VE7SL RADIO NOTEBOOK

THE TARGET

Single Yagi Moonbounce!


In the winter of 2007, after becoming increasingly more aware of the number of smaller EME stations having good success using the WSJT JT65B digital mode, I decided to try an afternoon of listening on 2m with my single 9 el yagi (M2 2M9SSB on a 14.5' boom). Developed by Joe Taylor, K1JT, JT65 utilizes a compliment of 65 tones in a sophisticated application of frequency-shift-keying and digital signal processing to dig out signals normally buried in the noise.

Since my antenna is fixed in elevation at 60' in the air, my 'moontime' would be limited to either moonrise or moonset. The best direction at my location favors moonrise, where I am able to point the antenna directly at the moon, across many miles of open ocean. As I watched the moon slowly appear above the ocean I was surprised to immediately hear signals of 'speaker' volume! It was W5UN in Texas, calling CQ. As I tuned down the band another signal popped out of the speaker. It was long-time moonbouncer, KB8RQ, in Ohio. A few minutes later, with the moon barely above the horizon, the speaker-quality signal of RU1AA in St. Petersburg, Russia, was also heard calling CQ.

Although I knew that these were all stations with monster-big antenna systems, I was still surprised at what I was able to easily hear using my small yagi. No doubt the salt water horizon was enhancing signal levels to some degree due to the 'ground/sea-gain' effect that I have noted from here on other bands as well.

Determined to see if I could work any of these stations, I enlisted the help of my small 2m solid-state 'brick' amplifier which, although never measured, supposedly puts out about 140 watts. Since the JT65 mode is duty-cycle hungry, I added an old squirrel-cage blower salvaged from a microwave oven to blast a stream of cooling air across the amplifier's heat-sinking fins. After reading (once more) the QSO protocols for the JT65B mode, I waited for moonrise the following day.

Once again the first signal heard was W5UN calling CQ. He quickly responded to my first 'random' call, sending both his call and mine, along with an "O" signal report. I responded with an "RO" report, indicating that I had copied both calls as well as my signal report. Dave's "R" was quickly followed by my "73" and my JT65 'initial #1' contact was completed.

Over the next few weeks and months I was able to complete with a number of other stations both big and small, as conditions vary from day-to-day as well as from month-to-month. As of February 2008, I was up to 54 'initials' (new stations) on JT65 using the single fixed yagi and low-power amplifier on my moonrise window. Because of my over-the-ocean moonrises, it appears that my antenna is developing close to the theoretical 6db 'ground/sea' gain for unobstructed horizons. The single yagi is behaving similarly to a 4 x 9el array at these low angles.

As my older laptop became increasingly problematic I replaced it with a newer one. The new one had no serial port so I was unable to key-up my 2m transmitter and my EME work came to a halt.

Fast-forward to the spring of 2016 when I finally decided to search for a USB-to-serial-port adapter that would 'hard-key' the changeover system in the 2m rig as well as for my 630m operations. I was able to find an inexpensive adapter and provided the information in my blog.

The adapter info can be found here.

I have resumed monthly EME activities now that my system is working again, still using a single 9el M2 yagi, 140W output and moonrise (no elevation ability) only.
As of April 2016, I have completed contacts with 73 different stations using this system.

Since I am still able to hear more stations than can hear me, the next improvement may be to add a little more power, rather than increase the antenna size. But for now, there are still many stations that should be workable with the little system.

2m EME Contacts

W5UN - TEXAS

Dave was the first JT65B signal heard off the moon and came right back on my first call. His antenna is huge: 32 x 17el Yagis.

KB8RQ - OHIO

Like Dave, Gary was very loud, thanks to his monster antenna system of 24 x 13el Yagis.

RU1AA - ST. PETERSBURG, RUSSIA

Alex's signal is the loudest I have heard off the moon at -10db.

Like W5UN and KB8RQ, his antenna puts him in the 'monster' class of easily worked stations: 16 x 14el Yagis.

DK3EE - VERL, GERMANY

Another loud station (-13db) with a big antenna system: 4 x 24el Yagis.

OZ1LPR - SONDERBORG, DENMARK

Peter was my third contact of the day and like the other two stations, was easily heard on speaker. Peter runs lots of power and a pair of 10el Yagis.

K9MRI - INDIANA

With his 8 x 17el Yagis, Joe was another easily heard signal.

ES6RQ - VALGAMAA, ESTONIA

Another strong signal at -16db from 8 x 17el Yagis.

K2BLA - DELAND, FLORIDA

Al runs just 400W into 12 x 10el Yagis which puts out a great signal.

F1DUZ - MALVAUX, FRANCE

Philippe reports that I am his first '9el Yagi' station. His antenna consists of 4 cross-polarized 20el Yagis.

DL8GP - RIEGELSBERG, GERMANY

Hans always has a strong signal. His system consists of 8 x 20el crossed polarized Yagis.

CT1HZE - ALGARVE, PORTUGAL

Joe's -18db signal came from 4 x 11el Yagis.

HB9Q - REINACH, SWITZERLAND

Dan has a huge 'group' station and is active on all VHF bands and modes. On 2m Dan uses an 8 x 19el Yagi array. A few weeks later I worked him on 432MHz EME while running the 25W exciter into my 22el Yagi.

F6HVK - CORCELLES les MONTS, FRANCE

Andre's 600 watts into 4 x 17el Yagis was -22db here. He reported my signal -24db.

UA9YLU - SLAWGOROD, RUSSIA

Victor was -19db with his KW and 4 x 15el Yagi system.

UA9SL - ORENBURG, RUSSIA

It's always nice to work another "SL" especially off the moon. Vlad's 800 watts into a 4 x 15el Yagi array was -22db.

EA6VQ - BALEARIC ISLANDS

I worked Gabriel on a random CQ during the EME contest. His signal from an 8 x 17el Yagi array was an outstanding -16db.

UA9FAD - PERM, RUSSIA

Victor is running a 4 x 16el Yagi system and was good copy at -21db.

RA6DA - KRASNODARSKIJ, RUSSIA

Vitaly's 8 x 12 el Yagi system was -23db and was my third contact of the afternoon during a period of excellent conditions.

UA4AQL - VOLGOGRADSKAYA, RUSSIA

Al was running a KW into a 4 x 13el Yagi array. We were both hearing each other at -20db.

UR5LX - IWACHKI, UKRAINE

Sergey was running a KW into a 4 x 13el Yagi system. This QSO was a good example of how conditions can vary so much between one end of the path and the other due to Faraday rotation. Sergey's signal was only -25db here yet he was hearing me at -21.

RK3FG - MOSCOW, RUSSIA

Anatoly signal peaked at -23db with his 4 x 15el system.

PA0JMV - OIRSCHOT, NETHERLANDS

Joop runs 2KW into a 4 x 10el Yagi array. His signal peaked at -19db while mine was a more realistic -27.

DL9MS - BAD DOBERAN, GERMANY

Once again the 'one-way' propagation so commonly observed on EME was evident on this contact. Joe's KW and 4 x17el Yagi array peaked here at -27db yet he was hearing me at -23db.

N9LR - DUNLAP, ILLINOIS

Larry must have his small system perfectly tweaked as he is always loud here. His KW and 4 x 8el Yagi system is very impressive.

PA3CMC - MEIJEL, NETHERLANDS

Lins uses a 4 x 16el Yagi antenna and an 8877. His -18db signal was easily copied.

DJ7OF - BRAUNLAGE, GERMANY

Non-reciprocity once again as Klaus peaked at -29db here while his report to me was -24db. Klaus runs 6 x17el Yagis.

S52LM - SOLKAN, SLOVENIA

Milos's 4 x 17el Yagis were easily heard at -19db even with my moon at 15 degrees elevation.

DL7FF - BERLIN, GERMANY

Ben's 2KW and 4 x11el array peaked at -24 during a period of tough conditions.

LY2BAW - SIRVINTOS, LITHUANIA

Tadas's 4 x18el m2 array and a homebrew KW work very well as his signal was an easy copy -19db.

I2RV - SEGRATE, ITALY

Pietro runs a singl 3XC800 into 4 x 16el Yagis. His signal was speaker copy at -17db.

IW4ARD - BELLARIA, ITALY

Gianni was peaking -22db during our mid-summer QSO. He runs a 3CX1500 into a 4 x 8el array.

WQ5S - PRINCETON, TEXAS

Brad was my second Texan on EME. His KW and 4 x 12el array peaked at -20db. With 424 initials on EME, Brad reports that I am the smallest station that he has worked so far.

DH4FAJ - RUSSELSHEIM, GERMANY

Mathias runs an excellent 4 x 9el system which works very well. His signal was speaker copy at -18db.

JH0MHE - NAGANO, JAPAN

This was the first time that I had listened on my moonset. I worked Shiro with the moon at 11 degrees elevation but was able to copy him down to 4 degrees when my moon became obstructed by local terrain. Shiro's 4 x 18el Yagi array peaked at -25db while he was hearing me at -27db.

SM5CUI - UPPSALA, SWEDEN

Rune peaked at -22db with his 4 x 15el and 800 watts. My signal was -26db at his end.

DF2ZC - BREITSCHEID, GERMANY

Bernd was worked after several tries, with an excellent -18db signal. Bernd runs 4 x 18el Yagis. Final 'R' was received at 18 degrees elevation!

OM3BC - FIL'AKOVO, SLOVAKIA

Jozef was -19db with my moon at 15 degrees elevation. He runs a 4 x 12el Yagi array.

KD3UY - GLENWOOD, MARYLAND

Bob's 4 x 13el Yagi array puts out a great signal. He was peaking -19 with my moon at 3 degrees elevation.

PE1L - TYTSJERK, NETHERLANDS

Rene runs a 2 x 14el array and a KW. His signal peaked here at -27 while mine was a -29.

W8WN - ELIZABETHTOWN, KENTUCKY

Shelby and I tried several times until we easily worked in Dec '07. His 4 x 16el array and 8877 peaked at -19 while he was hearing me at -23 in Kentucky.

RX1AS - ST. PETERSBURG, RUSSIA

Alex was worked with the moon at 14.5 degrees elevation.

ALSO WORKED BUT AWAITING QSL
RA3AQ - KRASNODAR, RUSSIA

YU1CF - KRUSEVAC, SERBIA

RN6BN - KRASNODAR, RUSSIA

SM2A - SKELLEFTEA, SWEDEN




The links section shown below will direct you to some of the pages that I have found helpful. As well, a Google search of "EME" or "MOONBOUNCE" will bring up a lot of information for you to ponder. Here are some of the things that I have discovered that may be of help to you.

1. The newer versions of WSJT will require a pretty speedy computer to work their best. Using an older Toshiba laptop with Windows98SE, I have found that the earlier version (4.9.8) works well although the speed of my computer makes the decodes slower than a faster machine would produce.

2. You will need to have your computer clock 'bang-on'in order for JT65B to work properly. Most use software that will update their computer clocks when they are online. DIMENSION 4 works very well and will keep your clock synced-up regularly.

3. Read then re-read the user manual for JT65. Consider getting your feet wet using the WSJT meteor scatter software which comes in the same package. There are enough similarities between these two programs to make you feel more at home with the JT65 software and many of the protocols are similar.

4. If your antenna is limited to moonrise or moonsets only, a good source of moonrise and moonset times, for any location, can be found HERE , allowing you to plan your best windows well in advance.

5. If you are using the earlier version of WSJT, run the audio through SPECTRAN, which will provide a very helpful visual waterfall display of received signals. I believe that the newer versions of the program have this feature built-in.

6. If you are running any type of amplifier, make sure that it can take the 100% duty-cycle required for JT65. I found that a small blower, directed on the outer heatsink case, would keep my little solid-state brick amplifier quite cool during the 60 second transmission periods.

7. Spend a few days listening and getting used to the software. This will also give you an idea how accurate your frequency readout is. Many of the signals from the larger stations can easily be heard on the speaker.

8. If you do not have a preamplifier, consider building one that can be placed at the antenna (best) or in the shack. Many of the solid state bricks have a receive preamp built-in which is very convenient.

9. Make sure that your antenna rotator's position indicator is correctly aligned so that you know exactly where your antenna is pointed.

10. Don't be afraid to get started, even with a small antenna. Every location is different. If you have a fairly clear unobstructed horizon, you may be well-suited for single-yagi EME.



MOONBOUNCE LINKS


K1JT's WSJT PAGE  - Download the program and manual from here.

EA6VQ's EME PAGE  - Lots of up-to-date information on what you need to know.

THE JT65 EME LOGGER  -Set up skeds or follow the action.

VE7TIL's EME PAGE  -A good description of a basic station.

K7XC's EME PRIMER  - A well done page on some of the basics that you will need to think about if you want to get serious!


CLICK FOR HOME PAGE        e-MAIL ME