Living the multiband life, Q65 on 23 cms, KST, Airscout, IC9700 vs Leo Bodnar and all that stuff.

This is another long one, sorry.

I am grieving for the loss of 6m. I have put up the half wave vertical. How sad, I will not be able to work Japan any more. Perhaps I should let that rest. Get over it.

The QSL cards arrived from the bureau today! Ten in total, one took five years, two took four years and the rest between three and one year to arrive.

And one was this, in case I had forgotten, or was trying to forget ...

QSL Card received by GM4FVM on 16 April 2022

This card is, of course, lovely to receive. However, it reminds me what I will not be doing this Summer. I will not be joining the throng trying to work Japan on 50MHz, nor those striving for various Caribbean and South American countries either.

Instead I will be ploughing a more isolated furrow on higher bands. That is fine by me. Erm, I think.

Is the 6m yagi still in the garage?

I mean, a decision is only made on the basis of the available evidence. As John Maynard Keynes never actually did say "When the facts change, I may change my opinion". There may be wiggle room there.

There was a bit of a radio aurora on 14 April, not that I could participate. I was feeling a bit tired and had to skip that one.

I did manage quite a bit of activity on 1296MHz. First, on 12 April I tried and failed to work G4BAO in JO02 square using JT9F fast mode. 423km seemed a long way but JO02 would have been a new square for me on 23cms.

1296MHz data mode contacts at GM4FVM, 13 to 17 April 2022

Then on 13 April I tried and failed to work David G4YTL. Not only would IO92 have made my 23rd square on 1296, at 428km it would be a handy bit of DX for that band. I am still living under the impression that 23cms is just a thing on the IC9700 which I am not likely to use. Evidence suggests that has been proved to be old history now.

That non-QSO was established in the KST chat room. I do not like KST chat room but it has its uses and especially for 23cms. Many of my 23cms QSOs have been set up using KST. So that day I had gone on to KST and Dave G0DJA asked for a try on 23cms Q65, which led me eventually to trying with G4YTL. I am a big fan of modes such as JT9, ISCAT and Q65 for use on 23cms as they are less distorted by Doppler effects and therefore best placed to benefit from scatter enhancements.

To be fair, I had never used Q65 before apart from listening on moonbounce. It was designed mainly as a Earth-Moon-Earth mode but then so was JT65 and it was well used all the way from Top Band to microwaves for terrestrial contacts. So I tried Q65, mode B, 30 second periods and I was able to work Dave easily. He also kindly sent me some WAV file recordings of my signal as recorded at his station. I went on to work him on 70cms to complete contacts with him on five bands.

Now I have to say how pleased I was with this 23cms contact to G0DJA. This was a "flat band" QSO with a comparable station but bear in mind 297km on 23cms is far beyond what I ever expected under normal conditions. As far as I know Dave uses an IC-9700 barefoot with 10 Watts, so reports of -15 from me and -10 from him suggest that 10W would have done it for me too. 

As part of that effort I also worked Nick G4KUX. At 135km this is more the sort of contact I had been expecting on 23cms. I sent Nick a +04dB report. It just goes to show that this is a handy band for all sorts of contacts. The stories I have heard about total lack of activity do not seem to be correct when I can work two stations and attempt a third in an hour or so.

G4YTL would have been 429km. I thought that was asking rather a lot. Another time maybe?

I was back on 1296 on 16 April. Jeremy, M0XVF in IO94, saw me on KST and suggested an SSB QSO. This was the strongest signal I have heard from Jeremy on the band, S7 on average but up to S9 at times. The path length is almost the same as to G4KUX, but it is over much more difficult terrain. We had a good chat, one of the benefits of SSB which is often forgotten.

After this David, G4YTL, came on and we tried again on Q65, this time successfully. I gave David -18 and he gave me -22, and the path was still 429km. That is not bad at all. Of course I almost messed it up by transmitting on the wrong period despite David making it clear which one he was using. Still it was a really good one and square number 23 was in the bag.

Then after that Richard G4HGI in IO83 got in touch and we completed a QSO in which I gave him a -01 report over a difficult 267km path.

1296MHz QSO with G4HGI at GM4FVM on 16 April 2022

I was pretty pleased with that one too. HGI's signal was stable and clear, and you can see aircraft crossing the path by the inclined reflections on the waterfall. However, for the most part Q65 coped with the Doppler interference and continued to decode. It seems to me that Q65 is both sensitive and reliable for 1296MHz tropo contacts, and certainly better than FT8 for this purpose. Richard sent me a screenshot of the QSO as seen from his end ...

1296MHz QSO with GM4FVM as seen by G4HGI on 16 April 2022 (Image: Tnx G4HGI)

Once again, a good QSO by my standards. Richard went further and captured the Airscout image at the time the QSO was going on. It is well known that aircraft scatter is important for securing QSOs on 23cms, and this is especially so for SSB contacts during contests. For this to work you need to know an aircraft will be in the right spot at the right time. Perhaps surprisingly, there are often enough planes around to make it fairly likely to happen.

Airscout is a piece of software created by DL2ALF which allows amateurs to see any aircraft which may cross the paths along which they want to work. Not only does Airscout show up the planes, it shows the area of sky in which a plane is likely to influence the signals. To do this it builds a database of the terrain between the two stations. Whilst planes on different paths show in grey, ones likely to produce a reflection are shown in red, along with the time until they are likely to reach the key area.

Airscout during G4HGI-GM4FVM QSO on 16 April 2022 (Image: Tnx G4HGI)

On the Airscout map you can see the path between our two stations by the red line. Red aircraft show planes which are likely to affect us. When the software is active, if you hover the cursor over the plane icon you can see the flight number, altitude, design of aircraft, and other details which can be looked up on aeronautical sites. These other sites will show, for example, where the flight started and ended and so forth.

The information can be very useful, for example, as it is possible to check if a flight which looks helpful is going to land nearby. In my case if it is landing at Edinburgh or Newcastle it will hardly do much good. The aircraft design can be very useful information. On the face of it, a 747 or military transport plane is likely to have a good chance of giving a strong reflection. The word "Heavy" or just the letter "H" can indicate a large aircraft, and this designation is used by pilots to show that this plane may well create turbulence in its wake. For amateurs "Heavy" is a good sign of a chance of a big reflection. 

It does not always work out that way, as I completed a 1296MHz QSO with GD1MIP some time ago using a reflection from a Jetstream, a small turboprop passenger or corporate aircraft, after larger planes had failed to produce strong reflections.

Jetstream 41, even a small aircraft can help for Aircraft Scatter (Image: Arpingstone, Wikimedia)

At the bottom of the Airscout screen is a map of the terrain. In the case of the path to G4HGI (above) you can see the large mass on the Pennine range of hills. Getting over the Pennines makes this type of path into a very satisfying route to work. A year or two back I would not have thought it possible on 23cms. I think that Q65 mostly defeats rather than uses aircraft scatter but I am willing to be corrected on that point. Certainly if it has some Doppler correction it can only stand to gain from added scatter, but I need to learn more about how it works before being certain. Anyway, it clearly does work.

The diagram on Airscout between the terrain map and the aircraft map is a vertical section of the area (shown in pink shading) into which a plane must fly is there is likely to be a reflection. This is constructed from the terrain data, the path direction and the aircraft height, direction and speed information. A plane flying too low or too high will not help, but neither will it work in an area where the terrain casts a shadow. It does not follow that the centre of the path is the best place for a plane, and this is especially true for me if I am beaming South towards the headland in that direction. Once a plane shows up as a red square within the pink shaded area you may be in business for an aircraft scatter QSO.

Airscout for GM4FVM-G4YTL, note small area available for reflections offset to the GM4FVM end

In my opinion Q65 during tropo is the star of these QSOs. Aircraft scatter is great where you would normally not have path. However in these cases I reckon that the path existed in the troposphere using Q65 even without aircraft assistance. Although there was some QSB, the signals were mostly stable and surprisingly strong, unlike the sudden off-on-off I see on aircraft scatter contacts. As the G4YTL chart above shows, very little of the path is open to aircraft scatter anyway. It may help, but I think it was not key in this case.

As if this was not enough, I was feeling bold enough on 17 April to call CQ on 1296. It has often been said that calling CQ at random on 23cms is very unlikely to succeed. Jeremy, M0XVF has told me it works for him sometimes so I decided to try. I tried SSB first and then FT8. On FT8 I saw a trace which was mangled by aircraft scatter. Was someone replying? Swinging the antenna I managed to peak it though the signal was impossible to copy. Eventually one decode worked and it was G4HGI again, but he was very hard to copy using FT8 compared with Q65. I tried replying but he said later that he could only see a strong distorted signal with no decode.

At this stage I turned on KST to find that Richard was trying to work Martin GM6VXB in IO97 on Q65. Martin asked for a test after that contact and I worked him at -05dB here and I was -07 at his end. The path is 204km. On this occasion Q65-60C was in use with 60 second periods. Q65-60C is more of  a moonbounce configuration so that was probably as sensitive as possible. I think that 30 seconds in mode B would have worked just as well.

As an aside I have been talking with Richard HGI about using a GPS with the IC-9700. Oddly enough, my Leo Bodnar GPS stopped working at some point on 16 April. I noticed it when checking the GB3NGI 1296MHz beacon. I took a screenshot of the result.

GB3NGI beacon at GM4FVM on 16 April 2022 showing effect of disciplining

 At the lower part of the waterfall you can see the beacon gradually appearing to drift upwards in frequency (left to right) suggesting that the IC-9700 receiver was drifting slowly downwards. At 15:55 I turned on the GPS (the DC supply plug had fallen out of the socket). There is a sudden wobble as the radio received the GPS signal followed by a jump to more or less the right frequency and a corkscrew action as it begins to stabilise.

In my set-up the IC-9700 is not directly locked to the GPS but the TXCO is disciplined to it. Thus it takes a few minutes to stabilise fully. Eventually it shows a rock steady link to the GPS-locked beacon.

GB3NGI beacon at GM4FVM on 16 April 2022 showing IC-9700 stabilising after linking to GPS

So what do I learn from all this?

1) I cannot do everything so trying 23cms means downgrading 6m,

2) Q65 seems to work very well on 1296MHz tropo,

3) Aircraft scatter is pretty ruinous to FT8 signals on 1296, so that mode is really only useful for me when AS is not present (such as ducting where it works exceptionally well),

4) GPS frequency stability is needed for the IC-9700 on 23cms (but maybe not on other bands),

5) I may not like KST on lower frequencies, but it works well on microwaves,

6) 1296MHz is not as deserted as I had thought.

Microwave operation can be fun. The 1296MHz band is not just available on the IC-9700 for show. I think that many 9700 operators do not use it. It may be worth a try.

73

Jim GM4FVM. 

P.S. There was an Es opening here on 17 April and I worked OE4WHG, 9A1Z, OE5XBL and GM3PPE. So even with a half wave vertical there is still DX to work. [Don't give up, Jim].