Building a big Battery for 12V in the Shack and the Lab.

After buying 28 LiFePO4 100Ah cells I started building batteries.

In the shack:

The intention is getting a battery build for powering the majority of my radio station, especially the monitor equipment, using mainly solar power for charging.

This has two aspects:

1.

Reducing the power needed for radios that should be on at all times, and the ones that are powered a lot of the times. This means that the older radios drawing 1-2A during stand-by are out of the question for 24/7 use.

Fortunately I do have some radios that can be used with low power consumption, more about this later.

The other radios with higher power consumption can then be switched on whenever I want to operate.

More about this in other posts.

2. 

Improving the power supply situation, so most of the monitoring can be run on solar power only.

This will be in stages. Right now I have 2 solar panels with a peak power of about 130W, feeding a charge controller. The batteries consists of 2x 12V - 100Ah LiFePO4 batteries, with a total of 200Ah available when the batteries are fully charged. This is just not quite enough for my use, so some of the cells will be used to create a 12V - 400Ah battery for the 12V supply in the radio shack. At the moment I have prepared 8 cells, running a "12V balancing" process right now. The test battery looks like this:

Yes, this needs to be protected against short circuits, but this is the preliminary setup.

What I need is finishing another 8 cells and make some more bus bars (connection between the batteries), getting the other 8 cells completely ready. Getting them balanced and fully charged, then connected together in a 12V configuration with 4 cells, then the second set of 4 cells connected as the second battery.

All this is done upstairs in my lab, and then I will have to use a cupboard for the 12V system with the 2x 12V batteries in parallel, plus heavy switches and fuses for the charging and power supply. 

I should then have a solid 12V power supply system in the shack, with a capacity of close to 200Ah.

As I expect to have some power amplifier using 24-28V, and some laptop power supply, plus a 24V soldering iron I expect to add a 24V battery in the shack for this purpose. This could be a 50Ah battery, as it will be in use infrequently, or a set of 8 cells with BMS (100Ah).

If I want to use the radios with high power, (>500W) output I expect to use the mains for powering those, as the batteries and a corresponding inverter is not practical for this purpose.

In the Lab (upstairs):

The two 12V batteries in use at the shack right now will then be free to use in the lan upstairs, creating a 12V - 200Ah. As I expect the lab to be less in use than the shack, I think this will work nicely.

In the lab I have a few pieces of test equipment running on 220-230VAC, and I suspect that using a (pure sine wave) inverter is quite capable of providing power for those, as they will be used infrequently.

I do want to have 24V available in the lab. This could be done in 2 ways:

Either creating a true 24V system for the lab, or adding a 12V battery system in series with the existing 12V system.

Winter is coming:

For both systems, but especially for the shack system I suspect that there will be a energy deficit in the deep of winter, especially Dec/Jan, and probably also Nov/Feb.

If that happens, and the battery voltage drops below a certain value, I intend to get some power into the system from the mains power system, preferably in "low tariff" periods.

Solar panels:

This expansion means that I will have to mount more solar panels outside.

I have some, alrerady, now I need to make some solid supports for them. There will be some experimentation with amall panel arrays first, then I will go larger.

I am afraid I have been bitten by the solar power bug ;)

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.