Trough Line News.
Posted by: George F on 07 November 2015
Some may have observed that since August I have been messing around with first one and then additionally a second Leak Trough Line “3” mono valve tuner from the early 1960s.
At first with one that was definitely working, and then with one that was reportedly not working. I found it intermittent, which is the most frustrating thing as the fault as such may not show up at the point of testing or servicing!
The first one is lovely, and subject to a slight problem with one of the front panel switches that selects for distant or local transmissions. Effectively it is a built in selectable antenna attenuator to prevent overload and clipping from the powerful signals of a close transmitter. This one now works with a tooth-pick jammed into the switch to maintain the contact! Okay that is a bodge!
It went off the boil - as I thought - because of this switch, and seemingly no amount of waggling the switch would restore decent function ... So I got out the other one that was reportedly non-functional. Well the intermittent nature of the fault in this one meant that I got it going long enough to realise that it was potentially the better one!
As it is now known, the fault was in that most ruinous part, the mains transformer. It is having a transplant, and should be up and running again within the next week.
Far too nice to let it become recycled electronic scrap!
In the meantime I have the first one back in service and running well. Of the two it is noisier and plummier in tone though it never gets that chesty voice on male radio announcers that is the sign that the tone is too fruity! I has been modified at some point though the one currently in dock is completely untouched from original up until its current repairs ...
Probably not of all that much interest to many here, but the way these things work has been a revelation to me. The last time I had regular access to a mono [valve type] FM/VHF tuner was at school up until 1975. That one was an even older type that only worked on three pre-tuned internal adjusted stations. I imagine that it was tuned in situ by the installing engineer. It had three letters on the control: L, T and H, for Light Programme [Radio Two nowadays], Third Programme [Radio Three] and Home Service [Radio Four]. Of course I remember the effect of this on live Radio Three concert relays, but the Trough Lines have revived the memory and brought the thought that sometimes old legends are not exaggerated!
ATB from George
These rather poor photos were taken in poor light, but today is so dark and grey that I could not improve on them.
I am sure anyone here will recognise the mains transformer that was changed.
Best wishes from George
George, thanks for the top shelf photos ... Nice 
I have just listened to a recorded concert from Wroclaw of Handel’s Concerto Grosso, Opus Six, No.5. And two settings of the Magnificat by Vivaldi and Bach. Plus two encores.
The Trough Line brought this out as if by magic!
At one point the church bells sounded softly in the distance during one of the silences, and I had to check the front door to make sure that this was in the broadcast!
Yes, the Trough Line is on the top-line now! 
ATB from George
PS: Good job tomorrow is leave. A late music session would not be a good idea on a Sunday evening normally!!!
OK George, no probs. but I was not talking precise.
If you are on Ridge Hill & it works well with your window mount loop, a properly mounted outside/roof yagi will be just fine.
I would add to Simon's post on using coax to specify a satellite grade - WF100 or CT100 - I always go for WT100 as its foam insulation is more tolerant of bending compared to the air spaced CT100. Satellite grade has so much better signal loss properties than standard coax & the cost diff is peanuts.
Also the largest Antiference antenna is a 5 element FM1085
-- 3x directors
-- 1x the Antiference "signature" design twin rod dipole
-- 1x reflector
Dear Mike,
Sorry to get the element thing wrong. The one I’ll go for is the one you show, and there is a smaller one.
If it works in the window, I shall avoid using up neighbourly good with going onto my neighbours high rail! Through his apartment!
As it goes, I am lucky that even from a low position I can get a good aim at Ridge Hill through the window. Most people would not accept a VHF aerial in their listening room, but it would not worry me!
According to the BBC, there is nowhere in Worcester where Ridge Hill is to be preferred to Sutton Coldfield, and no doubt that is correct for very high mounted aerials. I know that in our delivery vehicles that have RDS automatic tuning, the selection is mor often than not for Ridge Hill rather than Sutton Coalfield. I know which is which by the actual frequency displayed as tuned.
In practice Ridge Hill does perform well.
Anyway, thanks for your interest.
Dear Chris,
What I am trying to do is get something nice going as I can within restraints. I am only doing it for the fun of it, really. Nice to get something vintage going well. If I lived where I used to till 2002 [on top of a small hill west of Worcester], I could have the choice of Ridge Hill as sight of line or Sutton Coldfield with no barriers in the way. I was also sight of line for the Malvern digital TV mast and also the Droitwich LW array! That was a great place for radio, and the VHF was so strong that a simple wire dipole got superb reception! You could tune to Ridge Hill or Sutton Coldlfield with complete lock!
I could somehow imagine that a TV comedy skit might be made about this! I want Leo McKern in the part of the loop aerial! Alec Guiness as the multi-element ... And Ian Richardson as the connecting wire! With special guest appearance from Albert Finney as the Trough Line!
Michael Gambon as the ESL. Oh goodness, I better stop now!
Best wishes from George
Interesting comments from Mike with regard to the types of coax cable available.
.......... some more with pictures 
The graph shows cable loss in dB per 10m for the three main cable types.
Low loss - this is the cheapo thin braid only screen stuff you buy at DIY stores
Alloy foil & braid screen - alloy has a questionable life when outside
Copper Foil & braid - the best for sure. I prefer Webro WF100 as its "solid" foam insulation is less prone to crush damage than the traditional air spaced coax
Note how at the FM frequencies the losses are far lower than at TV and satellite frequencies, so while FM is less affected by attenuation losses than is TV (UHF) & satellite, the proportional dB loss differences are still significantly better.
Interesting comments from Mike with regard to the types of coax cable available.
.......... some more with pictures
The graph shows cable loss in dB per 10m for the three main cable types.
Low loss - this is the cheapo thin braid only screen stuff you buy at DIY stores
Alloy foil & braid screen - alloy has a questionable life when outside
Copper Foil & braid - the best for sure. I prefer Webro WF100 as its "solid" foam insulation is less prone to crush damage than the traditional air spaced coax
Note how at the FM frequencies the losses are far lower than at TV and satellite frequencies, so while FM is less affected by attenuation losses than is TV (UHF) & satellite, the proportional dB loss differences are still significantly better.