Radio W4KAZ

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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

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!

 

 

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

2017 FD @ N4GU as AA4NC – Still No Will

The 2017 Field Day is in the bag.  Operated with the group as AA4NC at the farm of N4GU’s XYL.  Showing a surprising lack of judgement for a second year in a row, AA4NC again allowed us to use his call, despite a shoebox full of notices from last year’s operation.  Still No Will….but N4GU, N3ND, N4YDU, N9NB, W4BBT and W4KAZ all on the air.

2016’s as-yet-undocumented FD last year was done as class 2A, while for 2017 we rode with class 3A.  Given the improved conditions on 15m/10m/6m, that was quite a bit less boring than I expected.  Gave N4YDU grief for wanting to run that third station for the high bands, but they were maybe the money bands this year.  Great call on N4YDU’s part.  With so much activity on high bands through the evening and mid-watch, 80m under-performed.  Boooo.  Hoooo.

Stations:

2017 FD - 15m/10m and 6m stations

2017 FD – 15m/10m and 6m stations

2017 FD - The REAL Night Shift

2017 FD – The REAL Night Shift

2017 FD - The "40m station"

2017 FD – The “40m station”

We ran 2 stations on N4GU’s 1kw generator, and ran the third station and VHF stations on deep cycle batteries.  The two stations on generator power were Elecraft K3’s, and the battery station was a Kenwood TS-590.  VHF was run on the Kenwood until N9NB arrived with an Icom 703.  Battery power for the 590 was two deep cycle batteries paralleled and connected to a solar cell, and the 703 was on a single deep cycle battery.

Antennas were a Frankenstein ??ta33M?? tribander for 10/15/20@35′(split via triplexer), an OCF mostly for 40m@34′, an 80m dipole@~45′, a 10/15 fan dipole @ 30′,  a 20m vee dipole at 24′ and a hastily erected 40m dipole @ 40′.  VHF station used a 5 element 6m yagi @24′.  Most of the antennas were strung by late Friday afternoon, leaving time on Saturday morning for testing and a last minute wild hair(the 40m dipole.)

Operating:

Given the strange conditions on Sunday morning, the dipoles played quite well as supplements to the tribander on 15m and 20m, with good signals from New England often better on the dipoles.  The tribander won on stations out to the west of 9-land, and about equal in the middle grounds between.

For my part 15m was the best news on the subject of propagation.  20m and 10m were close behind.  All three bands were very productive.  6m even coughed up QSo’s this year, with 160+ Q’s logged.  The night shift on 80m was a bit sluggish, probably many stations stayed on 20m later than normal.

Something must have worked correctly, event with W4KAZ constantly changing the function key settings on every N1MM computer attached to an HF radio.  Despite KAZ’s  best efforts at disabling the dread “Enter Sends Mode”, almost 3500 Q’s were logged across all of the stations.

WX:

Friday afternoon the WX forecast of rain was quite thankfully incorrect.  Instead there were crystal clear blue skies and a slightly gusty wind.  The wind helped keep the insects at bay, and cooled the crew off a bit.  Saturday morning was overcast, but remained dry right up until a 6pm shift change.  As soon as the new shift sat at the stations, the wind began gusting, enough to slide the camp chairs across the cement floor as if of their own volition.  Enough wind to make ops press down on tables to keep them from tossing radios about like so much flotsam.  The rain soon came in buckets, making the nice covered carport seem like luxury FD accommodations.  The nice 30 minute storm cooled things down and brought the insects from hiding for most of the evening.  Things remained cool enough overnight that a light rain jacket was perfect for both staying warm and fending off the creepy-crawlies.

Food and other:

Many thanks to Mike’s XYL Sherry, who kept us stuffed to the gills over the weekend, and caused disputes to break out over a certain blueberry dump cake.  Also many thanks for allowing us to invade her domain for the weekend and play radio geek.  Good QTH, a good crew of ops to work with, and entirely too much fun.

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

 

Red Pitaya SDR as Core of CW Skimmer Station Rebuild.

[Updates, 2018-08-22, also see:  Red Pitaya SDR as Core of CW Skimmer, Part2:  A link to status updates and additional notes going forward]

[Updated 2017-07-11, also see text on my own compatibility issue]

Bob, N6TV has a step by step guide on setting up a Red Pitaya posted to the skimmertalk list in which he documents version compatibility issues he encountered and outlines the steps he needed to follow to get his system functional.  As of this date it seems wise to follow these instructions, or know that by diverging you may encounter issues of your own.  There is also an illustrated how-to guide now available from the folks at hamsci.org.

[Updated 2016-12-23, see text on Compatibility issue]

Recently discovered an interesting,  affordable,  and relatively new product called Red Pitaya, designed as an open source based piece of test equipment.  As a piece of test equipment the Red Pitaya has basic oscilloscope,  spectrum analyzer, and signal generator apps available.  The apps are designed to run as web applications with Red Pitaya board running a custom Linux and acting as a web server.   Currently the apps are quite basic, but useful despite their simplicity.

Possibly more interesting for hams are the SDR receiver and transceiver apps available from Pavel Demin.

With the SDR apps, Pavel has taken this little Red Pitaya board into the areas of interest to many ham ops.  The SDR receiver app has the ability to function with several currently available SDR programs.  The ability to support feeding six channels into CW skimmer server is of particular interest.  There are also transceiver apps which are being used by experimenters to build Red Pitaya based transceivers.

Red Pitaya

The Red Pitaya itself is a board that runs a customized linux OS(their term is ‘ecosystem’) off of an SD memory card.  The board has two RF inputs and two RF outputs for use as the heart of a test system.  5V USB power supply input requires 2A.  The board has a heat sink on the CPU but a small fan helps cooling.  It can connect via ethernet to the network or via a wireless connection.  The OS and apps are downloaded from the Red Pitaya website.   SDR apps are available from both the Red Pitaya site and directly from Pavel Demin’s website.  This little SDR kludge is a viable substitute for the Softrock skimmer system previously being run @W4KAZ.

SDR Uses and v0.96 Compatibility Issue

A couple of issues turned out to be a mix of hardware and software problems.  The largest problem was a software incompatibility issue between the [then]latest OS v0.96 and the SDR software.  This caused problems in the SDR with interference that looks like intermod artifacts.  Too much time was spent here looking for hardware problems before stumbling across the documentation on the issue.  The solution was simple.  It simply required building an SD card with the previous OS version v0.95, and  then configuring(secure password) then re-installing the SDR app.

A couple of the SDR apps available on Pavel’s site originally included an OS that did not allow a persistent password change.  To avoid that security vulnerability, the original SD card here was built with v0.96 of the OS.  As of October 2016, do NOT try to use v0.96 OS with the SDR apps.  V0.95 works with the SDR.  Better to have several SD cards with different OS versions should you need a more recent OS for new apps as they are developed.  [Update 2016-12-23.  Per comment from Pave Demin, the SDR applications have been updated and should now work with v0.96 and v0.97 of the Red Pitaya ecosystem.  Not yet migrated to the updates here in the W4KAZ SDR setup.]

After building the v0.95 system, the SDR app was good to go.   Several different flavors of SDR support are available from Pavel.  The SDR app version that supports CW skimmer server also supports PowerSDR, which has a nice spectrum and waterfall display.

There is not a tremendous amount of information available, as folks are just beginning to explore the possibilities.  PA0AER has an interesting post, with a few findings of his summarized in this table.

PA0AER published test data.

PA0AER published test data.

Yeah, -120db floor and 75 db of intermod suppression should work just fine in a CW skimmer application.  Keep in mind, the softrock system being replaced has about 45db of useful dynamic range as implemented here. Plus we get the bonus of using Red Pitaya as a minimal spectrum analyzer and oscilloscope.  Maybe even a VNA app.

SDR Station With Red Pitaya

First of all, one huge thumbs up to Pavel Demin for his open-source work on the SDR apps.  Outstanding!

The time spent here going in circles chasing my non existent hardware issues was not a waste.  The power supply  was cleaned up with better filtering.  Very nice.  Using the AADE filter design program we also came up with a simple-to-build design for a high pass BCB filter.  This filter optimizes the nulls at 680am and 850am,  and attenuation drops off rapidly above 1Mc the broadcast band.

This BCB filter exhibits low loss on 160m, with the modeled 3db cut off frequency being at about 1.2mhz.  Ordinary C0G/NP0 capacitors are used in its construction, having had acceptable results with that type with the W3LPL design receive only band pass filters.  The result was good with testing on the base station.  The difficult part was finding good leaded C0G/NP0 capacitors in proper values to use for construction.  Through hole components are becoming rare.  NOTE: Be aware – As designed this filter is a short circuit at DC via the inductor at “dipole 12”.

W4KAZ version of BCB filter. Built using NP0/C0G leaded capacitors, t-80-2 torroids, and a 220uh choke.

W4KAZ version of BCB filter. Built using NP0/C0G leaded capacitors, t-80-2 torroids, and a 220uh choke.

w4kaz_bcb_filter_designplot_edit

AADE predicted performance plot of the w4kaz BCB filter from DC to 10Mc. Note the nulls on 680 and 850.

The plot projected by the AADE filter design program above is a best-case prediction.  WPTF, 50kw at 680 and WPTK, 10kw at 850 have transmitters about 3 kilometers and 12 kilometers respectively.  They produced all sorts of intermod in the softrock system.  The BCB design here is tailored to place the largest nulls where they might do the most work in the KAZshack.  Getting the 3db cutoff at 1.2Mc was just to try to keep the losses as low as possible on 160m.  To get an idea of its performance, I plugged it into the station and took S-meter readings on the Kenwood TS-590s.  The BCB filter dropped WPTF at 680 from pinning the S-meter down to just another strong S9+ signal, not even 10 over S9.

S meter comparisons on the TS-590s using the W4KAZ BCB filter and built in attenuator

S meter comparisons on the TS-590s using the W4KAZ BCB filter and built in attenuator

Skimming with Red Pitaya SDR

With the software issues corrected, let the CW skimming begin.  Skimming tests seem to have spot signal levels from Red Pitaya SDR slightly better than those from the Softrock skimmer system.  Full system stress test coming during 2016 SS CW.  The Red Pitaya also seems to be very frequency stable, something that was a minor issue with the softrocks.  When running PowerSDR, comparing Red Pitaya by ear shows it to be a bit less sensitive than the main station rig, a Kenwood ts-590s.

Does it work?

Random selected North American spot counts from days with W4KAZ skimmer station under Red Pitaya

Random selected North American spot counts from days with W4KAZ skimmer station under Red Pitaya

System Reconstruction – Permanent New CW Skimmer

After a good shakedown voyage through Sweepstakes CW, it will be a good time to re-arrange the test Red Pitaya SDR system into a more permanent and compact single system.    One of the dead softrock CPU’s will donate a nice clam shell computer case, and all of the components should fit easily.  The plan is to wall mount the completed system near the shack cable entrance.  The softrock system will be raided for its discrete components, the W3LPL style band pass filters as well as the W7IUV pre amps.  New splitters will be built for the new system to allow for antenna options to change in the future.

Unexplored are some more experimenting to find a proper matching transformer and  Red Pitaya input jumper combinations for the best results.  Some research into the transceiver experimenter comments indicate using a step up transformer is best.  Some have also made mods to the front end that are supposed to boost the sensitivity by lowering the noise floor significantly, from 9 to 12 db.  Currently using a 3:1 cascaded into a 4:1 transformer as step up, with the input attenuation pads bypassed via jumpering on input#1.

Block diagram of likely W4KAZ Red Pitaya SDR CW skimmer system

Block diagram of likely W4KAZ Red Pitaya SDR CW skimmer system

Important Notation[see update]:

If you choose to experiment with Red Pitaya and the SDR apps,  be sure to create your bootable SD card from a compatible OS.   If you do not, you will be very disappointed at the 25db BDR and the interference and low performance you will experience.  Currently, as of 2016-10-28, the 0.96 ecosystem/OS IS NOT COMPATIBLE with the SDR apps from Pavel Demin.  Either use the ecosystems Pavel has or the last archived version 0.95 from Red Pitaya’s archive.  Do NOT TRY SDR with v0.96 OS!  Been there, done that, have a clean power supply and nice BCB filter to show for it.  [Update 2018-12-23.  Per comment from Pave Demin, the SDR applications have been updated and should now work with v0.96 and v0.97 of the Red Pitaya ecosystem.  Migrated to the updates 2017-11-15 here in the W4KAZ SDR setup.]

The Red Pitaya ecosystems come with default root passwords.  Suggest resetting your password ASAP.  Also, at least one of the pre-built ecosystems Pavel provides does not allow a persistent root password change.  I suggest using the 0.95 the current ecosystem from Red Pitaya archive and that the root password be reset to something secure if the Red Pitaya is going to be running on your home network.  With the default root password, your network is open/vulnerable to having a hacked linux system behind your router’s firewall.

Other Useful Red Pitaya SDR links circa 2016-10-28:

PA0AER on a comparison of Red Pitaya to Flex radio, with intermod test result(google translate to english).

FOSDEM 16 program by open source SDR app designer Pavel Demin (Brussels, January 2016)

Red Pitaya as SDR

Red Pitaya Quick Start Guide

Video 2Khz BDR 107 dbm by Yevgeni Kolganov

**

2015 IOTA Recap W4O – Better Late Than Never

Photo of most of the 2015 W4O IOTA station from Okracoke Island.

Most of the 2015 W4O IOTA station from Okracoke Island.

Tri band yagi at 18 feet.

Tri band yagi at 18 feet.

After a lot of foot dragging and interruptions, all of the components required for a 100w battery operation had been acquired at casa W4KAZ in late spring 2015.  The first test run was a 1E Field day operation at home.  But better to put it to use afield.

So N4YDU was game for the field test on Okracoke island for 2015 IOTA.  N4YDU and I operated as W4O from Okracoke Island on the NC outer banks, just south of Hatteras.   Access to Okracoke is by boat, so we booked slots on the ferry out of Swan Quarter for Thursday afternoon.  This worked well, allowing for set up and test operating well before the Saturday start.  Also a nice break for a meal for lunch Friday down in Okracoke village.  QTH of the operation was the NPS campground on Okracoke.

WX Conditions on Thursday were cool with an all day drizzle.  Ugly, but no thunder and lightening, so not terrible.  Set up of camp was delayed until early evening.  Thursday night was warm, damp and still.  Friday morning brought clear skies and an nice cooling breeze out of the north.  The WX was much improved for the rest of the weekend.  Thursdays rain was the harbinger of a very welcome unseasonable cool front, and WX for the bulk of the weekend were very comfortable with much lower than normal temperature and humidity – perfect for field operations.

Radio propagation did not live up to the WX, so there were periods of slow conditions.  A nice breakfast is always good.

Breakfast.

Breakfast.

Solar Power

The solar set up included two 30w solar cells sending power to the charge controller and two deep cycle batteries.  Our solar cells were augmented by the temporary loan of an 85w solar panel by WB8YJF, Jon.  WB8YJF vacations at Okracoke every year at this time, and with his help we had a strong 8A charge current throughout the day Saturday.

 

Solar cells catch a tan

Solar cells out catching a tan on the island. My own small cells in the foreground and WB8YJF’s loaners in the rear.

Batteries and charge station

Batteries and charge station

Having the battery fully charged going into the evening hours was nice.  Rates slowed fairly early, so two days of beachside life had us leaving a few possible qso’s on the table.  Sleep was the better option.

Station

The station consisted of the batteries, feeding power to the Elecraft K2.  Antenna supports consisted of several fiberglass masts.  All of the masts have been modified by drilling holes at the base of each mast section for pins.  Hitch pins are used for the smallest sections, and 2 inch cotter pins are used in the larger sections.  This was faster and more secure than using hose clamps, but it may ultimately weaken the masts over the long term.  That trade-off seems worthwhile for the time saved on deployment and take down.

The W4O station, an Elecraft K2, a couple of tuners and logging laptop

The W4O station, an Elecraft K2, a couple of tuners and logging laptop

The 33 foot fiberglass pole from TheMastCo was used as the center support for a lightweight fan dipole for constructed from 300 ohm twin lead and surplus field wire, covering 40m/20m.  A 22foot fiberglass flag pole combined with most of a 20 ft. Shakespeare wonder pole was used to support an inverted-L for 80m.  Thirteen foot crappie poles were used to get the ends of the dipoles and vertical as high as possible in the limited space offered by two spaces in the campground.  We also deployed a 2 element triband yagi on five sections of surplus military camo mast, at a height of about 18 feet.

Radio conditions were poor, but the WX was unusually good for the NC coast at the end of July.  Great trip and another successful field test of something different.

 

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.