Early UHF aerial.

[FERNSEH]

Found this article in the June 1958 Practical Television magazine about a new Wolsey UHF aerial. Note the frequencies it is designed to receive. 651.25 and 654.75Mc/s Band 5. 405 lines on UHF.

DFWB.

[SteveCG]

... Aaah, if only...

[Panrock]

That's around Channel 43 as it later became, so this aerial would have been well suited for my local BBC2 relay at Tunbridge Wells (Ch44) - seven years later!

Steve

PS. Hopefully the BBC has forgiven me by now but 405-lines was put out on BBC2 UHF in about 1969 - only for a second or two - when I tried cutting to a 405-line Test Card during an idle moment in Network Control 2. I had the Sony off-air monitor ready to receive this (with both buttons in). It came through just fine...

[Focus Diode]

Interesting indeed. I've consulted the BBC 1966 Handbook which mentions these experimental Band V UHF transmissions from Crystal Palace.

Initially they started on 11th November 1957 on 405-lines, yet further tests on 5th May 1958 are listed as being 625-line! David is absolutely right re the typical 405-line bandwidths employed. Had the tests been 625 the limited bandwidth would've become apparent. The PTV article doesn't mention these tests being on 625 nor 405 for that matter.

The UHF aerial also looks experimental: Five elements and no reflector! One would have to have been very close to a transmitter to achieve good reception from that.

Cheers,
Brian

[trickie_dickie]

Look again. The reflector is right behind the folded dipole.

BTW, I made a few like this, centred on Ch33 (Crystal Palace) and all worked well in Slough in the late 60s.

[Focus Diode]

Originally Posted by trickie_dickie

Look again. The reflector is right behind the folded dipole.

Indeed it is, I stand corrected. The aerial resembles a smaller version of a BIII array, not the typical UHF aerials with the multiple or twin back reflector or "mesh" type we got used to seeing and still around to this day. Perhaps I should've instead commented commercial UHF aerials were normally not like the example in the photo.

I can imagine your home made examples working well in areas of good signal strength. I got away with a simple folded dipole made from inner coax cable in some parts with excellent results!

Brian

[Mr Hoover]

Originally Posted by Focus Diode

Initially they started on 11th November 1957 on 405-lines, yet further tests on 5th May 1958 are listed as being 625-line! David is absolutely right re the typical 405-line bandwidths employed. Brian

Yes,they used audio 6.5 MHz above the vision carrier for the 625 tests apparently.

Hugh

[ntscuser]

These have high gain

The five element design is almost identical to the indoor aerial I currently use to receive Freeview in a back bedroom. "High gain" it is not!

[Nicklyons2]

In fairness to the aerial in the cutting its gain figure would have looked high (as a figure) to those used to 'H' s on Band I, additionally given its narrow bandwith it would genuinely have been 'tuned'. The similar looking cheap dross around today usually proclaims itself as being wide-band or 'suitable for all channels' which, in reality means 'useless on all channels'. A friend some years ago made a similar looking aerial especially to get Tyne-Tees TV on ch29 from Bilsdale - it fabulously out performed the XG 8 Group A I'd put up in a similar location.

[SteveCG]

Early J-Beam Parabeam designs worked quite well - until the junction box corrosion set in.

I remember looking at the Group C aerials which were being installed to receive BBC2 from Winter Hill on Channel 62 and pondering on the impedance mismatches given the diameter of the Co-Ax and the (short) element dimensions. But there again, I was also amazed that valve UHF tuners actually worked at such a high channel number!

[Hybrid tellies]

Originally Posted by SteveCG

Early J-Beam Parabeam designs worked quite well - until the junction box corrosion set in.

I remember looking at the Group C aerials which were being installed to receive BBC2 from Winter Hill on Channel 62 and pondering on the impedance mismatches given the diameter of the Co-Ax and the (short) element dimensions. But there again, I was also amazed that valve UHF tuners actually worked at such a high channel number!

It was the same around here with BBC2 from Mendip with BBC2 being on ch64. I did see quite a few early dual standard sets with valved UHF tuners working well off small 5-6 element aerials some of these were loft mounted. For a while I had an early GEC dual standard set with valved tuner working well on all Mendip channels using an Antiference 6 element group c/d set top aerial. And we lived some 12 miles but in line of sight of the Mendip TV mast.
So yes small well designed UHF aerial aerials can and do work surprisingly wel.l

[SteveCG]

Simon,

For what it is worth, the UHF TV aerials I have the best opinion of are the Early J-Beam Parabeams and the Antiference 'Trumatch'. Having compared many designs over the years I find they are the best. In both cases the achilles heel is junction box moisture ingress: In the case of J-Beam resulting open-circuit inverse baluns; and for Antiference open circuit joints on the aluminium posts to the aerial cable clamps.

Of course any aerial mounted in a dry loft will be as good now as when it was put up there.

Some things are too sealed, a hole in the bottom is the solution. Why is a loft dry? it's the hole in the bottom of course (the bit we live in).

[crusher19860138]

Originally Posted by Hybrid tellies

It was the same around here with BBC2 from Mendip with BBC2 being on ch64. I did see quite a few early dual standard sets with valved UHF tuners working well off small 5-6 element aerials some of these were loft mounted. For a while I had an early GEC dual standard set with valved tuner working well on all Mendip channels using an Antiference 6 element group c/d set top aerial. And we lived some 12 miles but in line of sight of the Mendip TV mast.
So yes small well designed UHF aerial aerials can and do work surprisingly wel.l

Until,that is,Channel 5 came on air using channel 37!