2024-11-21

What a Mess. Projects.

 Yes, a literal mess.

The whole house has gradually become so messy that I have trouble finding space for a guest. Yes, that kind of mess.

So now the huge project is getting it pushed out. This may take some time, but in between there are a few radio related projects I want to get started, so I started making space in the electronics' lab.

While everything else in that small room is a total (well, not total, but still..., the workbench surface is now mainly visible, and I can access some test equipment and tools. It's still a long way to order, but slightly less chaos.

Now for some projects:


Antennas.

In freezing temperatures and snow outside? No, not for me. When the weather gets warmer and better again, there is still several antenna projects, as my antenna system has been deteriorating for a while.

I am glad I got my 23cm vertical up and running in a decent way, with a preamp at the antenna. It's working well in most directions, there are still some poor directions. 

A rotatable horizontal directional antenna is in the plan for better weather conditions. Some preparations are needed, so I will get there, probably in the spring.


23cm.

I can hear more stations than can hear me. I think this is due to my use of the preamp near the antenna, almost no one else around here does that with their verticals, just using an existing cable and possibly a triplexer. A quite lossy system to work with. So what do I do? Build a PA.


23cm Power Amplifier.

I got a linear amplifier built with 4 power modules. It is supposed to deliver about 50W, although I would not try that with a mode like FT8 (or other digital modes). I will need to build a coax relay system and more importantly, a sequencer, so I can avoid blowing up the preamp.

When that system is up and running, I will focus on another amplifier, running 40-50W, but for FM only.

I found a module in China, that has been used for sweeper jammers, a power amplifier covering 1200-1300MHz, with a nominal 50W output with about 10mW drive, quite some gain there. The module has no cooling, so some external cooling is mandatory.

This module requires a more elaborate sequencing procedure, as the output needs to be connected to a correct load before even applying supply voltage (28V). Initially all this will be indoors, but it could be mast mounted at a later stage. Ughh! Weather proofing needed, so maybe not ;)


QO-100 Uplink Power Amplifier.

My uplink system for the QO-100 satellite broke a while ago, the power amplifier blew at some experiments, so I need two things:

- repair the amplifier I had, if I can find the IC or transistor.

Before that I will be testing a 13cm PA module from SG Lab in Bulgaria.


This is my test setup. The mechanical part will come later.

This PA should deliver 15-20W (enough for the narrow band uplink) with a max drive of 40mW.

I intend to use my IC-905 directly on 2400MHz As this transceiver has a 2W output maximum, I will mount a 10dB attenuator, followed by a 6db attenuator at the inout of the PA, and then run the TRX at 80% output power. I don't want a power spike from the TRX to ruin the PA.

No relays are needed, as the PA has a built-in RF-VOX circuit with delay, not for the test. There is a PTT output from the IC-905, so that can be used in a permanent setup.


2024-11-20

Surprise on 6m.

The solar activity has been low the past few days, and is slowly picking up again. 

Still, the past 2 days there have been a bit of DX spotted with my modest setup.

Stations from Vietnam, Indonesia spotted with FT8, and today I spotted VE1PZ in Nova Scotia. No, I didn't work any of them, but just receiving them is good.

With a solar flux as low as 163 that was a bit of a surprise for me.

I know. FT8 has made weaker signal detection much easier, we are in for interesting times.

2024-11-06

New DXCC on 6m.

There have been DX signals on 6m every day for about 2 weeks.

I have received signals from 6 continents, and had QSOs with 4:

North America, Europe, Africa and Asia.

Last one was TR8CA today, Gabon, Africa using FT8.

All this with a small station, using a V-2000 antenna and 75W from my IC-7300.

I should try building a better antenna for 6m, capable of running more power. I do have a linear, and it would be nice to be able to run 3-400W with a bit of a directional antenna.

2024-11-01

6m F2. 1979 - 2024. Update. F2 to North America.

Today I made my first two-way QSO on 6m by F2- propagation ... from my station in Denmark.

Why not before? You may ask.

My very first experience on 6m was in November 1979. At that time 6m operation was not permitted in Denmark, as there were still TV stations operating in that band in many places of the world.

Yes, it would be listening only. I had been chatting with a local ham about building a converter, and he had done that.

One Saturday afternoon he re-transmitted a ton of strong 6m signals on the local 2m FM frequency. I thought, now is the time, so I found a crystal in my drawer. Normally I would have used a 22MHz crystal to convert to 28MHz, the closest I had was one on 21.4MHz. 

That would work, so I found the components from the junk box and that Saturday evening and Sunday morning I finished the converter, built according to the ARRL Handbook.

Sunday afternoon came, and the US and Canadian stations were booming in, but all I could do was listen and make RX log entries.

That was OK for the first day. I contacted a friend who had borrowed my HF receiver and asked him to return it. He did, and now the crossband fun could begin.

The next days I was working many QSOs, transmitting on or near 28.885MHz, listening on 50MHz, and I followed that up for the rest of (solar) Cycle 21, and had a lot of fun with that. Later the UK and Irish stations started getting permits and I could continue the crossband fun with them.


Then, in 1989 I moved to the Netherlands for 25 years, and did not have the opportunity to work much ham radio in Denmark. At that time there were still no 50MHz permits in Denmark (or the Netherlands for that matter) In those 25 years we had 2 pretty good solar cycles with 50MHz openings, and I worked a bit from apartments in the Netherlands. when it was finally allowed there.

I can say a bit more about this, and maybe I will do that later.


Moving back to Denmark in 2015, it was at the decline of the weakest solar maximum in memory, with no 50MHz F2 propagation, so this year, with the prospect of a much better cycle 25, I could hope for some F2 propagation. 

Come November 1st. the wait payed off.

Yesterday, October 31st, I did hear some transatlantic propagation, after having some indications of openings into Australia and Asia. All with a very poor antenna located between lots of trees, and just monitoring.

Yesterday I got my 6m radio connected to a V-2000 antenna (6m-2m-70cm vertical) and got it working with WSJT-X. Still no QSOs, and I got it working a bit too late.

Today I got up at about 8 local time, and there were signals coming in from several areas of Kazakhstan UN..., and some EX, and more in that area.

I managed to work two stations with this setup: UN3G and UN7GW. It was not that easy to get through the European callers, and I received reports about 20B worse S/N than I sent. I am guessing it's because of Eu-QRM and maybe a high noise level at the UN stations. yes, OK, I worked "only" 75W to protect the transceiver and the antenna and I am guessing that a minimum of 10dB difference in transmit power is not unreasonable.

Finally I made it! F2 propagation on 6m from my modes station at OZ9QV.

I do hope that the solar activity will continue high in November and over the winter. It could give some excellent QSOs on 6m, even with such a small station.


Update Saturday afternoon, 2nd November, in the afternoon:

After trying in the morning with stations in UN, EX etc, Finally some success in the afternoon.

I worked Two stations in North America: N1BUG with CW, and VO1SIX with SSB.

I tried a lot with FT8 on 50.313, but no luck. I guess my signal was mostly drowning in European QRM from stations much bigger and much more well situated than mine.

If we get another opening like this, I might try to use the secondary frequency, 50.323 with FT8, and possibly trying out with FT4. I need to look up the frequencies used for FT4, though.

I did see a lot of reports of my signals being received, in the East Coast, from VO1 in the North to Southern Mexican stations.

I will regard this as a very successful day with my modest station. Excellent propagation.

2024-10-29

6m DX openings.

We have F2 openings.

The past week I have received Australia 3 times, Vietnam once and Kazakhstan several times. The 6m F2 season has started. 

This morning 4 stations from Kazakhstan are reported  with my monitor station using the 6m part of my HF (half wave) vertical, which is a very poor antenna.

I suspect that the many European spots are F2-back scatter, with distances above 2500km are probably F2.

I have heard (seen) many local stations working the DX

So yes, the F2 season has started. I will not be surprised if we start hearing North American stations within a week or two, if the solar flux stays high.

Today the solar flux is 256, and from what I learne decades ago, at this time of the year (late October, early November) this could easily result in Trans-Atlantic F2 propagation.

My best 6m antenna at the moment is my V-2000 tri-bander, and I am a bit worried about running continuous modes like FT8 with 100W, so I will probably stick to using 50-80W. 

If the openings get like back in 1979, that should not be a problem.

Exciting times.

2024-10-21

New Vertical Omnidirectional Antenna for 23cm.

Finally, today I got my new mono-band vertical omni-antenna up for 23cm. I was using the 3-band antenna X-7000 from Diamond on 23cm, only and it had one serious drawback. The signal into the preamplifier from an adjacent antenna a few meters away was killing the GaAsFET in the preamp.

The second srawback of the X-7000, also connected to the 3-band configuration, is that the gain of the antenna on all bands, and 23cm in particular is not fully optimized, and it probably does not radiate so much from the top end.

The X-7000 is nabout 5m long, and the new F1-230A II is only 3.5m long.
The new antenna has been mounted about 1.5m higher, with the feed point about 7.5m, and the old X-7000 was at 6m. The tip of both antennas is approximately 11m, so I suspect that the radiation from the new antenna is located higher in altitude.

The new antenna was intended to be raised yesterday, but it got caught in branches of nearby trees. Those trees ahve now been trimmed, so today we could finish the work, and make a test of the new antenna system.

A fresh preamp has been mounted, so the receiver sensitivity is back to the optimum, and a transmit test revealed improved signals from stations in several directions. OZ1GIN who could only hear an extremely noisy signal before, can now read my signal with an Okay-ish signal.

I can still improve the transmitter capability with a power amplifier module, probably increasing the power at the antenna from about 5W to about 25W.

Given that many stations do not work with preamplifiers near the antenna, this should be a solid improvement of my station range.

This is the best I can do with an omnidirectional vertical, so the next 23cm antenna project will be getting a modest 23cm horizontal antenna up on a rotator as high as I can. As far as I can see, I can get a small yagi up about 11.5 - 12m, and with a good preamp and decent linear amplifier that will be what I can achieve. 

It should be a decent setup at my QTH, the best I can do. 

As the small yagi is "front mast" mounted, I might add another one, vertical, in the opposite direction, when I can repair one of the3 destroyed preamplifiers. Yes, I have ordered new GaAsFETs.

For now I have the vertical omni-system to work with, and I think I will have some fun with that.

2024-08-25

Back on the Local FM Frequency on 23cm.

Today a local ham came here and assisted in getting the 23cm vertical up and running.

My X-7000 antenna is now mounted with the feed point 6m above the ground.

A quick test showed decent signals at a distance of about 40km, so the system is working well enough.

I can still hear the OZ7IGY beacon, even though it is horizontally polarized.

Now I need to get some more antenna work done before winter. 

Focus will be on 23cm, because it's a fun band and we need to use it or lose it.

Second band focus will be 6m, as we might get into an autumn season with very high solar activity in the comning winter half of the year