Found at Rally: Triplexer.

 A few weeks ago I found this at a local get-together taking place at a repeater site. At this meeting they sell (often donated) stuff for the benefit of running the repeater.

This year I found an unknown set of band filters in a box, I suspected that it would be a kind of triplexer, and toady I got my NanoVNA out, and yes it is.

The connector at the far side is the common one. On the near side we see two very recognizable labels, VHF and UHF. I did not know what the third one was, but measuring I found.

Testing from the common port:

TOS: Low pass filter, flat up to 117MHz, then a small dip of up to 5dB, then a 3dB cut-off at about 134MHz.

VHF: Flat from 135MHz - 270MHz, but some feed through up to about 315MHz. Good attenuation below 100MHz and above 400MHz.

UHF: High pass filter with 3dB cut-off around 336MHz. Attenuation on 1300MHz was about 3dB.

Residual attenuation:

Below 100MHz: Practically flat with <0.5dB attenuation

VHF: <0.5dB at 144MHz

UHF: <0.5dB at 435MHz

Attenuation between band ports was more than 22dB at frequencies where I would expect to transmit, so that is insufficient for a transceiver triplexer. For a VHF-UHF monitoring receiver system, this would work nicely.

I got a few of the filters for experiments. I had decided that the shielded boxes, at least, could be useful for other RF projects, and there were some decent looking (SMD) capacitors for VHF and UHF. There were quite a bit of these filters,  so I might have got a few more. If they are there next year I may get some of them again.

 Yes, finally I got to use my RF test equipment, now it is time to get some construction done.

Test of HB-1B for Digital Modes.

 For a few years I have had the HB-1B transceiver.

This is a small sized 5W CW transceiver capable of operating on 80-40-30-20m with CW. It does not transmit on 60m. 

The receiver covers 3.2 - 16MHz, and the RX mode can be set to USB/LSB on 40, 30 and 20m. For some obscure reason it only runs LSB on 60 and 80m. The variable CW filter can be set to receive in the full SSB bandwidth, so I thought this could be used for digital modes without problems.

The set runs with a headphone only AF output, so the AF attenuator I used with the higher end rigs (with speaker output) provided an insufficient signal to the computer sound input, no surprise. 

In any case, this makes the receiving setup simple for the frequencies the HB-1B is capable of. I was a bit worried to see if the frequency stability would be sufficient for WSPR monitoring.

I have run tests with 20m WSPR, and 20-30-40m FT8, and the system works very nicely with sufficient frequency stability. The fact that the transceiver draws only 80mA at receive, makes it a decent candidate for this kind of monitoring, until some receivers with lower power consumption have been made. 

Because my main interests are in the higher HF range, like 10m, and also in VHF/UHF, the initial receiver for the International Beacon frequency of 28200kHz could be reached with a simple down converter, using a 19200kHz crystal oscillator that I have, a diode balance mixer, and a 28MHz preamp should be sufficient for using the HB-1B as a 9MHz IF. Then a "real" 9MHz IF/detector/AF amplifier and filter can be built later. I suspect that the full receiver for 28200 could draw as little as 20-30mA, depending on the power consumption of the 19200 oscillator.

When that is done the HB-1B other types of monitoring can be done, both on 10m, e.g. with a 22MHz canned oscillator as converter LO, covering 10m - or other oscillators for covering the following bands:

30MHz: 40MHz monitoring

40MHz: 50MHz monitoring

60MHz 70MHz monitoring

The 10m monitor with a "base" frequency of 6.000MHz

the 40, 50 and 70MHz with a "base" frequency of 10.000MHz

Each converter should draw less than 30mA.

The 50MHz monitoring could initially be done with an older 3-band Tokyo Hy-Power hand held (like in holding a building brick ;) ) that runs 40-15-6m, since it draws about 120mA in receive mode. 

All this "power saving" happens because I want to run most of my station with solar power (maybe not possible in the deep of winter, then it will be assisted by mains power charging the batteries in low-tariff hours), and because some of it will run unattended 24/7, and other stuff just running when I am awake and at home. 

Quick Test of Some Receivers for Monitoring.

Over the week end I found some older scanner receivers etc that I want to use for propagation monitoring and general (local) traffic monitoring.

Because I like to have the monitoring running for hours every day, and using solar power, I want to limit the power consumption.

Monitoring FM channels:

I have a 10m FM transceiver that I intend to use for monitoring 10m FM on 29.600. Draws 160mA on receive, which is acceptable, though not ideal. Current consumption is still about 160mA, but it is better than using the IC-703. For 10m FM it is also possible to use a Bearcat UBC92XLT handheld scanner running 6V with 70mA current consumption. A voltage regulator reducing the 13V to 6V will be necessary for this (easily built).

For 6m FM, monitoring frequencies in the 51-52MHz segment I can use my older Yaesu VX-5.

The best results of those came with 2 handheld scanner receivers, Bearcat UBC65XLT. These are 10 channel units capable of running in the 4m, 2m and 70cm bands. They draw 5mA when off, and 50mA when receiving. 

I think that one of those should scan the 4m FM segment - 70.300 - 70-500 - 9 channels, and 69.900. the frequency pair 69.900/70.500 is allowed in Denmark for use with repeaters - yes 600kHz spacing, just like the 2m repeaters.

The alternative would be using a (Wouxun?) handheld for this purpose, if I can find out how to program its memories.

The second one can be used for 2m, and the 143.625 MHz, all in 25kHz spacing system. 143.625 has been used by the space stations Mir and ISS for communication with the ground stations in Russia.

For 2m FM I could also use my older Kenwood handheld TRX, or a Baofeng as monitor, again if I can figure out how to program the beast. Since I have no intention of transmitting with those I have no problem using those Chinese radios for monitoring.

For 70cm I could use the Baofeng's again.

Now, what to do for 23cm? I do have an old Kenwood TM741 triband radio, and that could be useful for FM monitoring on that band. I will have to test the power consumption of this one, but it does have the advantage of being capable of running 3 bands simultaneously, with additional transmit capability. I can likely find a low power scanner capable of running 23cm. We shall see.

I am well aware that some antennas will be necessary for all this (and more) monitoring.

The advantage of receive-only antennas is that the preamplifier, if it is necessary, can be placed close to the antenna, so a low cost coax cable (cheap satellite cable) can be used.

The 10 - 6 - 4m, and 8m bands could be covered by a TFD antenna about 2.5m long, hanging in a tree in the garden. Essentially invisible.

For 2m, 70cm and 23cm a short tri-band vertical can be used, with a wideband preamp, and stilll the low cost cable. Not invisible, but relatively discreet. Yes I am aware of the possible overload of some receivers when transmitting, but that is, for now, an acceptable compromise.

For reception on bands in between - such as air band and FM broadcast radio of both Western European and Russian stations, a wide band antenna, such as a discone or a log-periodic antenna could be used with a wideband preamplifier.

The next level will be some monitoring using FT8 and beacon reception, and this requires more sophisticated reception systems capable of SSB. I have some ideas, but this will have to wait for another time.

Idea Box: A Small Solar Lighting System Etc. for the Bedroom.

 Overview:

Using some GEL batteries for providing light in the bedroom. Using small panels mounted to the "top window panes", and a simple charge controller, e.g. the 10A model I already have. Tests of small solar panels will have to be made to see if they can provide sufficient power for the night light, as well as power for MP3 player(s) and amplifier(s), so some audio (e.g. audio books) can be played in there. If necessary, an externally mounted solar panel can be used, but a fully indoor system is preferred.

If this works a similar system can be used in the living room. Both rooms have windows facing South, so it might be possible.

A bit of testing and design:

All this should be tested, (and possibly used) until a more permanent system can be made for solar powering more of the house, e.g. a solar powered audio player system. 

A video player system will require more power, but this can be a start before more solar (entertainment) becomes available in the house.

Bedroom system:

Here is an idea for a small solar power system for the bedroom. As you can imagine, the power requirements for bedroom lighting are not very large, so I would like to add a low power "entertainment system", just for audio, some very low level "orientation lighting" with short LED strips, a "reading light", and a tiny audio system with one of my MP3 players, so I can listen to audio books when resting there, and a charger for the mobile devices, such as phone, tablets and e-readers. I suspect that I can keep the daily energy consumption down to some 10s of Wh, so I need to make myself a budget. 

First I will have to test the energy consumption of the different devices I have, then calculate the needed overhead of power, e.g. make an estimate of the number of sun-less days I need to have energy storage for.

I finally located some small panels I have. They are so-called 20W ones. I need to test them to see how it works in full sunlight (open circuit voltage and short circuit current test), and how they they work behind my windows I will try to make the system with some of those. I have 9 of them, so I should get sufficient power for some low light and some audio in the bedroom, probably using 3 or 4 of them. Even if they are only 10 - 15W the system should work. An effective 40W will likely be sufficient for the bedroom system.

Somewhere I should have a box of single cells and very small panels that I should test and see if I can get sufficient power out of them for similar systems

For similar systems I might also try to salvage some small panels from worn-out (discarded) solar-power-packs as well.

If I consider the idle current draw for the charge controller too high, I have to make a simple one myself, or a switching circuit for disconnecting it when there is no sunlight. 

If I get satisfied with this system I may make other low power systems for other uses, e.g. a weather station with remote sensing and rechargeable batteries as power supply.

Let this be the first test ...

Es on 10m, 6m and 4m.

 The sporadic E season seemed to start a bit slow this year.

OK, I was away for a week around 3. June, so I have probably missed several openings.

Now I am back, and the activity has got going again.

In my 5W challenge I have worked a few dozen QSOs on 10 and 6m. The QSOs worked in the challenge just passed 200, so I am fully on track. On 4m I worked a single station with 25W, and could probably have done more with more activity.

The solar activity has been a bit lower after the quite strong activity we have had in April and May. The SFI just dropped below 100 for a few days, but now it is coming up again. There was one spotless day (the first this year, I think). The geomagnetic field has been rather quiet, as there have been no significant flares or coronal holes to send any substantial solar wind in the direction of Earth.

The solar power for the shack is still insufficient for the use of all the radios I want to make use of in this time when propagation monitoring is quite interesting for the high HF bands and the VHF bands. More battery capacity as well as solar panels need to be connected, and some low power monitor receiving equipment is also needed.

There are now 8  LiFePO4 cells ready to build a battery for the lab I have upstairs. All have been charged and balanced with the small solar power system for the lab, and I still have 20 cells to prepare for more energy storage.

What I need for making a good, solid battery (12V - 200Ah) will be some bus bars (heavy duty copper connections between the cells) Right now I will test the system with a somewhat lower load, and therefore I *can* use some heavy duty wire for the connections, but I will have to locate or make some of the bus bars if I want to use the battery efficiently for powering the main part of the lab. 

When ready the lab solar power system should be able to deliver/store 12V - 200Ah and shared with the 12V system, an added 12V -> 24V for use with soldering iron and computer. I also have a 100W inverter, so it should be possible to power the spectrum analyzer and the TRX test set, plus other 230V test equipment for limited periods. This system should also be used for the charging/balancing of the remaining LiFePO4 cells.

Also, I noticed a substantial amount of switching noise from my primitive switch mode charger for the single cells, so I will have to limit the charging/balancing of the remaining cell to the night time, then get some EMI filtering connected as soon as possible.

New LiFePO4 Cells For Use With Solar Power. Test And Charging.

I picked up 28 unused, but older LiFePO4 cells, and started setting up a test system for them.

I also picked up some BMSs (Battery Management System), 2 for 12V 50/100A, and one for 24V 50/100A systems. I may need to get one or two more.

Solar Power Charging: 

The charging system for those batteries are configured like this:

I am using my solar system in my lab, described in the previous post, i.e. 2x 100W solar panels, charge controller and 3x 30Ah / 12V batteries. This may be expanded a bit with more batteries in parallel. providing a nominal capacity of about 180Ah. Because the batteries are GEL type, I count on a total usable capacity of about 90-100Ah.

The single cell charger consists of a DC/DC buck (step down) converter capable of delivering a maximum peak current of 20A, with CV (Constant Voltage) and CC (Constant Current) settings available on the PCB. To be sure of avoiding overheating I have set those like this:

CV: 3.60V (the upper limit of charge voltage for LiFePO4 cells)

CC: 10A (Just to keep it cool)

The circuit does have a fuse in the battery lead, a 15A one. A bit of redundancy is good. The system should not make a show of spontaneous combustion ;) .

This system is now running, and the first cell is being charged. Things seem to run smoothly right now - no overheating.

More Efficient Energy Use:

The intention is to get all 28 cells tested for capacity, then match them for the best possible batteries.

For this I could just use a resistive load and waste all the energy. Here is the idea to avoid some of this waste:

When I have 4 cells fully charged I will get them balanced for voltage. This happens with 4 low-value resistors, one in series with each battery (plus connection). When connected all in parallel the 4 battery-resistor sets will slowly balance the voltage of the cells. This is the simplest way to do this, and may not keep the batteries in balance long term, but that can come later, when all cells have been fully tested.

The first 4 cells can then be connected with a BMS to form a second 12V power supply, provisionally. With this and a second charging circuit, and considering the losses in the system, this system should be capable of charging 3 cells from (near) 0 to full charge. The 4th cell can be charged from the solar system, providing a new 4-cell battery for test charging the next cells. I could also be connected as a provisional (second) solar power system.

This is a long process, but it will test the cells for reaching the full charge voltage.

Checking Capacity Of Single Cells:

The intention is expanding the 12V system for the radio station, and also create an expanded battery capacity in the lab upstairs.

I expect the 12V battery at the station to be about 300Ah (12 cells), and the lab system to be 200Ah (8 cells).

The first system should likely be the one for the lab. So a full test will have to be made of enough matched cells (8 pcs) to make the 12V - 200Ah battery with all cells the closest possible with respect to capacity.

For this a discharge system has to be made. This could be a simple resistive load with a digital meter. The meters I have seen, however, need 6.5V, so they cannot be used for testing a single cell. Hmmm!

Can I program an Arduino (or the like) and make a simple circuit for testing capacity? Of course...

The simplest solution will be making a simple constant current load (or a simple resistive load) and measure the time before the output voltage reaches the lower limit of 3V, then read out the time and switch off the load. Not too difficult with an Arduino, even with my limited programming skills.

I do not need to measure the absolute capacity, just to match the cells, so the resistive load should be sufficient. The absolute capacity can then be measured when the cells are connected as a 12V battery.

It will take a while, as I am not constantly home to monitor the process.

Also, making this with simple means, things do take time, although they battery/cell testing is not too time consuming, as other things can be done while the tests are running.

I suspect some building of supports for solar panels, and some simple receiver circuits and/or microwave stuff, is in my future, along with the battery testing - and doing some QSOs with the radios.

No time to be bored...

Update: After some hours of charging the first cell still charges with about 8A, and the voltage rises very slowly.

Solar Power Expansion.

I moved the older GEL battery system batteries upstairs into the lab:

The 4x 30Ah battery is now connected in parallel (again) and placed on the shelf next to the lab desk. 

I set up 2x 100W solar panels in series with a (max) 6A cable to the indoors. (maybe more). This is a preliminary setup, so the system can be tested (well, it has worked before, so why not again?) . A certain voltage loss is expected, but less so as the panels are in series, and the current in the cable is therefore reduced. Preliminary cable laid, and a charge regulator added, the lab 12V 60Ah system is now running and charging.

Further needed:

- improved (and shorter) cable from panels to the indoor charger/battery system

When I get more batteries I will probably move the 2x 12V/100Ah LiFePO4 batteries upstairs to use as the base 12V system. The existing lead-acid batteries can then be used together providing 24V/about 100Ah along with providing 200Ah -> about 100Ah at 12V. More solar panels will be needed for this extension, of course, as I want the charge to be the best possible.

The 12V - when finished - should be powering things like the GPS/10MHz reference generator for the spectrum analyzer, frequency counter and the transceiver test set.

The 24V part should be powering the small 24V temperature controlled soldering iron, and also a small laptop. 

When the bigger battery gets installed I can try using a (pure sine wave) inverter to power some of the 220V instruments, like the transceiver test set, spectrum analyzer and a few more.

While this system should work well in the summer time It may need some additional assistance from the mains grid in winter time. I should build some relay switching for this before the winter comes, because, of course - Winter Is Coming  (but not for several months) ;) 

For now I do have enough panels for improving the existing system with the batteries at hand, but I need to build much better supports for the panels. I also expect to start getting some larger panels, a few at a time.

Right now it is about extending the solar power system, and getting the antenna system maintained, and some indoor activity with getting some microwave (and other) stuff up and running.

There are interesting times ahead at OZ9QV. I hope it is not in the Chinese sense ;)