Another Ever Ready .... 5216 this time

[Ed_Dinning]

Hi Folks, for those who want to delve more deeply into tracking there was a recent thread by Regenfreak on the UKVRR that covers this topic and practical problems

Ed

[Kalee20]

Thanks Ed! I looked - couldn't find one by regenfreak, but there is another from a couple of months ago, which I contributed to (I'm rather interested in tracking ATM.)

There's really two issues - the designers faced with getting appropriate L and C values for really good tracking, and the engineers who then have to arrange for sufficient adjustment to absorb production tolerances within the exigencies of cost constraints.

Sometimes fixed values are nearly spot-on - the Ever Ready Model K that I have is an example. Sometimes tracking is mediocre - the Cossor 500 that I have is an example.

But Amie's post about the 5216 describing the frame aerial adjustment is interesting. It means that the 5216 left the factory as good as it could be, even if realignment in service later on, maybe after something needed to be replaced, is rather difficult (a bit like Philips's IFT's trimmed by rolling a groove in the can, or their trimmer capacitors adjusted by stripping turns of wire off the outside of a ceramic tube).

[Amie]

Peter/Dr Ed

The redo on the coil for the 5216 is done without the ER adjustment scheme, what I've got planned is a small adjustable inductance in series that can be oriented variometer style to provide some adjustment of the loop overall inductance, so that it can be done with the back and the battery pack/PSU in place...

[Ed_Dinning]

Hi Peter/ Amie, Regenfreak (Sing) is doing quite a bit of work on tuned circuits, with is present interest being with FM sets. As a uni engineering lecturer he has the maths for it as well as a flat full of test gear. He explains that it has greatly helped him through the lockdown.

Any thoughts if tracking was easier on the Synchrodyne circuits that Prof Tucker at Birmingham developed in the 50's then I think revisited in the 70's in WW

Ed

[Amie]

Sounds interesting, have you a link Dr Ed?

Thanks
Amie....

[Kalee20]

Sounds interesting, have you a link Dr Ed?

+1 for that!

[Ed_Dinning]

Hi Folks, EE magazine (do you still have copies Peter?) if not I think they are on the worldradiohistory site
March 1947 P75, an introduction; (also some good theory on tuned transformers, but gets a bit mathamatical)
Aug 1947 P241 , practical design pt 1
Sept 1947 P277, various designs
Nov 1947 P368, design correspondance

There was also a revisited version of the circuit, again by Tucker in WW in the 70's or 80's, but I don't have these indexes available

Hope that helps

Ed

[Kalee20]

Thanks, Ed! Will look up (no, I passed on the Electronic Engineering mags).

And the regenfreak thread? I looked at the threads he started, but didn't see one which fitted your description.

[peter scott]

Hi Folks, EE magazine (do you still have copies Peter?) if not I think they are on the worldradiohistory site
March 1947 P75, an introduction; (also some good theory on tuned transformers, but gets a bit  mathamatical)
Aug 1947 P241 , practical design pt 1
Sept 1947 P277, various designs
Nov 1947 P368, design correspondance

There was also a revisited version of the circuit, again by Tucker in WW in the 70's or 80's, but I don't have these indexes available

Hope that helps

Ed

Hi Ed,

I wasn't born until 1949 but even if I had been a member since birth I've never kept the mags.

Peter

[Ed_Dinning]

Hi Peter (Scott) it was Kalee20, the message was directed at. However, if you are interested there are several volumes of this excellent periodical available on the worldradiohistory site; lots of other good articles within its pages on electronics theory and applications

Ed