17 September 2016

Activating Fort Bowie for NPOTA with the W7AI Gang

About 10 members of the Oro Valley Amateur Radio Club made a 2.5 hour drive to Southeastern Arizona on Saturday, September 17, 2016, for another National Parks On The Air activation.  This is OVARC's 7th activation for NPOTA this year, and it was my 2nd time joining them for the fun.

The operating location for this one was the Fort Bowie National Historic Site (NPOTA NS18), which was a military outpost in the 1800's when Arizona was still a Territory, and some infamous history was being made involving Native Americans such as Cochise and Geronimo.  There are still a few remnants of buildings on the site, which is nestled among the hills in an area that apparently was significant due to its proximity to a natural water source.


I carpooled with my friend Quinton NU7Y, who brought along the antenna we used.  It was a homebrew inverted V which we hoisted on a 30-foot push up pole.  Quinton parked his truck on top of a homemade mast stand, and an LDG auto tuner did a nice job finding optimal SWR for us.

The radio gear was supplied by Tom, W8TK, who has a nice box full of gear that he hauls out for these portable operations.  The rig was a Kenwood and we logged using N1MM.

Quinton snagged some nice DX on 20m CW including Belgium, Germany, and Slovenia.  We also worked a lot of stateside stations, all of who were happy to add NS18 to their NPOTA credits.  The antenna and rig were working very nicely, although propagation was a bit up and down.  We primarily worked 20m although George NG7A worked a few on 15m and we also tried 30m and 40m.  Other ops included Ken, Paul, Rick, and Steve, 

The OVARC club call sign is W7AI, obtained after one of our local hams, Ron W7AI became an SK.  Ron had been a friend of mine since the 1990's and I have many memories of shared amateur radio experiences with Ron, including Field Days on Mt Lemmon and trips to the Dayton Hamvention.  To be able to use his call sign for operations like these is quite an honor for me.

My operating these days is most often CW, but for this activation we were using both phone and code, and my time at the station was during the phone mode.  I had fun working stations all around the country, and the QSB was very interesting as we went from chaotic pileups to a totally quiet band in seconds.  That's one of the things I love about ham radio - the unpredictability.

We sure had a fun time and were on the air for about 4 hours.  During that time we made 171 contacts.  It wasn't a competition but towards the end we realized we might be able to make more QSO's than another club who had activated this same park, so we had a little fun squeezing out a few more to up the ante.  All in all we had a wonderful time and I'm looking foward to doing it again!

16 September 2016

VOACAP and VOAAREA - September's Monthly OVARC Meeting

The September meeting of the Oro Valley Amateur Radio Club has a nice presentation by Bill Hickey, AB7AA, on a pretty cool propagation prediction program.

VOACAP stands for "Voice of America Coverage Analysis Program".  It's a software program that allows hams to input certain relevant data (such as antenna type, height above terrain, and power levels), and produce a reasonably accurate model showing where signals will reach.

Propagation predictions are a bit like weather forecasts - they are often based on good science but there are too many variables involved to be 100% perfect.  Still, this looks like an interesting tool and I'm planning to play with it a bit.

10 September 2016

Mt Wrightson Hike and SOTA Activation

My interest in the Summits On The Air program continues to grow, and as a result I've become fascinated with the idea of hiking some of the local area peaks in Southern Arizona.  On Saturday, September 10, 2016 I was able to spend the day hiking and playing radio, and I had more fun than I even imagined.

My goal was to reach the summit of Mt. Wrightson, which is designated W7A/AE-014 in the SOTA maps database.  This requires a fairly strenuous hike but that was what I wanted - and I got it.  I knew it would be a long day so I packed 70 oz. of water, 2 bottles of gatorade, and food.  In addition, my pack had to carry my radio gear, emergency kit, and miscellaneous important stuff like toilet paper.  My wife looked at it and asked, "are you moving out?"  The pack was heavy - I weighed it after loading it up, and it came in at...over 26 pounds!  That's heavy, but it didn't include the antenna - which added another 14 pounds.  That 40+ pounds of weight is a lot, but I figured it would be manageable.

There are several options to hike to the summit.  I decided to start at the trailhead from the parking lot of Madera Canyon, which is just about a mile high in elevation.  I hiked on the Old Baldy Trail, which is steeper but shorter than the alternative from that area, the Super Trail.  Old Baldy was a nice trail, mostly rocky and a bit steep.  At various locations, I was able to see my target rising up ahead of me.

Much of the trail was shaded, which was a good thing because I didn't begin the hike until after 10 am, and the temperature was in the 80's.  The scenery was beautiful and recent summer rains had created plenty of green.  The hiking was slow, due to elevation, steep trail, and excess pack weight, but I was really enjoying the quiet and fresh air. I had my APRS beacon going out on my HT, but I don't think my signal made it out too many times.  My friend Quinton was watching online for my beacon, and did see me a few times.  In some places, the trail opened up to nice vistas looking out towards Tucson, and these were the best spots for APRS to get out.

I reached Josephine Saddle in a little under 3 hours.  At this point, there was almost a mile to go to the summit.  The views from the saddle were spectacular and I was excited to be getting close.  I was carrying my Buddipole in the sling bag and I was looking forward to giving my shoulders a break!  At this point in the hike, my shirt was drenched with sweat.

The final push to the summit started with a pretty meadow on the saddle, although the effects of a forest fire were evident.

Near the very top, the trail became very rocky and narrow, maybe even a bit dangerous.

The remains of an old fire lookout building are at the summit, but there were a few people already there, so I set up my antenna and equipment next to it.  I was tired after about 3.5 hours of hiking, and the elevation of about 9,500 feet made for thin air, but was looking forward to making some QSO's.  I set up the Buddipole for 10 meters (including hanging my new SOTA flag!), and called Quinton on the OVARC DStar repeater to let him know I was ready to go.  He was first in my log with a quick 10m CW contact.  I worked a few more stations on 10m, including WA7JTM Pete who was activating a summit in Yavapai County - that was a surprise, as the distance between us is normally too close for sky wave and too far for ground wave propagation.

I then switched over to 20m and began working the pileup.  I was struggling with the code for some reason.  Many mistakes were made and it seemed like I was having difficulty with the paddle making the correct number of dits in certain characters (i.e. "4" and "H").  It felt like the paddle was loose but I wasn't able to get it tightened; but really I think my problems were because (a) I was tired from the hiking, (b) I was experiencing some muscle trembles in my hand after carrying the antenna bag, which required me to hold it awkwardly to prevent slipping, and (c) I'm not the best code op anyway.  Nevertheless, I had great fun and worked 25 QSO's total.

At about 4:00 local time I realized that sundown was going to occur before I got down unless I left soon.  I was sad to pack up but really wasn't planning to hike in the dark, so I quickly took the antenna down, loaded everything up and began the trek down the mountain.  On the way down, I was caught in a refreshing rainfall for about 30 minutes or so.  The downhill allowed me to go much faster, and I reached the canyon parking lot after about 1 hour 45 minutes.

This was really such a fun day.  There are two other peaks close to Wrightson - Josephine Peak will require a similar hike, while Mt. Hopkins can involve a hike but it's also possible to drive much closer.  I could easily see them both during my hike, and I'm hoping to activate both eventually.  According to the SOTA Mapping Project page, both summits are worth 10 points due to their peak elevation.  I really like the mapping page, and after this hike I uploaded my Garmin's .gpx track file for the climb up to help other users of their database.

05 September 2016

Constructing a Linked Dipole

One project I'm currently working on is to build a "Linked Dipole".  This antenna is just a simple wire dipole, but it has breaks along the wire that can be either connected or disconnected, allowing the antenna to be tuned for one of several different bands.  I expect this will be a useful antenna for portable operations; in fact we used my friend NU7Y's linked dipole very successfully on my first SOTA activation.

The SOTA website has an excellent calculator app that I used to determine approximate lengths of wire for each side.  My goal was to build a dipole that will cover the 15, 17, 20, 30, and 40 meter bands.  After putting in my parameters, here is what the app recommended for my design (note this is only one side, the dipole requires two for each side).

I used some 14-gauge "THHN" style wire that I obtained from the local Home Depot.  The coating on THHN wire does have some effect, but I was willing to sacrifice a little perfection in exchange for the low cost of this wire and for my first attempt at this particular antenna design.  I cut each length approximately 10cm longer than suggested, with the plan to trim them down to obtain optimal SWR (it's much easier to trim shorter than extend longer!)

For easy connect/disconnect, I decided to try using Anderson Powerpoles.  One side uses all red, and the other side uses all black - that helped me keep things straight during the building process.  I used a label maker to indicate which band each wire section was cut for.  I began by placing a powerpole on only one side of the wire; the other side was left bare until I had trimmed it to the correct length, after which the second powerpole was crimped on.  The powerpoles do work, but if I build another linked dipole, I do not think I'll use them again, because they come apart a little too easily - it's likely I will need to reinforce the connection when the antenna is hanging for use.  I've seen other designs use alligator clips and even bolts to hold things together.

I also used a short piece of parachute cord to keep the dipole together when the powerpoles are disconnected.  Tie-wraps hold the cord and wire together, with a few drops of super glue to create a pretty solid bond so they don't slip.  Like the second powerpole, the cord was not connected until that section had been trimmed down to the correct length.  Here is a close-up of one of the links (note the whole antenna has a total of eight links):

I set the antenna up in my back yard for testing and trimming.  I also thought this would be a good chance to practice setup of the entire antenna system, including an extendable mast.  I had acquired a 10 meter pole from SOTABeams, a store in the UK which caters to SOTA enthusiasts.  10 meters is quite high and to make a portable mast, the poles become extremely thin at the top.  So thin, in fact, that most photos you see of them show considerable bending at the top.

So, I thought bending was normal and proceeded to hang my antenna on the top section and hoist it up.  I had each side of the dipole connected to a balun, and a run of RG58 coax connected to the balun.  As the mast went up, it began to bend.  Unfortunately, the weight of the balun and antenna were too much for the tiny top sections, and I only had it extended about 10 feet up when I heard a loud cracking sound and the mast bent in an ugly downward v-shape.  My brand new mast broke on my first try at setting it up!

It was quite a disappointment but I suppose it's better to have this happen in my backyard than after I have traveled to some remote site.

I still wanted to complete the antenna construction, so I set my frustrations aside and went to plan B.  I have a fairly sturdy tripod mast from MFJ, one that is most definitely NOT light enough to carry on a hike but is good for home use (I usually have a magnetic loop antenna hanging on it inside the house).  So I brought it out and set it up, and proceeded with the somewhat tedious process of fine-tuning the link element lengths.

I began with 15m, and once it was reasonably tuned I connected the 15m/17m link and tuned for 17.  Next up was 20m, which much to my surprise turned out to be too short!  This was not a huge problem, but I did need to re-cut a longer length of the wire and replace this section.  Then I moved on to 30m, and finally 40.  For the 40m section, I have left it intentionally long until I get out in the field with the antenna.  Once I'm in the field, I will either trim it down or determine a fold-back method to effectively shorten it to the best SWR.  I actually would have preferred to do this at home, but my back yard is just a bit too short, and it was getting too hot (105F) to continue the work.

Here are some SWR measurements of the various bands:

Certainly this is not the perfect antenna, but it does look like it will be a useful piece of gear for some of my ham radio portable operations.  I wound each side around kite winders for simple transport and deployment.  Now I just need to find a better mast solution.  It could be hung up in trees as well, but many of the peaks in Arizona that I may hike to won't have any trees available.  I realize that the real test will be how well it can perform, but I know what to expect from dipoles and this does appear to be a great way to get 5-band capability from a single antenna, at a very low cost.  I'll probably build another one to cover the 10 and 12 meter bands.

01 September 2016

Wallpaper From SOTA!

My first SOTA awards have arrived!  These two are basic Chaser awards - a fun start to my SOTA wallpaper collection, which I hope will eventually expand to include Activator awards as well.

The Chaser awards are given for contacts made from my home QTH to stations that are activating a summit somewhere.

Most of my QSO's so far as a Chaser have been with stations in WA, OR, CA, NM, and CO.  This is partly due to my current HOA-limited home station, and partly due to generally weak propagation conditions.

Sometimes I log in remotely from my office to my home, and make a QSO using the CWX function of my SDR.  But I prefer to use an actual code paddle when possible instead of computer-generating the CW, it's just more fun.