Monday 18 April 2022

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].

Friday 8 April 2022

Configurations in WJST-X plus human decay.

Thanks to those of you who enquired about my health. I am not too bad. Perhaps I can try to explain what happened in terms which a radio amateur might understand.

1) First they went under my outer panel by cutting a hole, rebuilt a leaking electrolytic capacitor and then they put the cut bit of panel back and waited for it to rust back together again. Painful and slow to recover.

2) Second they decided to check out the circuitry by shoving a camera and a pair of wire cutters up the rear SO-239 antenna socket. Leaving me to watch it all on the screen, they cut a few bits of circuitry out and retrieved them for testing. Undignified, but at least it avoided cutting another hole through the outer panel and leaving it for weeks to heal over. Of course the RF stage had to thoroughly emptied before all of this, which was more of an issue than anything else. It was rather like applying a depth charge down the rig from the microphone end and then blasting everything out the antenna socket.

3) Ongoing knee issues which are like a sticking VFO control. This is one of those old time VFOs with ball bearings. Either the VFO control is rubbing somewhere and some easing will help, or the ball bearings have gone and are crunching and biding together. Both have happened in the past on this old worn equipment I live in.

So there we are. None of this is unusual or unexpected on old equipment. It is just that it is all happening together. Thanks for asking and for your support.

Moving on...

I have mentioned WSJT-X Configuration settings before on this blog. It is time for some discussion about what use these can be put to. Sadly I cannot cut and paste the drop down menus so I will photograph them, which means that the images for that part of this posting will not be up to the usual standard (whatever that is).

As is well known, I monitor several bands at once using several radios. However, you do not need to be as mad as me and configurations can be useful for many set-ups including just one radio.

First of all I will consider my 70MHz layout where I use an IC-7300 for either MSK144 or FT8. I can also use the IC-7300 for 50MHz by swapping round antennas and rigs using an RF transfer relay. For MSK I use different settings for the watchdog from the ones I use on FT8. For FT8 I only use a 3 minute watchdog, whereas for MSK I prefer it much longer. Also, for 50MHz I use more power as 70MHz has a more limited peak power authorisation. Sure, I could use a single configuration and change the power or the watchdog time each time I switch. Maybe somebody else can do this, but when I tried that I tended to transmit for the wrong time or with the wrong power.

Configuration options for the IC-7300 at GM4FVM

Now if I want to change bands or modes all I do is select the right configuration. In each configuration you can set lot of parameters beyond power and mode such as stored frequencies, reporting preferences and so on. What you cannot do is use one instance of WSJT to control two or more rigs - for that you need separate instances.

Unfortunately you cannot alter the received signal strength as recorded by WSJT-X using configurations. This is set at rig level in the audio tab. Early versions of WSJT had a slider for receive gain which you could set independently. That setting disappeared years ago. I would find it handy to have that setting back as the background noise levels here on 50MHz and 432MHz are very different (see later about controlling the IC-7100). Last time I used MSHV it did have a receive gain setting slider, but here I am only talking about WSJT-X. As it stands I believe that you cannot set the receive level to a different value for different bands on one instance of WSJT-X. Unless you know differently ....??? 

Actually setting up the different configurations is a bit tricky as the options on the drop down menu are hard to understand. I generally clone the one I am using, switch to the copy, and then rename it and reset all the other settings.

Another advantage of using different configurations to change band rather than changing band on the WSJT-X panel directly is that changing configurations closes that instance of WSJT-X and reopens it afresh. The benefit of that is that, unlike changing just the band, you do not report to PSK reporter all the stations you heard on the first band but marked as stations on the second band. I see this often on PSK Reporter where a band suddenly seems to have opened, but on close inspection somebody has changed from the 20 metre band or the like onto 2 metres, and all the stations they heard on 20 metres just before they changed are reported as 2m contacts. That is hardly earth shattering but I do not want to look like an idiot any more than I need to. I find that being an idiot in private is less concerning than proving I am an idiot to the entire amateur community.

Configurations can do much more than this. I use my cheap second hand IC-7100 for both 50MHz and 432MHz (plenty of scope for reporting the wrong thing to PSK Reporter there).

Configuration options for IC-7100 at GM4FVM

Here I need to switch between the power levels and modes for 4m and 6m in the same way as I do with the IC-7300 but adding 70cms makes it even more complicated. If I use the 70cms configurations the IC-7100 also changes over to UHF and transfers the antenna connection to the right port. My 70cms linear needs only 3 watts drive so the power change is very important to avoid blowing up the linear - the 70cms configuration takes care of that. So too does selecting 6m WSPR, where the power is already set under 5W in that configuration.

For the 70cms JT65 configuration I have various beacon frequencies programmed in and power set to zero. When I do EME I put a long series of moonbounce frequencies in on a separate configuration called 70cm EME, but I have deleted that for now and it will reappear in Q65 mode. It is very handy to have the moonbounce frequencies in that configuration but missing from the others as it makes the lists of frequency both mode-specific and shorter. That creates less of a chance of getting things wrong. 

Since I set this up I hardly need to touch the IC-7100 at all. That is a big plus as it is not a great device to work with. It tends to tip up when I try to use the VFO (even with the stabilisers extended) and it slides around when I adjust anything directly. Plus, the display and ergonomics are not in the same league as the 7300 or 9700. However it has many other pluses such as it is quite cheap and it does a lot of things the other two cannot do.

With the IC-9700 the multiple configurations are not so straight forward if you use the second receiver. This problem has nothing to do with WSJT-X configurations; the 9700 is apt to confuse me in any mode or band. I have two instances of WSJT-X, one for the main radio and the other for the second receiver. The second receiver cannot be controlled by CAT. The rather odd way the IC-9700 works means that if I change the frequency to a different band in the main radio using the CAT, what happens next depends on the VFO in use for the second receiver. If, as in my case, the second receiver is set to a 23cms frequency, the radio changes to 23cms and substitutes the 2m frequency I was using into the second receiver, making this a different frequency from that shown on the second instance of WSJT-X on the second receiver. To prevent mis-reporting to PSK Reporter I have turned PSK reporting off for the second receiver, which stops mis-reporting but means that version of WSJT-X then shows 2m contacts with a 23cms frequency readout. At least only I see that, not the whole PSK Reporter world. Handily, just two clicks brings up the 2m configuration on the second receiver instance of WSJT-X.

As I monitor four bands I find it far too complex to remember all the permutations of settings and power levels needed. The risk for me is that I might exceed the power limits, blow up a linear or, deary me, miss some DX. Missing DX would never do. Setting up different configurations takes a bit of time but it is worth it for me.

If you install any new version of WSJT-X to the same location as the one you are using the settings should transfer to the new version. It is worth being careful over this as other settings could be lost too if you get the installation wrong.

So there we are. Simples! Well, not so easy with my set-up because I make my life unnecessarily complex whatever way I run my shack. But still, if you want one click to change settings, bands, power, reporting or any other thing short of changing rig, that is the way to do it in WSJT-X.

Incidentally, this is period of the year when Trans-Equatorial Propagation occurs. Occurs somewhere else, not for me. Maybe on the Southern extremities of the UK, but not in GM. I have to sit and watch, waiting for Sporadic E to restart. Grrr.

50MHz on PSK reporter, as seen at GM4FVM on 5 April 2022

Well I suppose I cannot have everything.

Hey, why not?

73

Jim

GM4FVM