Some Thoughts on 10m Propagation Monitoring.

It is no secret that one of my favourite bands (especially on HF) is 10m, and I want to be able to make the best possible use of that band. 

At the moment several receivers are used for monitoring the 10m band:

- the FRG-100 for 28200 "International Beacon Project" (IBP), current draw 500mA

- The IC-703 for 10m FM, 500mA

- The AR-8200 for 10m FT8, 200mA

All in all 1.2A of current consumption, just for monitoring 10m propagation using existing (older) equipment. Even using IC-705s for all it would be less. But for monitoring this could be considerably reduced by using simple home made receivers:

- Polyakov DCRX for FT8, using a (pulled) 14.04MHz Xtal as LO, 20mA?

- Polyakov DCRX for WSPR/QRSS, using a (pulled) 14.06MHz Xtal as LO, 20mA?

- Simple DCRX or superhet w/AGC for monitoring 27.555 (20-50mA?)

- simple FM RX with FM-IC for 29.6 FM likely 25mA

- simple superhet w/AGC for 28.200 IBP, likely 25-50mA

- the box could incorporate a Raspberry Pi 2 for decoding WSPR/QRSS and/or FT8, ???mA

Some LO signals could be made with an Arduino controlled Si5351 synth board.

A modular build of this is feasible, and could start with the 28.200 IBP TX.

After this the priority would be like:

- FT8 RX

- 29.6 FM RX

- 27.555 DXB RX

Signals from all could be mixed/matched into a stereo amplifier for "placing the audio", e.g.

28.200 in the centre, the 29.6 in the left channel and 27.555 in the right channel. If more audio monitoring, the 29.6 FM channel (squelched) could be shared with another (SSB or CW) channel audio.

A start would be a simple superhet for 28.200, using a 19.2MHz crystal oscillator (probably originally used for some GSM base station) as the local oscillator, followed by a simple 9MHz "IF receiver" with an audio filter. I do have 9MHz crystals, so if I can place the frequency correctly, a simple crystal ladder filter can be used. Alternative is using a simple audio filter. A limiter for audio (probably a combined clipper/AGC) should be used for reducing the shock value if a strong signal comes up on the frequency.

It should be possible to limit the total current consumption to about 50mA for all, including the audio output amplifier, replacing a receiver using about 500mA.

It should be possible to keep the total current consumption for all those receivers, including audio amplifiers, below 300mA. This should provide a considerable power saving when used with the solar power supply, compared to the present setup, and with more functionality when finished.

Considering that at least some of this should run 24/7, the solar budget looks considerably better.

More Radios on the Solar Power System.

The new solar charge regulator connected into the system, and more radios connected as loads. With the new controller I can manage around 600W peak power from the solar panels. Right now the panels provide only a maximum of 230W, so there is room for improvement, and I have some panels available

Setting this revised system up took a few hours. 

Radios connected now:

- IC-705 (running 6 - 80m with the new 30m "long wire" antenna).

- IC-7300 (running 4-6-10-(12)-15-(18)-20-40-80m with the dipole antenna)

- IC-703 (running 10 FM RX)

- FRG-100 (running 28200 Beacon RX)

- AR-8200 (running FT8 RX) will run continuously

- FT-8900 (running 70cm)

Total current consumption for all the above radios is about 2.7A, though not running all the time. 

Main radios for use will be the IC-705 and the IC-7300 and the FT-8900 for now.

As the system has been running all evening, the batteries indicate about 85% capacity left. Let us see how much sunshine is needed to get the power back up to above 95% tomorrow.

The IC-703, the FRG-100 and the AR-8200 are very inefficient as stand-by receivers and should be replaced with less power consuming receivers. Some of it should probably be home made, especially the FT8 receiver and the 28200 beacon receiver. This will likely reduce the total power consumption of the system by almost 1A - this could then be used for other  purposes, like a Raspberry Pi for running WSJT-X (FT8 monitoring).

In general, for general monitoring, the receivers should be really low power ones, as much as can be done 

I will need to test a Raspberry Pi 2 to see if it runs WSJT-X smoothly, and how the current consumption is.

Now I will have to see how this works as an independent power supply. I expect no problems from now, until October or November, but the few winter months will likely provide too little power from the solar panels. We shall see when that time arrives.

30m Wire Antenna Update.

 The 30m long piece of wire has found its place for a while.

The feed point is placed 2m high at the end of the out-house under an apple tree. It then goes up through the tree and lead to the second apple tree - the largest in the garden, then down to a smaller tree where the end is attached. Most of the wire is about 5m above ground, not particularly high, but definitely better than 1m above ground. 

The antenna now has a counterpoise added, about 50m of wire, about 2m above ground (and lower).

The system works nicely on 30m, and does not need a tuner when operating from 80 - 6m. On the resonant bands of the dipole, the dipole mostly works better, but on 20m in particular the wire gives signal mostly equal to the dipole. On 30m the dipole is useless, as it is not resonant at all, and the wire works nicely. A TZ station (Mali) was coming in nicely with up to S9 signals, but 5W was (as expected) not sufficient to break the pile -up. I will have to try again when signals are good, and less stations are calling.

The present set-up of antennas and transceivers for the 80 - 4m bands is now as follows.

IC-705:  Wire antenna, workable on all bands 80m - 6m.

IC-7300: Dipole working on 4,6,10,15,20,40,80m

IC-7600: The old R-6000 antenna running 10-12-15-17-20m, and the 6m part of the V-2000 antenna.

IC-7100: A vertical Sirio half wave antenna for 4m, mostly used for the local FM traffic.

New Antenna Experiment: 30m Wire.

 Today I made the initial test of the 30m long antenna wire I had lying around. I located a low power (probably absolutely max power 100W) 9:1 UN-UN.

I found a free cable end at the end of the out-house, and strung the wire from there to the low end of the garden. Both ends are only about 2m above ground, and the centre is sagging, so it is only about one meter above ground. There is a lot of room for improvements. The centre should be mounted near the centre of the dipole, i.e. about 5 - 6m above ground, and the end(s) should be higher up as well.

This antenna is right now connected to the IC-705 with about 15m RG-58 cable. Not the best in the world, but for the low frequencies it will work. Surprising that the OZ7IGY beacon is clearly audible on 2m and 70cm, despite the low height. 

The dipole cannot operate on 30m, so the 30m band was tested. A bit of a surprise, a QSO with a French station was easy, even running the 5W from the IC-705.

For now the wire antenna is connected to the '705, and some improvements are in my plans:

- mounting the antenna higher up

- adding some "radials", a 50m long piece, and a 10m long one, to see if the 160m band can be reached with a decent SWR. Right now the SWR is a bit up-and-down across the HF bands, starting being low-ish around 3.5MHz.

- adding a common mode choke at the feed point, so I can avoid RF running into the shack (and some of the noise being picked up on the outside of the cable).

If the weather permits, some of this will happen tomorrow, as well as weather proofing the setup.

The dipole is now connected to the IC-7300, and can be used on 4-6-10-12-15-17-20-40-80m, using the built-in tuner on some bands. At the moment the '7300 has been set to 5W out on the HF bands, but there is, of course some reserve if I *really* want to work a station - new country or the like.

I am expecting some packages tomorrow, so I can start improving the solar power setup. I expect to add the IC-7300 as one more load for the solar power setup, so in essence the "mainly QRP" setup will running on solar only.

HF Dipole Improved.

 My HF  dipole antenna for the IC-705 has been hanging very low for quite a while. Even then my 5W (mostly CW) challenge for the time of the year is on track.

Yesterday I made an effort to raise the feed point for the "inverted V"from 3.5m to just over 6m, just at the top of the largest apple tree in my garden. It can be brought higher, but for now it stays there, because some of the wires are somewhat entangled in the branches of the tree, and I have not yet un-tangled them.

The antenna is a Diamond make, 5-band dipole with one branch for 10 and 20m, and the other for 15 - 40 - 80m. It is likely that I can add 30m, maybe even 60m to this antenna, as I have some coils from a previous antenna. But this will be for later.

The result? It may be too early to say, but tests yesterday indicate more band noise on some bands.

First of all, the resonance frequencies are a bit high on the bands, mostly in the SSB parts of the bands, so the antenna is too short. I will have to "cut on" some wire (yes, I know, add a bit of wire, but I couldn't help playing with the words)

10m has not done too much, neither has 15m.

On 20m I have had clearly better signals, and it looks like more stations than before are coming back to my calls.

On 40m the band noise is clearly higher, as are the signals. Same for 80m. Some CQ calls on 80m gave a QSO to SP3CW last night.

This concludes the first stage of my antenna maintenance and improvement work, there is a lot more to do.

Shack Solar Power Update.

 During the past week I have worked a bit on my solar power system. 

A local friend had some panels he could not get much use from. They work fine, so I decided to get some of them and put them to work. The panels are:

2x 130W peak, 17V

4x 100W peak, 17V

Just before going to my friend I purchased and picked up 2x 12V/100Ah LiFePO4 batteries, as they are considerably more efficient than the (gel) lead-acid batteries I already have. For the shack I want to use them in a parallel connection configuration, so I now have 200Ah at 12V.

First step: Setting up some of the new panels.

I started setting up the 2x 130W panels, connected in series, and connected them to the old batteries via a charge controller. This controller is capable of delivering 20A charge current, and capable of accepting up to 55V (open circuit voltage, OCV) input from the solar panels. The OCV from the panels is under 40V, so there is a good margin. The panel setup is just an intermediate step. They are resting on the ground, leaning to the out-house South wall. I will need to build a lasting support, but right now it is a matter of getting the system up and running.

When coming home from the trip I realized that I missed a bit of hardware, so I went and got 2 100A switches, some 16 mm2 cable and some eyelet connectors for the battery. Next problem: The connectors were impossible to crimp with my current tools, so now I am waiting for a hydraulic crimp tool for the connectors.

The initial indoor set-up is them made with some 2x 4 mm2 speaker wire as the connections, so there is still a good deal of improvement to do, but apart from the improvements needed, the system is essentially ready to use, and the two radios originally connected to the old system have been re-connected.

The first test shows that in the good sunlight, even in the mid to late afternoon, the batteries charged from 89% up to 100%, even with the small load of the IC-705. Right now the 10m FT8 has been added, and the remaining sunlight is insufficient to provide much charge (well, sunset is about now (2000 MEST) in Copenhagen). The real test will be adding load, and see how this works long term. 

Here is the experimental setup of the panel:

Given that we are in the summer half of the year I expect the system to be running nicely with lots of surplus energy, even with just the 2x 130W panels. In the deep of winter time it is a different matter. I expect to have to use some supplemental power from the mains, in order to keep the batteries sufficiently charged.

For now I need to make myself a power budget to see what I can connect to the system. This will also involve testing the power consumption of modules, like the Raspberry Pi(s) I intend to use for FT8/WSPR decoding and QRSS grabber(s)

Now it is time to connect some more load - yes, more radios running on pure solar power here. I think that the first should be either:

1) running the QO-100 down converter (satellite LNB), possibly the 739MHz IF receiver - and the Chinese up-converter mounted indoors. Then I need to test the stand-by power drain of the old IC-821 transceiver. ... or

2) running some more stand-by monitoring equipment, such as more receivers and/or raspberry Pi(s) for QRSS/WSPR or FT8 monitoring, first on 10m, then on other bands, such as 6m, 4m or 2m.

A preliminary second solar power system can be used for powering the 2.4GHz power amplifier(booster) at the feed point of the TX uplink dish. For energy saving reasons I should make the voltage for the booster remote switchable from the shack.

Some antenna work will also be necessary, for the lower frequencies. I want to be able to work on as many bands as possible from 160m (630m?, 2200m?) to 13cm, and later 10GHz, maybe 3.4 and 5.7GHz, but I expect the latter two bands to be just experimental as part of my band-QSO-challenge.

Interesting time ahead for OZ9QV