2023-11-18

New Toy. IC-9700.

I have been thinking of getting myself a VHF/UHF transceiver with a matching screen, like on the IC-7300 I already have for HF, 6m and 4m. 

I already have my older IC-910, running okay on 2m, 70cm and 23cm. It a good transceiver, especially after I replaced the standard reference oscillator with a high stability one, and installed a 1200MHz module. It's perfect for general operation. It does multimode, including SSB and CW, but I have missed the possibility from my newer HF rigs, for having a spectrum display. But the '910 is an ageing transceiver, and who knows when it might break down?

For 2m and 70cm, this can be achieved with the IC-705, a bery nice l0ow power transceiver with a neat spectrum display, like the one in the '7300. However, I have plans for trying 1296MHz again. I did that some decades ago, and found it good fun.

Enter the IC-9700. This transceiver This comes with all three bands included as standard, 144MHz, 430MHz and 1296MHz, and it does have the spectrum display, much like the one in the '7300.

I found a used one recently, with 6 months remaining warranty a few days ago, and decided to make the jump.

The box arrived yesterday, and after a bit of work installing it, it is now running on 144MHz with a Big Wheel antenna, and on 70cm FM using the 70cm part of my V-2000 antenna (via a triplexer) I still need to test it on 1296MHz, but my antenna for this band is still mounted very low, and it's difficult to make even local contacts. Yes, there is low activity on that band, but I hope to get more stations running, as a lot of fellow hams have '9700s with an unused 1296MHz band.

So next year I should try to make the update of my antenna system, for various reasons I did not get that done this year.


2023-11-14

QCX Test and Ideas.

 I got the receiver checked. 

Sensitivity on 30m looks good. a signal from the generator at -130dBm is clearly audible. at -135dBm, it's barely audible. This looks quite good for the 10MHz band. 

The audio filter sounds good, with a bandwidth of about 400Hz. That works nicely for me.

I have not yet gone through the alignment process, but I should do that before mounting in a casing. It is probably well adjusted by the previous owner, but it does not hurt making a check. 

Now I need to add an AGC circuit (yes, it's necessary to protect my ears), and use a suitable box. I am likely to add an audio amplifier for use with a speaker.

I will need to move the display, the AF gain potentiometer, the rotary encoder, and the connectors.

I may build a power amplifier to get the level up to about 20W, making this a neat 10MHz CW transceiver.

I am likely to try using a dedicated 10MHz antenna, but initially I can use my 30m long wire antenna.


2023-11-09

More Openings on 6m.

 Moments ago I saw two spots on my 6m FT8 One from South Africa and one from Botswana.

I am guessing that it's some kind of propagation to the Mediterranean sea, extended by F2, given the time of the day. If I remember correctly, it would be a bit early for Transequatorial propagation from the Mediterranean to Southern Africa.

All this with a very poor antenna on the receiver. 

If the solar activity increases to a solar flux of about 200 for more than a week, and without too much geomagnetic storms, within the next 4 months, we could get some really spectacular world wide propagation on 6m. 

But then again, prediction is difficult, especially about the future ;)


2023-11-07

Rally, "Amatoertraef Fyn". QCX PCB.

 In the past week end I went to the annual HAM radio rally, "Amatoertraef Fyn".

There are a few presentations, and a license exam at the event, and of course a flea market.

I was close to get a MCRF SDR, but passed on that.

At some comissioned stand there was a neat little thing:

- An assembled QCX transceiver (CW single band, with the option for transmitting WSPR)

- An assembled filter switch board for 5 filters

- 6 assembled low pass filters for 6,10,15,20,30,40m

Not a bad catch for DKK 200 (about $30)

At the rally no one knew the band that the transceiver was built for. someone said 15m, but looking at the toroid phase transformer that looked like it had too many windings. My guess was 20 or 30m.

Time to look at the stuff:
As I brought it home, I found that the PCB still had some solder flux residue, but otherwise the soldering work looked good. A bit of cleaning with isopropylene alcohol and a toothbrush cleaned that up, and the test begins.

Switching on the transceiver starts up on 30m, as shown on the LCD display. A quick TX test shows about 2W output (a bit low for the 5W spec, but as there is no cooling of the PA transistors this should work nicely I will leave it at that. The TX test was easy, as there is a spring/microswitch on the PCB, so I could just key the TX.

The TX frequency was shown as 50Hz off on my TRX tester, so I went into the adjustment menu and fot the synthesizer reference oscillator frequency adjusted. The TX is now within +/- 10Hz of the nominal frequency. 

This will work perfectly for CW work. For WSPR work the reference oscillator should probably be replaced with a TCXO, so it remains stable enough to 1-2 Hz.

The only serious draw back of the original QCX is a lack of AGC function. However, there is an add-on for this, so I should order the kit PCB for that, and for the other two QCX+ kits I have already, and should start building (for 20m and 60m).

2023-11-02

Surprise. 6m DX Opening With my Poor Monitor Antenna.

 For 6m FT8 monitoring I am using the 6m part of the R-6000 antenna. 

This antenna works fine on 20-17-15-12-10m. On 6m it's a poor performer.

The past few days I have had many European spots, and I suspected that it was F2 back scatter signals.

This morning a surprise spot appeared on PSK reporter. I decoded DU3LA (Phillippines) in the PK05 square. The first station in Oceania I have ever received on 6m.

The solar flux has not been particularly high the past few weeks (130s), but jumped up the last few days, to about 160.

Who knows, if the solar flux stays high, we might get some interesting DX on 6m.

2023-10-19

A Bit of Antenna Maintenance.

 There was a solid wind blowing from the East this morning.

Looking out at my rather heavy (and high wind load) R6000 antenna, it was swaying quite a lot in the wind. The top moved 1/2 to 1 meter.

A quick check showed one guy wire to  slack. 

Yes, I got a small step ladder, as I could grab the lower end of the wire from there, and added some stronger guy wire from that point.

The antenna is now rather steady in the wind, as the other guy wires are now quite tight.

There will have to be more maintenance next year, but the antenna should be okay for the winter season.

The R6000 has also lost a bit of its "radials", but as it is a half wave vertical (10-12-15-17-20m), it will work okay-ish for the winter season. I will order spare parts so I should have them before the spring antenna work begins.

Next, I will have to add new guy wires to my 10m EFHW, as the old ones are gone by now It does stand steady at the moment, but I should take no chances, as it's mounted at the gable of the long shed.


2023-09-26

A Bit of MIcrowave.

A while ago I went to a rally and got myself  power amp for 1296MHz.

The amp is built with 4 10-15W power modules and has a built-in linear power supply. It is quite heavy, so it is not suitable for portable use or outdoor mounting. The nominal output is about 50W.

The amplifier has no T/R switch relays built-in, so I will have to make myself an external relay system. As I am using a preamplifier I will have to use a sequencer as well, as I would not like to destroy the preamp.

Yes, I have already destroyed one preamp for 1296, not by transmitting reverse into it, but likely for one of 2 reasons. Either a lightning strike nearby, or (more likely) transmitting up to 100W on 2m from an antenna a few meters away. The antenna for 1296 was a 3 band antenna for 144/432/1296MHs, with no 1296MHz filter. 

I noticed it one day, when the preamplifier was switched in, the noise increased, but the signal from the local beacon went down into the noise. Bypassing the preamp reception had a much better signal to noise ratio. I can replace the preamp for a next try, and I intend to mount a triplexer (144/432/1296), so the 2m and 70cm signals into the 1296MHz preamp will be attenuated considerrably. More to do, once again, and I will need to call for assistance to get the system up and down.

I am still thinking of a portable system for 1296MHz, so I can operate from hilltops or other suitable places. That is a bit further into the future.

Now for some 10GHz news.

I found an old transverter, built with much assistance from a friend. It has been dormant for several years, and I have retrieved it from my storage. A mounting plate for a tripod is included, so the system is made for portable use.

This is a quite old construction built with modified modules from Qualcomm, and should privide about 500mW of power. 

The system was "born" with a home made waveguide transition and a 48cm dish. During transport the dish has been bent out of shape, so it will need some repair.

I intend to use a smaller horn antenna (15dBi gain) with WR90/WG16 waveguide  for the first experiments.

The wavequide was using a non standard flange, so I deeded to use a modified waveguide extension, modifying the flange used at the transverter end, and standard at the horn antenna. That modification is done.

I also got myself an old FT290R (1) transceiver that should be suitable for controlling the transverter. The T/R switching uses a DC (bias) voltage (>5V) for switching into TX mode, and the FT290 should provide that voltage to the transverter through the antenna cable. Unfortunately the voltage drops below that threshold when the transverter is connected (only 2V). Not good, so a modification or repair of the FT290 is needed, or maybe a modification of the sensing circuit in the transverter.

The receive side appears to function properly, there is a sufficient increase of noise in the FT290 RX when the transverter is switched on.

When the TX part is activated, however, there appears to be a quite low output from the transverter, the needle of the built-in power meter hardly moves, but it does move. More to investigate.

There is a possibility that the negative gate voltage for the PA stage has dropped out ... Oops, new PA module needed. It's not a disaster if this is the case, I do have another PA module.

We shall see when I get more tests done, and when I can get it up and running. Hopefully before winter.