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Television Standards Converters, Modulators etc Standards converters, modulators anything else for providing signals to vintage televisions. |
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11th Feb 2015, 6:31 pm | #1 |
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An ITV converter.
Just taken delivery of this 1950s ITV converter. This one is of the type that didn't involve any modifications to the BBC only TV set. The ITV Band 3 channel was converted to the same frequency of the BBC channel.
The output from the converter simply plugs into the aerial socket of the TV set. I remember these converters well. There was always that problem of breakthough of the BBC channel when watching the ITV channel. I'd imagine these converters were useless when the user lived close to a powerful BBC transmitter, the Crystal Palace Tx for example. This is a particularly well made unit. The Band 3 channels 6 thru to 13 are selected by an incremental coil system, like the tuner in the Pye VT4. Three valves are employed. ECC84, ECF80 and an EZ90 HT rectifier. There is no indication which manufacturer made it. It has a Masteradio look it about so if that's the case we'll know it'll be good. Or, maybe Spencer-West? DFWB. Last edited by FERNSEH; 11th Feb 2015 at 6:39 pm. |
11th Feb 2015, 7:41 pm | #2 |
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Re: An ITV converter.
Hi,
I have a Sterling band III convertor with its box and instruction leaflet. Not as sophisticated as yours, as it only selects one ITV channel. I've no idea how it would be set up to recieve other channels. It has a single ECC81 valve, but I'm certain I've seen others with a PCC84. A mod perhaps? I've had a few of these in my youth, and used to strip them out to use as project boxes. I once set one up on the arm of the comfy chair with three co-ax cables and a mains lead across the living room so I could change the channel without getting up! The old lady next door was most impressed when she visited. Cheers, Pete.
__________________
"Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..." |
11th Feb 2015, 9:07 pm | #3 |
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Re: An ITV converter.
My Pye LV30 came with a Stirling converter which was fitted inside the cabinet. Instead of the usual converter practise in having it's own power supply the Stirling took it's heaters and HT supply from the TV receiver.
The valves in my Stirling converter are PCC84 and PCF80. Spencer-West made a single valve converter, the type 80. The valve was an ECC85. The circuit resembled FM tuner practise. I'd imagine the single valve Stirling was similar. DFWB. |
12th Feb 2015, 1:13 am | #4 |
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Re: An ITV converter.
I don't recognise that one and I thought I had seen them all. I started in the local TV shop in 1955 just before ITV started, there were all manner of converters and we worked late into the evenings fitting them. There were a number of ITV-45mhz converters some of better quality than others, we had some very cheap ones called 'Unisal' they gave a good picture but also radiated ITV to the neighbors.
Most manufacturers of superhets did a tailor made converter for each model, some of which were very easy to fit, others were not. They were the days. Peter |
12th Feb 2015, 10:49 am | #5 | |
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Re: An ITV converter.
Quote:
These converters were fitted to many Bush models using the two deck chassis, such as the TV22/TV24 and console sets such as the TUG24. It operates by a push/pull switch to select BBC and ITV, fine tuning is by rotating the knob. It also has a dedicated band111 contrast pot on the rear. The converter has a PCF80 and PCC84, there are three wires to connect beneath the chassis, the original plug from the RF deck is then plugged in to the converter, then an identical plug from the converter connects to the main deck. I have returned my set to band 1 operation, by disconnecting the converter and reinstating the original wire to the contrast pot. I have left the converter in situ, as it is part of the set's history. It would also leave a big hole in the back if removed! Mark |
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12th Feb 2015, 12:55 pm | #6 |
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Re: An ITV converter.
A superhet BBC only set could be converted to dual band operation by adding a 13 channel turret tuner. The attachments show the Brayhead tuner which was fitted into a rare Griffin TV set. The conversion was carried out by first removing the RF and mixer valves. The tuner is simply plugged in by using two B9A plugs in the valve sockets. The HT for the tuner is supplied by the RF valve socket and the IF signals from the tuner are injected into the mixer valve socket.
However, one of the problems encountered is correct matching of the low impedance output from the tuner into the IF amplifier. In this receiver I overcame that problem by employing an additional EF80 pentode which as you can see is attached to the mixer plug. So by doing this method there is hardly any interference to the IF alignment plus the added bonus of extra IF amplication. Some time ago I tidied up the installation of a 13 channel incremental switch tuner in my wondeful Masteradio T852. Like the Griffin TV the 6F1 mixer valve took on the role as an extra IF amplifier. Again to achieve correct matching between the tuner and the IF amplifier. It was common practise with these plug in conversions simply to supply the tuner IF output direct into the anode circuits of the mixer valve. In the Masteradio T852 there are complex passband shaping traps and so if the direct injection method was employing the alignment would be altered badly. Link to the Masteradio T852 tuner: https://www.vintage-radio.net/forum/...io+T850&page=2 See posts 29 and 33. DFWB. |
12th Feb 2015, 1:20 pm | #7 |
Nonode
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Re: An ITV converter.
My first TV set was originally a single channel one but the previous owner had had a new tuner fitted with two ITV positions and a single BBC position. It plugged into the RF and mixer valve sockets drawing power from one and passing the IF through the other. I've no idea what the set was as I just had the chassis and no case as the donor wanted the case for some other purpose. Once I'd got it working I realised why he'd got rid of it - very poor field sync.
Keith |
12th Feb 2015, 6:10 pm | #8 |
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Re: An ITV converter.
I make it a point to add a Band 3 converter to all my single channel TRF models. There are many variations but the little Sterling [pictured by Tractorfan] with just a single valve performs remarkably well. There appears to be many variations as mine has an ECC85 usually seen in VHF/FM tuners.
That is a smart converter David. Like PeterN I have never seen one! It certainly has a Sterling look about it. Oh no! I thought we had killed off the Nastyradio David? It appears you were just waiting for an excuse to resurrect it... Uncle John's bonfire awaits. Regards, John. |
12th Feb 2015, 6:37 pm | #9 |
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Re: An ITV converter.
This is the Stirling? converter that was removed from my Pye LV30. This example has no power supplier, it scavenges it's heater and HT from the TV receiver's circuits.
So it begs the question do I reinstall the converter in the Pye? It was common practise among TV collectors to remove these units, perhaps it's time to reconsider DFWB. Last edited by FERNSEH; 12th Feb 2015 at 6:55 pm. |
13th Feb 2015, 6:48 am | #10 |
Nonode
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Re: An ITV converter.
Is the Band III converter at interest the same as shown in the attached Wireless World 1959 March advertisment?
Cheers, |
13th Feb 2015, 10:37 am | #11 |
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Re: An ITV converter.
That is very interesting. It may well be a unit manufactured by PYE for their TRF range including Invicta. Aerial type frequency converters were never really recommended by set makers due to Band 1 breakthrough and radiation producing Band 3 pictures on a neighbouring Band 1 Receiver!
Pye were very nervous of anything that might harm their name and marketed new ideas under their off shoot companies. Polaroid screen: Pam. Printed circuits: Pam. First transistor radio: Pam and a few more I can't bring to mind. Just guesswork but it looks a nice unit. J. |
14th Feb 2015, 5:14 pm | #12 |
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Re: An ITV converter.
The Type 245 converter did need some fiddling about with to get it going.
The ECF80 mixer-oscillator has been replaced, the ECC84 RF amplifier is OK and so is the HT rectifier, the EZ90/6X4. On initial tests the HT voltage reading was too high at 250V. Replacing the low emission ECF80 brought the HT down to 220volts. I've hooked the converter up to the RGD 2347T. Unfortunately the set is not giving a good account of itself and as you can see from the attached picture some work needs doing to it. DFWB. |
14th Feb 2015, 5:54 pm | #13 |
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Re: An ITV converter.
The whole idea of these add-on converters is that any BBC only set can receive ITV simply by a connection into the TV's aerial socket. Nothing needs to be done to the the TV set.
So what better set to test the converter on than our old friend the Masteradio. The results are impressive, no patterning or strange noises. The RGD was disappointing. Both sets are superhets. So the next TV to try the converter on will be a TRF receiver. DFWB. Last edited by FERNSEH; 14th Feb 2015 at 6:06 pm. |
14th Feb 2015, 7:08 pm | #14 |
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Re: An ITV converter.
I have just finished restoring one of my LV20's, maybe I should dig out one of my converters. I am pretty sure I could get one up and running in no time, the best one is a huge blue hammerite box that I removed from the back of a decca console set some years back, the make escapes me for the moment.
Mark |
15th Feb 2015, 12:08 am | #15 | |
Octode
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Re: An ITV converter.
Quote:
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15th Feb 2015, 9:36 am | #16 |
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Re: An ITV converter.
When the BBC1 Crystal Palace transmitter opened we were swamped with signal but I don't remember it interfering with the ITV picture, I think the signal level from the converters was sufficient for them to be able to hold their own, the problem was with the dual band sets with only one aerial socket, it needed a special tuned attenuator to just reduce the the BBC signal overload, a conventional resistive one practically killed the much weaker one from Croydon.
Peter |
15th Feb 2015, 12:02 pm | #17 | |
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Re: An ITV converter.
Quote:
I'll try that experiment today. DFWB. |
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15th Feb 2015, 1:02 pm | #18 |
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Re: An ITV converter.
These pictures show just a few of the many Band 3 converters that were available during the early days of the ITA.
The little Champion unit utilizes the same cabinet as their radio model 851/3, a clever use of the same very expensive Bakelite mould. The dark red arched Ferguson was supplied for connection to their TRF receivers. It reminds me of the railway tunnels that Hornby used to manufacture for their model clockwork trains. The Aerialite unit was very popular and many turned up at jumble sales when I was a kid. The Philips set top box complete with adaptors to replace the RF and frequency changer valves in their 10mc/s IF receivers. Very sensitive. The bronze unit was marketed and badged by many companies including EMI who probably built it. A very good Band 3 converter with an internal matching stub to help eliminate BBC breakthrough. Converters usually had a three position switch OFF 1 3 and mains socket at the back to plug the tv receiver into. The receiver switch could be left 'on' and the converter switch used to prevent double switching. Aerial converters were best used when working in a moderate signal area. BBC breakthrough causing patterning and in bad cases BBC sound and a floating BBC picture in the background. They could also transmit the ITA picture to a neighbouring receiver even if the owner did not want it! The Stirling and David's little unit are probably the neatest and most efficient of the converters but saying that they all performed well, even the home constructed ones of which there were thousands. Regards, John. |
15th Feb 2015, 1:04 pm | #19 |
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Re: An ITV converter.
The Ferguson converter for their TRF range. [841T 842T 941T 968T]
[I'm looking for the Pye 47 and F124 external tuners with the piggy back adaptors. I've put them away somewhere safe....] |
15th Feb 2015, 1:17 pm | #20 |
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Re: An ITV converter.
Griffin, DoDo, Buzzard, Flying Crow and the infamous Nastyradio.. Were these strange receivers only supplied to the North East David? I didn't think you were allowed to receive the ITA till just before the start of colour. I can't remember seeing one south of Watford Gap services. I didn't know you could Cadmium plate rust. John
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