Does anyone have a working VHF modulator for use with vintage televisions for sale? Most of the modulators I find for sale are UHF only, and the VHF ones are generally several hundred dollars.

I did try the cheapy $20 XPose VHF modulators from Jaycar, but none of them worked, and I'm pretty sure Jaycar no longer stocks them (probably for the best I expect).

Thanks,

Chris

I think the cheapest solution may be a salvaged VCR?

Yep, thats pretty much your option. (Wow! vcr's are worth saving..)
Silicon Chip this month describes this exact solution.

Unfortunately the full article isnt viewable online.

Ben

Hi Ben,

I, for some reason, have never been able to get VCRs to work as an effective VHF modulator. Is there a certain mode that the VCR has to go on?

Chris

How do you define "effective" in regards to VCR modulators?

They are fairly average quality wise but are better than the $20 Jaycar units.

It's worth keeping an eye on Ebay for a decent modulator at a reasonable price. The Kingray MD100VS is one of the cheaper semi-professional grade modulators and with some hunting can be found for $100 to $200.

There are some units for about $50 that appear to be better than average with adjustable input levels but I have no experience with them. They may turn out to be fairly good for normal use.

Chris
you would have to go for an older vcr. the 'newer' models where UHF

ben

There was a letter in the October Radio Waves that had a few suggestions.

"VHF modulators are also prevalent on the US eBay. The US channels 3 or 4 that these output on are close enough to the Australian 1 or 2. Only a simple modification is required and that is to retune the 4.5MHz sound IF oscillator to 5.5MHz"

He mentions an Astec UM-1285 of which he bought a bag of 10 for $28 which he fits internally to digital boxes. He goes on later to talk about the differences in 10 channel tuners, the frequencies of channels 1, 4 and 5 were altered after 1960. Channel 3 did not change. To complicate this a bit more, some 1956-1960 TV's from Melbourne and Brisbane may have been modified to receive channel 0.

Mind you, he also says the Jaycar units aren't too bad.

Some vintage computer accessories should do it.
A lot of them had RGB/Composite output with a modulator to connect them to a telly.

You could probably smash up a Sega Megadrive for one,
I think theirs is internal, and the console should be found cheap.

The problem I have with using VCRs as VHF modulators, is that I can't get them to work properly. I connect the coaxial line-in from my UHF modulator, and connect the VHF line-out to my television, but I don't get anything on the channels (0 & 1). I have the same problem with all my VHF VCRs, and no amount of adjustment of the fine tuning on the television helps.

Is there some sort of menu you have to set-up on the VCR, to enable it to output with the VHF modulator?

Chris

I don't know if all VCR's were the same, but the ones I've had you needed to manually select the ext input for it to work. Some had a switch and a couple of mine had a channel below the lowest channel (channel 0 if you like) which was the ext input. Most vhf VCR's also had a switch on the back with a choice of output channels, either 1/2 or 3/4 and quite often a test position to enable you to tune the TV.

Warren

VCRs and TV modulators built for the American market provide output on our channels 3 or 4, which appear to overlap your channel 2, according to this chart
http://upload.wikimedia.org/wikipedia/en/c/cc/VHF_Usage.svg

I heard that VCRs in Europe outputted their modulated channel somewhere in the UHF TV bands.

Only thing is that the FM subcarrier in a USA modulator will be at 4.5MHz instead of the Aussie subcarrier frequency. This is usually set by an LC circuit, so it should be changeable. The modulator otherwise won't care if the video is NTSC or PAL.

Ahh yes, I see your problem!

The RF input and output on VCR's is a pass-through design when the VCR is in standby, or when in "TV" mode when operating.

To get it to output an RF signal via the modulator, you must have the VCR in the ON or Operate mode and the TV or VCR switch set to VCR. These are normally controls on the front panel unless the VCR is very new.

The simplest way to confirm the RF modulator is working is to play back a pre-recorded tape in the VCR, this will mean you will always see a modulated output. You should be able to then tune the TV into the VCR signal before trying to use the VCR as an RF converter.

I've had a tinker around with my two older VCRs (a National NV-L15 & Goldstar VCP-4300H AC/DC) with my newly trashpicked VHF-only National TR-602A - and to no result. The National is a higher-end unit, but is lacking the TV/VCR you mentioned Andrew. I spent an hour or so, and several cups of tea, fiddling around with different functions, and to no result.

The fact that I don't have the original manuals for either VCR (both trash-picked) doesn't help much either. I'll see if any of my newer VCRs do have VHF-output.

Also, does anyone have any experience with the XPose VHF modulators that Jaycar stocked? They came with no manuals, and I couldn't find any. Is there a certain way it has to be connected up, as no combination of connections seems to have got mine working. This is the second one I bought from them, and I also have a friend with a VHF-only Sanyo who bought one from them - and we couldn't get any of them to work! Faulty batch, I suppose...

Thank you for everyone's patience and help,

Chris

What you'd be better doing is ripping a modulator out of a VCR and just running it from a DC plugpack or even a dolphin battery. and just connect directly to and from it. It is the shiny box that the two Belling Lee (75Ω antenna) sockets are on. The composite video and audio would be fed through studs sticking out of the box.

The trick is making sure its output is on either Ch0/1 or Ch3/4 - there were two types of VHF modulator for some reason. If the output is on Ch37 as most late model VCRs were then it won't be much good to you.

I also did as Scraps suggested, the modulators from the US work great. You need a clean 7.5 vdc supply & re tune slowly with a non metal screwdriver. Mine works great.

There is a problem with a lot of VCR's as most are UHF, You need an old one that was VHF to be of any use.