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
With the development of GPS and other radio navigation satellite systems, the part of the radio spectrum above 1 GHz has become very attractive and this has put pressure on the 23cms / 1.3 GHz amateur radio band. For the last few years, it looked as if the decades old allocation might be lost altogether.
The International Amateur Radio Union (IARU) are now reporting that an agreement has been reached for a recommendation for 23cm band amateur operations to be allowed on a non-interference basis alongside the co-frequency radio navigation satellite service (RNSS). The recommendation from the the ITU‑R Radio Assembly (RA) will form a component of the WRC-23 discussions which are ongoing until December 15th. (see update below)
While the threat to the 23cms band hasn't been removed completely, it is significant that a technical sub group has reached an agreement and hopefully it will be approved at the main conference.
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Update - 8th Dec 2023:23cm band outcome approved at the 7th Plenary meeting of WRC-23
The following was posted today on the IARU web site: During the WRC-23 deliberations, strong positions were expressed by all the parties involved. The result is a well-supported compromise for a footnote in the Radio Regulations regarding amateur and amateur satellite service operation in the 1240 – 1300 MHz range. The footnote reminds administrations and amateurs of the need to protect the primary RNSS from interference and provides guidance to administrations to allow both services to continue to operate in this portion of the spectrum. The compromise was formally adopted by the Conference Plenary on December 8 and is not subject to further consideration during the final week of the WRC. The IARU team continues its work on other WRC issues including the development of agendas for future conferences.
IARU President Tim Ellam, VE6SH, noted “This is a very good result for the amateur services. The decision reached at WRC-23 on this agenda item makes no change to the table of allocations nor incorporates by reference M.2164 into the Radio Regulations. The addition of a footnote that provides guidance to administrations in the event of interference to the RNSS is a good regulatory outcome for amateurs and the primary users of this band.”
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The image above from the IARU gives a good overview of what is going to happen to the 23cms amateur radio band.
1)Parts of the band restricted to just milliwatts... The current band is 60 MHz wide going from 1240 MHz to 1300 MHz. There will be a severe power restriction for large segments of the band that might overlap the radio navigation satellite signals.
Example...The section of 1240 to 1255.76 MHz overlaps the Russian Glonass system, Here, just 1.26-milliwatts in a 150 kHz wide signal is allowed. Note that this is effective radiated power so it includes any antenna gain. In simple terms, this prevents any amateur use of these segments of the band.
2)Protecting the DATV segment... The key target for the IARU has been to protect the main centres of activity and one of these is the Digital Amateur TV segment around 1260 MHz. The frequencies below are from the current IARU Region 1 band plan...
There will be power restrictions in terms of EIRP (combined power and antenna gain) and the IARU gave these examples...
1255.76 to 1256.52 MHz (760 kHz) = 250W eirp... 4W into typical beam antenna (18dBi) or 60W into 6dBi mobile ant.
1256.52 to 1258 MHz (1.48 MHz) = 125W eirp...2W into typical beam antenna (18dBi) or 30W into 6dBi mobile ant.
3) Protecting the narrowband segment... The other important part of the band from an amateur radio point of view is the segment for narrowband modes from 1296 to 1300 MHz (e.g. CW, SSB, FM, FT8). Here, the plan is for a simpler power output restriction rather than taking the antenna gain into account as well.
1296 – 1298 MHz = 50W pep into antenna & 1298 – 1300 MHz = 150W pep into antenna
There is a higher power limit for moon bounce operation as long as the antenna has more than 30dBi gain and is pointing more than 15 degrees above the horizon.
4) Amateur Radio Satellites... There is a complex set of power restrictions covering narrowband operation in the amateur satellite band from 1260 – 1262 MHz. These range from very low power at low elevation angles to higher power levels at high angles (−3 dBW for 0° to 15° / 17 dBW for 15° to 55° / 26.8 dBW for 55° to 90°).
I'm not aware of any amateur satellites using these frequencies or if any licensing authority will be keen in the future to give permission to any potential new satellites considering the contested nature of the band.
23cms / 1296 MHz... Why does it matter??? AMSAT UK sums it up nicely... "The 1240 – 1300 MHz band is important for the amateur radio service, being the lowest allocation for radio amateurs on which typical microwave propagation can be experienced. Access to these frequencies is facilitated by commercially available equipment and provides a ‘bridge’ building motivation to become involved in more specialized higher frequency microwave and millimeter wave operations providing the self-training which is at the heart of amateur radio."
In conclusion... As the IARU notes..."The final recommendation represents the culmination of more than 4 years of work by the IARU team within the ITU‑R study groups to ensure the best outcome for amateur radio in the face of intense regulatory, political and commercial pressure."
Some people may be disappointed with some of the proposed changes but there really isn't another alternative. The choice here is pretty simple... either the amateur radio service can co-exist with radio navigation satellite systems in the 23cms band on a non-interference basis or have no amateur allocation there at all.
If the plan is agreed at the conference as expected then it offers some certainty to radio amateurs who want to use the band, They can buy or make equipment safe in the knowledge that the band won't be gone in a few years time.
It also allows the radio amateur service some protection in that we can hide under the protection of these radio navigation satellites. It's highly likely that the various governments would have serious objections to any commercial interests trying to get access to the 23cms band in the future.
Further reading... You can find more information at the links below...
Addendum...After I put up this post, the RSGB released this related video which was made in October 2023 (1h 42m in length)...
1. Barry Lewis, G4SJH talks about "Amateur/RNSS coexistence in the 23cm band" 2. John Worsnop, G4BAO considers "How will the possible RNSS changes affect narrow band DX operation and EME?" 3. Dave Crump, G8GKQ looks at "The future of ATV in 23cms"
On Sunday the 18th of December 2022, ICOM Japan held their own exhibition at their Narayama Research Institute to display some of their new projects. This included the upcoming IC-905 transceiver which will cover 144 MHz, 432 MHz, 1296 MHz, 2.4 GHz & 5.6 GHz. They also have an optional 2.4 GHz to 10 GHz transverter.
I won't go into the full details of the radio here but you can read about it in my previous post HERE
The big question is what is the price going to be and when will it be released? In my earlier post, I guessed that it might be in the $2000 to $2800 price range.
HAMLIFE . JP reports on Twitter from the exhibition that the guide price for the IC-905 will be 400,000 Yen. This is around $2930 or €2760.
The optional 10 GHz transverter will be 150,000 Yen which is about $1100 or €1040.
The release date is expected to be the Spring of 2023 which is a bit earlier than I was expecting.
Now the unknowns are... Will it be too expensive??? What will the demand be like??? Will the demand be different in the various markets... Japan / North America / Europe / Australia ???
Back in October 2020, I had a post about how the FCC were proposing that radio amateurs in the USA would lose the 3.5 GHz (9cm) microwave band.
After some appeals and feedback, the FCC have now announced that US radio amateurs will only lose use of the spectrum from 3.450 to 3.500 GHz from the 14th of April 2022.
This represents a loss of 25% of the entire band which stretches from 3.300 to 3.500 GHz at present. In essence, the band is being reduced from a width of 200 MHz to 150 MHz.
The current band plan for the part of the spectrum that is being lost is shown below...
The 50 MHz of spectrum that was lost was auctioned off by the US Government for around $22 Billion for 5G services.
The future of the remaining 9cm band for amateur use is by no means certain. In a news article, the ARRL said... "Secondary operations are permitted to continue indefinitely in the remainder of the band, 3.3 – 3.45 GHz, pending future FCC proceedings."
While this loss of spectrum may not matter to most, it does highlight the value of the microwave spectrum in the low GHz range to commercial companies and how there is a very real threat of losing many more parts of the spectrum in future.
It was interesting to see that a contact on 1296 MHz was made between EA5TT in Spain and SV8CS in Greece on the 2nd of January 2022. The distance was around 1850kms.
Manolo, EA5TT reports working SV8CS on 1296.174 MHz on FT8 after working him on 144 MHz and 432 MHz earlier. EA5TT was using just 10 watts with a 35-element Yagi antenna.
As for the mode of propagation, it looks like it was a tropo duct over the Mediterranean Sea. This is the tropo forecast from Pascal, F5LEN...
I'm not sure what the record is for tropo in the Mediterranean but it looks like there is a 3300km sea path between the SW of Spain and Israel. Is it possible on 23cms?
As part of their Tonight at 8 series, the RSGB had a video presentation recently from Neil, G4LDR about getting started on the amateur radio microwave bands.
The talk itself is about 1h 15m in length and it is followed by a 20-minute Q&A session.
The video covers propagation, antennas and equipment for the amateur bands from 1.3 to 10 GHz.
The Tasman Sea is an area where there are regular tropospheric ducting openings between Australia and New Zealand. On the 13th of December 2020, Hayden VK7HH and Richard VK7ZBX portable on an elevated location in Tasmania made successful SSB contacts with Nick ZL1IU in New Zealand on 144 MHz, 432 MHz and 1296 MHz.
As the tropo prediction map from F5LEN suggested, the 2380 km path from New Zealand to Tasmania was indeed open.
The really amazing contact however came at 05:58 UTC when there was a successful contact between VK7HH and ZL1IU on 2.4 GHz!
The contact was completed by using CW (morse code) as the signals were too weak for a SSB (voice) contact.
This 2380 km contact was a new Australian tropo record for 2.4 GHz breaking the previous record between VK4OX and ZL1AVZ by some 60kms.
27th Jan 2011 - 2317.5kms - VK4OX - ZL1AVZ
A video of the contact is shown below. It starts at where the 2.4 GHz contact takes place although you can of course go back to the start to see the site location in Tasmania and the contacts on the lower VHF bands.
If you look at the video at 9:45, you can see that they managed to complete a contact on 144 MHz SSB with just one-watt which gives an indication of just how good the conditions were.
It was also nice to see that in a digital age, CW still has a place for very weak signal contacts!
Other paths???... Obviously the one constraint with making contacts on 2.4 GHz are the low number of stations on the band. This limits experiments with other sea paths which might show some suprising results.
The one that springs to mind for me is the sea path from Ireland/UK down to the Canary Islands.
In a ruling issued on the 2nd of October 2020, the Federal Communications Commission (FCC) in the USA announced that the amateur radio service is going to lose access to the 3.4 GHz microwave band. It is proposed that the spectrum from 3.3 to 3.55 GHz be cleared for 5G networks.
Up to now, radio amateurs in the US had a secondary allocation from 3.3 to 3.5 GHz based on a non-interference basis to primary users. The FCC have now proposed clearing 3.4 to 3.5 GHz in the short term and 3.3 to 3.4 GHz at a later date.
Excerpt from the ruling regarding the amateur allocation...
This might be of interest to those who operate on the microwave bands. Backscatter is a compendium of the best technical articles that have been in Scatterpoint, the UK Microwave Group newsletter over the period 1999 to 2006.
The original publication in 2008 was an A5 size book of 445 pages and is an excellent reference with many articles on all aspects of microwaves.
