Small Transceivers and Low Power.

I now have a rather good collection of small, low power transceivers (and receivers)

Some are low cost Chinese builds, some are small kits assembled by me over time.

Some years ago I purchased some "single frequency" (crystal controlled) transceivers (from Ukraine) tuned to the old frequencies used for the JT65 mode. When FT8 took over, the use of JT65 ceased, because the over all efficiency of FT8 is much better, especially because the transmit sequence is 4 times faster, compensating for the lower sensitivity. and the frequency was moved 2kHz up. 

Usually the crystal frequencies can be tuned down fairly easily, tuning upwards is more limited, so I don't know if I can tune the local oscillator (yes, those are superhet transceivers). If I can, I will try that and use them for FT8.

This would make for a very nice, low power (1W) single frequency transceiver on the 40, 20 or 15m bands. Yes I have those three.

Then there are some simple single frequency kits, (Pixie, Rockmite, and others).

I do have some crystals for the 40, 30 and 20m bands for reception of FT8 and WSPR/QRSS frequencies, and I might use those for monitoring those frequencies.

All this is part of an ongoing (open) challenge of making QSOs on as many bands as possible with my own equipment, and expand this with using home built equipment, too.

Until now I have made QSOs with my own erquipment on all available (in Denmark) bands from 160m to 13cm The equipment can do 6cm and 3cm, too, but no contacts done yet.

Contacts with home made equipment has been done on 80, 40, 30 and 20m on HF, and 2m on VHF.

When I use the expression "home made" I include modified equipment intended for non amateur use, and partly home made equipment, like using a home made 2m transverter with my HF transceiver.

Somewhere I have a Pluto SDR "transceiver" that can be used for all bands from 70MHz to 6GHz, albeit with extremely low power, so that one is a candidate for home made equipment on 70, 144, 432, 1296, 2400, 3400 and 5760MHz, with added front ends for the different bands.

I wish I had more time to do all those experiments. (Don't we all?)

1296 Tropo.

 I am reorganising my station, so the activity level is not so high.

Yesterday, however, 1296MHz was open up to a few hundred km.

I didn't make QSOs, but with my omnidirectional vertical monoband antenna I could hear 9 beacons during the day and evening:

OZ7IGY (of course, it's local at 26km, and always audible) - Everyting else is over about 200km

SR1KOL at about 270km

OZ1UHF at 222km

DB0XY at 438km

SK6MHJ at 229km

SK6UHG at 261km

SK1UHG at 416km

LB2SHF at 369km

LA3SHF at 372km

I am pretty sure I would have heard more beacons with a horizontal antenna, but this tells me that propagation was very good.

Yes, a horizontal antenna system is in the planning, probably for spring next year.

NAC on 1296MHz.

Yesterday I was up at the local hill with the '905 to operate a bit in the Nordic Activity Contest.

This time I brought a bit more equipment, apart from the 23cm yagi antenna:

- a tiny 3 band FM handheld, the Standard C710

- a 2400MHz long yagi.

Among a few contacts with SSB on the '905 and the 12 element yagi, with the local OZ4HZ, after the 1296MHz QSO we tested the 2400MHz band.

On 2400.500 we worked a nice QSO on FM with S9 signals noth ways. Now, with the correct polarization and operating from the hilltop, that was a massive improvement from the first test.

The test with the handheld radio was actually quite a lot of fun.

The radio operates a maximum of about 300mW on 1296, and some of the strations in the Copenhagen area had excellent signals. This radio comes with a tiny 10cm long "rubber duck" antenna, so I was a bit in doubt about the range. The first QSO was with OZ1GIN, working with an indoor antenna 2 small yagis, and reported S9 signals from the radio at about 25km. Yes, he was running horizontal polarization, so it was simple to turn the hand(held) for that.

A bit later I tried with OZ4HZ, and again wee had S9 exchanges, and a less local station, SM7FMX, just over 40km away)  came in for another handheld QSO with good signals.

All worked well, and then I noticed that the radio was in low power mode, so all those FM QSOs were actually worked with a mere 100mW. Now, that is fun portable work on 1296MHz.

I will probably try going light-weight portable on the hill with the handheld and a somewhat larger antenna, so everything can be carried in the rucksack.

New Toy: Handheld "Micro" QRP Transceiver.

 Today I received a small (even for my hands) handheld transceiver. 

The price from Ali Express was not too high, about €130.

This rig is based on the uSDX transceiver, but built into a handheld type casing with a rechargeable 1100mAh Lithium battery. 

I consider this Chines radio as a bit of a toy, so if it won't work for my purpose, it's worth the price for experimentation.

No manual included, so I pushed the power button to see what happened. Lo! and behold ...  The thing switched on and showed 14.074 (yes, the FT8 frequency on 20m), ans sound in the speaker. At least it appears to be working. 

Now, how to switch off this thing???

The power-on switch now acted as a PTT switch, so no good. long push (PTT), double push ... nope!

Internet to the rescue (almost) I found that the volume control set to level "0" should switch it off. Not quite ... I needed to push the wheel, and then turn it off.

Okay, at least I would not deplete the battery capacity.

The TRX essentially does what the uSDX does, so I am interested in how it will work with digital modes, like FT8.

This little radio can receive from 500kHz (?) to 30MHz, and is capable og transmitting on all the HF amateur bands. However, the filters are adapted for the 10-15-20-40m bands, and if I want to use it on other (especially lower) bands, I will need external filters. So the first tests will be on those bands.

I need more testing. I have seen a test by OM0ET on YouTube, and that's why I wanted to try it out, as a fun experiment.

OM0ET also has a video describing some modifications that would make the transceiver more useful, so after an on-the-air test, I might try those mods.

QRO or Not QRO? That Is the Question.

Some years ago I got myself a used HF power amplifier for 1kW.

The ACOM 1000 is regarded as a solid amplifier that holds it promises from 160m to 6m. That is also my experience.

However, with quite short distances to neighbours' houses, I am not quite comfortable with using it.

In fact I used it briefly on 10m with about 400W out. That was when the solar activity was still quite low.

Then I used it on 50MHz, also with about 3-400W. Tha antenna that could endure that kind of power was removed, and for some years I have used the V-2000 for (2m, 70cm and) 6m. Under no circumstances would I use more than 100W with that one, especially with  FM or digital modes like FT8. The capacitors will not stand that, and will be transformed into carbonized components.

So today the ACOM 1000, which has been on the radio shelf for a few years witout being connected to the power outlet (or a transceiver), was taken down from the shelf. I am probably going to sell it and get some more UHF/SHF equipment.

I will not abandon HF completely, but focus more on VHF/UHF/SHF, going a bit back to my old interests.

Over 30 years ago I was working a lot on 2m, 70cm and 23cm with relatively low power and decent antennas, and over 40 years ago I was working crossband 50 or 70MHz to 28MHz, and had a lot of fun with that. Now I want to try the even higher frequencies, too. probably mostly portable from hilltops, but also with a (very modest) station at home.

QSOs on a New Band. 2400MHz.

 A few days ago I got a mail, someone was planning to do activity from the island of Moen. A distance of about 77km from me.

The operation was planned for this afternoon, and they would acttivate both 1296 and 2400MHz.

I went out about 2km from home and set up the IC905 with small antennas for the 2 bands.

I think they stopped activity about the ime I got set up, so I called some of the locals who had 2400MHz capability.I was not on the hilltop as the earlier tests, so it's always interestingt to see how a new band works. I called OZ4HZ, who had a station with antenna on a balcony. Signals on 1296 were booming in, so we decided to test 2400. Signals from Hans were weak, but readable, and we made a marginal QSO in SSB, exchanging callsigns and reports both ways, 52-53 reports. Not bad for a first test on the band.

I had texted OZ1GIN and told him about the activity, and h came on after a while. Also with booming signals on 23cm. The test on 2300MHz had weak, but easily readable signals in CW. We exchanged 559 reports at 25km distance. This is a special case as Allan was running with a completely indoor system, including the antennas.

After the experiments I started listening for beacons on 1296, and heard 2 in SM6, at least one in LA, and also OZ5SHF at Yding, one of the highest points in OZ, and the whole time, most of the time booning in, and audibl with the antenna in all directions. There was most certainly tropo today. It's now about 2200 local time, and with my vertical at home it's still coming in with  solid copy, even at the other end of th4e house.

There is still a lot to optimize in the portable microwave system, so maybe better results next time.

Right now I am not complaining.

New Repeater on 1297MHz in the Copenhagen Area.

 A while ago I wrote about signs of a possible new repeater not too far from me.

Then it was gone for a while, and in the past week it reappeared, fully functional.

It is located on a tall building on the island of Amager (not terribly far from the airport for Copenhagen.

I don't have any technical information but I can say that it works very well.

Ii is located between 20 and 25km from me, and I made a test with the IC9700 connected to a reasonably well placed antenna with the feed point about 7m above ground.

I called in with the normal power (10W), and the signal was completely noise free. Not surprising, as the repeater antenna is high up.

Then I tried reducing power, to 5W, 2W, 1W. Still completely noise free.

0.5W, no change, 0.2W hardly any change.

I tried to go to 1% power output of the '9700, yes, a little bit of noise. 

Finally I tried to reduce the power to the absolute minimum od the radio. Still a readable signal.

The sensitivity of the receive system is simply excellent.

Now it's time to find an alternative setup to operate via the repeater, the '9700 is so much overkill.

I have an old Kenwood TM741 that is in need of a repair and possibly alignment. I found the settings for operation with this repeater (needed the "odd split" memory to set it up, byt when testing no transmission (at least at the wanted frequency), and reception wasn't good either. Initially I could use my IC.905 for repeater operation (even if it's even more overkill), with a much lower (and smaller) antenna, until I can make a dedicated set up.

I may come up with a post with some crazy ideas that might never be used, for getting to operate such a local repeater on 23cm.

Here is what I know about the new repeater:
Output frequency: 1297.000MHz

Input frequency: 1257MHz (yes, 40MHz spacing)

Activation: CTCSS 82.5Hz