George's Leak Troughline Antenna

 Dear ion,

So many thanks for your information and advice!

I am just off to Maplins now to get three hundred ohm ladder line wire for an experiment!

I so pleased you started a thread on this! I'll post some pictures of it all in the next few days. I love fixing good old things up, not unlike getting the old Carlton bike into tip-top condition!

Very best wishes from George

Dear Simon,

I looked for transition ladder/window line wire from Marlins, as there is branch twenty minutes away on the bike, but they do not see it!

But the good news is that is can be home made with suitable insulated wire of the correct gauge and spacing, so I'll buy that and make my own! If that does not work well then I'll spring for the factory made stuff over the internet.

But I am currently transfixed by the most beautiful performance [on Radio three] of Elgar's Enigma variations, so I am nailed to the seat for the nest half hour anyway!

I love tinkering, and this will be a job for a real tinker! 

ATB from George

 ----  just for your info ---- the classic loop used with FM hifi nuts is the Ron Smith "Galaxy" series,  they have reflector & director elements & these reduce impedance close to 75 ohms.  They are feed by a 75ohm coax & do not have a balun.  

I have a Galaxy roosting in my attic & have tried different voltage 1:1 baluns & found they do nothing positive that I can detect,  I settled instead on three clamp-on ferrite's that add 800ohms at 100MHz to keep the antenna from straying into the coax outer screen.

Good luck with the antenna tinkering,  keep posting you might get me back into it (again)

Dear Simon,

I am sorry about the auto-spell-correct! I was in a rush earlier!

I have made the transmission line from decent quality single wire, speed - we need not worry about the calculation, but it is easy to find on the inter web thingy - to calculate the correct spacing to give approx 300 ohm transmission ...

Here are some photos:

This is the aerial prior to the change from Co-ax.

Without the balun

Not WAF likely, but the it does not matter and is not finished yet!

Connected to the 300 ohm input.

The result is beautiful! I would never have done this change without your nudge. I like the idea that the aerial is entirely home made and works so very nicely!

Thanks for the push!

ATB from George

Hi George,

Funny enough I was talking to a HI FI mate last weekend and The Leak Amps and Tuner got into the conversation and I said that the tuner was the stuff of vintage legend.

He said that Graham Tricker of G.T audio does work on them changing bits etc.

Out of interest how does F.M for you compare to digital streaming ?

Loving your new Avater.

Cheers Ian

Dear Mike,

I hope you enjoy the photos. They are hoot really, as it is hardly a beautiful looking effort, but with another length of home-made connector, routed properly the result will look less hideous! 

Thanks for your encouraging words.

To listen to Radio Three with this ancient tuner is to be reminded that things were sometimes pretty fine even fifty years ago! I was a bit lazy about precision on this proto-type connection wire pair. 

My radio system is really rather classical. A fifty plus year old tuner with an aerial of the type popular in the 1930s, feeding an ESL from 1960 ...

The only modern part is the NAP 100, which does seem to fit in very well, amongst the ancient equipment and ideas ...

ATB from George

Dear Ian,

The quality of VHF from this tuner causes me to say that the old thing is still that most elusive of things,  an elegant musical animal no less intense in its presence than a wild Tiger!

It is peculiar compared to modern digital methods like using a computer and DAC. Many of the recordings I love most [though I have many favourites recorded in the digital era] are from the era of the Leak and ESL [57]s. so the quality has similarities, but also the Leak acting as pre-amp onto the NAP 100 is actually radically different. The DAC V1 provides a pre-amp section that is very good in the modern style. Beautiful and slender as a Greek Godess. The Leak has the strength of great athlete! 

Visceral in just the right way. Not weighty or clumsy, but very strong and ultimately significantly more musically pleasing. 

Spoken voice has a quality that sometimes has me want to reply to questions asked! 

This whole project is crazy, because I was given this old tuner about five years ago, and really liked it with a roof aerial, and because I am in a flat with a useless VHF aerial, I imagined that I'd never get the tuner going properly. I gave it to a good friend, who gave it back about a month ago. I then determined to "have a go" at getting it working properly. I made the aerial in time for the last few Prom Concerts, and now that I have implemented Simon nudge on connecting the aerial to the 300 ohm inputs, I am staggered by a set-up that so far has cost me less than a half decent kitchen radio might.

Very gratifying!

ATB from George

George - great stuff - it really is worth while experimenting and your lovely update demonstrates that - just need to make sure you don't decapitate anyone coming through your front door now!

PS as Mike says a true circle is 133 ohms - the 100 was only approximate. 133 ohms is an even better match for 300 ohm feed of course

Simon

Proper RF engineering. Nice work on the feeder 

Dear Ian,

The picture is of me rowing and my brother not helping! In 1967 when I was five in a Faering [two man rowing boat] made in the same style in mid Norway for a good fifteen hundred years.

These were the little boats that were derived from Viking Long Boats, which were the best Warships of their day, while the Faering remains a most useful and coastal seaworthy fishing and transport boat to this day. Of course with a point at each end they never have a motor, though they can be rigged as a very good sailing boat. They race them in Norway!

This one was made in 1918 from my great grandfather. 

ATB from George

+1000000

I hope you've been well, George.

Great to have you back George!  I guess one learns to duck going in and out of the front door?

ATB,

Charlie

Hi George thanks for your reply.

You have certainly got a nice tuner there.I have never got into streaming not that I think it's bad but the sound on f.m with my NAT 01 or A@R Cambridge T 21 is more than enough.

It's weird as I am sure most of radio 3's output would be digital recordings.

You should consider the G.T audio mods for the tuner if you want to push the performance more.Having said that though I am unsure how long f.m will continue,think we might have at least 5 years.Who knows ?

Thanks for your Avater description very educational.Really like the colour understated and stylish.

ATB Ian

'

George,   quick question  .....  what are your blinds & windows made of as anything metallic will affect the antenna performance.  The blinds are most likely steel or aluminium.  Also from the photo its not clear if your sash windows are original wood or PVC,  if PCV they will contain steel or aluminium re-enforcement inside the frame parts.  

Possibly not a concern & you seem to be more than happy with it as it is,  but experimenting with raised & lowered blinds & changing the distance from window to antenna might bring some betterment.  

How nice this thread is!

For Mike, The blind is only a cheap little nylon thing. No metal except the screws at the top, and the sash is a genuine wooden [listed] feature. It is interesting that the aerial actually worked no better immediately outside the window, though I suspect that might offend the tidier minded residents in out street some of whom are in very smart apartments ...

For Ian, I know the people at One Thing Audio, and already discussed referring in original mono condition with them. They are truly enthusiastic of ESLs of 57 and 63 types as well as the TL tuner series. They made a modern MPX decoder to allow the TL3 Multiplex output to be available in stereo, but in that case I loose the pre-amp aspect, which I rather like. They might even find me an orphaned Leak 12.1 power amp that would be rather fine between the tuner and one ESL. Only twelve Watts, but quite enough if the Watts are good enough which in the lower powered power amplifiers from Leak, they certainly were.

Then I could run a totally discrete radio set-up, and simply unplug the one speaker and feed it with and speaker wire run from a mono amp. It is an idea that is germinating! After all the Leak equipment was many ways as good as - possibly even finer - than the contemporary Quad amplifiers and tuners though these are legendary of course. The weakest link in those days was their pre-amplifier production, but I can avoid that by staying mono with the Trough Line.

For Wat, As it goes I would not fire up the ESLs for anything but live concerts on Radio Three. I find a Tivoli quite good enough to enjoy all other radio broadcasts I listen to. Mostly Radio Four or the World Service.

I can stream Radio Four Extra with the Mac, but it surprising to me that I have only done so a few times over the last three years.

So in conclusion. Thanks for the lovely replies. A good start to my return [and reformation], and particularly to Simon for his starting of this thread, which came as an offshoot to the Musicality versus Soundstage thread. If we had inserted this thread into that one I would immediately have contributed to some serious off-topic posting.

Thanks from George

This has motivated me to move the system to a place that allows the tuner to be directly below the aerial, and the NAP 100, DAC V1 and Mac Mini to go to the left of it in all probability this weekend.

Oddly this has a peculiarity as the mains electricity will then come from a single spur with its own fuse from the CU. I might speculate that a previous occupant wanted a socket in that corner and rather than dig in the walls for existing ring for the rest of the room, it was easier to plumb into the adjacent CU. Not big gauge or anything like. I do not anticipate any changes will result. The main benefit will be to get the odd connection between the aerial to the tuner tidy!

I have been planning this for ages, and was never sufficiently motivated to get round to it. The NACA 5 can then easily be routed under the floor through an air vent and re-emerge right behind the ESLs, which itself will tidy things up!

ATB from George

On the tuner itself, I have been taken aback by its quality, and have just spoken to One Thing Audio about the possibility of getting the old radio serviced. We conversed about the way it was working, and the conclusion was rather nice. "Don't fix what ain't broken!"

I was also explained to about the difference between my Trough Line 3 and the Tough Line Stereo.

Essentially there is no difference, except for the inclusion of the Leak Multiplex decoder, and the deletion of the volume control. In the opinion of OTA, the TL3 and TL Stereo were the best of bunch.

They said that I can gingerly dust off the internals, as the construction is rather more robust than solid state. Just be careful of the valves!

By the end of the weekend, I'll have reduced the antenna connecting wire length by moving the electronics to a new place that will be much tidier!

ATB from George

ATB from George

Dear Lars,

This full wave [length] loop antenna [as shown] is about as good as possible short of a roof-top aerial. I cannot have one of those, but this is very easy if you are handy. 

ATB from George

Lars, do you have a loft or attic space you can use?

Naim tuners, as with most tuners receiving stereo will need a good signal. Typically unless you are very close to a transmitter, (that is within miles away) you will really need a Yagi, and this will have typically 2 elements or more. The more elements, the more signal gain, the better, but the more directional to the transmitter it becomes.

An attic can be viable, although there will be some loss through the roof tiles assuming they are not metallic.

Naim tuners require unbalanced antenna feeds, that is 75ohm coax. Most antennas such as full wave loops, dipoles and Yagis are balanced antennas, and so require a little transformer at the antenna called a Bal-Un  to convert the balanced antenna signal to unbalanced for the coax. Typically this transformer will match the antenna impedance to the 75 ohm coax impedance where required as well.

George's internal full wave loop above is using  balanced 300 ohm cable, and his tuner can connect to balanced antennas directly, so the efficiency raises and no Bal-Un is required in his case. The maximum gain of this loop is when the faces of the loop point to the transmitter (IE the direction of George's window) . Plotted out it will look like a figure of '8' , just as with a dipole.

low gain antennas with RF amps are to be avoided as they will typically create a noisy signal for the tuner and provide a poor to mediocre overall result.

Simon

Dear Lars,

I have been reading further on this. It seems that with a full wave-length circle loop [133 ohms[] the signal gain is approximately 3.49 dB which is similar to what the best multi-element aerials get.

However if one uses a wavelength multiplied by 1.3 loop then the gain is maximised for the type at 4.75 dB, which short of amplification is as good as it gets.

During my shifting about this weekend, I'll make this arrangement to see if it really works. For me the full-wave is 3.24 metres, so multiplied this comes out at a circular loop of 4.86 metres, or a circumference of 1.55 metres.

More gain from an aerial is always useful in marginal reception areas. Mine is marginal. Nothing like full strength on the magic eye, but solid for all that. I have the materials so I might as well try it. In balanced connection to the Leak [where one end of the loop connects to the one terminal and the other, the other [without balun], via a spaced wire connection [see pictures above] I guess this can only be beneficial. 

I'll report back on this ...

ATB from George

My reference for the above:

http://pa0fri.home.xs4all.nl/Ant/Quad/quadeng.htm

This thread is really interesting. I have two TroughLine tuners in the loft. One mono, one stereo. I'll have to get them out and have a play. I also have a matching Leak stereo amp, I forget the model. I should find time to fire it up and see how it sounds :-) 

Not correct George

A very basic 3 element Blake FM has 7.2dB

A typical medium reception area TV Yagi will have around 14dB 

My Ron Smith G-14 - effectively has 3 element stages but is a lot more complex to enable mixed V&H reception - has 14.7dB gain.  http://ronsmithaerials.com/catalogue/G14.php

A confusion factor is dB gain numbers published by manufactures do not specify if they are using dBi or dBd - Blake are an exception who quote both.

dBd is gain referenced against a dipole. A reference dipole is defined to have 2.15 dBi of gain.

All the above gain numbers I have used are dBd & I suspect its the same with your reference www