Modulator for 405 Line from PC? - UK Vintage Radio Repair and Restoration Discussion Forum

ConnorFOD · 27th Mar 2021, 12:16 am

Hi, I've been looking at Peter's nostalgia site http://www.nostalgiatech.co.uk/240%20lines.htm and I'm interested in getting a setup along these lines as a few hundred pounds for a standards converter is just a little too much at the moment.

I'm looking at the image of the modulator circuit and it's blowing me away, I have very little electrical experience and this is a little over my head. Does anyone on here know of different modulator designs or someone who sells them?

FRANK.C · 27th Mar 2021, 12:12 pm

Hi
One option is you contact forum member Freya. He builds and sells this type of System A modulator.

Frank

rambo1152 · 27th Mar 2021, 1:45 pm

I use an ATI Radeon HD 2400 XT graphics card (about £10 on Ebay) and this modulator
http://www.earlytelevision.org/405_modulator.html

Hopefully that will look less intimidating as a project, and you could tackle the sound and vision parts separately if you want.

No expensive crystals to buy and no frequency synthesis, just a pair of free running oscillators, but it is quite stable enough, picture and sound are excellent.

I didn't bother with a custom PCB I just used perforated project board.
The chips are still available from Littlediode.

Nuvistor · 28th Mar 2021, 8:41 am

That modulator from early television looks good, for $30 inc shipping the kit is not expensive.

AdrianH · 28th Mar 2021, 9:25 am

Just watch out for delivery from the US to the UK and things going missing when in the UK.

I ordered one that was shipped 17th September 2020. I got a notice from Royal Mail that I may have to pay import duties, which was not an issue it was under the value, that was on the 21st September, it cleared customs on the 25th September. From that point on the parcel went missing.

After a while I checked with the Museum to see if they had any better information than me, that was on the 10th October 2020.

By the beginning of November I had given up and around the 7th November paid for another modulator kit.

On the 19th November the first one turned up, around two months on our soil. The second one has never arrived to this day.

Yes I have probably been unlucky, but my suggestion get something from Freya if you can we seem to have a poor postal system here in the UK. There are no qualms with the Museum side.

I have lost several small value parcel items from overseas after they land with us.

Adrian

murphyv310 · 28th Mar 2021, 4:06 pm

Hi.
I'd definitely speak to Freya here. All Hedghog designs are excellent and extremely reliable, plus its coming from the UK.

27th Mar 2021, 12:16 am	#1
ConnorFOD Triode Join Date: Mar 2021 Location: London, UK. Posts: 23	Modulator for 405 Line from PC? Hi, I've been looking at Peter's nostalgia site http://www.nostalgiatech.co.uk/240%20lines.htm and I'm interested in getting a setup along these lines as a few hundred pounds for a standards converter is just a little too much at the moment. I'm looking at the image of the modulator circuit and it's blowing me away, I have very little electrical experience and this is a little over my head. Does anyone on here know of different modulator designs or someone who sells them?

27th Mar 2021, 12:12 pm	#2
FRANK.C Heptode Join Date: Feb 2006 Location: Roscommon, Ireland Posts: 697	Re: Modulator for 405 Line from PC? Hi One option is you contact forum member Freya. He builds and sells this type of System A modulator. Frank __________________ www.electronics.frankcuffe.ovh

27th Mar 2021, 1:45 pm	#3
rambo1152 Dekatron Join Date: May 2010 Location: Manchester, UK. Posts: 3,626	Re: Modulator for 405 Line from PC? I use an ATI Radeon HD 2400 XT graphics card (about £10 on Ebay) and this modulator http://www.earlytelevision.org/405_modulator.html Hopefully that will look less intimidating as a project, and you could tackle the sound and vision parts separately if you want. No expensive crystals to buy and no frequency synthesis, just a pair of free running oscillators, but it is quite stable enough, picture and sound are excellent. I didn't bother with a custom PCB I just used perforated project board. The chips are still available from Littlediode. __________________ -- Graham. G3ZVT Last edited by rambo1152; 27th Mar 2021 at 2:00 pm.

28th Mar 2021, 8:41 am	#4
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,222	Re: Modulator for 405 Line from PC? That modulator from early television looks good, for $30 inc shipping the kit is not expensive. __________________ Frank

28th Mar 2021, 9:25 am	#5
AdrianH Octode Join Date: Mar 2020 Location: Blackburn with Darwen, Lancashire, UK. Posts: 1,425	Re: Modulator for 405 Line from PC? Just watch out for delivery from the US to the UK and things going missing when in the UK. I ordered one that was shipped 17th September 2020. I got a notice from Royal Mail that I may have to pay import duties, which was not an issue it was under the value, that was on the 21st September, it cleared customs on the 25th September. From that point on the parcel went missing. After a while I checked with the Museum to see if they had any better information than me, that was on the 10th October 2020. By the beginning of November I had given up and around the 7th November paid for another modulator kit. On the 19th November the first one turned up, around two months on our soil. The second one has never arrived to this day. Yes I have probably been unlucky, but my suggestion get something from Freya if you can we seem to have a poor postal system here in the UK. There are no qualms with the Museum side. I have lost several small value parcel items from overseas after they land with us. Adrian __________________ Asking questions and learning, or trying to! Youtube EF91Valve

28th Mar 2021, 4:06 pm	#6
murphyv310 Dekatron Join Date: Sep 2006 Location: Kilmarnock, Ayrshire, UK. Posts: 5,210	Re: Modulator for 405 Line from PC? Hi. I'd definitely speak to Freya here. All Hedghog designs are excellent and extremely reliable, plus its coming from the UK. __________________ Cheers, Trevor. 2M0GZQ. RSGB, GQRP, WACRAL, K&LARC. Member