[ARC5] OT: Hally Instability

[Fuqua, Bill L]

  The ARC-5 dial linkage does not have the nice flywheel knob action but does have a lot of friction.
The problem being that with no friction on the consumer product and nice flywheel free spinning knob which may have a slight
imbalance and the drum on the capacitor is certainly not balanced and the very off set weight of the rotors on the capacitors, a drop will cause some rotation.
73
Bill wa4lav

________________________________________
From: ARC5 [arc5-bounces at mailman.qth.net] on behalf of Robert  Eleazer [releazer at earthlink.net]
Sent: Sunday, November 15, 2015 6:08 PM
To: arc5 at mailman.qth.net
Subject: [ARC5] OT: Hally Instability

When I started researching ham band receivers in 1974 I noted a magazine review of the NC-270 that mentioned the 1/8 thick steel front panel - and said you could tune in a signal, raise the front of the radio a inch or so, let it fall, and still have the signal tuned in. That was one reason I bought a National NC-155, a "Chevy" version of the "Cadillac" NC-270.

But I have noticed something about military receivers that have excellent stability, such as the 274-N and ARC-5 series as well as the BC-348 and I would guess the BC-342, too..  The tuning cap is not turned directly by the knob on the front panel but instead through a 90 degree turn.

Is this 90 degree turn a feature designed help stability or just a consequence of the packaging and the need for a proper gear ratio?

Wayne

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