[Boatanchors] Comarison?

[Carl]

----- Original Message ----- 
From: "Ian Wilson" <ianmwilson73 at gmail.com>
To: "Boatanchors" <boatanchors at mailman.qth.net>
Sent: Friday, December 18, 2009 7:13 PM
Subject: Re: [Boatanchors] Comarison?


> Good stuff, Carl. A few questions and comments:
>
> What sort of tuning range(s) do you aim for in the preselector?
> (I very much like your use of submini relays to get all the lossy,
> unreliable,
> rotary switches).


** That will depend on the band and the achievable Q. What bandwidth curves 
do you have in mind?  All the answers are in Radiotron 4th Edition.

 Related question, what sort of Q in the preselector?

** Ive been working with toroids in the 225-250 range which dont have the 
deQing effects of slug tuned coils in typical close proximity. Also have to 
use the 4 section variable that I have so its an exercise in juggling fixed 
caps to make it fly from 160-10M

>
> IF passband tuning: what sort of thing did you have in mind?

** Ive been playing with varactors to control the LO and BFO in both IF 
shift and PBT config.  Still in breadboard using SS (Its easier for 
experimenting) with seperate controls.

>
> S meter!! Completely forgot (an excellent excuse for using a magic
> eye, though, unless you want real numbers).

** I hate eye tubes. They are all over the house in many pre WW2 consoles 
and some table models.


>
> My attempts usually add AGC as an afterthought. Next time I will plan
> for something more modular so I can try alternatives (instead of having
> to squeeze in something that will fit).

** I include it at the very beginning of the process so I can then see what 
tubes I want to use.


 If you are using more than one AGC
> loop, do you split up the controlled stages or are they all on one bus?

** Completely seperate loops for front end and IF.

Carl


>
> 73, ian K3IMW
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