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Old 24th Dec 2019, 1:03 pm   #1
CambridgeWorks
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Default Pipe dream projects.

I wonder how many of us have ideas of something (radio or similar related, as per forum) that never was pursued?
I have two.
First, a top band am portable transceiver designed around a battery valve superhet that was common in the 50s. DK9* series b7g valves. Rx modified/ tuned as required. Tx using rx oscillator maybe crystal controlled and the af o/p stage suitably modified as the rf pa.
Rotary switcch for tx/rx and changing the functions over. A separate aerial socket for use as well. Maybe a carbon mic to provide "power" for an efficiency modulator.

Second was a topband mobile transceiver using an old car radio cassette. Rx was modified as required and with all the cassette parts removed, hopefully provide enough space for a tx.
Doubtful that I would attempt the second, but the first still intrigues me.

About 30+ years ago I received a good working Yaesu FT77 as part of a swap.
It annoyed me that it only covered 80M to 10M bands.
I found articles relating to removing one of these bands and replacing with 160M.
Not good enough! I wanted to ADD 160M. I did NOT want to drill holes to accommodate extra switches either. I spent a long time thinking about this and studied the circuits.
Then a eureka moment!
The bandswitch control was used for diode switching by applying a "band select" voltage.
What I did was drill out the end stop so that the switch now clicked into a blank position with wiper selecting itself. That is, no output voltage was selected, therefore no current flow either. I put a current sense circuit with inverted output in series with the switch. This then, via further transistors controlled the extra circuits when 160M was selected. Those used were the same circuits from the modification article. The blank switch location which had previously been the switch stop position now enabled 160M.
The biggest headache which I had was interference from the fluorescent display. Although I attenuated it substantially, I never made a 100% cure.
It had maybe 20 or so hours use and I then lost interest in top band. But it was a worthwhile exercise in my opinion to make the 160M modification better. Still in a wardrobe, I think!
I imagine that this FT77 that I still have with ALL the hf bands included must be unique.
Rob
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Old 24th Dec 2019, 4:42 pm   #2
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Default Re: Pipe dream projects.

Mine was a SSB transmitter using the Weaver "Third Method". This technique was never really embraced apart from by Redifon who used it in a couple of early-60s military radios [GR410] which were not exactly market-successes.

I studied the maths in intricate detail, and wrote a few FORTRAN programs [back in the days of punched-card program-decks] to do some simulation, but that's as far as it went.

These days you could do the lot in software for a few quid.
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Old 24th Dec 2019, 6:22 pm   #3
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Default Re: Pipe dream projects.

Yes. Also used in the Datong rf speech processor. Can give very good results when used correctly.
Rob
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Old 24th Dec 2019, 6:36 pm   #4
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Default Re: Pipe dream projects.

Interesting: I've got an as-yet-unused Datong speech-processor board here (bought from Lee Electronics in Edgware Road sometime in the mid-80s) - I'm inspired to finally box it up and get it on-air, if only as a sort-of proxy for my onetime design-dreams of Weaver-mode SSB.

Historically, it's intriguing to look back at David Tong's history - from some first time-at-university published circuits, into 'intriguing' stuff sold to the amateur-market in the late-70s and through to the mid-80s [he did a cunning doppler-direction-finder!] and then on into more-serious professional gear...

https://www.yorkshirepost.co.uk/news...w-in-1-2597079

Last edited by G6Tanuki; 24th Dec 2019 at 6:42 pm.
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Old 24th Dec 2019, 6:56 pm   #5
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Smile Re: Pipe dream projects.

My pipedream project was to attempt to make valves!!

I remember seeing the valve lab at the Dulwich museum years ago and would love to have set it up in my garden. Would have need a huge well made shed though!. No idea what happened to it?.

I was thinking if I could learn glassblowing techniques and convert a clapped out old lathe into a glassblowing lathe and use a fly-press with stampers to stamp out anodes ECT. I could be well on the path to make a working valve. When the materials lab at Perkins was refitted, there was some very nice equipment such as miniature heat treatment furnaces which would have been ideal to de stress valve and CRT envelopes in and such things as a Bakelite press (to mount specimens in for microscope work) was scrapped.

My ultimate dream would have been to successfully make end viewing magic eyes (ME41, AC/ME, EM34 ECT.) as these are no longer being made and they look relatively simple devices to construct if you could make up the tooling and jigs for assembly. It should be relatively simple to carefully dismantle one and reverse engineer it so that simple press tools and construction methods could be worked out. A chemist could analyse and work out the various materials needed. Also to make vintage round CRT's though I think that would be a step too far!!

Christopher Capener
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Old 24th Dec 2019, 7:36 pm   #6
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Default Re: Pipe dream projects.

Not really a pipe dream more of a memory that would be a dream today. Shortwave with loads of stations as it was in the 70's. OK most where propaganda, the programmes where well made and had some power (RF!) to "inform" the world of (communist) perfection.

Real pipe dream, a huge field for lots of aerials, given the above not a lot of use, I like making aerials. Always fancied an Adcock DF setup replete with underground station. This would have to have (RF noise free) internet, fully equipped workshop, mechanical, electrical and electronic, climate control, a bar (beer), kitchen (I like cooking)... This would also have a "Hilbert's Hotel" attached to accommodate all the very welcome guests from this forum.

Well, it is a pipe dream!
 
Old 24th Dec 2019, 8:32 pm   #7
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Default Re: Pipe dream projects.

Is that a hotel with two exits at 90 degrees to each other?

David
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Old 24th Dec 2019, 10:55 pm   #8
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Default Re: Pipe dream projects.

Quote:
Is that a hotel with two exits at 90 degrees to each other?
Oh no, much better.

https://en.wikipedia.org/wiki/Hilber...he_Grand_Hotel
 
Old 25th Dec 2019, 12:03 am   #9
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Default Re: Pipe dream projects.

Mine was a full U-matic edit suite.

I had the tape machines and one ENG camera just needed the edit controller and a vision mixer when personal circumstances put a sudden stop to it.

Still have the camera, everything else sadly is gone.
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Old 25th Dec 2019, 12:10 am   #10
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Default Re: Pipe dream projects.

Mine was sail off into the sunset around the Pacific islands.

Mike
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Old 25th Dec 2019, 12:16 am   #11
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Default Re: Pipe dream projects.

I’ve been building a feature packed HF transceiver for three years now. I have managed to get absolutely nowhere so far because I keep getting distracted by test gear. I finally sold most of it off and persuaded myself not to buy any more and actually have some focus now. And what did I do? Well I went and bought three kits to build instead.

This will remain a pipe dream I suspect at the current rate.
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Old 25th Dec 2019, 3:07 am   #12
Graham G3ZVT
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Default Re: Pipe dream projects.

Quote:
Originally Posted by robinshack View Post
I wonder how many of us have ideas of something (radio or similar related, as per forum) that never was pursued?
I have two.
First, a top band am portable transceiver designed around a battery valve superhet that was common in the 50s. DK9* series b7g valves. Rx modified/ tuned as required. Tx using rx oscillator maybe crystal controlled and the af o/p stage suitably modified as the rf pa.
Rotary switch for tx/rx and changing the functions over. A separate aerial socket for use as well. Maybe a carbon mic to provide "power" for an efficiency modulator.
I had read the thread title only, and thought about my pipe-dream, then reading your post I realised that mine was very similar to the above.

It's more a thought experiment, I am being held hostage/prisoner and I have a valve radio in my cell, let's say it's a Bush DAC90A, my guards have inexplicably given me access to some basic tools including a soldering iron, and my task is to re-engineer the set into a CW Tx to send a message that will secure my rescue.
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Old 25th Dec 2019, 7:32 am   #13
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Default Re: Pipe dream projects.

My truely pipe-dream project is to build the ultimate pocket calculator for electronic enthusiasts. Maybe one day I'll get started

My slightly more practical project which I sort-of started 5 years ago and has been on-hold ever since is to add the disk drive (HP7900 mechanism) to my HP9830.

As for the previous message about being a prisoner and modifying a radio into a transmitter : I must admit that when I first head 'Desert Island Discs' my thought was that if I was ever in that situation I'd not care about the music, I would be trying to use parts from the record player amplifier to make a crude transmitter to send out an SOS message.
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Old 25th Dec 2019, 10:09 am   #14
Malcolm G6ANZ
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Default Re: Pipe dream projects.

I used to work in NHS repairing linear accelerators and occasionally took home a lot of useful and not so useful stuff from work. This usually coincided with a machine being scrapped. It came a standing joke that I was building a partical accelerator in my garage. So to confound my critics I would construct a partical accelerator in my garage!
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Old 25th Dec 2019, 10:32 am   #15
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Default Re: Pipe dream projects.

Quote:
Originally Posted by high_vacuum_house View Post
My pipedream project was to attempt to make valves!!
Like this?
https://www.youtube.com/watch?v=EzyXMEpq4qw

Peter
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Old 25th Dec 2019, 11:51 am   #16
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Default Re: Pipe dream projects.

Quote:
Originally Posted by Malcolm G6ANZ View Post
I used to work in NHS repairing linear accelerators and occasionally took home a lot of useful and not so useful stuff from work. This usually coincided with a machine being scrapped. It came a standing joke that I was building a partical accelerator in my garage. So to confound my critics I would construct a partical accelerator in my garage!
I would think most of us already have particle accelerators, provided the particles are electrons and the energies are at most a few keV. I refer of course to cathode ray tubes (and for that matter valves)
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Old 25th Dec 2019, 12:10 pm   #17
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Default Re: Pipe dream projects.

I'm glad some of these are 'I would like' rather than 'I would have liked' - it's never too late to make a start!

I would like to make myself a record cutting lathe for acoustic 78s. Over at lathetrolls there's some discussion about the possibilities for re-engineering the shellac/filler material but that it would be too expensive to get a company to mix the minimum order. Wouldn't it be great to record, cut and listen to a new 78 on a gramophone that would never have reproduced such music?

Making microgrooves is a lot easier, apparently.

Perhaps a shorter term pipe dream is to be able to educate myself to actually understand some of the circuits in artefacts I admire - a dream most of you lot have already achieved!
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Old 25th Dec 2019, 1:32 pm   #18
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Default Re: Pipe dream projects.

To find the time and the commensurate effort to reduce the 'round-to-it' pile to zero. But that's a double-edged sword: if I achieved that, I fear that I would ask "O.K., fine. Now what?"
Apart from that, most of my unfulfilled pipe-dreams are not radio / electronics related, so cannot be mentioned in this thread.

Al.
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Old 26th Dec 2019, 12:15 am   #19
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Default Re: Pipe dream projects.

Al, you don't know how true that can be with " "O.K., fine. Now what?""
A pal of mine, Frank, was a motorcycle spares breaker. He liked to invest his profits, which he did over many years.
One Thursday, about 3 years ago, he rang me up. A rather downbeat conversation which went along these lines. "Hi, Les. --etc. -- I had my financial adviser around on Monday. He said 'Well Mr. S, I can't really suggest anything. You have the house of course, enough for both of you if you live to 120, you have provided for both your children.' " Frank then said something along the lines of "I am not sure what to do now. It seems everything is all tied up nicely".
After the call, I rang my B in L who knew him, and told him, and how I thought it was a strange conversation.
On the following Tuesday, B in L rang me to say that it had been on the radio that Frank had died peacefully sleeping in the chair on Sunday evening.
That did not surprise me at all.
Les.
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Old 26th Dec 2019, 2:23 am   #20
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Default Re: Pipe dream projects.

In a drawer in one of my workshops there is my dream project, half built. In various storage places lie the parts to complete the project. In my head and on paper the design is almost finished. In my fantasy is enough free time to realise the dream.

It’s a valve stereo radio. The tuner part is a Leak Troughline, the amplifier uses four EL84 per channel, the RIAA pre-amp uses two low-noise valves. It’s all built on an aluminium chassis that fits into a lovely steel cabinet.
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