31st Jan 2018, 7:40 pm | #1 |
Nonode
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Location: Spalding, Peterborough, Cambridgeshire, UK.
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Weird experiments as a beginner in this hobby
Thought I would share some experiences and see if it was not just me that did weird and wonderful things in our early years of this radio/electronic hobby we share and enjoy.
Firstly, in the mid-late 1960s, whilst studying for my RAE I experimented with a spark transmitter. No ordinary one, but a "Concorde Linear" 30W valve audio amp driven by my record player (a Pye transcription type deck and amp from my employer's record sales counter). The output was connected to the primary of a car spark plug ignition coil with a spark plug across the HV secondary. The HT side to my 250 foot longwire, the earth, to earth. Playing my favourite Sandie Shaw record produced a very distorted but recognisable tune EVERYWHERE on my little MW transistor radio! Made a change to Radio Caroline! Rob
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31st Jan 2018, 7:49 pm | #2 |
Dekatron
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Re: Weird experiments as a beginner in this hobby
This sounds a bit like the experiments me and a bunch of schoolfriends did in the 1960s: we had a 'net' using juicy PA amplifiers [with 100V-line outputs] feeding tens-of-Watts into spades rammed into the ground 50-100 feet apart. And sensitive receive-amplifiers [repurposed magnetic-cartridge amps from old record-players].
Best we managed using this was about half a mile. Big problem was AC mains-hum rejection - we learned to reduce the coupling-capacitors in the receive-amps to control this; I series-tuned a couple of old output-transformers to gibe 50/100Hz notches. [Some of us then went on to use 'ground-carrier transmitters' with PL519 TV output-valves on 60-75KHz and CR100 receivers - best we managed that way was five miles. No mains-hum!] |
31st Jan 2018, 9:54 pm | #3 |
Retired Dormant Member
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Re: Weird experiments as a beginner in this hobby
My very first 'transmitter' was sort of by accident when as a child someone taught me how to build a 1kHz multivibrator using a pair of OC44s and I found out that if I connected the output from my record players speaker transformer in series with the supply to it that I could transmit on every frequency from DC to light at the same time as the whistling noises.
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31st Jan 2018, 9:58 pm | #4 | ||
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Re: Weird experiments as a beginner in this hobby
Quote:
Quote:
What was your received audio quality like?
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1st Feb 2018, 1:25 am | #5 |
Dekatron
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Re: Weird experiments as a beginner in this hobby
Back in the late 1970s a workmate was listening to the ground with a small battery amplifier.
He came up with various theories as to what he was picking up. He came round to my place with it so I set about getting something meaningful. I connected a mains transformer primary to a 25W ILP amplifier module and connected it between mains earth and a spike in the ground in step up mode and fed it with an audio sweep oscillator. The distinctive signal got about half a mile and by placing the receiver pins at various angles we proved that it was directional. |
1st Feb 2018, 12:11 pm | #6 |
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Re: Weird experiments as a beginner in this hobby
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1st Feb 2018, 3:19 pm | #7 |
Dekatron
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Re: Weird experiments as a beginner in this hobby
My obsession with weird experiments was probably triggered by a very curious early childhood experience. We lived in the country and it was possible to fall asleep most nights surrounded by a stark but velvety silence, in which the slightest hint of tinnitus or the hum of neurons on tickover became very obvious.
The odd thing about my tinnitus is that it often started well before I had fallen asleep or after I had awoken in the morning (which excludes hypnopompic or hypnagogic hallucination) and it took the form of very rapid, and distinct morse code, at a fairly low volume. I was too young to decode it, and the speed at which it was delivered would have made it really tricky anyway. It went on for minutes at a time. For a while I asumed this was the same for everyone, and it certainly didn't faze me- I just wished Icould understand the dots and dashes! I don't believe I yet had amalgam fillings at the time, thus I can't fully explain the cause. |
1st Feb 2018, 4:29 pm | #8 |
Nonode
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Location: Spalding, Peterborough, Cambridgeshire, UK.
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Re: Weird experiments as a beginner in this hobby
About the age of eleven or twelve I became interested in extending the life of U2 type torch batteries. Putting them in the oven for a short time revitalised them slightly.
My dad worked for Lansing Bagnall as a fork lift truck service engineer. One day, he came home with 4 redundant but working 12v 99Ah batteries. These were huge! Two were wired in series to provide low voltage lighting for a small shed down the garden. One day, I had the brainwave to use this supply to charge my 1.5V U2 batteries, one at a time. I decided it was probably safer to use just one 12v battery. This I did. The next thing I recall was a loud noise (cannot remember exact description!) and a sudden pain in my eyes. Yes, it had "exploded", showering my face with all sorts of black debris. I went indoors and mum cleaned me up. Very lucky no serious damage was done to my face, just my shirt or whatever I was wearing. Mum chastised me. "Wait until your father gets home" or similar. A short while after, this same shed was to hurt me again. This time I had been up a ladder to sit on the roof for some reason. Upon descending, I bravely jumped off from about 2 or 3 rungs up. One foot landing on a piece of scrap wood with a rusty nail sticking out. My dad was ill in bed and I remember hobbling indoors crying and limping upstairs to show him the wood still attached by the nail right through my shoe to the side of my foot. When he started to prise it off, I begged him not to because of the pain! I then had to cycle about 2.5 miles to the doctor for a tetanus jab. Rob
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1st Feb 2018, 6:25 pm | #9 |
Dekatron
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Re: Weird experiments as a beginner in this hobby
I once linked the audio (white phono) output of a CD player to the video input of a Matsui CRT TV, and the other (red phono) output to my ghetto blaster. With the contrast and brightness at maximum it was fascinating to hear the music, and also 'see' it as groups of white lines of various brightness dashing across the screen from left to right. I couldn't quite believe that it worked as it did. I was unable to replicate it with any other TV set.
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1st Feb 2018, 7:08 pm | #10 |
Dekatron
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Re: Weird experiments as a beginner in this hobby
What a fascinating thread! and almost every posting so far has some parallel in my youth.
First though something not mentioned so far. Modulated Light: I had a permanent set-up between my bedroom and the guy across the road who had a radio and TV repair shop. Nothing powerful, a torch-bulb with an ORP12 behind it mounted at the focus of a large condenser lens from an enlarger. Half duplex. My spark transmitter experiments took place while I was still at school, I had a large heavy Bakelite ozone machine, which was simply a big mains transformer with a secondary of several kV. This connected to a pair of terry clips upon which sat a cylinder of waxed paper with a wire mesh on the inside and outside between which sparks jumped producing the ozone, I added an aerial and earth. I had a 12V battery in my shed with a thin run of bell-wire going up to the shack window, I used to hope for a power cut, and when it eventually came I switched my R107 to DC and continued my "highly important" radio watch. I briefly did some ground conduction telephone experiments, but I too was more interested in the weird sounds that you could hear. The multivibrator with the adornment of a couple of tuned circuits in the collectors was a well known practical joke to deploy in the garden of a fellow radio enthusiast. The Philpott, we could probably talk a long time about tinnitus (I can't remember a time when I didn't "suffer" from it), or indeed what I call "visual tinnitus", the visual auras I experience in the dark, or those associated with migraine, but they will take us way off topic.
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1st Feb 2018, 7:20 pm | #11 |
Nonode
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Re: Weird experiments as a beginner in this hobby
I also made a remote (vhf, 2M AM) radio controlled switch. This was connected to my Philips EL3302 (I think?) cassette tape recorder via the aux input, with "Careful With That Axe Eugene" by Pink Floyd set just at the play position of all the screaming. Turned up the volume full and left it in the front room, paused, waiting for my remote command when gran sat in there after lunch. This she did after a short time. I remotely operated it and then appeared innocently a few seconds later. She didn't bat an eyelid! Probably more stone deaf than a fan of Pink Floyd I imagine!
Rob
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Apprehension creeping like a tube train up your spine - Cymbaline. Film More soundtrack - Pink Floyd |
1st Feb 2018, 8:44 pm | #12 | |
Nonode
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Re: Weird experiments as a beginner in this hobby
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1st Feb 2018, 9:39 pm | #13 | |
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Re: Weird experiments as a beginner in this hobby
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1st Feb 2018, 10:39 pm | #14 |
Dekatron
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Location: Colchester, Essex, UK.
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Re: Weird experiments as a beginner in this hobby
..It's..feasible- angle-iron formed the frame and there were the standard links and springs arranged between these angle-irons in a sort of geodetic arrangement that you would expect on an old dismantleable bedstead. When breaking these up and repurposing the angles many years later we found the steel to have nasty hard inclusions in it that laughed at an HSS drill bit- it was really scabby material. The house was a bit damp in places (1800 vintage) and my Dad had Marconi transmitters and receivers stashed away in the junk room downstairs.. i wonder if he was a closet 'ham at the time and was playing downstairs after bedtime!
There was a disused, (damp) blocked up chimney and fireplace next to the bed- can't think how this would be relevant but one never knows. The smoke from the rayburn downstairs went up a parallel chimney and the two merged within the chimneystack. I always used to know when my metal detector had found a dumped underground bedstead or mattress in the grounds because of the interference generated by the mesh pattern- whenever this interference appeared i didn't bother to dig! |
1st Feb 2018, 11:17 pm | #15 |
Hexode
Join Date: Oct 2016
Location: Newport, South Wales, UK.
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Re: Weird experiments as a beginner in this hobby
I was probably about 6 when I learned that two or three U2s in series lit a bulb brighter than one. It was to puzzle me for several years afterwards that a battery in series with a loudspeaker did not increase the volume.
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2nd Feb 2018, 2:50 am | #16 |
Dekatron
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Re: Weird experiments as a beginner in this hobby
When I was trying to learn Morse code, "Subliminal Learning" was in vogue. This used a speaker under your pillow playing the lesson while you slept.
I has a reel-to-reel battery operated tape recorder, but did not have a time-switch, so I had to improvise one. My bed-side cabinet had two shelves so I put my clockwork alarm clock on the top shelf and a metal tray on the bottom shelf. Cotton was wound onto the shaft of the alarm winder so that when the alarm went off a metal weight on the other end of the cotton wold be lowered onto the tray and electrical contact made between them. Believe it or not, this Heath Robinson contraption actually worked occasionally, the only problem being that even though I tried to muffle the sound of the alarm, it invariably woke me up. That very tape recorder can be seen in the centre of this image.
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2nd Feb 2018, 3:09 am | #17 | |
Dekatron
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Re: Weird experiments as a beginner in this hobby
Quote:
He told me that should move the tuning knob (which incidentally moved a beautifully made variometer) back and forth to get the loudest sound. The thing was I misunderstood him and believed if I kept doing it the sound would get louder and louder, which of course, in my mind, it did.
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2nd Feb 2018, 9:02 am | #18 |
Pentode
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Re: Weird experiments as a beginner in this hobby
My first experiment worthy of comment, occurred at approximately seven years of age.
At the time I sometimes spent time with a cousin, “Digger”, who was into the hobby of constructing radios and thankfully sent me on a lifelong journey. He called his young annoyance “Why Why” for good reason. My question, “how do they make a magnet?" The answer, “they sort of, well, pass electricity through the metal.” Back home, dad’s basement space, concrete floor, small brass bracket, quite low and accessible ceiling light, batten holder bayonet fitting with lamp removed, big bang, fuse blown, operator down, house lights out. Importantly and luckily, a dry wooden box knocked asunder. Digger acquired his nickname having been born at the end of the first world war. During the second, he lost his life north of the equator as a pilot officer. How about during the war, when Ham bands were outlawed and regular power shut downs became necessary and two young guys, a mile apart across a main road were hell bent on making contact. All that vacant copper going the waste !!! |
2nd Feb 2018, 12:42 pm | #19 |
Dekatron
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Re: Weird experiments as a beginner in this hobby
I decided that my alarm clock should have a 'one shot' function, ie sting like a bumblebee and then die as a consequence. It was placed on a muckheap to provide a cushioning effect. My father was using a hammer drill in a 30' x 12' workshop some distance away and heard nothing; he did however feel it. I think i may have overdone it, not for the first time. I do recall the noise of small parts falling on the roof behind me. (on-topic to a certain extent as prototype electronics were involved)
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2nd Feb 2018, 12:57 pm | #20 |
Dekatron
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Re: Weird experiments as a beginner in this hobby
Martin G7MRV had an odd (accidental) occurrence which had people foxed for a while:
He had a NiCd pack with displayed a stable voltage, but that voltage would not drop when he tried to demand a current from the battery pack. The connections between the cells had rotted to a dubious looking gunge which seemed to have rather queer semiconductor properties. Andrew Crosse would have been proud. |