[Heath] AR-3 - vernier

[Kenneth G. Gordon]

On 19 Apr 2016 at 19:47, Glen Zook wrote:

> I must be lucky in that both my AR-2 and AR-3 the variable capacitors
> are working correctly. 

Yes. You most certainly are lucky. NONE of mine are working correctly. They were all so 
frozen up that unless I had known they had some sort of gear-reduction in them, I would 
never have known from the way they worked.

> However, above the broadcast band, even with the reduction, it is not
> easy tuning in any particular station. 

Yes, indeed.

> That is where the bandspread dial 
> comes into play.  Using the bandspread, it is easy to tune in any particular station 
> even on the highest frequency band.

Yes, but what I find interesting is that many of the AR-3s I have seen for sale are missing 
that small, plastic dial which is just behind the bandspread knob. There is a hole in the 
bottom of the cabinet right over the setscrew for that dial, and apparently, most builders 
missed that.

Of the three AR-3s I own, only one has that dial.

BTW, IMHO, Heathkit did the bandspread thing correctly: they use a dual section capacitor 
which includes a vernier. The dual-section capacitor tunes both the HFO and the RF input. 
Many of the cheaper receivers used only a single-section bandspread cap which only varied 
the HFO frequency and not the RF circuits.

If anyone has a spare bandspread dial they would part with, please let me know.

Ken W7EKB