I did as you suggested but rather using a fixed mica Cap I used a small trimming Cap. Magic. The radio is selective. Bang on the tuning scale and with great volume and sensitivity. Many thanks. Another great set to add to the collection. Display in the museum of American Fives and midgets. And of course to impress my pals with over a can ot two when they come calling.

Frank
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: : : : : : : : : : : : : :Sir Frank. . . . . . . . : : : :Whoaaaaaaaaaaaa there Nellie . . . . .I overlooked your being in Limey land . . . not to worry . . . . just kick into your frugal/learning/experimentaion mode now and lets try three possibilities. : : :Initially, you will either be selecting a mica trimmer adjustable or a varuiable inductance / slug tuned unit. :Soooooooo, lets just see if you can connect in a 455, tone modulated signal generator to the front end and and "push" a 455KHZ modulated signal thru the system with a 470 transformer tacked in to use for the second IF transformer. : : :Skewing from a 455 design transformer to trying to sub in a 470 one will mean that the "new" 470 unit will be needing more capacitance to shift its tuning capability on down to a 455 resonance. : : :Be it the tightening of the mica compression trimmer on a variable capacitance unit/ or /the positioning of the slug(s) on a variable inductance unit , more towards the very center of each of the coil core(s). : : : :Using some empirical computational figures of Frequency-Inductance-Capacitance, our typical 455 IF transformer (United States) will be having ~1020 uh as its coil inductance and a companion tuning capacatance of ~120 pf shunting across it to be able to tune to a 455Khz resonance. : : :If one then cross computates for the shifting of that resonance point, getting it on up to 470 Khz, that then requires the loosening up of the compression mica tuning cap to a lower capacitance value of only ~112pf. : : :(Conversely if you are dealing with a variable inductane tuned IF transformer, that will then require the decreasing of tuning inductance [slug moved further OUT of the coil] to get a lower ~956 uh value for resonance at 470 Khz.) : : :CERTAINLY seems that low of a value of C or L change/shift would be achievable on either mode of IF transformer with its inductance core/slugs or using its mica compression capacitor(s). : : :HOWEVER, in your case you, are wanting to DECREASE the IF resonance from 470 on down to 455 Khz. : : :Sooooo . . . . now in review of YOUR situation . . . . you need to tighten the trim capacitor on a 470 Khz transformer for an additional ~20 pf of capacitance. To then make it tune to 455 Khz resonance. OR, in the case of a variable inductance tuning, the slug needs to move further into its coil core to inecrease the effective tuned inductance an additional ~60 uh. : : : :These small values certainly seem achievable with the IF T-formers stock L and C values, But if NOT being so, one merely needs to tack on ~20 pf silver mica fixed capacitors to make that range achievable. : : :Thaaaasssssit . . . . .: : : : : :73's de Edd : : : : : : :Ya know what . . . . . I sometimes find that Project Management is like pushing a wheelbarrow of frogs to market. : : : : : : : : : : : : : : : : : : :/html>

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::Hello Bill
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::I supposose I will have to put it on to the - to be finished later - shelf
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::Thanks Frank
:::Hi Frank,
::: Be patient and you will find one. We all have spares that will work. 455KHz is the most common IF.
::: You may be able to get someone here to send you one.
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:::Best regards,
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:::Bill Grimm
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