UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Television Standards Converters, Modulators etc

Notices

Television Standards Converters, Modulators etc Standards converters, modulators anything else for providing signals to vintage televisions.

Reply
 
Thread Tools
Old 17th Jun 2019, 8:59 am   #181
FRANK.C
Heptode
 
FRANK.C's Avatar
 
Join Date: Feb 2006
Location: Roscommon, Ireland
Posts: 600
Default Re: Hedghog standards converter

Hi Taz
Thanks for the better picture.
it is something that I can keep in mind if I am updating the firmware again. I will need to look into it further.

Frank
__________________
FRANK.C is online now   Reply With Quote
Old 18th Jun 2019, 3:56 pm   #182
Tazman1966
Nonode
 
Tazman1966's Avatar
 
Join Date: May 2006
Location: St Albans, Herts, UK.
Posts: 2,035
Default Re: Hedghog standards converter

Thanks Frank
__________________
All the very best,
Tas
Tazman1966 is offline   Reply With Quote
Old 19th Jun 2019, 8:38 pm   #183
volte-face
Pentode
 
Join Date: Oct 2015
Location: Middlesex, UK.
Posts: 184
Default Re: Hedghog standards converter

Ah, I recognise that photo!

Below is a picture, taken at the time, of the 'scope trace of that actual ITS line (line 13 / 215) from the actual generator that was used to feed the actual television in that actual picture, in case it helps at all.
Attached Thumbnails
Click image for larger version

Name:	405_its.jpg
Views:	94
Size:	103.7 KB
ID:	185389  
volte-face is offline   Reply With Quote
Old 18th Jul 2019, 6:37 pm   #184
Superscope
Pentode
 
Join Date: May 2017
Location: St Austell, Cornwall, UK.
Posts: 181
Default Re: Hedghog standards converter

I have an interesting problem with my Hedghog and wondered if anybody on the Forum
might have some ideas?

Can't seem to get a clean Picture at all.
Looks like the Video is extremely noisy and the TV's I've tried look like they
are struggling to Sync properly, some can't display anything sensible at all.

Stephen (Freya) has very kindly retested the HH and found no faults at all!

All my VHF TV's are mid 70's Portables and all are Uk Models and none of them
will display a clean Picture and most won't display anything viewable!

TV's tested from my collection are:
JVC 3050Uk Only Noise but clearly a signal of sorts is present
JVC CX-500GB Very Poor, just able to make out Test Card.
JVC CX-60GB Displays the best Picture, but very noisy.
JVC P100-UK Only Noise but clearly a signal of sorts is present
Crown 5TV-65R Just able to make out Test Card
Crown 5TV-525R Only Noise but clearly a signal of sorts is present

Stephen asked if the TV's were 625 Line?

I wasn't aware any VHF transmissions in the Uk were 625 Line, can anybody tell
me if the Uk used VHF 625 Line and if they did, when did this happen?

I know using VHF 625 Line was considered before the UHF 625 Line system was
established, but can't see any mention that is was ever used, having opted instead
for duplicate BBC1 and ITV on VHF and UHF.

Ian
Superscope is offline   Reply With Quote
Old 18th Jul 2019, 6:51 pm   #185
Superscope
Pentode
 
Join Date: May 2017
Location: St Austell, Cornwall, UK.
Posts: 181
Default Re: Hedghog standards converter

Mistake on previous message.
Ignore the Crown TV's they are UHF only and were from a different Test.

The other TV tested on the HH was a portable Panasonic, but I haven't got
the Model No in front of me at the moment.
It couldn't display anything either, but clearly a Signal was there.

Ian
Superscope is offline   Reply With Quote
Old 18th Jul 2019, 8:03 pm   #186
FRANK.C
Heptode
 
FRANK.C's Avatar
 
Join Date: Feb 2006
Location: Roscommon, Ireland
Posts: 600
Default Re: Hedghog standards converter

Hi Ian
I am not familiar with the JVC TV's you have listed but from googling them they look to be probably too modern to be 405 lines. I think one is a colour TV.
Maybe others can confirm.


Does it say on them that they are dual standard?
Here in Ireland we had VHF 625 lines.


Frank
__________________
FRANK.C is online now   Reply With Quote
Old 18th Jul 2019, 9:01 pm   #187
Superscope
Pentode
 
Join Date: May 2017
Location: St Austell, Cornwall, UK.
Posts: 181
Default Re: Hedghog standards converter

Hi Frank,

Yes, they are all fairly Modern Mid 70's TV's.
Two of them are colour, the CX-500 and the CX-60.
The Cx-60GB actually does display the best out of all of them,
the Picture is stable, viewable but very noisy! No sound though!

I guess it boils down to whether the Uk used 625 Line VHF,
or JVC sold incompatible 625 Line VHF Equipment in the Uk?
This is what I was hoping somebody on the Forum might be able
to shed some light on.

I had never heard of 625 Line VHF before Stephen mentioned it.
I had assumed all VHF (at least in the Uk) was 405 Line.

The User Manuals I have make no mention of any compatibility issues,
so I assume they met Uk standards of the time.

Ian
Superscope is offline   Reply With Quote
Old 18th Jul 2019, 10:57 pm   #188
FRANK.C
Heptode
 
FRANK.C's Avatar
 
Join Date: Feb 2006
Location: Roscommon, Ireland
Posts: 600
Default Re: Hedghog standards converter

Hi Ian
I don't think that the Cx-60GB was made specifically for the UK market as Radiomuseum states that it is capable of both multistandard PAL and SECAM reception. But no mention of System A.

Frank
__________________
FRANK.C is online now   Reply With Quote
Old 19th Jul 2019, 1:50 am   #189
rambo1152
Octode
 
rambo1152's Avatar
 
Join Date: May 2010
Location: Manchester, UK.
Posts: 1,355
Default Re: Hedghog standards converter

625 VHF was not broadcast in the UK.
However,
when UHF transmissions, beginning with BBC2 started, it was the practice to frequency-convert the UHF signals to unused VHF channels in blocks of flats where the existing cabling was too lossy for UHF, so a 625 UHF/VHF set was quite handy, but more often it was a dual standard set modified so that the VHF tuner was active on both standards.

Another option was to use a converter box, the Labgear Televerta with a single-standard 625/UHF set
http://www.wrightsaerials.tv/alberts...a_CM6022RA.pdf
__________________
--
Graham.
G3ZVT

Last edited by rambo1152; 19th Jul 2019 at 1:55 am.
rambo1152 is online now   Reply With Quote
Old 19th Jul 2019, 1:42 pm   #190
1100 man
Octode
 
1100 man's Avatar
 
Join Date: Apr 2016
Location: Ventnor, Isle of Wight, & Great Dunmow, Essex, UK.
Posts: 1,040
Default Re: Hedghog standards converter

Hi Ian,
I very much doubt if any of your TV's are 405 line! It's easy to see 'VHF' and assume it's 405. Plenty of sets tune across the VHF band as lots of other parts of the world used VHF but they won't be 405.

You should easily be able to tell just by looking at the line structure & listening to the line timebase. 405 is a very course line structure when compared with 625, but the giveaway would be the 10Khz line whistle. If you can't hear it, it's probably 625.

Instead of a HH converter, all you need is a 625 line source and a VHF modulator!

Cheers
Nick
1100 man is offline   Reply With Quote
Old 20th Jul 2019, 10:11 pm   #191
rambo1152
Octode
 
rambo1152's Avatar
 
Join Date: May 2010
Location: Manchester, UK.
Posts: 1,355
Default Re: Hedghog standards converter

Quote:
Instead of a HH converter, all you need is a 625 line source and a VHF modulator!
Another way of looking at it, he's now got a great intensive to acquire a 405 or dual-standard set.
__________________
--
Graham.
G3ZVT
rambo1152 is online now   Reply With Quote
Old 20th Jul 2019, 11:22 pm   #192
kan_turk
Hexode
 
kan_turk's Avatar
 
Join Date: Mar 2014
Location: Dublin, Ireland
Posts: 251
Default Re: Hedghog standards converter

Quote:
Another way of looking at it, he's now got a great intensive to acquire a 405 or dual-standard set.
Doesn’t have to be a VHF modulator, UHF modulator will do nicely as all the sets listed, which I can confirm are single standard 625 line, appear to be fitted with both VHF & UHF tuners i.e. the global norm
kan_turk is online now   Reply With Quote
Old 21st Jul 2019, 9:32 am   #193
Superscope
Pentode
 
Join Date: May 2017
Location: St Austell, Cornwall, UK.
Posts: 181
Default Re: Hedghog standards converter

Thanks for all the replies,

As I had hoped for, this Forum has shead light on what appears to have been happening,
and I have learned something along the way.


This all started with me wanting to test the VHF on a Dual standard (VHF & UHF)
JVC TV.
The UHF didn't work even though the TV was described as fully working and I was
interested to know if the VHF worked and assumed it was 405 Line because the Set
was a Uk Model. First Mistake!

Hence I thought it was the right Time to get a Hedghog!

The JVC could not resolve a picture, and so the first course of Action was to test
the Hedghog on other Sets I have and to my surprise none of them worked properly.

It would appear as others have suggested, that all my VHF capable TV's are actually
625 Line VHF ! Although I haven't been able to test this for sure yet, but it looks to be the case.

So it spite of all my research on Uk VHF before purchase of an HH, I got caught out!


Why was 625 VHF used in other countries?
Was it to simplify the Broadcast of VHF when Production had moved to 625 for the new UHF?
and if so, I assume there was a change from 405 at some point?
As I understand it, 405 Line was specificaly chosen due to the technical difficulties of the time.



I have since found a small note in the JVC 3050Uk User Manual (but not in any others)
which does say that the VHF will not work in the United Kingdom.

I am amazed that a Main Stream Manufacturer would sell incompatable VHF TV's in the
Uk, when VHF was still being used in some Areas, and on top of that, not make that clear!


So for the time being, I have a redundant HH :-(


My area of interest is small Portable TV's.
Are there any 405 Line small portable Sets out there that I can search for?
Don't tell the Wife!

Ian
Superscope is offline   Reply With Quote
Old 21st Jul 2019, 10:02 am   #194
Davewantsone
Pentode
 
Join Date: Dec 2011
Location: Wigan, Greater Manchester, UK.
Posts: 180
Default Re: Hedghog standards converter

A dual standard 405/625 line set is the Sony TV9-90UB (9inch screen) quite frequently advertised on the well known auction site.
Phillips TVette dual standard with 11inch screen. Usually gives a very good 405 line picture.
Most of the UK had 625lines by the early 1970s. Foreign set makers could now sell TVs to most of Europe with only a small modification to the sound spacing 5.5MHz most of Europe and 6MHz UK and Ireland. Most of Europe including Eire used VHF for 625 lines at the start of their TV services. 405 lines was the state of the art in 1936. 15 years later 625 lines was the state of the art when most European TV started.. This helped in the demise of the UK set makers. France went their own way sticking with AM sound and using a different colour system known as SECAM.
Davewantsone is offline   Reply With Quote
Old 21st Jul 2019, 10:53 am   #195
1100 man
Octode
 
1100 man's Avatar
 
Join Date: Apr 2016
Location: Ventnor, Isle of Wight, & Great Dunmow, Essex, UK.
Posts: 1,040
Default Re: Hedghog standards converter

Quote:
Originally Posted by Superscope View Post
My area of interest is small Portable TV's.
Are there any 405 Line small portable Sets out there that I can search for?
Hi Ian,
Have a look at this thread. http://www.vintage-radio.net/forum/s...d.php?t=156989

I was surprised how many 405 or dual standard portable TV's there were! Some are valve or hybrid and some are all transistor.

By the time your TV's were sold in the UK (late '70's or early '80's), 405 would have been considered a 'legacy' system. I'm always amazed there was such a long transition time and that 405 dragged on for so long. As long as the new tv's could receive the new UHF transmissions, it didn't matter that they also came with incompatible VHF tuners. Manufacturers weren't going to remove them just for the UK!

Cheers
Nick
1100 man is offline   Reply With Quote
Old 21st Jul 2019, 11:13 am   #196
TonyDuell
Dekatron
 
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 3,217
Default Re: Hedghog standards converter

Is the JVC3050 the little portable radio/TV set? If so, I also have one which I have not got round to working on.

It is 625 line only. The VHF tuner, as others have said was for models used outside the UK, which also had modifications due to the different spacing between the sound and vision signals in the UK as against, say, the rest of Europe. There is a comment in the manual that came with mine that the UK model can be modified by a TV service engineer to work elsewhere (I assume by retuning the sound IF strip).

Do you have the circuit diagram for it? Mine came with a circuit diagram folded up inside the user manual, and I would be happy to provide a scan of that if you need it.
TonyDuell is offline   Reply With Quote
Old 21st Jul 2019, 1:22 pm   #197
kan_turk
Hexode
 
kan_turk's Avatar
 
Join Date: Mar 2014
Location: Dublin, Ireland
Posts: 251
Default Re: Hedghog standards converter

The normal progression worldwide when television was introduced was to start with VHF (initially band 1 then band 3 as additional services were required) and only utilising UHF when VHF spectrum was fully occupied - no change of line standard took place so 525 line territories remained on 525 lines for VHF THEN UHF , similarly with 625 line territories - only exceptions were Britain and France where legacy systems occupied the VHF spectrum (405 line in Britain, 819 line in France) - this scenario led to a number of misconceptions such as UHF is superior to VHF - it is not, quite the reverse in fact and VHF = 405 line, UHF = 625 line - not so, any line standard can be used with any frequency band - there is absolutely no correlation between the two

Hope this clarifies

Rgds to all
John
kan_turk is online now   Reply With Quote
Old 24th Jul 2019, 11:08 pm   #198
ntscuser
Hexode
 
ntscuser's Avatar
 
Join Date: Mar 2013
Location: Coventry, West Midlands, UK.
Posts: 269
Default Re: Hedghog standards converter

There was a plan at one time to replace 405-line transmissions in the VHF bands with 625-lines but nothing ever came of it. There were even experiments (discussed elsewhere in the forum) to squeeze 625-lines within the original 405-line channel spacing.
__________________
Classic TV Show Theme Tunes
ntscuser is offline   Reply With Quote
Old 25th Jul 2019, 1:21 pm   #199
Richard_FM
Heptode
 
Richard_FM's Avatar
 
Join Date: Sep 2017
Location: Stockport, Cheshire, UK.
Posts: 796
Default Re: Hedghog standards converter

I did wonder if there were plans to use VHF for Channel 5 early in the planning.
__________________
Beware of the trickster on the roof
Richard_FM is offline   Reply With Quote
Old 26th Jul 2019, 12:09 am   #200
hamid_1
Hexode
 
Join Date: Aug 2009
Location: High Wycombe, Bucks. UK.
Posts: 409
Default Re: Hedghog standards converter

Quote:
Originally Posted by 1100 man View Post
By the time your TV's were sold in the UK (late '70's or early '80's), 405 would have been considered a 'legacy' system. I'm always amazed there was such a long transition time and that 405 dragged on for so long. As long as the new tv's could receive the new UHF transmissions, it didn't matter that they also came with incompatible VHF tuners. Manufacturers weren't going to remove them just for the UK!
Quite a lot of the imported B/W portable TVs were sold in the UK without the VHF tuner which would normally have been fitted for other countries. Usually the hole for the VHF tuner on the front of the set was covered up by a badge saying "Portable Deluxe" "I.C. Mains/Battery" or similar boast. I have an unusual ""Cihan" 17 inch B/W portable TV imported from Turkey which still has the VHF tuner inside, but the knob has been removed and the hole covered up. They couldn't remove the VHF tuner completely, since the I.F. strip appears to be part of it. Removing the VHF tuner on UK models was desirable from the manufacturer's point of view. Not only it saved the cost of the tuner, it also avoided customers accidentally switching to VHF and then complaining that the TV is faulty, it can't get a picture.

Sets with 625 VHF were useful for visiting Ireland on holiday, or other European countries if a 5.5 / 6.0 MHz sound system switch was provided. This was often a selling point for small portable TVs that you could take on holiday with you. 625 VHF TVs were sought after by DX-TV enthusiasts in the UK, hoping to catch a glimpse of foreign TV signals given the right atmospheric conditions. Many cable TV networks in the UK used 625 VHF as well. Normally the cable operator supplied a VHF to UHF converter box, but if your TV or VCR could tune VHF, you could avoid the need to buy or rent an extra converter box.

If you want to run your 625 line TV on VHF, it's easy. You just need a suitable modulator and 625 line source such as a DVD player, digital set top box etc. The Hedghog modulator is not suitable, it's designed for System A. You need one that is System I (or B/G if your TV has a 5.5 / 6MHz sound system switch). A possible example is here:
https://www.amazon.co.uk/Jinxuny-Digital-Modulator-110-240V-Converter/dp/B07QTPZ6DH/

(I don't own that product and can't personally vouch for it, but I'm sure someone else can recommend you a suitable VHF modulator for your 625 line sets.) I have another device called A2B Multibox which is a 3-channel Freeview receiver and VHF/UHF modulator in one. It works, but was a bit fiddly to set up.

You could of course get a real 405-line or dual standard 405/625 TV to go with your Hedghog. The Sony 9-90UB has already been mentioned. There are quite many of them around, they cost no more than 10-20 and surprisingly usually still work, despite being 50 years old.
hamid_1 is online now   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 12:54 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Copyright ©2002 - 2019, Paul Stenning.