SOTABEAMS PP 4-Way DC distribution box modification

I started with this unit from SOTABEAMS.

I decided to add an extra input lead; this frees up another Powerpole (PP) connector for DC output and it meant I could have a high-current cable coming from the main connection posts on the power supply.

I also decided to add reverse-polarity protection and a Digital Voltmeter (DVM).

For the reverse polarity protection, I copied the circuit that I’d used before. I used the Infineon IPD 90P03P4-04 MOSFET device. It was quite easy to cut a solder pad on the PCB for the gate contact. I used a scalpel to cut a strip of copper out so as to make a copper island/pad.

In the first picture you can see the black lead wire soldered to the PCB and the red lead wire soldered to the MOSFET device. The MOSFET package is glued to the section of the PCB free of tinned copper.

The 0.36 inch DC4-40V DVM came from superpioneer-08 on Ebay. Note the DVM was pressed well into the case so that it does not foul the PCB, then glued in place. The main lead is anchored to the bottom of the case by a cable grip.

The gate solder pad has been separated from the main negative copper strip. The resistor and the zener diode attach to the gate pin there.

Here is the supply lead end of the box. You can see the positive connection to the tab on the MOSFET package. I added a lead clip to the PTFE mounting screw in that corner so as not to stress the connection.

Here is the view of the DVM end:

And this is the unit when connected to the power supply. To the eye, the DVM said 13.8. The camera saw it differently.

I switched the leads to reverse the input polarity. An external DVM showed -0.2 mV, so the protection seemed effective.

Blackview “BV6600 Pro” Infra Red/Thermal Imaging phone

This is a Chinese phone. I get the impression that Blackview has little presence in the UK, so I may be on my own as regards faults, customer service etc. Let me know if I’ve got this wrong. If the phone proves reliable, then I think it is good value for money. I paid £225 including VAT and delivery.

Apparently the IR camera is a FLIR unit. I may have missed it, but I have checked the FLIR website and I can’t see any mention of Blackview.

I think the IR camera has great possibilities for identifying hotspots on circuit boards, looking at heat leakage from the house, spotting cold spots inside the house etc. Maybe it might assist with 30 THz communications?!

There is a cross-hairs feature for estimating a temperature at that spot. It is possible to manually set the minimum and maximum temperatures for the colour range. You can add more than one cross-hairs. Likewise you can add square zones to the picture for giving an average temperature for each square. Different presentation colour spectra and black-white spectra are available. I chose “rainbow”.

I cannot see any image of me at visible wavelengths reflected in the bathroom tiling with the lighting switched on, but this is my IR image as reflected in the tiling. This is just the tool for “ghost” images!

When it got dark this evening, I took some pictures outside. This is my neighbour’s house opposite. The software attempts to overlay a visual image of edges on top of the IR image. This is a good idea for a feature, but by default, the edges do not overlay automatically. Note the bedroom window edges towards the left side of the picture, do not fit over the red heat from the window; it is shifted left somewhat. There is an alignment button for sliding the optical and IR images together.

The red blob to the bottom right is a parked car, viewed front on.

This is a picture of the rear of our terrace. The red stripe is the warm terrace. Note the warm chimneys along the top. The yellow blob to the left is the oak tree which supports one end of my G7FEK antenna. The “blue” sky above is not really blue; just cold sky.

This is looking roughly north across Rivelin Valley. The foreground orange is a grassy bank. The yellow stripe above is the slightly colder field below (in the dark and unlit). The red blob in the yellow is a dog-walker and dog, perhaps 200m away. The reddish strip is Stannington on the other side of the valley, perhaps 1 to 2 km away. The upper yellow stripe is moorland. The green and blue towards the top is sky. There are just a few overlaid edges from lights in the distance.

This is the road outside our house. The front wheel of the car in the foreground is hot (pink), perhaps showing brake heat. You can see some visual imaging of cars and curb stones, somewhat mis-placed again. I had not applied the alignment function.

Transferring files via USB: Developer options

I found that when I plugged the phone into the PC via the supplied USB cable that I saw a USB drive appear on the PC, but this showed no contents and it would not allow me to add any content to the empty folder. The USB cable is for both data & charging.

Some faffing about is necessary. First I had to enable Developer options, another list of system options. To do this, go to Settings/About Phone/Build Number. Seven taps on the Build number gave me a screen requesting Pin Number. This is the PIN number you have set which unlocks the phone and moves you to the icons screen.

When the PIN is accepted, you are told that Developer options has been enabled. The feature appears in the System menu.

Go to Settings/System/Developer options. There is a long list of options. Some way down is a USB symbol against Default USB configuration. Tap the radio button for File Transfer. On my Linux PC, this immediately showed an Internal shared storage folder and within this a list of 14 sub-folders including DCIM (containing Camera sub-folder), Documents, FLIR (containing the FLIR .jpgs), Movies, Music, Pictures, etc. You can then use the phone as a mounted USB drive.

Some other Developer options worth setting are:

  • Stay awake, so the screen does not go to sleep when there is external power via USB
  • USB debugging
  • Show taps

If you don’t want the system automatically updating, clear (slide the switch left/off) for Automatic System Updates.

17-October-2021 6m AFS

I found this contest slow going. I only escaped England to work Tony GW8ASD in Wales. On the key, John G3XDY was my best DX in JO02 square.

A bit after the contest I worked Massimo IZ4DPV on SSB, 59 both ways via Sporadic E propagation. Of course, Massimo won’t count for contest points for me, but I hope he gets some points for the contact.

21-September-2021 23cm UKAC

There were some good conditions for this contest. Conrad PA5Y was a huge signal. Nick G4KUX seemed to be working all over the place. UK stations were strong.

I could hear Kjeld OZ1FF fairly weak on CW (morse code). After a few tries, he heard me well enough for a contest contact on the key. He must have a wonderful antenna. I was using the LT23S producing 8W fed to the 44el Wimo yagi. We might have had a bit of enhancement from an aircraft. He gave me 519 & I gave him 559.

Five other stations worked Kjeld: Jon GM4JTJ, Keith G4ODA, Nick G4KUX, Pete G4CLA and John G3XDY.

Magpie damage

The driven element had come adrift from the 2m Tonna yagi boom. On checking this out I found the plastic block in good condition (this has been up decades). There is a coarse-threaded screw with a plastic wing-nut handle. It was as if it had just been unscrewed. For the time being, I have just screwed it back on.

The magpies love worrying away at parts of my antennas. I had put some polystyrene foam in the opening to the dish feedhorn to keep spiders and insects out. I watched a magpie remove this. I thought I would scare him off by rotating the dish. He just rode round with it as if it was a fairground ride.

A couple of weeks ago I watched a magpie attacking the connection between the coax and the driven element on the 6/4m yagi. I had carefully covered this with Liquid Tape.

I went up on the roof (with protection: rope, safety harness, stitch-plate etc.) and checked the 2m yagi & screwed the driven element back on. While I was up there I noticed that the 13cm box (containing pre-amp, relay and Bandpass Filter – BPF) had holes through the upper hole plugs. The plugs look like they are made from some sort of artificial rubber.

On taking the lid off I could see some water damage to the outside of the BPF. For the time being I have replaced the damaged plugs with new plugs. In order to get one inserted I had to disconnect a bit of semi-rigid coax. I could not get this reattached, (I needed one hand to stop me falling), so I am off 13cm for the time being.

These were the box contents from about two years back.

More recently I saw a large crow having a go at the 13cm Wimo yagi on the top of the pole. The folded dipole driven element looks very fragile compared to a crow’s beak. When he had finished with 13cm, he moved down to 23cm.

Magpies and crows are intelligent, inquisitive birds. I just wish they would keep to digging the moss out of the gutters and leave my aerials alone.

I recall the squirrel which snipped through my kevlar cored guy line which used to support my 40m delta loop. I suppose it was in his oak tree.

I haven’t caught the jackdaws at it yet, but I am suspicious…

4-August-2021 2m Trophy contest

There was a bit of tropospheric propagation (tropo) for this contest. Contacts within the UK were strong and I contacted a number of continental stations.

My best DX was OL1R in JO70LR square at 1,163km, closely followed by OL1C in JO60UQ at 1,083 km, both using SSB (Single Side Band) and both on the Saturday. Some UK stations worked Scandinavians, but I didn’t hear any.

Sunday the propagation was not as good, but it brought a number of stations in Northern Ireland, Scotland, France and Germany.

I was awarded a certificate for the contest:

Leo Bodnar GPS Reference Clock – GPSDO

The unit is named a “GPS Referenced Clock“. The outputs can be set in the range 450 Hz to 800 MHz. The frequency of the secondary output is dependent on the primary output frequency.

There is another version available with a single output.

The units do not tell the time, so it is not a clock in this sense; it produces accurate, square-wave “clock” output.

The unit arrived well-packaged along with its GPS antenna and USB lead. I like the plastic case for keeping the bits together. The unit is a neat, small package.

I installed the control software on my Win10 PC and connected the Leo Bodnar GPSDO to the PC via its USB lead. I attached the GPS antenna and placed the patch block antenna on the outside of the Velux skylight. My unit is the version with two outputs. Firmware version: 1.17.

The unit took its power via the USB cable.

The “No GPS Signal” message went away. Actually, I later found that I could place the GPS antenna inside on a shelf and still get satellite lock, so the unit is quite sensitive. I have a fair bit of screening by way of foil-covered insulation reducing signals from outside.

On the software I enabled one output only.

Setting a frequency

I set the “Master” (primary) frequency to 106,500,000 Hz, 106.5 MHz and clicked Find. The software displayed:

N31: 11
N1_HS: 8
NC1_LS: 6
NC2_LS: 6
PhShift: 0
BW: 6  (internal PLL bandwidth; 15 is optimum)
F3 Hz: 403 409
Fosc: 5112 (internal PLL parameter)

So the software found a way of setting the unit to the frequency I had chosen: 106.5 MHz.

32 mA drive strength should give 1.6 V peak-to-peak to 50 ohm.

As possible secondary frequencies, the software offered me: 106.5, 319.5 or 159.5 MHz.

Harmonics used as a frequency marker

I put a random rubber duck antenna on the output (possibly 70cm band).

144.08 MHz x 3 = 432.249 MHz
144.027 x 9 = 1296.243 MHz
255.57 x 9 = 2300.130 MHz
257.8 x 9 = 2320.200 MHz
266.69 x 9 = 2400.210 MHz
691.214 x 15 = 10.368.210 MHz

With the 10,368.210 MHz frequency, I received this on my DB6NT transverter from a dish pointing at the rubber duck (not a good match at 10 GHz!). The DB6NT+K3 configuration is frequency locked to a Jupiter based GPSDO. Using the K3’s spot function gave me a dial reading of 10,368.210,003 MHz, so within a few Hz.

On the K3, the transverter off-set frequency can only be adjusted to the nearest 10 Hz, so I cannot tune it any more accurately. The LB GPSDO accuracy is probably within 1 Hz at 10 GHz; I just can’t set the K3’s internal transverter band off-set that accurately.

So I am really pleased that I can use harmonics from the LB GPSDO as frequency markers in the higher bands. I wonder whether I might be able to receive a marker in the 24 GHz band? “white screen of death” on trying to Write or Edit

I hadn’t been able to add to or edit my blog for some time. I tried help chat on the WordPress site & got nowhere. I was running quite an old version of Firefox: 66.0.3. I downloaded the latest version: 89.0.2.

This seems to have fixed the problem with the WordPress editor. I was able to add an article to my blog today and to do some edits.

Perhaps somewhere on the site there are specifications for minimum system configurations?

19/20-June-2021 6m Trophy contest

There was sporadic E again, which was good, as intra-UK contacts were very difficult. I did hear a canadian station on SSB just before the contest. He might have been workable with 25 W, particularly on CW, but I didn’t hear any stations across the Atlantic during the contest.

My best DX was Z3A at 2,230 km.

The pattern of contects was a bit different to last year, 2020. Last year, intra-UK contacts were easier and the sporadic E favoured more distant contacts: