|
Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
|
Thread Tools |
27th Sep 2017, 9:56 pm | #1 |
Nonode
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,579
|
Mini LCD Analogue TVs
Hi.
I have a number of small LCD analogue TVs (mainly Casio) and something occured to me, there's no coax aerial socket fitted nor any AV input facilities. There's just a telescopic aerial. I wonder if a signal from a UHF modulator can be efficiently coupled to the telescopic aerial. Any ideas or experiences on this matter? As another thought, what about a very low power transmitter driven by composite video and audio signals? The RF signal would then be received as normal via the set's own telescopic aerial. Again, any suggestions welcome. My plan would be to use a Goodmans digital set top box which has a built in UHF modulator. Regards Symon. |
27th Sep 2017, 10:00 pm | #2 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,007
|
Re: Mini LCD Analogue TVs
Quite a lot of these used a 3.5mm jack-plug as RF-input rather than the expected BNC or Belling-Lee coax socket.
These sockets are often confused with headphone sockets (usually by people plugging in headphones and complaining they can't hear anything!) |
27th Sep 2017, 10:03 pm | #3 |
Hexode
Join Date: Mar 2012
Location: Liverpool, Merseyside, UK.
Posts: 453
|
Re: Mini LCD Analogue TVs
I'm sure I saw a youtube video of someone using just the modulator from a VCR with no additional amplification and tuned in on one of these. Not sure what he used as an aerial for the "transmitter". He seemed to get a reasonable range
|
27th Sep 2017, 11:08 pm | #4 |
Heptode
Join Date: Feb 2011
Location: Washington DC, USA
Posts: 619
|
Re: Mini LCD Analogue TVs
I have a mini CRT TV which came with an adapter for a 3.5mm plug to 300 Ohms balanced line and then to 75 Ohms F type TV plug
__________________
David |
28th Sep 2017, 5:20 am | #5 |
Dekatron
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,215
|
Re: Mini LCD Analogue TVs
The service manuals for some of the Casio pocket LCD TVs are on Elektrotanya.
The 3.5mm (2 contact, 'mono') jack socket for the aerial seems to be wired so that the break contact disconnects the telescopic aerial, the sleeve is grounded and the tip is the signal (to the tuner input, in place of the telescopic aerial). Given that, if there's no such socket, I would have thought that feeding the UHF modulator signal to the telescopic aerial connection (remove the telescopic aerial to prevent it radiating, I guess) and the ground to the -ve side of the battery or somewhere would work. For some unknown reason, the Casio model I bought a week ago (old, UK, PAL-I) has the socket, but it is not labelled on the case and has a plastic blanking cap fitted. The service manual shows it, and it seems to be used on other models. Quite why it wasn't a feature of the UK model I don't know. Licensing (does a portable set have to have an internal aerial or something) |
28th Sep 2017, 11:13 am | #6 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,724
|
Re: Mini LCD Analogue TVs
I can't remember why I took this picture of my Casio five years ago, but it does seem to address your question.
Graham. G3ZVT |
28th Sep 2017, 11:21 am | #7 |
Pentode
Join Date: Jan 2015
Location: Wakefield, West Yorkshire, UK.
Posts: 151
|
Re: Mini LCD Analogue TVs
Hi Symon,
I plugged a piece of wire into the RF outlet of a modulator and laid the other end behind my mini telly's just to get this photo..... Marc. |
28th Sep 2017, 12:09 pm | #8 | |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,536
|
Re: Mini LCD Analogue TVs
Quote:
ISTR that to count as portable (so you can use it anywhere on the strength of your home licence, it has to run on its own internal batteries. I don't think the aerial type matters. Whether charging internal batteries whilst viewing is technically legal or not is a moot point. Chances of anyone caring are slim.
__________________
....__________ ....|____||__|__\_____ .=.| _---\__|__|_---_|. .........O..Chris....O |
|
28th Sep 2017, 1:03 pm | #9 |
Guest
Posts: n/a
|
Re: Mini LCD Analogue TVs
A nice oddity with licensing is that ones staff in their independent living quarters are covered by ones TV licence.
I bet some posh lawyer wrote that bit in. |
28th Sep 2017, 4:46 pm | #10 |
Nonode
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,579
|
Re: Mini LCD Analogue TVs
Hi.
Thanks for all your replies and for the pics from Marc and Graham and the link to electrotanya from Tony. It seems then that it's not that critical coupling the signal to the set. I must admit not even trying any form of signal on these sets as I've had so many other things on the go. It's just that recently I came across one of my sets in the garage and realised there was only the telescopic aerial. I'll have to try and get one or two sets operational. I hope the surface mount electrolytics are OK, something I've been plagued with in the past with Canon camcorders. Regards Symon. Last edited by Philips210; 28th Sep 2017 at 4:48 pm. Reason: typo |
28th Sep 2017, 5:08 pm | #11 |
Nonode
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,579
|
Re: Mini LCD Analogue TVs
Hi
I just checked the Casio set in the garage and it's a model TV-1750 U and it does indeed have a 3.5mm jack socket for an external aerial. There's also the usual 3.5mm jack socket for headphones. The aerial socket isn't actually marked external aerial and it seems strange why Casio omitted marking the function of this socket on the casing. I like the matched adapter that MrElectronicman has shown in his pic. Regards Symon |
28th Sep 2017, 7:08 pm | #12 |
Nonode
Join Date: Jan 2016
Location: Stafford, Staffs. UK.
Posts: 2,532
|
Re: Mini LCD Analogue TVs
Some years ago I had a Sony Watchman. No telescopic aerial, it was built into a neckband to hang it round your neck.
|
28th Sep 2017, 7:12 pm | #13 |
Nonode
Join Date: Jan 2016
Location: Stafford, Staffs. UK.
Posts: 2,532
|
Re: Mini LCD Analogue TVs
About licensing, I think things might have changed. I say this because you are OK to use a TV in a touring caravan or motorhome, no matter whether its portable or a normal one, on the back of your home TV licence.
|
29th Sep 2017, 8:42 am | #14 |
Dekatron
Join Date: Mar 2008
Location: Worthing, West Sussex, UK
Posts: 5,185
|
Re: Mini LCD Analogue TVs
I use a UHF transmitter for my analogue TV's, it accepts composite video and audio from a freeview box, VCR, ETC.
The range is pretty good, it certainly covers my house I have two of these units, one in the house and one in the workshop. I think they date from the late 80's, one I have had for years and the one pictured was a recent find from ebay. Mark |