2018-10-15

10m open to South America

The shack now has the capability of monitoring 13 frequencies simultaneously (except when transmitting).
Two more computers are set up for running WSJT-X (mostly FT8)
After setting up the computer for FT8 on HF, following the setup of the PA as previously described, 10m opened to Brazil, Argentina, Chile - and finally the Falkland Islands. PY5OD was worked.
The time of the year is the best for F2 propagation on the higher HF bands, and the solar cycle is at a minimum with a flux around 70 SFI. Even then 10m can open.
The old belief that 10m is closed during a solar minimum is clearly not correct. I know, FT8 makes thing possible that were previously impossible, but this gives new life to the 10m band, which has been my favourite HF band for decades.

2018-10-13

Using the PA for both HF and 6/4m transceivers.

I have a IC-7300 covering HF, 6m and 4m, and a IC-7600 covering HF and 50MHz. I would like simultaneous use through the PA of both transceivers to a R-6000 antenna and a 6m 1/2 wave antenna.

How to proceed? Here is my idea. Between the radios and the input of the PA I can use (lazy as I am) a commercial diplexer, like the CF-360 from Comet or the MX-62 from Diamond.
The problem with using those at the output of the amplifier is the limited power they can handle. 600W PEP or about 200W continuous. Not exactly fitting for the 1kW capability of the amp.
Looking a bit around on the net I found this : https://www.ka6wke.net/hf-vhf-diplexer , describing the use of a IC-7300 with an HF antenna and a 6m antenna with a home construction diplexer. There is a design that I could use, albeit with components capable of withstanding the higher power.
What about 4m ? At the moment of writing this, the power limit for 4m in Denmark is 25W, so the PA is not really necessary. If the limit goes up, I might think of a modification to the existing PA, or using a second transceiver for 4m and building a separate amplifier for 4m.

Next step is to find those components.

At the moment the amp is running low power, 200W, with a CF-360 at the output, connected to a vertical 1/2 wave 6m antenna, at the VHF port and the R-6000 at the HF port.

Now, here is the question some will ask :Why use a separate antenna for 6m when the R-6000 does 6m, too ? I have compared the two antennas, and I find that the 1/2 wave antenna for 6m performs far better than the R-6000 on that band. Further, since I do not intend to set up a HF beam, but at a later stage I do intend to have a small 6/4m capable of accepting the full power of the amp, so here we go !
I may design some high voltage capacitors , maybe made with PCBs, if I can not find some suitable for the 1kW filter I prefer to design for higher power than I intend to use, so I can avoid burnt components and/or equipment.

Oh, Boy ! Yet another project added to the pile ;)

2018-10-11

More Shack Reorganisation

A bit more connected
Low band (160 - 30m) antenna connected to the 7600.
It looks like there is a loose connection in the connector/cable, and the cable is a bit short for proper reach. A repair or replacement of the connector is in order, but not today, as the soldering iron and other tools are not yet back in place.

The cable for the 6m/2m/70cm vertical is now shorter, with less connectors/junctions. As of now a single 25m run of CFD(LMR)400 with N-connector for the radio. This gave a clearly detectable improvement of the signals on 2m and 70cm. The cable was previously routed through an entry in the attic, as I started having the shack up there, and moved it down later. A cable is still routed that way, and can be used for some non-critical antenna, maybe as an antenna for a cross-band repeater (2,m/70cm) not to far from here.

The brilliant 2m tropo conditions of the last few days seems to have evaporated to a degree that I have difficulty working 2m DX, but may return, in different directions, in the week end. That is the prediction, at least.

2018-10-10

2m FT8 Up and Running

This morning I detected tropo (which was probably already there last night) on 2m FT8. Just heard the signals audible, and there was a lot.
Now was the time to get a computer connected, and set up. The tiny netbook was connected and showed good signals from the East and South-East.
Time to increase power from the about 8W. An old Tono MR 150W PA was connected, and measured about 80W output, providing about 40W to my Big Wheel omnidirectional antenna, running it quietly until the bigger one arrives in a few weeks.

I was a bit late to join the party, but I am now more ready than before to join again.

Best signals heard were UT2VR and R5WM at 1550 - 1600km. Not too bad for a small omnidirectional antenna.
It is not likely that I can get a much better antenna up before spring, so I will try to work a bit of tropo in the winter season, and see what I can do with that antenna and 40W, later about 300W at the antenna, running a bit of CW/SSB, but probably more FT8.

Update : Tropo again tonight. ODX with FT8 (2-way) UR3EE in KN88dc, 1840km. Not bad with a Big Wheel antenna.

2018-10-09

Rearranging the Shack Corner.

I recently started rearranging the corner of my living room holding my shack.
I needed a bit more space and a more convenient operation space for my transceivers and the new PA.
I have now started reconnecting radios/antennas/power supplies, and will get to the computers running the ham software soon. First things first ;).
Now, this time I am trying to arrange cables more neatly, so things take a little longer. Having enjoyed visitors does not speed up the process, but in any case, I will get there.
Most tricky part is monitors for the computers which take up a lot of the shelf space, vertically and horizontally, because they should also be readable from the operating position.

- and possibly, if the weather allows, a bit of antenna work should be tested as well.


2018-09-30

Idea Box : Multiband QRSS receiver.

This idea is from some years ago, when the QRSS frequencies were (mostly) harmonically related.

Today I would probably use a SI5351 (3 output clock generator) as local oscillators for three receivers.

From 2009 :
This could be extended to 3 or 4 bands with some effort, but here is the basic idea :

I have some Crystals on 3500 , 7000 and 14000 kHz. This could make for an easy setup of a dual band grabber using a single local oscillator :
Here is the trick : 
- make a single oscillator on 3500 kHz - use two buffers (possibly use the gates as buffers)- take one signal and use a direct conversion receiver circuit on 3500kHz, using the crystal filter of Joachim's QRSS receiver
- take the other signal and use the 3500 kHz LO signal for a receiver almost exactly as PA1GSJs receiver, 
- making it a *simultaneous* dual band grabber receiver for :- 3500.800 - 3500.900 kHz- 7000.800 - 7000.900 kHz
Of course, the same idea could be used to make a 7000 / 14000 kHz dual band grabber receiver using 7000 and 14000 kHz Crystals.
There is even the option of making a doubler for the 3500 kHz signal, using this for extending the dual band grabber to a 3-band grabber for 3500/7000/14000 kHz.
Actually Joachim and I have been talking about the 3-band idea, but I have come to think that the 2-band idea is better in terms of simplicity of construction

2018-09-17

Very Simple QRSS Low Cost Grabber Idea.

I did not come up with the idea, but Radovan, OK1FCX on the QRSS mailing list did.

Here is the basics :

Use the cheap Pixie 40m TRX and a Raspberry Pi running QRSSPig, a program created by Martin, HB9FXX. This could be done within $50 for a complete grabber, uploading the grabber files to a free service like qsl.net, which is just for HAM radio.The crystal in the original Pixie is on 7023kHz, so a bit far from the frequency normally used for QRSS on approx.  7040kHz.

Now, OK1FCX used a 7030 crystal (the European QRP frequency on 40m), so got the audio frequency down to about 10kHz. It is possible to reduce that audio frequency to about 5kHz with a 7035 crystal available from Box73.de . However, I am in possession of a single crystal on 7038kHz, brining the audio frequency down to about 2kHz. It may be possible to adjust the crystal to fit in with the WSPR frequency on 40m, so the receiver could do double duty as a WSPR and QRSS RX.

Somewhere I should have an almost finished Warbler TRX, modified from the original 80m frequency to do 40m WSPR. If I can find it after my move, I should probably use that for a more permanent solution, but that is beside the point of the "cheap and dirty" QRSS setup. I should probably use one of my 7030 crystals as Radovan did.

In addition, the 40m Pixie could be used with crystals (that I have available) on 7000kHz to monitor the old (and maybe not used any more) QRSS frequency of about 7000.9kHz

I may have to ask on the QRSS mailing list, if more than one instance of QRSSPig can be run on a single Pi. How about a $50 dual frequency grabber ?