WSPR Station

The Solar Eclipse QSO Party urges, “Operate a wide-band automated receiver at your station” like a wspr station.  The station has been in staging at home before it gets deployed to the permanent site in Strasburg but not working correctly.  Finally a breakthrough.   Today we figured out a problem.  Now we’re seeing our wspr station being spotted on wsprnet.org, running only 1 watt and feeding a Hustler mobile whip antenna.

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This is the Hustler mobile antenna getting that big 1 watt signal around the country.

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The WSPR station being staged before deployment looks like this.

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The computer is an Intel Compute Stick, on the left side half way up running Windows 10 and WSJT-X version 1.8.  The red box is a West Mountain Radio PlugNPlay Rig Runner to interface to the Yaesu FT-817.  The yellow candy wrapper is shrink wrap around a dc-to-dc converter.  It takes in 12 volts dc and converts it to 5 v dc for the powered usb hub and for the Intel Compute Stick.  Green and blue plugs from the PlugNPlay go into an external usb sound card.  One of the usb dongles is a Yaesu CT-62 CAT interface cable.

Deployment plans include packaging the above apparatus into a fiberglass outdoor enclosure, then adding a solar panel, controller, and batteries.  The permanent antenna will be a Cushcraft AP8A trap vertical picked up at a recent hamfest.  The complete 12 volt station draws 1.3 amps when transmitting (at 1 watt) and draws .6 amps when receiving, including the computer. Can’t use an automatic tuner because wspr changes bands and listens before transmitting.  That means the tuner is still tuned to the previous band instead of the current one.  Must use resonant antennas like trapped vertical.

We’ll turn on band hopping and cover 80 through 10 meter bands.  If we get the ambition we’ll add a 6m vertical stub and cover that band, too.  This project is targeting the August 21, 2017 solar eclipse.  In addition to WSPR we plan to operate the Solar Eclipse QSO Party using weak signal modes JT65, JT9, and FT8 on the main station. We’ll be receiving on 630 meters and transceiving on 160 through 6 meters making as many QSO’s as we can.

First plan went out the window because a trapped vertical needs radials and the weeds  make that impossible.  Plan B is to try a Comet CHA250B because it requires no radials.  It just didn’t get a signal out. Out the window.  Plan C is to receive only at Strasburg and transmit only from home.  Can’t receive from home due to a high noise level.  But at Strasburg  when unchecking all the transmit boxes in wspr it no longer band hops.  Is this a bug?

A solution popped up while reading the manual to try to see why it stopped bandhopping.  There is a “tune” checkbox that sends unmodulated carrier for a few seconds after changing bands.  We just happen to have the ideal tuner — a SGC SG-211.  We’ll try that next.

The SG-211 failed because it needs more than a watt for tuning.  Next we tried a LDG RT-100 and it worked perfectly.

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Second Tower

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

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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.

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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!

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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.

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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.

What a bird sees…..

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

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