Sunday, November 25, 2018

A Grand Day Out - QRP Portable

With apologies to Wallace and Gromit.

I was able to operate portable four times this year.  Briefly, here are some photos and comments.

Texas State Parks on the Air (TSPOTA)

I operated only on Saturday - April 7th.  As it was cool (~39F), damp and threatening rain, I elected to operate while sitting in the car at Longhorn Cavern State Park (EM00tq).  I only made 15 QSOs  No other Texas state parks were heard.  As of this writing, no scores have been posted.  Used the K1 @ 5W with a 20M dipole.  This is a pleasant and scenic location, and my closest state park.




QRP to the Field (QRPTTF)

Two weeks after the TSPOTA event, I was out again - this time at Black Rock Park in Llano County (EM00ss).  More on Black Rock Park later.  Rig was again the K1 and this time I hung a 40M EFHW in addition to the 20M dipole.  25 QSOs was good enough to get me into the top five..  Got to meet a dog named Gussie.  She was interested in my stash of Ritz crackers.


The Flight of the Bumblebees (FotBBs)

This was on the 29th of July and again at Black Rock Park.  I made 29 QSOs and had another good time.  It was very warm and lots of folks were enjoying the park.  Same rig as above.


The Skeeter Hunt

This was on the 29th of August and once more at Black Rock Park.  Again 29 QSOs with the K1 @ 5W, the 20M dipole and the 40M EFHW.


More on Black Rock Park

This park, on the west side of Lake Buchanan, is operated by the Lower Colorado River Authority (LCRA).  This is not a state park, but is operated in a similar manner.  In my experience, these parks are very popular with families, especially in the summertime.  I would strongly suggest reservations or getting there early and being flexible.  Here are some links:

LCRA

Black Rock Park

I had a very good experience at this park.  The staff was both friendly and very helpful.  I did a scouting run through the park early in 2018 and made note of the sites with 20 and 40M spaced trees.  :-)   No one seemed to have any problem with me hanging antennas - and on my last visit, I was greeted with, "Oh, you're that radio guy."




cln - Nick
WB5BKL



Monday, October 22, 2018

QCX - 30M Transceiver - Mods

Two more mods for my 30M QCX.

I have already completed several mods, as detailed in QCX - 30M Transceiver .  The final one I did last year was intended to increase the power output, but was only marginally successful.

Recently, I purchased a 20M QCX, but after finishing construction, I found that the ATmega328P microprocessor was not working.  Hans, at QRPLabs, had seen this problem before and was happy to send a replacement - and I ordered an additional latest firmware chip for this 30M rig.  While waiting on the replacements to arrive, I elected to replace the capacitors in the low-pass output filter.

I replaced C25 and C26 with 560pF silver micas and replaced C27 and C28 with 270pF silver micas.

These capacitors were huge compared to the originals - so I had to get creative in placing them.









I





Note that C27 and C28 had to move to the bottom of the PCB - and were tilted slightly to provide clearance for the enclosure.




I am fortunate to have a low-priced but effective solder-sucker that I bought some years ago.  This would have much, much more difficult without it.

Here are the parts I removed.  The largest is about the size of the head of a kitchen match.  I used silver micas as I had the correct values for the 30M QCX on hand.





Just as I was completing this modification, the replacement microcontrollers from QRPLabs arrived - with firmware version 1.00f.

The only volatile information that I wanted to keep was the correction for the 27MHz frequency reference (Entry 8.5:  27.004.550), so I made a note of that and replaced the 1.00b firmware with 1.00f.  As expected, no re-alignment was really needed, but I touched it up anyway.

After all these changes, I now have 3.4W out measured with the same equipment as earlier.  This is just about what the designer predicts, given my 12.4V motorcycle battery power supply and the polarity protection diode.

I am pleased and will call this good for now.

My thanks to W5IQS for suggesting mounting the capacitors on the bottom of the PCB.   And to Hans, of course.  The more I use this little rig, the more I like it.

Here is an image of the 30M QCX in its new enclosure.


cln - Nick
WB5BKL



Saturday, September 22, 2018

Automated XLog backup - Revised version

Back in the days when I worked for a living, one of the computer guys at the plant corrected me while I was talking about disc drives in our computers - I was saying "if it fails..."  He corrected me with "Not if it fails.  When..."

Though no longer required, lots of old-school Radio Amateurs keep a log.  Some use pencil and paper, but most do it digitally (and some, like me, do both).  Belt and suspenders.


With that in mind, I have written a Linux script that will help me avoid manual re-creation of my digital Amateur Radio log from the pencil and paper copy - which dates back to 1970 - when the computer finally fails.  I use XLog, but this should work for other Linux logging programs.

You will need some basic familiarity with Linux scripting and permissions, have crontab up and running and Dropbox installed.

The general scheme is to copy the XLog log file to a safe place at least once a day.  When my computer dies (and they all will), I could re-install XLog on a replacement and retrieve the latest of my daily log file copies kept remotely by Dropbox.

The scheme has three parts:
     (1)  Linux 'crontab'
     (2)  Dropbox
     (3)  The 'xlog_backup.cmd' script


'crontab'

Linux has a very handy program that allows users to schedule events at intervals.  I will not do a tutorial on cron or crontab, but will just show you the appropriate crontab file entry, below:

#       min     hour    day     month   day of  command
#                                       week            
#    
30 * * * *                        /home/MYHOME/bin/xlog_backup.cmd


Crontab reads this file and is directed to run the command xlog_backup.cmd (in the directory given) on the half-hour of every hour of every day of every month on every day of the week.  For you old timers, that's every time Mickey's long arm points down.


Dropbox

Dropbox is a commercial file sharing and storage program.  There is a fee if you want to store lots of data, but since XLog files are relatively tiny, we can just use the free ('Basic') version.  Check out:

          https://www.dropbox.com

You will have to create an account.  The script below could possibly work with another file-sharing program that works in a similar fashion.  Your decision.  I have no commercial interest in Dropbox, but it is quite handy for things other than saving Amateur Radio log files.

One you have Dropbox running and understand how it works, make a subdirectory, perhaps named "XLog", to match the script location below.


'xlog_backup.cmd'

Here is the backup script.  This is a revised version (23 February 2019) that is slightly more logical and creates a new backup if you change your log.  You will have to edit the various lines that are unique to your application - one example is the name of XLog's log file.   XLog typically keeps this file in the hidden directory '.xlog'.  Mine is named wb5bkl.xlog.

Make a copy of the script below and edit it:

#!/bin/bash
#  /home/urhomedir/bin/xlog_backup.cmd
#
#
###  Edit each of the following for your situation:
###    urhomedir - your home directory
###    YOURCALL  - your callsign in CAPS
###    yourcall  - your callsign in lowercase
###  Note the asumptions about directory locations
###  including the Dropbox directory structure.
###  All the 'echo' statements can be commented out once
###  you've got it working to your satisfaction.
#
#
#  Define paths to xlog data file and Dropbox backup
YOURCALL_XLOG=/home/urhomedir/.xlog/yourcall.xlog
DROPBOX_XLOG=/home/urhomedir/Dropbox/Xlog/yourcall.xlog.`date +%j`
#

#  Housekeeping  -  comment this out if you want to keep them all
#  Get rid of all but the 10 most recent log backups
rm -f  $(ls -1t /home/urhomedir/Dropbox/Xlog/yourcall.xlog* | tail -n +11)

#
#
#
  First, check to see if the backup for today exists
#  If not, create it and exit
#
#
if [ ! -f $DROPBOX_XLOG ]
then
    # create it
    cp $YOURCALL_XLOG $DROPBOX_XLOG
    echo -e "\n Creating today's backup file:   yourcall.xlog.`date +%j` \n"
    #  place a note in .xlog containing the latest backup time
    date > ~/.xlog/Last_Cloud_Backup
    exit
    else
    :
fi
#
#  Or see if the logfile in Dropbox is newer than your logfile
#  If so, do nothing and quit
#
if [ $DROPBOX_XLOG -nt $YOURCALL_XLOG ]
    then
    echo -e "\n yourcall.xlog.`date +%j` exists and is newer."
    echo -e " Quitting xlog_backup.cmd...\n"
    exit
    else
    #  if the Dropbox version is older than the logfile, overwite it
    #  with the newer version
    cp $YOURCALL_XLOG $DROPBOX_XLOG
    echo -e "\n Overwriting today's backup file:   yourcall.xlog.`date +%j` \n"
    #  place a note in .xlog containing the latest backup time
    date > ~/.xlog/Last_Cloud_Backup
fi
#
exit
#


Save the edited copy in your 'bin' directory (or wherever - but match your crontab entry) and make it executable.  The script only makes one Dropbox copy per day - but overwrites that copy if your log changes within the last hour.  Safe enough for me - but you can modify the if/then routine above and the crontab entry to suit your needs.

The backup file will have the name yourcall.xlog.Julian_date, for example:  wb5bkl.xlog.147

And the the latest backup time will be noted in your .xlog directory.  Backups from at least the last 10 days will be saved.

I hope this works for you - and keeps your log(s) nice and safe.

cln - Nick
WB5BKL
Lake Buchanan

Tuesday, May 29, 2018

Fiberglass center support - 40M extended double Zepp

I do not recommend anything to anyone anymore.

Having said that, I am personally pleased with the fiberglass tubing products from Max-Gain Systems.

I wanted to replace the relatively short fiberglass over galvanized steel center support for my 40M extended double Zepp (edZ).  I had two goals:  make it higher and make it non-conductive - simplifying the routing of the ladder-line feed.  

The telescoping fiberglass mast from Max-Gain is very nicely made.  The clamps are well thought-out and the instructions are clear.  The problems I had were entirely my own.

The clamps are entirely non-conductive and have a clever over-center lever to hold the tubing in place.  My problem was similar to the old British motorcycle joke about fasteners in aluminum castings:

Stages of bolt tightening for the novice mechanic:
                                               Loose
                                               Snug
                                               Tight
                                               Very Tight
                                               Loose


I snapped one of the clamping bolts during extension of the third fiberglass tube - it had been tightened to the 5th stage above.  After that, I was much more cautious.


Within a month I discovered I was too cautious.  With the constant flexing in the wind, two of the sections had partially collapsed - you can see one just above the roof level in the image to the right.  The looped ladderline is a dead giveaway.  

My QTH is in an area with almost constant breezes (a good thing in the Texas hill country).  The mast has one clamping support (at the roof apex) and is guyed only by the 40M edZ itself.

This means the mast is free to move in the wind.  In strong winds (say around 45 mph), I have seen the top of the previous fiberglass mast bent to almost 45 degrees.  We have had wind gusts of over 65 mph during storms with no permanent damage - it waves around like a fishing rod.   But all this movement did allow the telescoping mast to creep downward, especially in the lower sections which bear the weight of the sections above plus the downward component of the tightened edZ wires. 

[I know I am taking a chance here with minimum guying - but I am willing to bear that risk.  The previous fiberglass support was up for well over 12 years with no
apparent damage.]

I did not want to secure the sections with non-conductive pins. Sooner or later I would have to lower the mast and Max-Gain specifically warns against damaging the tubing finish as clearances are tight.  The same argument applies for any sort of clamp that would mar the tubing.


What I devised is shown to the left, just above the clamp mechanism.  It consists simply of three or four layers of electrical tape overlaid with a very tight tie-wrap (I have lots of tie-wraps, so I don't mind snapping one to get to stage 4, above).  Obviously I had noted that the tubing collapse halted when the electrical tape and tie-wrap holding the ladderline hit the clamp.  

Seems to work well.  I will post a follow-up report in a year or so.   





40M extended double Zepp details:

Orientation:                Roughly North-South
Center height:            about 46 feet
South end height:      about 25 feet (Live oak)
North end height:      about 30 feet (Pine)
Feed:                          450 Ohm ladder line


Best wishes to all.

cln - Nick
WB5BKL