A Long wave coil for Marconi 22 - UK Vintage Radio Repair and Restoration Discussion Forum

vinrads · 2nd Oct 2022, 12:44 pm

I am in the process of restoring this Marconi 22 it came with just the M/W coil as I like the listen to radio four I decided to try and make a L/W coil pack using a couple of transistor radio coils one for the aerial and one for the reaction ,I must say I was very pleased with the results ,the reaction works as it should , I aim to fit a black spray can top to the assembly , Mick.

vinrads · 2nd Oct 2022, 1:37 pm

A bit of trimming and the top fitted ,two very small screws hold it in place, it's looking good now . Mick.

G6Tanuki · 2nd Oct 2022, 2:49 pm

That's rather cunning!! Good to hear that it works in the intended way. Must admit. I wouldn't have thought of doing it.

Mr 1936 · 2nd Oct 2022, 4:07 pm

Hi

Those Litz wound coils with a ferrite core will have a better Q than anything you could easily wind by hand. Probably better Q than could have been achieved in period. The screen will knock this back a bit, but is generously sized so shouldn't be much of an issue.

I am guessing you are in the region of 2 mH tuned with 320 pF for 198 kHz.

vinrads · 2nd Oct 2022, 4:56 pm

Thanks fort the replies, I peaked the aerial coil with a bit of ferrite rod for about mid way on the tuning knob ,the screen is plastic so it made no difference on or off ,I would say the signal is stronger on long wave than that with the m/w coil , an original would be nice ,but couldn't find one so this was the next best thing . Mick.

2nd Oct 2022, 12:44 pm	#1
vinrads Dekatron Join Date: Feb 2009 Location: Chesterfield, Derbyshire, UK. Posts: 3,766	A Long wave coil for Marconi 22 I am in the process of restoring this Marconi 22 it came with just the M/W coil as I like the listen to radio four I decided to try and make a L/W coil pack using a couple of transistor radio coils one for the aerial and one for the reaction ,I must say I was very pleased with the results ,the reaction works as it should , I aim to fit a black spray can top to the assembly , Mick. Attached Thumbnails

2nd Oct 2022, 1:37 pm	#2
vinrads Dekatron Join Date: Feb 2009 Location: Chesterfield, Derbyshire, UK. Posts: 3,766	Re: A Long wave coil for Marconi 22 A bit of trimming and the top fitted ,two very small screws hold it in place, it's looking good now . Mick. Attached Thumbnails

2nd Oct 2022, 2:49 pm	#3
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,007	Re: A Long wave coil for Marconi 22 That's rather cunning!! Good to hear that it works in the intended way. Must admit. I wouldn't have thought of doing it. __________________ I'm the Operator of my Pocket Calculator. -Kraftwerk.

2nd Oct 2022, 4:07 pm	#4
Mr 1936 Heptode Join Date: Mar 2017 Location: Romsey, Hampshire, UK. Posts: 524	Re: A Long wave coil for Marconi 22 Hi Those Litz wound coils with a ferrite core will have a better Q than anything you could easily wind by hand. Probably better Q than could have been achieved in period. The screen will knock this back a bit, but is generously sized so shouldn't be much of an issue. I am guessing you are in the region of 2 mH tuned with 320 pF for 198 kHz.

2nd Oct 2022, 4:56 pm	#5
vinrads Dekatron Join Date: Feb 2009 Location: Chesterfield, Derbyshire, UK. Posts: 3,766	Re: A Long wave coil for Marconi 22 Thanks fort the replies, I peaked the aerial coil with a bit of ferrite rod for about mid way on the tuning knob ,the screen is plastic so it made no difference on or off ,I would say the signal is stronger on long wave than that with the m/w coil , an original would be nice ,but couldn't find one so this was the next best thing . Mick.