Return of the Sunspots.

The sun is rotating. 

The sunspots that disappeared from the visible side of the sun 2 weeks ago have returned in force.

An emerging sunspot group adds to the show.

3 weeks ago the solar flux was well above 200. When the big sunspot groups disappeared the flux went down to about 135, still well above the 100 mark. 10m has been excellent for several months now, and there have been some openings on 6m.

Today's solar flux is again above the 200 mark, as today's (Thursday) solar flux No. is 215, and it looks like this will continue for some days. Today (Thursday) has seen several M-class solar flares.

What does this mean for our propagation?

Most of the time pretty good HF propagation, especially on the high bands. At times of solar flares there can be some SIDs (Sudden Ionospheric Disturbance) with the lower bands in particular having fade-outs.

Filters for AR8600 and AR7030 Arrived.

Two new Collins Mechanical filters have arrived.

A 2.5kHz SSB filter for the AR8600. This will be mounted in the Mk 2 I have, and is intended for use as back-end for some microwave converters/transverters. Initially the main use will be for the QO100 reception system on 10.489GHz, down converted to 739MHz, and probably switchable to the 10.368GHz down converted to 618MHz.

The original SSB filter in the AR8600 is not very good, the main weakness is a poor selectivity, resulting on poor rejection of the unwanted sideband. The SSB filter should solve that problem.

A quick alignment of the AR8600, especially of the BFOs for SSB, and the D/A converter for the fine frequency steps.

Now I need to make space on the lab desk for doing this, so a bit of tidying is in order. 

The CW 500Hz filter will go into the AR7030 receiver for HF ... well, 15kHz - 32MHz. This is a very nice receiver, albeit with a relatively high current consumption.

The AR7030 also needs a replacement of the backup battery. Yes, with time the batteries go empty. I have a few other radios and other stuff that needs new backup batteries, but this one comes first.

This year, I suspect, will be a year for getting much more of the equipment I have up and running for my propagation monitoring system and some of the microwave activity. So maintenance, repair, and renewal is on my program, as well as some building projects.

Last year's challenge was operation, so I did not write so much about "working a QSO a day" or so. This year I will write more about my progress or completion of many projects, large and small.

Adding Load to Solar Power.

For the winter the old load on my shack solar power system has been just the IC705.

The nice thing about the IC705 is the band coverage. All bands between 160m and 70cm, with the exception of 4m. Then there is the spectrum scope. That is a great feature. Third, the power consumption is only 300mA at receive. I am considering getting one more, but as the more advanced HF stations draw much more power, just receiving:

FT817: 400mA

IC703: 600mA

IC7300: more than 1A

IC7600: even more power than the 7300.

IC7100: I think it is below 1A, maybe about 800mA

In winter time with the current solar power system those on the list above cannot be run on solar power.

Today I made the beginning of a small  low power system:

Using a pair of computer speakers I connected the speakers to my 4-band CW QRP transceiver, the HB-1B, drawing only about 80mA capable of running 20, 30, 40 and 80m. The HB-1B only has a headphone output jack, so more audio power is needed for speaker volume. The HB1B does have a variable bandwidth crystal filer, and can be used for both SSB and narrow bandwidth CW reception without additional filtering. The system works nicely. Later the computer speakers may be replaced by a separate audio amplifier box (with additional circuitry) built into a single box. 

I intend to expand the system with more transceivers, and later some switchable filtering:

Split the inputs, so that one SSB/CW receiver goes in one audio channel and one more in the other. A third one can be added with the output evenly split between both inputs, creating a "centre channel".  One of those receivers could be the old PM2B set up for 20,40 or 80m reception. A repair/modification will be necessary for the 80m preselector, but that should not be too tricky. The PM2B is also very convenient to add to the monitor system, as the power consumption is only 20mA, easily added to the current solar power system.

This means that 3 different signals can be distinguished. Since these signals have a noise floor, the idea is to add 3 FM receivers in parallel, making the signals from 6 receivers distinguishable/audible via the 2 channel audio system. This requires a simple mixer system that I can construct without too much difficulty, making the monitoring of 6 different frequencies possible, as the FM receivers will be squelched, and therefore distinct from the SSB/CW audio.

Later some audio filters, and maybe equalizers and input switches can be added to this system. 

AR8600 Filters and Add-on.

As mentioned earlier, the AR8600 receiver originally has a poor SSB filter. 

I do have an old Mk1 and a newer Mk2, and the filters are different. Also, the Mk1 stops at 2040MHz, and the Mk2 continues up to 3GHz, so it is useful for reception on 2400MHz, too. 

I suspect that a preamplifier will be needed for those high frequencies. I can find one, or use a module I have for that.

I made a search on Ebay after looking at a video on updating the receiver.

I did locate one SSB filter suitable filter, and ordered it from Japan. This is an 8-pole Collins SSB filter that should be much better that the original Murata filter in the receiver. The post mentions the AR8600, so I hope that the filter fits in the PCB. I am hoping to receive the filter some time in February.

The filter I ordered looks like a fit for the Mk2, and that suits me fine, as the Mk2 has the wider frequency range.

I suspect that I will have to find an alignment procedure for the AR8600s, as there seems to be some misalignment, at least in the Mk1 I have used until now.

I do have an AR7030, too, and I also ordered a 500Hz CW filter suitable for that one.

When I look into my crystal ball I see some upgrade activity in my future ;)

An added Idea Box entry:

The other part is the audio output of the AR8600. The built-in speaker is very small and not very loud. So I am thinking (ouch! ;) ) of building myself a new audio device with an external audio amplifier, possibly with an equalizer circuit (I have PCB a module for that), and an audio CW filter.

I do have a stereo amplifier suitable for use with at least two radios. With a little mixing trickery that could easily become 3 radios simultaneously, one in the left channel one in the right, and the last one in the middle. With an external switch box (that I already have) more radios could be added to the external audio system, albeit not all radios simultaneously.

QO100 Reception Using HF Transceiver?

 I have been using an old AOR AR8600 with a stabilized LNB (indoor reference oscillator on 25MHz). This is essentially a glorified scanner receiver with SSB capability.

This works OK, but is far from ideal.

The filters for SSB are cheap ceramic filters. Those are quite wide, and lacks some good suppression of the opposite sideband. This was noticed when I operated at a frequency with interfering stations . The wanted station were sometimes weak, and were swamped by the neighbouring stations.

So what to do to improve the situation? The AR8600 does have an output for the IF band, used for add-ons like a TV demodulator. Maybe that could be used together with an old fashioned HF receiver. I located a suitable cable for the experiment and set things up, with an easy-to-read frequency.

Oops! No.

The conversion in the AR8600 inverts the down converted IF band. Further, the IF output only works with the AR8600 in WFM (wideband FM) mode. The second part could be eliminated by a minor modification of the radio. The inverted band is annoying, however. I could live with using the other sideband, but the frequency readout goes "backwards" , so I have to recalculate the frequency.

What do I do now?

First option would be an up-converter, converting the band up to 19,29,39 etc MHz, using a local oscillator above both frequencies.

There may be another option. the HF radio is my IC7600. That model has a transverter input(/output). There is one drawback with that. There is no setting for ah"high LO" , i.e. I cannot invert the band frequency readout once more. More oops.

Update:

I used it today, and it does work, even if it is inconvenient.

This leaves a second converter with high LO.

Yet another project to add to the already long list. This is no longer a very simple solution, but neither is it a very large project.

This Year's Challenge. Small and Mini Projects. And Antennas.

This year, as opposed to last year, I have the intention to do some more building and construction activities. Last year was the year of 365 QSOs with 5W, later 365 with just 5W and solar power.

This year is more about getting some physical things done. This does not mean that I will not do much operation. Especially as propagation is among my great interests.

My antennas need an overhaul, and an update. At the moment I have:

For HF: R6000 for 10,12,15,17 and 20m (6m usable for some monitoring). Then a 5 band dipole, 10,15,20,40,80m, passable on 4 and 6m. Also a 30m long wire antenna with some limited counterpoise. This is passable for all HF bands and barely usable for 6 and 4m, and should be usable if I want to listen on 8m (40MHz). a 1/2 wave antenna for 10-11m is OK.

For VHF/UHF I have the V-2000 vertical from diamond running 50, 144 and 432MHz. A cable is running into the shack to a triplexer, running up to 3 different radios. A short (1m long) dual or triband antenna is used for monitoring 2m and 70cm, and a clover leaf ("Big Wheel")  for 2m. My 4m vertical is not standing upright at the moment, so it is not very useful.

This year I want to get up and running on a few more bands/modes. That requires new antennas and some kind of rotating functionality.

For 2m I want to do some more SSB/CW etc. (DX) activity. The 4 element yagi mentioned in an earlier post should do that.

For 70cm I also want to add DX activity. The 11 (really 8) element yagi is intended for that.

23cm: I have had some activity on that band a few decades ago, and because there is an activity group active now on this band I want to get some activity going again, this time with better equipment than I had back then. The 16 element yagi is intended for that.

I am (a bit) active on the QO100 geostationary satellite, transmitting on 13cm and receiving on 3cm.

I want to become active  with terrestrial on those bands, even if it will be with small antennas form home. Those are more directional than the VHF/UHF antennas, and need to be rotated as well.

I suspect that some portable operation from hilltops will be good for the microwave bands (above 1GHz), as I have obstructions in several directions, so range is a bit limited. This means that both a home station and some portable equipment is needed. I am building up my stock of equipment and antennas, and no, I do not expect to finish all of it this year.

In any case I want to be able to extend the number of bands where I have made at least one QSO. In this case we are talking about 2400MHz and 10GHz, and maybe later on the two bands in the other end of the spectrum, 630m and 2200m.

Then there are the small projects and mini projects, I have the goal of making at least one or two of those every month, as they are limited in scope.

One (two) of the somewhat larger projects are about assembling two QCX+ kits I have, one for 20m and one for 60m. Those are 5W CW transceivers, and should provide much fun in the future.

Mini #5: Test of low pass filters.

When I picked up the PM2B mentioned in #3, there were two 30MHz low pass filters included in the price.

Further, I had some older low pass filters, a 30MHz  and a 50MHz one, so I got them all tested today:

Out came the NanoVNA F (4" screen). The tests were made with a wideband calibration setting, so the absolute values are not perfect. 

All filters are in good working order.

This means that I now have three 30MHz low pass filters and a 50MHz filter, all fully functional:

The old one I have is a Yaesu filter with a 100W rating. I have had that for decades.

The second one is a Trio/Kenwood filter, 100W rating.

The third one was a bit of a surprise. An old Drake filter rated 1000W.

The fourth one is a BNOS low pass filter for 50MHz. No rating on the filter, but I suspect it is 10W or so. It is a much smaller filter than all the others.

I reckon that all those ratings will be reduced to about 50% of the stated rating if I want to operate 100% duty cycle modes, like digital modes, e.g. FT8.

I opened the 1kW filter, and all looks clean, a beautiful mechanical construction with silver plated coils and high power capacitors, likely silver mica types. Somewhere I have a PA for 10-11m that I suspect has poor harmonic suppression so the 1kW rated filter would likely fit nicely in a system with that one - if it has sufficient linearity for SSB. OK, as I mainly want to use it for CW that is not so much of a problem. FSK digital modes will also work nicely.

The other option would be using this filter with an old IC-M710 that can deliver 150W continuously.

I would hesitate to use this filter with my 1kW power amplifier, even if I use it extremely rarely.

Given that I paid <$100 for the two filters, including the 1kW one, as well as the not fully functional PM2B, I consider this trade as excellent.

I picked up more at that rally, more about that later, as it is a different story.