CV2000- series valves

I have been investigating a series of CV marked valves specific to the GPO off and on (ok, mainly off) for a little while. The series CV2000-2031 are all listed as being specified for the GPO (later BT) and they have a special base fitted. Some, for example CV2000 are wire-ended valves with this base attached whereas others, CV2001 for example have tags welded to the pins of the valve base and then the special base fitted. Larger based valves get a similar treatment, for example the CV2006.

The EVS data sheets refer to PO documents CD712, CD713 and CD733. I have a copy of CD712 which is basically a drawing and parts list for the base but has no indication of why the base is fitted. the EVS sheet does however indicate the base is designed to be used with a solder-in base. I am not sure if this is to keep the valve secure or to get round possible contact issues with a pinned valve base, or both.

The plot thickens…

70cms fail…

Seeing there is a 70cm FT8 competition on tonight I sort of threw kit together to see if it even worked. So, one big wheel (‘big’ on 70cms is hardly big!) and a transverter plugged together and I managed a few decodes. Good, but…

It fell apart once I tried to answer a CQ. The caller was high on the waterfall and the amount of drift the blessed transverter managed after just one transmit cycle moved the received signal right off the right hand side. So that failed.

I did try to answer one more station that was in the middle of the waterfall but the same happened, this time still on the waterfall but no amount of chasing it across the screen yielded a decode. Fail again.

Apologies to those two stations, this transverter is clearly useless for digital modes but I thought it worth a try. A tad disappointing. I managed all of 14 miles – I think the transverter manages 10 watts. I can do 17 miles to the local 70cm repeater on a handheld and supplied short antenna on 5 watts FM.

ISS SSTV April 2022

Two events this month, the first from the 7th to 8th and the second from the 11th to 13th (ongoing as I type). I received nothing at all on the 7th and a few poor or very poor images on the 8th.

On the 12th I received one reasonable image at 13:29 UTC and an incomplete one at 15:06. I even received a partial image at 16:36 with the ISS mid-Atlantic. That probably had the benefit that this area is clear to the horizon roughly in an arc covering Wales the lower half of Ireland.

No more passes here until tomorrow… let’s see what happens.

Knobless FT2D

A minor disaster befell the FT2D, the tuning knob fell apart. Part of the inner plastic bit that holds the metal D-shaped ‘grip’ (?) that fits it onto the shaft broke away and the knob dropped off. The radio has never been abused…

Googling (actually, duckduckgo’ing, is that a thing yet?) finds a few people have created 3D printer files for this which suggests it may be a known weakness. Now, where is that 3D… oh, wait, it was on my Christmas list but Santa never brought it. Drat…

For now the bit that dropped out has been glued back in with some slivers of matchsticks as padding to hold it together. So far, so good.

A sea of screens

I’ve increased my screens to 4, all 24″ full HD things. I had 4 when I was at work, but not as large. This all came about because my main system, a 15″ MacBook was always at a poor angle. Laptops, after all are not intended to be day to day workstations.

A screen for the Mac was followed by an Apple keyboard – Apple old stock (but new) so it has all the relevant keys.

Having two screens on the Linux box already and those on a rather useful dual monitor stand it made sense to have a similar monitor stand for the new Mac screen (I say Mac screen, it’s LG not Apple. I’m not so daft as to spend a fortune on a screen!) but the screen on my Windows PC did not have a VESA mount. So, another LG screen followed…

I ended up then with a Windows PC, the MacBook (now with its screen closed and pushed out of the way), and the Linux PC spread across the desk. Three keyboards. Three mice.

Enter a program called Barrier… easy to set up, the Mac is now the master and the Mac keyboard and mouse can control all three systems by moving the mouse to the relevant screen.

No pics – the place is a tip. The next step is to make a platform for the monitor stands, move the PCs to under the desk, and set up the radios and stuff under that platform. Then everything is finally in front of me. Then I will post a pic…

There are a few issues to sort. First, the Linux key mappings do not fully like the Mac keyboard, so I have yet to enable characters like ‘|’, ‘`’, ‘\’ and some others – sadly some of the most used characters in Linux! For Windows, there’s no Windows key but that is no great loss. And anyway the keyboards and mice attached to the PCs still function. The other issue is for Linux Barrier cannot control the PC until the window manager is loaded, meaning I need to log in first. I can set it up so it does not require a login but that’s not really me with my background… Windows, being all window GUI works just fine on startup.

It probably goes without saying that you cannot drag windows between the systems (I can see Windows having a fit!) but the copypaste buffer works which is nice.

There are a few minor niggles, such as on some websites on the Mac the highlighting ‘trembles’ when moving the mouse up and down on one of the other systems. It happens rarely and isn’t an issue for me. The other thing is it is easy to completely loose the mouse! I have not yet investigated the hotkeys one can set up so there may be some help there…

Projects, projects…

So, my projects remain stalled… no idea where the time goes! I seem to be amassing bits for projects but they are just piling up. Thus far the Portsdown is still needing filters and PAs. I have a VLNA for 23cm to build. I need to move the QO100 dish from the back of the garage onto the house wall so I can mount a PA and transverter setup close enough to the shack to be able to use a transceiver, and finally get onto the wideband transverter using the Portsdown. I have dishes for higher microwave bands, a 10GHz SSPA, a 2.4GHz PA and more microwave bits coming soon including a bandpass filter for 23cm and some microwave relays.

Now the weather is improving hopefully I can make some progress. I need to get a mobile tower so I can do various pointing around the house (surprisingly I am actually qualified to build these things!) which will make it easier to move the QO100 dish as well as finally getting some antennas outside. But house DIY comes first, all else is secondary…

Check back this time in, umm, maybe 2025!

ISS SSTV tests February 20th 2022

Two pics from today’s ISS SSTV test…

This is a screenshot after the fact, I was not around to witness it. The ISS had already moved out of range for me by the time I got to the PC (ok, by the time I woke up!). I was there for the next one at around 10am UTC. The signal came in strong at first but faded out very badly after a few seconds, and then faded completely out after that so it’s not much of a pic.

These are received on 437.800 and given my internal collinear struggles a bit to receive the SSTV images on 145.800 it is probably not surprising that this UHF digital test faired worse. But the blocks that make it through are nice and clear.ss

APRS fiddling

I’ve had a Yaesu FTM100DE for a while now and for all that while it has had a USB adapter plugged in and doing nothing. The adapter, SCU-20 came with the transceiver. Anyway, I wondered what it could be use for. The handbook discusses it being used to extract GPS data and packet data and a quick search found some software, APRSIS32 for Windows (see http://aprsisce.wikidot.com ) that talks to various transceivers.

So, software loaded, I needed a driver from Yaesu. Here’s where it begins to get a little tedious as those of you who have had to go looking for drivers will no doubt know. First port of call was the Yaesu site and a search for FTM100. Ok, found that. Now ‘files’ and … a driver for a SCU-19. Searches for SCU-20 found a PDF which contained the filename of the driver but not the source. I eventually found it… under the files for the FTM400.

And that was the hardest part. Driver in, USB lead connected, APRSIS32 loaded and a few parameters configured and there is it.

The software will also send messages etc. but apparently Yaesu do not allow their kit, or at least the kit I have send data out from sources that are not internally generated. (ref: https://groups.io/g/APRSISCE/topic/76092175 ) Oh well, I didn’t get the radio for APRS anyway but it’s a bit annoying.

Anyway it was a fruitful ‘have wire, must make it do something’ episode. The APRSIS32 software is neat and full of functionality, and quite intuitive. It also has a whole support group on groups.io.

10GHz experiments

I am slowly getting kit together for 2.4GHz and 10GHz. So far I have SSPAs for both bands, one which will hopefully enable me to get onto the wideband DATV part of QO100, and the other as part of a 10GHz setup.

I got a Goobay LNB from eBay a while ago. My plan for this was to build it into a POTY for QO100 but I acquired a ready-made POTY that had an input for a 25MHz clock signal and that all works fine. So I wondered if this LNB could be persuaded to receive 10.368GHz. Fortunately I had not got as far as pulling it apart. The LNB is marked 67321, input range 10.7 to 12.75GHz, local oscillator frequencies at 9.75 and 10.6GHz.

Reading up on LNBs in general was advice that one can use the 24th harmonic of a 70cm handheld held in front of the LNB to generate a 10GHz signal. This I had to try and with a bias-tee feeding 12V to the LNB and an SDRPlay RSP2 and SDRUno it does in fact work.

Transmitting on 432MHz should have, in theory generated a peak at 618MHz on the SDR (10368 – 9750) but it actually came out at 618.6MHz. Well, close, and at least it is something. I checked the radio output on a counter which showed 432.0018MHz. I also checked the SDR receiving 432MHz and it showed it correctly.

So the LNB is not quite there but this was only a quick test and it does show the way to test my eventual transmitter actually transmits.

The next step is to assemble a 10GHz transverter and the parts for this are hopefully on their way.

The saga of the doorbell

When we got our house way back in the last millennium it had a fairly good doorbell consisting of two tubular bells, one of which was about 18 inches long. This sounded all over the house but eventually the solenoid last its sparkle and the doorbell went from ding-dong, to dong, to a little tinny ding. So we went through a couple or three battery powered bells which were pretty pathetic and ate batteries. Eventually we settled on a wireless type from eBay and this worked well, and had two plug-in mains operated bells. But the doorbell push itself, sat out in the Yorkshire wilderness that is our drive eventually failed. A new set of radio doorbells was acquired from eBay, and this time the range was a lot better reaching all the way to the workshop. Slowly the range decreased and recently the outside bell push has had issues relating to condensation. No matter what I tried I ended up having to take it apart, clean the battery and put it back in time for the parcel person. Then then tags that held it together decided to go away on holiday and never return.

The original doorbell way back when was AC driven, 6V or so from a bell transformer and it looked as if it had been in for many decades. So, given that these new fangled units are either too weak to be of any audible use or fail regularly or both I made up a little box with an 8V transformer and wired this to an actual bells, not a ding-dong. The bell push outside is now just a switch. Being AC it will probably fair better but I have a space switch just in case.

So how is this radio related? Well, first off I have a relay wired across the bell as I plan to connect this to our Homebridge Pi to generate doorbell alarms on our iPhones. Given this relay I took the previous wireless bell push apart, unsoldered the push and wired this to a n/o contact.

So now the doorbell rings the bell and also triggers the radio bells. There, a radio project! Well, ok, it was only unsoldering a switch…

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