Member postings for Geoff Theasby

The 'blob' is not necessarily a point of maximum signal, but the meteor exploding part way though its final descent. Yes, polarisation of received signals happens all the time, but is most noticeable in faint signals where it means the signal strength may reduce to below the noise.

To counter this, a 'turnstile' or crossed dipoles aerial may be made, which will pick up any polarisation whatever it is.

The doppler shift still applies, but the meteor isn't heading for 'you', the trail begins where the meteor hits atmosphere dense enough to be resistant, and stops when the meteor burns out.

I was listening this morning and didn't hear any either!

Geoff

Early? I'm often conscious, if not compos mentis, earlye in the morning.

Geoff

I was going to let Neil explain, but I had this idea...

This is a HDSR display, generated in the computer. It is listening to Graves radar, on 143.0488 MHz, which it can not hear, but when a meteor passes, the Graves signal is reflected, leaving a trail on the 'Waterfall' display.

Imagine a loom weaving cloth, which slowly lengthens, as the shuttle passes back & forth through the 'shed' formed by the raising and lowering of the alternate threads. If something is trapped in there, a lump will form, and be incorporated into the cloth. This is like a waterfall display.

Geoff

Bernard Lovell, using ex-radar equipment, at Jodrell Bank in 1946, was the first to discover and detect meteors during the day.

Geoff

Hi Neil,

Yes, "tune for maximum smoke"! I'll send you a copy after lunch. You can still buy back numbers!

Geoff

You can detect the sun with more than just a satellite dish. I have done that, but I also did it on 145 MHz, see Practical Wireless, January 2018. I can e-mail the article if required. You only need a 2m aerial, I used an HB9CV, feeding a 2m receiver, with the audio taken to a smartphone running a data-logging 'app' like Soundmeter. Then play back the recording into your PC and print as normal. I recommend Amateur Radio Astronomy, by John Fielding, 2nd ed, RSGB. I also find that SDR# is good for use with dongles.

Geoff

I'll be there on Friday.

Geoff

Ho Ho, I've been playing this game for a while. I lead them on, saying I've done what they ask, until they get to a point where they ask, "What does it say now?"

I say, "It says this is a scam and you are trying to defraud me"

Oh, I get called all sorts! Instructions to go forth and multiply, to commit various violence on me and disconnect my computer. I say '"That's what your colleague said last week"

Click...

That was a good 'link', David.

I tried Skipton, OK. I tried Selby, OK. I tried RIchmond, North Yorkshire, near where where my family originated, and Wow! Almost unintelligible, with strong Geordie overtones!

Geoff

I live near Pismire Hill in Sheffield. Yes, it's ants.

Geoff

I still like the old Gmail Tap.

Geoff

CF Booths in Rotherham. Highly recommended, they even cater for railway enthusiasts!

Geoff

Driving wheel is the steering wheel, as in the USB attachment for driving video games, as is the joystick for flight simulators. Alternatively, in the Junior Parker song, it is the provider of power, as it is in a motor cycle, or early go-karts, where only one wheel was powered.

And the sexual stuff, too.

Geoff

Another great scientist who did not get a Nobel prize is Jocelyn Bell-Burnell. She claims that her many later awards would not have been granted to a Laureate.

I claim to be one of the non-scientists who not only finished A Brief History of Time, but understood it..

Geoff

I don't think so. Andy has a good point, but in our case the recruits are more likely to be drawn from the recently retired.

Geoff

Would that be clubs that notify us, or clubs 'in existence''?

Geoff

Yes John.

Another thing, I worked in satellite communications for 15 years, and we began by using discrete logic ICs, and linear RF components. Within 5 years we were having the pcbs machine assembled with vital components only inserted by hand. Every one worked on being powered up, so very little remedial work was required. Include software driven menus, premade cables and ever reducing power needs, they got so small they only occupied half of a standard 1U chassis.

Geoff

As for getting something for nothing, the pcb is assembled by machinery, the box can be anything you like, sockets to your taste, left handed front panel, your choice of colour. You provide the power supply. Rather than a neat, sculptured, identikit piece of equipment, you have a personalised item. The £10 kits or modules can be left as pcbs as they are used only infrequently. OK, I am supporting a repressive, communist state. Where were the Maplin equivalents?

Geoff

Hi David,

In fact the £80 transceiver is from India, but the same principle applies. Due to modern components, a barebones, pcb only device can be built on a single circuit board, and the 'bells and whistles' provided in software. Auto keyers, recorded announcements, aerial tuners, PA protection, even automatic CW sending (via a keyboard) and reception, waterfall displays, spectrum analysis are all possible for not much extra cost. My point is that these were never available in Maplins, nor almost anywhere else, until the internet made it easy to see what was offered, even to the small, hobbyist market.

Geoff

DS1, I can not let this pass. Electronic modules and components, cheap or not, were just not available to the hobbyist until recent years. Just as we can obtain any 'in print' book from Amazon, whereas it took weeks from a bookshop, and we couldn't search their stocks without being in the trade, we are now becoming aware of electronics that were just not available, or didn't exist. Add to that the fragmentation of the hobbyist market into radio amateurs, robotics, drones, makers, micro computers, hi-fi, gadgets etc. In recent months, I have built power meters, transmitters, frequency counters, accurate, drift-free oscillators, motor speed controls, waveform generators, all for under £10 each. I have on order a multiband radio transceiver with lots of facilities, for £80. It needs a case preparing, sockets etc. fitting, but a similar plug&go product ready-built will be £several hundred.

Geoff