K6JEY talks to Ham Radio Workbench podcast about Earth Moon Earth Amateur Radio Operation

 

Over the last few months. I've been listening to some of the back catalogue of podcasts from the Ham Radio Workbench while I've been out walking. I recently listened to one titled 'Earth Moon Earth Operation'. 

In the podcast. Doug Millar, K6JEY talks to George, KJ6VU and Mike, VA3MW about his experience operating moonbounce on the 144 MHz and microwave amateur radio bands.

While the podcast is from September of 2020, I think a lot of people who are interested in the VHF and microwave bands will find it of interest.

The podcast itself at 2 hours 33 minutes is very long. The first 32 minutes is general chit chat with some microwave operation discussed.

The first part of the presentation proper begins at 32:00 and lasts until about 1:52:00. The photos and notes for this first section are shown in a PDF slideshow titled SIDEWALK EME... Link HERE 

The second part of the presentation starts at 1:52:00 and concludes at about 2:30:00. The second PDF slideshow is titled 10GHz EME Project... Link HERE 

W5LUA gets first Worked All States award for the 903 MHz - 33cms band

Radio amateurs in the USA have access to an unusual band at 902 to 928 MHz which is known as the 33 cm band. Due to its unusual nature, much of the equipment for the band has to be home made or modified with transverters being a popular choice.

In November of 2023, Al W5LUA was awarded the very first Worked All States award from the ARRL. He started collecting the states shortly after the band opened in 1985 and his quest has taken 18-years.

As a band in the UHF region, most of the 'local' states would have been possible via tropospheric propagation but to work all 50 US states, signals had to be bounced off the moon. i.e. EME or moonbounce.

W5LUA's station consists of a 5-meter dish with 400 W of power obtained from two 300 W Motorola amplifiers in parallel. His feed is a dual polarity patch feed.

As recently as September of 2023, W5LUA was stuck on 32 states and still 18 short. Thanks to Peter, KA6U who went on a roving 25-state expedition, the last 18 states were worked.

W5LUA writes... "I am extremely grateful to Peter Van Horne, KA6U, for his EME [Earth-moon-Earth] efforts. I was able to work Wisconsin for my last state on the 33-centimeter band on October 21. At the end of September, I was sitting at 32 states confirmed with cards and/or the Logbook of The World (LoTW), when Van Horne went on a 25-state expedition providing my last 18 states." 

W5LUA also notes that prior to that, recent expeditions by Brian, NX9O, and Jason, N1AV, also provided several states that were needed.

Background to the 33 cms band... In 1985, the FCC allocated the frequency band between 902 and 928 MHz to Part 18 industrial, scientific, and medical (ISM) equipment. In that proceeding, the band was also allocated to the Amateur Radio Service on a secondary basis, meaning amateurs could use the band if they accepted interference from and did not cause interference to primary users.

The list above from the North Texas Microwave Society gives an idea of what equipment is used on the band.

Links...
1) ARRL... The First Worked All States Certificate Awarded for the 33-Centimeter Band.
2) North Texas Microwave Society... 902 MHz Presentations (PDF)

Moonbounce on 21 MHz from the worlds largest antenna array for the band!

The 21 MHz antenna array of ES5RY in Estonia is reputed to be the largest in the world for that band.

The array is made up of eight 5-element Yagi's for 15m mounted on a 70-metre tower. It has a gain of 16dBd in free space with a beamwidth of less than 30 degrees.

It has a phasing system which allows the selection of five different take-off angles.... 4, 7, 10, 15 and 30 degrees.

Here is a video of ES5RY hearing a signal coming back from the moon on 21 MHz!



This next video shows the construction of the array...

World First FT8 Moonbounce contact completed on 432 MHz...

One of the niche areas of amateur radio and perhaps one of the most difficult is trying to make contacts by bouncing radio signals off the moon. 'Moonbounce' or EME (Earth-Moon-Earth) has its proponents who squeeze every last bit of improvement out of their antennas and equipment to overcomes the huge losses involved.

On a posting on the Moon-Net, Joe Taylor K1JT said he believed that the first moonbounce contact had taken place with the FT8 digital mode.

On the 21st of May 2020, an EME contact on 432 MHz had taken place between W2HRO in New Jersey and PA2V in the Netherlands.

While the weak signal FT8 mode is hugely popular on the HF and VHF bands, modes like JT65 are more popular for EME due to its better sensitivity.

Here is the posting from K1JT....

Some here will be interested to learn that earlier (21May20) today W2HRO and PA2V easily made (as far as I know) the first EME QSO using the FT8 mode.

Paul and Peter used WSJT-X 2.2.0-rc1, a beta-release candidate for version 2.2 of the program WSJT-X. Both stations have moderate 4-yagi setups on 432. Conditions today were not particularly good: degradation around 3 dB, and the Sun only 20 degrees from the Moon.

For terrestrial use the FT8 decoder searches over the range -2.5 to +2.4s for clock offset DT between transmitting and receiving stations. When "Decode after EME delay" is checked on the WSJT-X "Settings" screen, the accessible DT range becomes -0.5 to +4.4 s. Just right for EME.

FT8 uses 8-GFSK modulation with tones separated by 6.25 Hz. At the time of this QSO the expected Doppler spread on the W2HRO - PA2V EME path was 8 Hz, which causes some additional loss of sensitivity. Nevertheless, as you'll see in screenshots posted here, the copy was solid in both directions:

Why might you want to use FT8 instead of "Old Reliable JT65" for EME QSOs? FT8 is about 4 dB less sensitive than JT65, but with 15-second T/R sequences it's four times faster and it doesn't use Deep Search.

When I was active in EME contests on 144 MHz, I was always frustrated that even with reasonably strong (for EME) signals, one's maximum JT65 QSO rate is about 12 per hour. With FT8 you can do 40 per hour, as long as workable stations are available.

What about FT8 EME on 1296 MHz? It might sometimes work, but Doppler spread will probably make standard FT8 a problem. But if there were sufficient interest, we could make an "FT8B" or "FT8C" with wider tone spacing.

Please try FT8 for EME on any of the bands 144, 432, and 1296 MHz, and let us know your results.

-- 73, Joe, K1JT

For the FT8 moonbouce contact on 432 MHz, W2HRO was running 1KW into 4 x 15 el Yagis. PA2V was running 1KW into 4 x 27 el Yagis.

EI8JK works Japan on 70cms Moonbounce for an EI first

Working Japan on any band from Ireland is pretty good but what about doing it on 432 MHz? That's exactly what Tony EI8JK did on Monday the 10th of September 2018 when he worked Toshia JA6AHB by bouncing 70 cms signals off the moon!

The pair have been trying to make the contact for several weeks with Tony making small incremental improvements to his system to squeeze out every fraction of a dB. In the end, they managed to complete the contact using the JT65 mode on Monday morning during a 2-hour window to make it an EI-JA first on the UHF band.

In terms of equipment, JA6AHB was using 500 watts into a 7 metre dish while Tony was using 4 x 21 element yagis with a medium powered amplifier. His antenna system is shown below.

Tony lives on the scenic Sheeps Head peninsula in West Cork and no doubt the remote location with low noise background really helps on the VHF and UHF bands. With his current set-up and more improvements on the way, he hopes to work many more stations off the moon on 432 MHz.