg Swampy(SE Louisiana).

Antennas:

2018 was a time to test some antenna ideas.  I built a 2 band triangular yagi for 20m/15m, based on article by Herb,N4HA as published in June 2018 QST.  I kept to the published dimensions(mostly) but fashioned the driven element(s) from 300ohm ladder line.  For supports I used a mast from Henry, K4TMC as the support for the drive element/apex.  The tails sloped down to connect to the reflectors, and those ends were supported by 2 masts cobbled together by combining a Shakespeare Wonderpole on top of a section of 4 foot mil surplus mast.   Simple, and easier than I expected.  This antenna was fed with 300 ohm ladder line run to a tuner rather than coax.

40m was a simple inverted Vee supported by a Spiderbeam 12m telescoping mast.  Note: Simple does not mean “easy”.

10m was an afterthought.  After struggling with the 40m dipole-that-wouldn’t, I had a relaxing breakfast and gave some thought to 10m.  Had plenty of time, so may as well.  To get on 10m I made a dipole by cutting a couple of equal 8.5 foot lengths of wire and constructed a “FD style” center insulator from a pair of cable ties taped together.  Used a “composite” feedline – a ladderline drop to a 1:1 unun and a short coax run into the tent.  I had a length of ladder line about 25 feet long so the 10m dipole was up about 23 feet.   At the end of the ladder line at ground level I plugged the ladder line into a 1:1 unun, and ran the last 30 feet or so into the station with coax.  From start to finish this antenna took about 30 minutes to put up, including cutting legs and twisting it all together.

No antenna at all on 80m.  Decided I’d have enough business on 20m & 40m to keep occupied, and figured on sleep rather than a night of 80m T-storm QRN.  😮

Now, about that 40m Vee.  The antenna that would NOT.  Still not certain where the problem was, but it had an issue in one of the feedlines somewhere[update-think one of the legs has broken wire].  Far too much time was wasted raising and lowering the antenna trying to debug the issue.  Lesson1: Always have an alternative.   Lesson2:  Don’t dick around debugging when you have the alternative at hand ready to go.  Lesson3: Save debugging for down time.  Lesson4:  Read Lesson1 and Lesson2 until they really sink in.

Operating:

Once the CQ’s started, there were plenty of QSO’s to log.  Saturday was a bit slow at first, but I got a better rhythm in the evening.  Was tired though, and sacked early, including a 45 minute nap at 5pm in the nice cool breeze that came up.  Also got up early Sunday, 5am-ish.   Sunday morning was quite a bit of fun, right up until my keyer interface died around 11am.  So I finished the event with a bit of lackadaisical SSB, mostly S&P.

Camp:

The Cabelas tent goes up easily.  My only regret is not getting one of the larger sizes.  It has room for setting up a table for the station and also for a cot along the opposite side.  But it is a bit cramped.  Next time I do this I think I will use a screen tent for the station and the tent just for snoozing/bad wx.  Also, the ideal site would allow for the tent to use an overhead spike support and avoid the need for the center pole.

Overall a big win.  Keeping the ants away…..the real challenge!

 

 

NT4D Estate Items For Sale

This page will be used to list photos of items for sale from NT4D, SK late 2016.

The following items are for sale from  NT4D.

Alpha 87A – $3400

Good condition Alpha 87A

Good condition Alpha 87A

Drake MN-2000 #1  – $200

Drake MN-2000 #1

Drake MN-2000 #1

Drake MN-2000 #2 – $200

Drake MN-2000 #3 – $200

Drake MN-2000 #2 and #3

Drake MN-2000 #2 and #3

RBN Spot Counts, CQ WPX CW 2017

To get an idea of the efficacy of the Red Pitaya skimmer set-up, I pulled spot counts from the RBN via screen grabs off of the ‘Spots Analysis Tool’.  During the 2016 contest the skimmer station at W4KAZ was run with softrocks as the skimmer SDR, skimming only 160m/80m/40m/20m.  15m was better during 2016 than 2017, but the softrock for 15m was not reliable enough to run during a contest.

With that caveat, the W4KAZ spot  counts from 2017 are quite a bit better than those from 2016.  This reflects skimming 6 bands in 2017 as well as improvements  due to Red Pitaya vs Softrocks(2016 skimming was for only 160/80/40/20)

Spot counts from RBN for the CQ WPX CW of 2016/2017.  They are grouped by continent and sorted from high to low spot counts.

There are 4,489,640 total RBN spots for the period of the 2016 contest.

There are 4,431,759 total RBN spots for the period of the 2017 contest.

http://w4kaz.com/images/pages/skimmer_spot_counts_wpx_saturday.htm

http://w4kaz.com/images/pages/skimmer_spot_counts_wpx_sunday.htm

Despite a similarity in the total number of spots, the spot distribution shows the counts for Europe significantly higher in 2017 vs 2016.  In North America, the spot counts on

Mast Hoisting & IOTA Pages

For some reason this info never was documented here, so for my own uses, here it iz.  A few links about surplus masts, falling derricks, and IOTA.

Mast base fitting for falling derrick, and photos of falling derrick test.

Photos from 2010 IoTA, mast photos.

IOTA 2007

IOTA 2008

IOTA 2009

IOTA 2010

 

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).

 

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…