From the 4th of June 1960 edition of the Wireless and electrical trader. Three articles that might be of interest.
CRT rebuilding equipment.
TAC report recommending 625 lines for future TV broadcasting in the UK.
Export Bush TV with 23" CRT and push-button VHF and UHF tuners
Till Eulenspiegel.
Reading the TAC report, the system they suggested lasted nearly 50 years, they got the decision right.
Frank
Considering the space required by the 'Bush button' VHF tuners of the time, those rows of push buttons look very close together.
I don't know how they would have configured a 1960 UHF tuner but, possibly, it could they have mounted upside down under the VHF tuner? In which case, presumably, the valves would have been hanging down so a lot of care would have been needed in the tuner itself to prevent thermal tuning drift.
It's a pity that we are unlikely to ever see an interior view of the set!
When all else fails, read the instructions
Posted by: Terry
Considering the space required by the 'Bush button' VHF tuners of the time, those rows of push buttons look very close together.
Hi Terry, when one considers that the 23" Bush export TV set was designed in 1960, was the UHF tuner, (if it ever had one,) one of those tuners of the type fitted in American receivers in those times? That is, a with a valve local oscillator of the 6AF4 type and a semiconductor diode to do the mixer function. I don't think the two valve UHF tuner with PC88 and PC86 valves we are familiar with was available in 1960. Possibly 1961?
Till Eulenspiegel.
TV’s didn’t need to be supplied with a UHF tuner until the ”All Channel Receiver” Act of 1964, I reckon the Bush set had 8 VHF buttons.
UHF if required would be a set top box tuned to either channel 4, 5 or 6, what ever was unused. Internal UHF tuners were available from around 1952 but due to various problems didn’t take off in a big way. The All Channel Act did help though.
UHF Tuners took a different design path in the USA compared to Europe, even after the availability of a RF amplifier they seems to stick to tuned input then to a mixer diode, followed by extra IF amplification. I am sure I saw a circuit of a Japanese transistor UHF import to Europe use the same technique. They also used UHF biscuits in a VHF tuner for UHF reception.
Interesting seeing the way things develop on different lines.
Frank
Hi Terry, when one considers that the 23" Bush export TV set was designed in 1960, was the UHF tuner, (if it ever had one,) one of those tuners of the type fitted in American receivers in those times?
Till Eulenspiegel.
If it ever had one? That is what you stated in your post so I assumed that you got that from some editorial content associated with the picture,
I'm familiar with the one valve + diode tuners you mention but my original question still stands - where and how was it physically located? I agree about the timing of the PC86/8 2-valve type of tuner which almost certainly came about because of the decision to adopt the n, n+4, n+7, n+10 channel grouping at all UK transmitters [1] which necessitated four-gang tuning, rather that the 3-gang tuners used in the US and elsewhere.
I have also seen a Japanese diode mixer transistor tuner in an import (or, possibly , just noticed it on the circuit diagram.)
[1] The first transmitter at Crystal Palace was a notable excretion to this, being n, n+3, n+7, n+10
When all else fails, read the instructions
The RCA KRK120 UHF tuner as fitted in sets equipped with the KSC136 monochrome chassis. Earlier UHF tuners employed a tube for the local oscillator.
Till Eulenspiegel.
Some reading material, well it looks interesting to me.
http://downloads.bbc.co.uk/rd/pubs/reports/1954-31.pdf
Frank
The Bush 23" push-button tuner TV was presented at the 1960 audio products exhibition in New York.
From the text in the magazine article:
Bush Radio are the only firm of British set makers who are exhibiting, and they are taking across representative TV receivers using 23in tubes and the company's push-button channel control, which is standard on Bush home market models but will not have been seen before in the US.
Also in the New York exhibition article: BBC Reminds America
The BBC will be right up to date with a model of the new Television Centre in London, which will come into use for the first time three days after the New York show closes. By means of historic pictures the BBC will drive home the fact the Corporation introduced the world's first television service in 1936.
Till Eulenspiegel.
