[ARC5] AM broadcast reception on BC-453

[Kenneth G. Gordon]

On 20 Mar 2015 at 6:31, Leslie Smith wrote:

>   Now, listening to AM BC broadcasts this is what I hear:
>   When the '453 is tuned to what I judge to be the 'middle' of the
>   signal (here it's 480kHz) the sound is muffled.
>   To get natural sounding voice quality I must tune the '453 a little
>   'high'.
>   When I tune the '453 'low' the muffled quality is less, but not so
>   clear was tuning 'high'.

This is all indicative of too-narrow selectivity and side-band cutting.

> 
>   Important info.  The slug in the second I.F. transformer is 'stuck'. 
>   By that I mean I can't pull it out.  The first and third slugs are
>   "out".

OUT is the HIGH-SELECTIVITY position: IN is the LOW selectivity condition.

You can move a stuck coil but dismounting the IF can, opening it up, and 
forcing the coil up (gently) against the frozen bees-wax.

But in the interests of fidelity, you want all three slugs to be IN, 
close-coupled, not OUT or loose-coupled..

>   I haven't tried to align the I.F. transformers.  (How stable are these
>   sets over 70 years?)

Very unusually stable. Tweaks may or may not improve matters.

> 
>   I'm interested to know how many here listen to the BC band using one
>   of the 'nav' sets?
>   What quality of sound is heard?

I can only say it is "fair".

Ken W7EKB