Marconi 2018

[tautech]

I wouldn't say few sales over $1k, SDS2000X Plus is a good bit more but still great bang for buck and I prefer it over IMO the over-priced SDS1000X HD models.
Hobbyists would all like the 10" display but that pushes you into SDS2104X Plus territory and those with the coin to spare will chose it every time even though it's a good bit dearer.
Side by side vs a 7" display even with the same GUI is no contest.

[Zenith]

I thought the SDS800X-HD were the best bang per buck. Pity about the 7" screen. The SDS1000X HD definitely seemed over-priced. SDS2000X Plus was on special offer so I splashed out. I don't like touch screens, but it can be used with a USB track ball. The 10" screen is definitely worth having, especially as I need specs. The FG is sometimes convenient and saves clutter, although I have a better standalone FG. I would have liked 12 bit rather than 8/10 bit. I've no regrets about the purchase.

I looked at Rigol when buying new TE, but Siglent always seemed to have more to offer for the money. The other Chinese marques, Hantek etc don't seem to have such good software or community support. They might be OK if you are counting every penny, but it would be better to stretch to SDS800X if possible.

[EC8010]

I have to say that I think the Siglent approach is very sensible and practical. Only the better engineers are likely to hack their home 'scopes (indeed, only the better engineers are likely to have a 'scope at home), so if you can get them used to using Siglent at home, they're likely to buy them for work, but not hack them. Pragmatic and sensible.

[Zenith]

Producing the hack for a scope takes genuine software skills of a particular type, and some dedication.

Applying the hack or independently produced licences may involve basic Linux skills, such as logging on via Telnet and deleting or renaming a file, or running a Python script, entering the serial number, and then entering the licence codes it produces into the scope/SA/FG.

[tautech]

Producing the hack for a scope takes genuine software skills of a particular type, and some dedication.

Applying the hack or independently produced licences may involve basic Linux skills, such as logging on via Telnet and deleting or renaming a file, or running a Python script, entering the serial number, and then entering the licence codes it produces into the scope/SA/FG.

Very easy with instruments with webservers and a SCPI command page.....generate the license code/s then use a SCPI command to install them.
You can even show the instrument info on the scope display and watch it change instantly when the install license command is sent from the PC webserver.

I've followed the Python scripts for years and used them to generate license codes to compare with official licenses...they are the same !

Some get into trouble not being able to generate valid licenses and don't get the BW license outta the instrument first to have at hand to check against those the scripts generate.
When existing BW license = script generated license you know you've done it properly.

Using SCPI commands and the webserver command page is by far the safest as the instrument won't respond to anything but valid commands......unlike mucking with Telnet or such where you could/might brick the instrument.

[synx508]

Back to the 2018, for a moment. Yesterday I pulled the version 12 firmware out and replaced it with version 23 firmware. It hasn't made any obvious difference but I've read both sets of EPROMs then looked at them in an 8085 disassembler and there are many differences in the code. I really need to make a proper memory and IO map of the 2018/9 generators so I can figure out more about the firmware.
When I'd completed this upgrade I had a look at setting the OCXO frequency properly but found a persistent issue with low frequency FM that was present even when using an external reference. My test frequency was 90MHz because it's clear here and I can listen to the leaking signal on a normal FM radio, which resulted in feedback howl when I turned the volume up. Something was very microphonic. At 90MHz the 2018 uses oscillator two from its VCO block. The bank of four switched oscillators in the block covers 260MHz to 520MHz and is the same on the 2018 and 2019. For 90MHz oscillator two is divided by 4, so it runs at 360MHz. It was *very* microphonic, though, just sitting the generator on top of my 5335A counter produced hundreds of Hz of FM at the 5335A's fan vibration frequency.
Something was wrong in that oscillator block and the manual had the answer, in an almost "we know about this" sort of way, specifically mentioning the component causing it. The varicaps that tune the oscillator are fed through 10µH chokes wound with very fine wire on tiny two-hole ferrite cores, these are supposed to be held tightly to the PCB surface using enamel. On my VCO block one of these chokes was hanging down on its very thin wires, suspended immediately below a ground plane, this creates an excellent capacitor microphone style sensor for detecting vibrations. I have carefully glued it back on the ground plane.
After reassembly I had to run the FM calibration for all the oscillators again, not just oscillator 2. This takes a while without automation but I'm getting better at it and it seems as if it took around 35 minutes this time. No more microphony, though and much better results for residual FM all round. It seems that even when that oscillator wasn't selected the variable capacitance happening elsewhere on the board was enough to cause some trouble.

[Zenith]

Excellent deductive trouble shooting and something to remember for the future.

I have a 2019 which works apart from the OCXO really needing replacing - I have plans. I really want it to continue working as I don't want to mess with it. I have another 2019 which is "mostly working". It works on some frequency ranges. It's one of those things I have to get round to.

[synx508]

Today I completed the level calibration after checking the level meter (RACAL-DANA 9303) against my Boonton power meter calibrator and cross referencing the levels with a RACAL-DANA 9302 and Fluke 8920A (for the <30MHz checks). I am pleased with the results, it's now within 0.1dB everywhere, which is better than I expected to get it.
As I'd adjusted the levels I also recalibrated the AM modulator which is now doing 99% properly, previously it was too deep at UHF and would go to about 105% when set to 99%.
While I was completing the AM calibration I accidentally turned up the FM deviation preset, so I then had to turn it back to where it should be. Thankfully this is a separate calibration from the FM depth versus frequency map where you have to type numbers and nudge values up or down for 35 minutes. It is going to be very hard to sell this now as I'm sure it's better than my 2019 and 2019A in some ways. I suppose I should just replace the Philips small blue capacitors in those, next.

[Zenith]

It is going to be very hard to sell this now as I'm sure it's better than my 2019 and 2019A in some ways. I suppose I should just replace the Philips small blue capacitors in those, next.

An interesting question. They are very nice RF sig gens, if a bit big. They do have their quirks and common faults. Having put so much effort into it and got it into a bona fide working state, I can see you would be reluctant to part with it. How much need do you have for (yet another?) RF sig gen of that quality? What are SWMBO's views on the matter?

I was tempted by the two 2018s, one for £20 and the other for £50, and had an idea the bloke would have taken £50 folding money for the pair. On balance I'm glad you bought them and have returned one to factory condition, or better. Had I bought them they'd still be sitting in the growing To Be Fixed queue.

[synx508]

The chap with two 2018s on his stand had one for £20 which I bought, the other was £70 (working but needs ICs reseating to make it boot) and I'm fairly sure it went for £70. The second one I bought was on the stall to the left, which was tucked under the table and not that obvious. It was priced at £60 but I got it for £45 after initially offering £40.

[Zenith]

I thought they were £20 and £50 and the punter on the left was coy about the price of his. I didn't ask. I recall the patter about how one had been stored and just needed circuit boards reseated, which begged the question of why he hadn't just reseated them. There was another I saw in the back of an estate. I suspected it had been bought and set aside, but it may have been not set out. I've learned it's sensible to ask questions about unpriced items, or things apparently set aside, and ask questions and engage the seller, then throw in a low offer. Having seen things from the other side, the stall holder has to pay for the stall and the trip and would really rather sell his stuff than take it home.

An odd rally that. Not full strength Newbury but about 5 times the size of Chippenham. I'd say a random selection of a fifth of the Newbury stalls would compare favourably with the Chippenham rally.

It's a minor tragedy that Newbury was cancelled last year at the last minute. Apparently the showground charged for the rent anyway. It seemed to break the momentum. I didn't go a bundle on the new site. I can remember the days before the showground when it was held in a field to the south of the M4.

[synx508]

I think the cancelled Newbury boot sale sent more people to the chaotic crater-filled McMichael that year and the combined experience made them less enthusiastic about rallies generally. This year I managed to fail to sell at both because of factors unrelated to the events. I live in Berkshire but I've never had a stand at a Berkshire rally, pretty silly that I've sold at Rugby before… Hmm, that isn't in my calendar this year. It's 16th August. It's a long way, though. Last year I went to FRAS instead, which is also a long way.

[Cubdriver]

... I recall the patter about how one had been stored and just needed circuit boards reseated, which begged the question of why he hadn't just reseated them...

I love the clowns who say that. Or similarly, "It just needs a fuse." It's an immediate "nope" when I hear that, because in my head I'm always thinking "Then why don't YOU do it - reseating boards is free, and a fuse it typically less than a buck - then you could sell it as working and get a lot more money! Oh, and why is your nose getting longer as we talk?

-Pat

[Zenith]

I think the cancelled Newbury boot sale sent more people to the chaotic crater-filled McMichael that year and the combined experience made them less enthusiastic about rallies generally.

Unfortunately, for a number of reasons, the rally scene is slowly declining. Telford seems to get better year by year, but mostly they get smaller and some have disappeared, such as Harwell, Andover and Frome. Some big ones have stopped, such as Drayton Manor and Sandown Park. Drayton Manor was as big as Newbury.

I have the definite impression that Newbury was diminished by the cancellation last year. It was still big and worth attending and there was a lot there, but somewhat reduced from the last time it was held.

Ah yes, McMichael last year, held on the bumpy field with serious pot holes, is one few will forget. It was as if the ground had been undermined by badgers.
I wonder what the tally of broken ankles etc was.

[tggzzz]

Ah yes, McMichael last year, held on the bumpy field with serious pot holes, is one few will forget. It was as if the ground had been undermined by badgers.
I wonder what the tally of broken ankles etc was.

I've just looked on the https://geologyviewer.bgs.ac.uk/ That field is "London Clay", which is notorious for shrinkage in dry weather.

A rule of thumb when looking for houses in the London Basin is to avoid properties near roads with names like "Clay Lane".

[EC8010]

Unfortunately, for a number of reasons, the rally scene is slowly declining.

The same is true for mechanical engineering events, and for the same reason; the attendees are dying off. I would guess that the average age at such events is > 70. I don't see many people younger than me at either event and I put that down to the schools that became risk-averse and decided that letting fourteen-year-olds loose on machine tools was too dangerous, and doing practical stuff in chemistry and physics was too dangerous. My cohort was probably the last to have done stuff as a child that was potentially dangerous and been told to take responsibility for ourselves.

[tggzzz]

Yeah

I remember chemistry lessons where we were given mercury, others where we were issued with a small lump of sodium, and many many lessons where we demonstrated the presence of hydrogen using the squeaky pop method.

I know they don't do the latter anymore, since I demonstrated it to my daughter and SO, and it made them jump.

I wonder where I could get some iron II sulphide, to make stink bombs.

[Zenith]

Unfortunately, for a number of reasons, the rally scene is slowly declining.

The same is true for mechanical engineering events, and for the same reason; the attendees are dying off. I would guess that the average age at such events is > 70. I don't see many people younger than me at either event and I put that down to the schools that became risk-averse and decided that letting fourteen-year-olds loose on machine tools was too dangerous, and doing practical stuff in chemistry and physics was too dangerous. My cohort was probably the last to have done stuff as a child that was potentially dangerous and been told to take responsibility for ourselves.

That's definitely a major factor. Andover stopped because the membership felt they were too old to run it. Amateur radio is an aging hobby in the UK with relatively few young people taking it up.

Others are:

ebay, which is a convenient and arguably cheaper way to come by used equipment than swapmeets, when you factor in the cost of travel and the possibility of drawing a blank.

The disruption caused by Covid, which affected all sorts of things. A few rallies didn't restart after that.

Much reduced armed forces. They bought an awful lot of electronic and engineering equipment which eventually hit the second hand market.

Much reduced engineering and electronic industries. Quite a few of the lower end items I've bought, look as if they were bought to sit on a production line or be used by field service engineers. Higher end equipment, Tek, HP, Racal, etc would have almost all been bought by the military, industry and government bodies and eventually be sold off.

Recently, fuel price increases following affairs in the Middle East.

[Zenith]

I wonder where I could get some iron II sulphide, to make stink bombs.

Buy it on ebay or make it.

https://edu.rsc.org/representing-chemic ... 13.article

You could probably get away with iron filings rather than iron powder.

For stink bombs I recall the H2S was dissolved in acetone.