Both 65 Foot Masts Go Down In Storm

Both the north and the south 65′ aluminum masts went down in the snow storm Sunday.  They both failed in almost the same place about two-thirds of the way up.  What a mess.  First the south mast, then the north.

Plans for what to do next are not worked out.  KC0RF has made several suggestions:  slopers from the tower, a 43 foot vertical, a HyGain Hytower, and replacing the masts with 65′ Telrex tubular crankup masts.   We’ll use EZNEC to help us evaluate these suggestions and maybe come up with some of our own.  One of my ideas would be to replace the .058 tubing with .12 inch.

A Plan Emerges Finally

Consider this: they both failed at about the two thirds point and the highest level of guys had been moved up to the top of the mast against the DX Engineering instructions.  The top would not have been supported per the instructions and surely would have failed with  antenna ropes pulling horizontally.  That’s why the guys were moved up.  Unfortunately it left too large a section unguyed.  Armed with this analysis the next attempt will be to guy exactly per the instructions and then add a fifth set of guy ropes to the very top.  Replacements for the bent sections will be ordered.  Only one mast will be done this way as a test.

January 27, we salvaged the north mast and re-purposed the tubing that wasn’t damaged.  Taking one of John’s suggestions we made it into a 43 foot vertical.  The North mast now:

So far performance has been excellent, working quite a bit of dx.  Next upgrade will have to be a higher power tuner (MFJ 998RT) so we can run a few more watts to make up for the inefficiencies.  Frankly, I’m surprised at how well this antenna performs.

South mast:  A week later we cut off the bent top sections.    South mast now:

A road grader in the background is building an access road in the easement next to our property.  Progress I’d be happy to forego.

With John’s help we tried to raise the repaired 65 foot south mast complete with 5 guy levels.  Unfortunately it collapsed when it was just a few feet from being all the way up.  This makes the fourth time one of these aluminum masts has collapsed.  You know what they say.  Four strikes and you’re out.  This isn’t baseball.  No more 65′ masts at W0QL.  Next we’ll look for some suitable solutions closer to the ground.

Taller Vertical Antenna – “North Mast”

The main 56 foot low band vertical has been extended to 65 feet.  It took a full day to do it because of it’s unwieldiness and a constant 16 mph wind.  Thanks to John, KC0RF for giving up a full day to help.  Here’s what it looks like with the additional height and a small top hat to resonate to 3.573 kHz  (the FT-8 freq). This is both a vertical antenna and the north mast which is planned to hold up two dipoles.  The south mast (below) is planned to have the other end of one of the dipoles attached.

The 30″ top hat is very hard to see when it’s 65 feet up in air.  A better picture is coming soon.

The antenna is designed as a full quarter wave on 80 meters.  Using a MFJ 259B  the impedance at 3.573 kHz reads 55 -j0.  SWR is 1.1.   Apparently we hit the resonance perfectly but the ground screen needs to be improved to bring the resistance down to 36 ohms.  The match was planned to be a direct match for a 50 ohm coax.  As an experiment we left the existing tuner installed and tried it on other bands.  It works on all bands, 160 through 10 meters even though the take off angles may be awful and the tuner losses may be especially high at the even harmonic frequencies.  We’ll leave the tuner in for a a few weeks to see where it works and where it doesn’t.

 

WSPR Station

A Weak Signal Progagation Report (WSPR) station is on the air now from the permanent site at Strasburg.  It runs 1 watt on multiple bands.  WSPRnet.org shows the results.   Hardware is a Yaesu FT-817 transceiver and an Intel Compute Stick computer.  Software is WSJT-X Ver 1.8 running in WSPR mode.  Antenna is a Hustler 6BTV trap vertical.  Ground radials are welded-wire fencing.

KC0RF, John, and I were just finishing up when rain hit.

Control is done over the Internet using a remote access application, Teamviewer.  FCC regulations specify a beacon can only run when an operator is present to control it.  Whenever I leave the house the WSPR station is shut down by using Teamviewer.

Here’s a random screen snap of the WSPRnet.org results for the last hour.  These stations have “spotted” my 1 watt beacon and posted it to WSPRnet.org in the last hour.  We’re getting many more spots with the base antenna out here than we did with the mobile antenna at home.

August 15, 2017 – measuring the swr with a MFJ-259B antenna analyzer showed high swr on 30 meters and 80 meters.  We changed the WSPR configuration to only listen on those two bands.  Hopefully we’ll get time to readjust the 6BTV before the eclipse next Monday.

It’s working now but a few hurdles had to be cleared to get this station on the air, as you’ll see in the previous WSPR post.

Second Tower

Son Blake helped out by digging the hole for a second tower as a Father’s Day gift.  Thank you, Blake!

This second tower is intended to be the support for one end of a 40 meter dipole. The other end will attach to the other tower.  The towers are aligned so the dipole will aim toward Europe.  This tower might also support a 6 meter yagi some day.

Is It Working?

Here is a PSKReporter screen snap showing the spots from other stations hearing me on the new 20 meter yagi antenna.  I’m running 10 watts on JT65.  This was taken at 7pm local time.  The beam is pointed toward Europe.   Yup, it’s working.

Tower!

Wish I could shout it.  The tower is up!  Unbelievable thanks to KC0RF, John Neilson for his extremely hard work.  First look shows the Hygain 203BA yagi on top of the 60 ft. Universal Towers aluminum tower.  First qso was with R3OZ, European Russia with 10 watts and got a report of -11 db on JT65. That was followed up by another European Russian station calling me, R3HH. It’s working!

The balun we chose is a current mode balun consisting of 5 turns of coax through a stack of 4 ferrite cores.  The cores are 43 mix 2.0 inches, taped together.  The coax is splayed with as much distance between turns as possible to reduce capacitance.  Refer to the ARRL Antenna Book 23rd Edition chapter on Transmission Lines, Table 20.7.  This balun will provide 5000 ohms impedance at 14 MHz on the outside of the coax shield.  It looks like this before mounting at the yagi feedpoint.

John, KC0RF, finalizing the balun.

An advantage of this type of balun is that it can handle full legal power because only the common mode current on the outside of the coax is passing through the cores.  The main rf current is inside the coax and not passing through the cores.   It will not heat up like other types of baluns.  This balun has the approval of one of my favorite  rf experts and engineer Bill, N0CU, although he made one suggested modification which we implemented.  Originally the toroids were iron powder and Bill suggested we’d get a higher impedance if we used ferrite.

What a bird sees…..

Although the tower is supposed to be self-supporting we still attached Phillystran guy cables.  This enables sleeping better at night.

Cranking it up:

Tower Completed, Ready to Raise

Tower Assembly

Reminds one of an over sized Erector Set.

Repainting To Control Summer Heat

Temperatures of 104 degrees Fahrenheit were common inside the shed when outside temps were still only 85.  This had to be improved.  Step one was to cut two 6″ circular vents into one gable and add a solar powered fan.  No noticeable improvement.  Step two was to cut in a second vent in the opposite gable.  Same result.  Third step was to cut in a 8″ X 16″ vent midway up the north wall.  Same result.  Fourth step was to paint the shed white.  This helped.  Inside and outside temps since have been nearly the same.  The cute barn red shed is now almost ugly white.  But it’s cool inside.

Why the concern? We were worried more about the batteries than the equipment.  The electronic equipment was still within specified operating range at 104.  Sources say batteries, on the other hand, can exhibit thermal runaway (catch fire) at 122 degrees.  Summer’s highest temperatures hadn’t even arrived yet.

Tower Progess

This tower will be 60 feet tall, is made of aluminum, and will tilt over to allow work to be done on the antenna.  Today the concrete was poured for the 4′ X 4′ X 4′ tower base, a significant milestone.

In this picture I am proudly holding down a pile of dirt with my left foot.

Once the concrete cures the next step will be to tilt over the section shown here and bolt together the rest of the tower one section at a time.   Then the antenna, the rotor, the cables, the tilting fixture, and finally the grounding will be completed.  Thanks to KC0RF once again for the help today.  John easily won the prize for  “most stylish dresser”.