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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 10th Oct 2019, 9:47 pm   #21
m0cemdave
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Default Re: ECF82 frequency changer

Quote:
Originally Posted by turretslug View Post
Then the RA17 came along.... and both hands needed to dart around again. I wonder what US oppoes who were accustomed to the contemporaneous R390 with its complex but thorough ganging arrangements thought of it.
I think it may depend on whether a receiver is expected to be used for General Search (i.e. tuning around fishing for signals), or point to point communcation where it is set to a frequency and left there for long periods of time.
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Old 11th Oct 2019, 11:35 am   #22
Herald1360
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Default Re: ECF82 frequency changer

Tuning around was easy with an RA17 with preselector set to wide band. OK, you had to change "band" every 1MHz but that was easy too. STAYING on tune forever (nearly) after being set to a fixed frequency was its party trick. If there was serious noise or adjacent channel crap you could switch in the preselection and peak it by ear.
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Last edited by Herald1360; 11th Oct 2019 at 11:43 am.
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Old 11th Oct 2019, 12:57 pm   #23
Neutrino
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Default Re: ECF82 frequency changer

This circuit of a typical television tuner for Bands I and III does not appear to explicitly show a component coupling the oscillator and pentode:

http://www.r-type.org/articles/art-011.htm

However, the way it is drawn suggests inductive coupling between the oscillator and RF tuned circuits. Perhaps this was lost when the circuit in the RSGB handbook was drawn.

David
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