14-11-2012, 09:09 PM
Hi Gary, is it definately ferrite or iron powder, ferrite seems to be later developed by the japs and philips, a similar type of pot core construction is shown in the diagram in that pearmeabilty paper I put in the archives but obviousely the one illustrated in the paper is adjustable.
Interestingly I have a Hallicrafters SX 17 the manual states that the IF transformers are iron cored, these cores are not adjustable, aligning them is done by capacitor tuning, I have never taken one appart to see the type of iron core used inside them, the vintage is circa 1939, the xtal filter which is fed from one of these transformers pings up really well on CW and is bang on the nose resonance wise which is always a good indicator of a nice sharp IF stage.
All interesting stuff.
Lawrence.
Interestingly I have a Hallicrafters SX 17 the manual states that the IF transformers are iron cored, these cores are not adjustable, aligning them is done by capacitor tuning, I have never taken one appart to see the type of iron core used inside them, the vintage is circa 1939, the xtal filter which is fed from one of these transformers pings up really well on CW and is bang on the nose resonance wise which is always a good indicator of a nice sharp IF stage.
All interesting stuff.
Lawrence.
