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Television Standards Converters, Modulators etc Standards converters, modulators anything else for providing signals to vintage televisions. |
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17th May 2005, 11:37 am | #21 |
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Re: making of the London Birmingham modulator
Hi Darius
The modulator looks great! I have been attempting to build one using your methods but with copper-clad laminate instead of tinplate - it is not as easy as it looks! Perhaps I need much more practise. One question though: What does the 8.2V zenner in the sync-sep collector do? The supply voltage is only 5V so how does the diode ever "zenner" or am I missing something? Cheers Brian |
17th May 2005, 1:33 pm | #22 |
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Re: making of the London Birmingham modulator
Hi Brian,
the 8V2 is a protection against ESD for the gate-source oxyde of the BSN10. This MOS-FET is a very sensitive thing be very carefull with the gate!!! Kind regards Darius |
17th May 2005, 3:46 pm | #23 |
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Re: making of the London Birmingham modulator
Hi Darius
Thanks for the advice! I will be very careful. Brian |
17th May 2005, 7:23 pm | #24 |
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Re: making of the London Birmingham modulator
"with copper-clad laminate instead of tinplate - it is not as easy as it looks! Perhaps I need much more practise."
I think Peter Scott made it this way. Kind regards Darius |
3rd Jul 2005, 9:24 am | #25 |
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Re: making of the London Birmingham modulator
https://www.vintage-radio.net/forum/...ead.php?t=3723
Good morning In the pics you can see how the "sound modulation > 100%" detect stage is build in. I want to point out that both channels can be switched on without any inteference. Kind regards Darius |
4th Jul 2005, 3:58 pm | #26 |
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Re: making of the London Birmingham modulator
Hi,
I just got the summer Bulletin. Jeffrey Borinsky's article about the aurora is very interesitng. Please look at page 34: "Some minor problems DC offset This is... This has now be changed to a simple DC coupled output leaving sync tips at 0V and black level at +300mV." This is exactly what we need to drive Q5. So if you use the aurora, the modulator schematic is much easyer. Kind regards Darius |
18th Sep 2005, 11:31 am | #27 |
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Re: making of the London Birmingham modulator
Hi, sorry
I forgot an importand resistor in the sync separator Q3. A 220K Ohms goes from its base to ground. Here is the completed schematic: Kind regards Darius |
19th Sep 2005, 10:11 pm | #28 |
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Re: making of the London Birmingham modulator
Hi All,
Well, Seeing as Darius has posted such excellent diagrams and pictures, I thought I would knock one up for a laugh!! Addictive this television lark! Still a fair amount to do - the Video amps need buliding, as do the filters - the oscillators are not clean enough to use without them, still, so far my congrats to Darius for an easily repeatable design!! Sean
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Engineers make things work and have spare bits when finished Last edited by Sean Williams; 19th Sep 2005 at 10:16 pm. Reason: addition |
20th Sep 2005, 9:42 am | #29 |
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Re: making of the London Birmingham modulator
Hi Sean, looks good, I like what you are doing there.
Please let us see your progress here. Kind regards Darius |
20th Sep 2005, 3:49 pm | #30 |
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Re: making of the London Birmingham modulator
Hi Darius,
A simple question really - Do you use the same sound and vision amp for both London and Birmingham, or do you have two of each, and split the input signal?? Thanks Sean
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20th Sep 2005, 5:40 pm | #31 |
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Re: making of the London Birmingham modulator
"Do you use the same sound and vision amp for both London and Birmingham"
Good evening, yes of course. Please look at the schematic in thrad 27 for vision and thrad 25 for sound. Kind regards Darius |
24th Sep 2005, 3:53 pm | #32 |
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Re: making of the London Birmingham modulator
I'd love one of these modulators when they are available Darius. I use an extremely old (1980's) modulator which, whilst it works incredibly well, causes interference on UHF and only covers Channel 1. I'd love one of your modulators as I have not been able to have a Channel 4 signal before now. Any idea when they will be available?
All the best, Peter. |
24th Sep 2005, 5:10 pm | #33 |
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Re: making of the London Birmingham modulator
https://www.vintage-radio.net/forum/...ead.php?t=3045
At the moment I have not enough time to build them for sale. It takes several hours to build one and making it to earn some money would make it too expensive. The one I have is still available for swap. Kind regards Darius |
24th Sep 2005, 6:31 pm | #34 |
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Re: making of the London Birmingham modulator
Well I'd love it Darius, but sadly I don't have anything suitable to offer you as a swap, unless there is anything else you may be looking for to add to your collection? Alternatively would you sell it?
Peter. |
24th Sep 2005, 9:06 pm | #35 |
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Re: making of the London Birmingham modulator
Hi Peter,
Why not have a go at making one - the parts are fairly common, and the design is quite easy to build - just follow the photographs thatr Darius has kindly posted... Im sure we can help you get one working. Cheers Sean
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25th Sep 2005, 10:04 am | #36 |
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Re: making of the London Birmingham modulator
Yes, I agree with Sean.
This is why I made this thrad. Thanks to Paul Stenning for making this possible. I am sure there are "ham's" in your neighbourhood who can help you with the agliement. Kind regards Darius |
26th Sep 2005, 8:23 am | #37 |
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Re: making of the London Birmingham modulator
Unfortunately it's rather beyond my abilities, I don't have the experience to tackle something like this. I have been hoping for some time that someone would be able to make a modulator available for Channels 1 & 4. Maybe a little later that may be possible?
Thanks again for the reply. |
30th Sep 2005, 10:06 am | #38 |
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Re: making of the London Birmingham modulator
Hi Doctor Who,
I could build the RF and modulator stages for you - you could then fit it into a case and build the power supply, assuming there are no objections from Darius (it is his design after all). What do you think? Cheers Sean
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1st Oct 2005, 8:07 am | #39 |
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Re: making of the London Birmingham modulator
Hello Sean,
Many thanks for your kind offer. I would be very grateful if that is alright with Darius. Thanks for the kind offer, Peter. |
1st Oct 2005, 8:33 pm | #40 |
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Re: making of the London Birmingham modulator
Darius has contacted me regarding the modulator build, and as a result of this I have decided that my offer was not fair to make, so I will not be building these on anyones behalf.
If anyone wants to make one I am happy to offer my time free of charge to assist in alignment/troubleshooting. Cheers all Sean
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