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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

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Old 9th Nov 2020, 4:25 pm   #1
electronicskip
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Default What's this? (transmitter)?

I found this in an old toolbox of mine today, i know it dates from about the mid 80s from the other contents of the toolbox ,but for the life of me ive no idea where it came from .
Im guessing its a transmitter of some sort? maybe im wrong though.
Maybe someone can shed some light on it please.
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Old 9th Nov 2020, 4:45 pm   #2
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Default Re: Whats this?(transmitter)?

Possibly a Tx or a pre amp.
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Old 9th Nov 2020, 5:56 pm   #3
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Default Re: Whats this?(transmitter)?

FM 'Bug' possibly? Is there a printed circuit coil on the underside?
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Old 9th Nov 2020, 6:05 pm   #4
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Default Re: Whats this?(transmitter)?

Quote:
Originally Posted by SiriusHardware View Post
FM 'Bug' possibly? Is there a printed circuit coil on the underside?
Here are two pictures of the underside PCB
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Old 9th Nov 2020, 6:10 pm   #5
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Default Re: Whats this?(transmitter)?

Does that say Pantec? FM Pantry Transmitter has to be high on the list surely.
Same tech as an FM Bug but without the high audio gain...
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Old 9th Nov 2020, 6:37 pm   #6
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Default Re: Whats this?(transmitter)?

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Originally Posted by Jon_G4MDC View Post
Does that say Pantec? FM Pantry Transmitter has to be high on the list surely.
Same tech as an FM Bug but without the high audio gain...
It says Pantec No1
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Old 9th Nov 2020, 6:40 pm   #7
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Default Re: Whats this?(transmitter)?

That nice printed coil makes it almost certain to be a low power VHF transmitter. Maybe the 3.5mm 3-wire input is meant to be from a source with a stereo headphone output (Walkman, etc) - so, pantry transmitter as Jon says.

Unfortunately, it seems to have lost one of its RF transistors. (T4).
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Old 9th Nov 2020, 11:44 pm   #8
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Default Re: Whats this?(transmitter)?

It is indeed an FM transmitter, Pantec were big into this sort of stuff.

Early electronics mags used to have quite a bit of advertising for them.

If you do a google search for Pantec no11, it will show the upgraded version.

I don't know if I still have any of my early Pantec paperwork, but will have a look if you like when it cools down a bit outside.
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Old 10th Nov 2020, 6:06 am   #9
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Default Re: What's this? (transmitter)?

Ah yes, Pantec. I built one of those.

The oscillator & PA was a couple of 2N3866 or similar, as a multivibrator. There should be a heatsink on each one.

Output was more squarewave than sinewave. Lots of spurious emissions. The audio sounded quite good.

An Italian firm, IIRC. It was often said that the Italian authorities were rather more relaxed in their approach to RF spectrum regulation and protection than ours in the UK.

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Old 10th Nov 2020, 6:57 am   #10
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Default Re: What's this? (transmitter)?

Well. thats quite interesting ,ive googled Pantec No11 and found a bit of info on it, bu8t found nothing about the No1 kit.
Thinking back now , i may just have acquired it at an Army surplus store in Oxford back in the early 80s as i used to get a lot of ex army sets and other radio associated products there.


Shame its just languishing in a tool box so will stick it on the offered thread if anyone wants it.
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Old 11th Nov 2020, 12:18 am   #11
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Default Re: What's this? (transmitter)?

If memory serves me right, there was not a lot of difference between the No1 & No11 circuit.
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Old 11th Nov 2020, 12:47 am   #12
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Default Re: What's this? (transmitter)?

Hi,

I remember these. They were advertised as 'professional FM transmitters' claiming an output of 3W!

In actual fact they are just power oscillators, stability is non existent and the spurious emissions, as mentioned are horrific. I would certainly not advise trying to power one of these up if you come across one, they can generate a substantial amount of very nasty rf

Best regards

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Old 12th Nov 2020, 3:40 am   #13
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Default Re: What's this? (transmitter)?

This sounds like the "Jostykits" receivers for VHF that were a simple super - regen on 100-200 MHz that dumped QRM on the signal that you were trying to receive. Drove taxi controllers silly with >chirps<
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Old 13th Nov 2020, 1:53 am   #14
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Default Re: What's this? (transmitter)?

Quote:
Originally Posted by Andrew B View Post
This sounds like the "Jostykits" receivers for VHF that were a simple super - regen on 100-200 MHz that dumped QRM on the signal that you were trying to receive. Drove taxi controllers silly with >chirps<
Not as unwelcome as on the "Spectators Terrace" at Ringway et al.
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Old 16th Nov 2020, 10:53 am   #15
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Default Re: What's this? (transmitter)?

Hello all - I'm the new owner of this little device - the kind owner electronicskip has passed it on to me. Thanks again.

I need advice on how to go about a few things:

1. Drawing out the schematic (I cannot find one - so I'm drawing it to aid understanding). I've started on the circuit side (50:50 chance I have started right - or wrong!) and I'm finding it it difficult. Any tips?

2. I have no idea what voltage it should run at. Is it likely to be a 9v device and can that be determined by the layout and component values?

3. The No.11 version of this transmitter has spiky heat-sinks on the silvery transistors. I may have some somewhere, but if not I have some thick copper wire and was going to make a wound heat-sink with this - are there any known 'boy-scout' knots I should use for this?

4. Apparently this is quite a 'dirty' design, and may cause low power interference - so I want to tame this is possible. Is noise likely to be radiating from the circuit board, or the antenna. . . ? I can screen the circuit, but obviously there is no point if the antenna is broadcasting the interference.

Transistor names I can read on this 4 transistor components are:

BC550 (c 09) x2 black 'D' shaped encapsulation

?B555 silver round encapsulation possibly made by Motorola

Missing transistor - yet unknown

Thanks

SEAN
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Old 16th Nov 2020, 12:38 pm   #16
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Default Re: What's this? (transmitter)?

Ok:-

#1 if you can work with a scanner and photo editing software - scan the track side and mirror it.

Then scan the component side and in software make it as transparent as you can while still being able to identify components and pads.

Then overlay one on the other and you should be able to trace the tracks to the components.

#2 12 -15V from memory.

#3 They get hot - proper heatsinks advisable.

#4 Not likely that you will get it clean enough to be usable - they were basically a square wave multivibrator running at VHF - masses of harmonics.

#5 usually 2n3866's for the ones with heatsinks, can't remember what the others were.

I have to go out tomorrow if we haven't all been locked down again so will see if I still have any paperwork over the next day or so.
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Old 16th Nov 2020, 12:39 pm   #17
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Default Re: What's this? (transmitter)?

As I remember the O/P transistor was a 2n3866 series NPN silicon medium power.

https://uk.farnell.com/solid-state/2...o39/dp/2101467

Should produce QRM up to 800MHz but not cheap at £12 each.
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Old 17th Nov 2020, 6:41 am   #18
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Default Re: What's this? (transmitter)?

I've had a dig through the filing cabinets where I thought the info might be, but no luck, which means if I still have it, it will be buried in one of the hundreds of boxes down the back of the shed.
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Old 18th Nov 2020, 9:31 am   #19
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Default Re: What's this? (transmitter)?

Thanks for looking

It may not be vital as the layout is not huge.

cheers
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Old 18th Nov 2020, 12:17 pm   #20
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Default Re: What's this? (transmitter)?

I felt sure that I had one of these, complete with assembly instructions, but can I find it? Nope!

I did at least find this advert in an Everyday Electronics mag circa late 80s ...

(not that it's much help, sorry!)
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