The old modified CB radio for 29.310 - 29.700MHz that I had on the lab desk a few weeks ago, and just re-soldered the Audio output capacitor. This turned out to be insufficient, as the capacitor itself was going loose.
So I found a replacement and got it soldered in.
10 MF monitoring is a go, again.
Yesterday I reacted to an ad from an amateur less than 100km away, for some 1/2" low loss coax cable.
I got two pieces of close to 20m length. The loss is considerably lower than the previous cable, somewhere around 1.6dB. One of the cables has a set of M/F N-connectors and was ready for use.
Today I got a visit from Kent, OZ2KC, and we got a new experimental vertical antenna setup done. Yes, this is a temporary setup, but good for testing the improvement, and I still need to make the rotatable horizontal antenna. But for some local tests with other vertical/mostly FM stations this is more or less the best I can do right now.
The improvements are as follows:
- The cable los has been improved considerably, a difference of more than 6dB.
- The height of the feed point has been raised a bit.
- The antenna is now essentially free of the branches of the tree next to it.
A test with a local station showed a solid improvement, but more tests are needed with mpore distant stations. The top of the antenna is now close to 11m above ground, and the view from the antenna is relatively free in several directions, like SW to E, less so in other directions. SOme of the neighbour's houses will shade part of the antenna, but very little will shade all of it. This is the best I can do at this location.
The second cable has no connectors yet, and I need to find some, so I can get to mount the horizontal antenna, too.
A different option could be a different antenna setup with the vertical and the horizontal antennas switched. I will have to think a bit more about this, as I would like to use both antennas simultaneously, at least for receiving.
More on the results as the tests continue, and more on the planning for other antennas as I do more thinking.
The past few days I got all the parts located for my X7000 antenna. This is a 5m long 2m/70cm/23cm vertical, so it should have a decent performance when used for 23cm alone. Today I got the X5000 (1.8m long) antenna replaced with the X7000. The feed point is a bit lower for this one, but due to its length the top of the antenna is about 2m higher than that of the X5000 was.
I also got a preamplifier mounted close to the antenna, but due to the high cable loss (maybe less than 10dB) the effective TX power is not much more than 1W, and the feed point is rather low, about 4m.
The signal strength of the "local" beacon is a bit higher on average, but not significantly, probably mostly due to the cross polarization loss.
The first experiment was with the usual local stations, and the received signals were not surprisingly well improved. The transmitted signal was improved, too. Progress.
A test with a station a bit further away was a part success. I could hear the station intermittently (sounded like a mobile station with flutter/fading), but no reception of my signal.
More tests are needed when other stations become active and available for experiments.
Days are getting longer and that means more sunlight to convert into electric activities.
So, after the winter doldrums I restarted battery activities. Weather is too cold for outdoor activities, so indoor it is.
I restarted getting the Gel batteries up and running.
I have a set of 18-20Ah batteries that have been brought up nicely to about 14V with a total of 150mA current draw at 14.2V. Those should provide about 20Ah/240Wh of energy storage, and work nicely with a total panel peak power of about 100W, easily being charged, even on a non-sunny day at this time of the year In the winter season that will be a bit more tricky. For those I have been using a small switch mor´de power supply.
The next battery connected to the solar power system i the lab. The battery of the lab power system has a capacity of about 60Ah max. effectively and running with 2x 100W panels. I am using a current limit of about 500mA, and this should easily run the recharge of the 8Ah (or so) battery, without heating the battery up too much.
I have one more battery with about 6-8Ah, that one seems to have a decent voltage, so it will have to wait.
The smallest of the batteries (4Ah) is currently running off a linear power supply with about 200mA current limit.
The smaller (4 - 10Ah) batteries are intended to run from small solar panels and charge controllers for smaller projects, such as monitor systems and maybe a small outdoor mounted (in the summer half of the year) small thest transmitter, used for e.g. range tests on the microwave bands, maybe even a very low powered QRSS or WSPR transmitter. Maybe also for some portable operation, until I get some small LiFePO4 batteries up and running.
Then there are the LiFePO4 batteries:
For the shack solar power system I have been using 2x 12V, 100Ah batteries in parallel, and a charge controller for 20A (MPPT), connected to 2x 130W solar panels. This system could only power the IC705 during the deep of winter, especially Dec/Jan, so it needs improvements.
From the 100Ah LiFePO4 cells I have built a 12V/200AH system, and the intention is adding this to the shack power battery, giving me a total of 400Ah capacity. When full, the charge of this should last several days even with extremely low charging current. For the deep winter months this is still insufficient when longer periods of very low solar powermay only provide maybe 2Ah of charge. So the solar panel system needs to be considerably improved.
The current panel system is simply insufficient, so here is the general idea:
- Mounting a set of panels with 200W on the South facing side of the wall. This should provide maximum power in the deep of winter when the sun is down to a maximum of 12-13 deg above the horizon. This system should use its own charge controller.
- Getting two sets of 300W (total) panels mounted at an angle suitable for summer conditions. Even when there is very limited (or long duration cloudy weather) sunlight this should provide some additional charge,
However, even with this system I expect to need the use of mains power at the lowest point, to keep the battery charge at a decent level. This can be done when the electricity price is really low.
Some of the LiFePO4 cells can be made into a better battery (effectively 100Ah for the upstairs lab solar power system, so I can retire (or re-purpose) the old Gel batteries.
The LiFePO4 battery, 12V - 50Ah could be added to the lab power system, or be used when going out in the field with the car. As that is an EV, the 12V battery has very limited capacity, so a "real" battery is needed for portable/mobile operation. There is no reason to use the much heavier Pb (Gel) batteries in the field, especially if they need to be carried around - up to a hilltop.
Finally, I still have 16 LiFePO4 cells left.
I am thinking of making myself a 24V - 200Ah (5kWh) battery which can be used with a 230V (pure) sine inverter, and a sufficiently large solar panel/charge controller system. This could likely be used in the summer season (when I drive more than in the winter) to charge the EV, especially when the sun is shining, a´with the battery as a buffer. This is further into the future, the first priority is getting the shack system improved, and there is a lot of radio/antenna building in the planning this year. In any case, this can be a neat experiment, and if it is not useful for EV charging it can be used for the house, like the entertainment system.
My 10m FM monitor (modified old CB transceiver) lost its audio out a few days ago.
I waited starting the repair until I had some of the 23cm equipment better tested. As that has now happened I took the rig up to the lab and made a quick test.
Most of the receiver looked like it was working, as the S-meter acted normally, so the fault seemed to be in the audio output system.
Sure enough, when I had the rig open and rocked the output electrolytic capacitor the audio speaker went on and off.
Looking at the bottom of the TRX it looked like there was a dry solder point. I re-soldered the capacitor and the wire going to the speaker/jack, and all sounds normal.
It is possible that the electrolytic capacitor has gone bad. If that turns out to be the case, the fault is a known one, and I may change all the electrolytic capacitors in the TRX.
The TRX is a nice addition to the 10m monitoring, as signals will sometimes come through when nothing else is heard by casual monitoring, or even systematic monitoring on fixed frequencies.
I got the spectrum analyzer started today and got 2 things tested.
The spectrum analyzer also has a frequency counter (with external reference input in it, so I did a frequency test of the TS790. It looks good, the 1296MHz was less than 200Hz after some warm-up. Another test will be after several hours. This looks excellent! The spectrum also looks good, and the maximum outputis just over 10W.
The old SSB Electronics LT23 transverter got tested, too.
The frequency looks like 3kHz too low. If the stability is good enough that is acceptable if there is not too much drift.
The output looks like 5W at 1dB compression.
The spectrum is not really pretty. I see 5MHz sidebands about 50dB down. A quick test of the base transceiver, my Standard C710 showed no extra sidebands, so it must come from the transverter.
As I used manual TX switching I might have destroyed the RX mixer, this needs to be tested, too. Yes, that happens sometimes, even if you are careful.
It looks like the transverter needs some work, but it could be used for some initial experiments if the RX part still works.
Update:
After several hours of warm-up the TS790 is about 1.5kHz above nominal. This is likely to be adjusted in place, but can provide an acceptable performance in any case.
