Just clarifying; to ensure the search engine gets the right info, for those who have never seen it before..

One thing, it is less effected by dirt & corrosion.

One little hint might be that the tuner in my kingsley ( which I sold ) has made in the U.S on it. So if you are looking at Australian patents then your looking in the wrong country.

JFB I have found two threads I have started on my Kingsley Ferrotune. One photo in general discussion ( section ) shows the U.S patent number. If you are using a tablet or a smart phone you can hold your finger on the photo and you can directly download the photos to your device. I will attempt to send you the photo in question.

if you are looking at Australian patents then you're looking in the wrong country.

Note that both your photo and the one on RM are stamped Australian patent 12663.

However, the US patent numbers stamped on the units differ between 381875 and what appears to be 394879. I haven't been able to find either of those US numbers in the US Patent database relating to a permeability tuner.

Manufacturing location aside, by all accounts the Ferroutune tuner is an Australian invention of the company Kingsley Radio owned by Howard Kingsley Love.

Thanks Carl,
However both GTC and myself have been down the patent route without success and I suspect that the patent would not give me component values anyway but at least I could see whether there was one coil or two and what they connected to but I guess this radio may be heading for a display only piece.

For GTC. yes I would normally keep it, it would look good displayed alongside my Kingsley AR7 but unfortunately it is not mine. I am trying to fix it for a friend but it's looking increasingly unlikely. The suspect coils(s) is wound with Litz wire, whose overall dimension is at the limits of my visual acuity so no realistic chance of rewinding or even finding the missing ends.

Joe

Hi guys interesting problem.

Treat the tuner as a separate entity.
It has to have resonant properties.
Does it have any now in either circuit?

Perhaps disconnect the mystery coil and / or bridge the ends?
Then see if there is resonance.
After all it is just a couple of R/C circuits.

Maybe crazy wire a standard tuning gang and coil set onto the converter and make the rest of the set work.
Than all that is wrong is 1% of the set not some huge problem.

Heaps of things to try.
We know what it should do, make it do it.
Glass half full!

Fred.

Perhaps disconnect the mystery coil and / or bridge the ends?

A good idea methinks. In the photos that I can find, there appear to be at least two versions of the Ferrotune and the earliest one seems to lack that additional coil, which may have been added to modify the Q of the tuner.

Yes, go for it, what could possibly go wrong?

Fred.

Are there resonant circuits inside it - well at the moment no, but there are two Ls and two Cs. The C's have padders in parallel and the Ls are adjustable and the Ls are associated with the Cs. But as mentioned earlier the values seem strange.

The aerial side has max L of 0.5mH and a C of 0.18 nF which gives me (if my arithmetic is up to spec) a low of 530kHz which seems good,can't calculate the upper resonant frequency as my meter gives me an L of 0 at the other end of the travel. The problem with the aerial circuit is that it doesn't connect to the aerial terminal (Pin 1 on the Ferrotune unit) and the other end of the L goes nowhere.

There is however a major discrepancy with the oscillator which has a max L of 0.243mH and a C of 5.4nF which I think gives me a minimum resonant frequency of 138kHz bit supersonic for what I am after (530 + 455 = 985kHz). It also looks to be series resonant which doesn't doesn't make sense for a supposed Colpitts oscillator (there is also only one C).

I am assuming in this that all resonant circuit components are located within the unit and not dependent on anything external. As mentioned earlier much of the internal wiring to and from this coil/thingy has been corroded away, but clearly from the above it is involved in both the aerial and oscillator circuits.

But thanks for the rev up, probably just what I needed, although how much mental energy for a love job (read zero dollars) is questionable

Joe

although how much mental energy for a love job (read zero dollars) is questionable

I know that feeling. Those jobs can turn into boomerangs. I am very reticent to work on anyone else's stuff these days unless it's a 'simple' thing like fixing a switch -- although even that turned into a mess on one such job, as I recounted in the Serviceman's Log in SC a few years back.

Yes - no good deed goes unpunished!

Perhaps albiet inductive The LSG-11 has a colpitts oscillator as does some of the American Midwests around 1935/36

The Midwest has a master trimmer which is set first, then the rest.