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[Amps] Tuned Input

To: <amps@contesting.com>
Subject: [Amps] Tuned Input
From: 2 at vc.net (rlm)
Date: Mon Mar 10 10:48:17 2003

>Hmmm, 'minimum is under 1.2 to 1' ? that makes me wonder --
>
>1.2 to 1 seems pretty tight, what would the VSWR bandwidth be?
>
**  beats me but some solid-state transceivers begin to throttle back c. 
1.2:1.

>Makes me ask a question -- I have an FL-2100B, I bought it used and it seems
>to work FB, but I checked the input coil alignment and found one band (20 m
>if memory serves me correctly) that I could not bring down low enough to
>really make me happy. I think it was 2 - 3 to 1 at best.  (I don't think any
>were as low as 1.2 to 1). What do I look at to improve this? 

**  Increase the Q of the tuned input by increasing C-in, C-out, and 
decreasing L.  For 20m, a C-in of c. 390pF should do ok.  

> Is it likely
>to be the adjustable inductor? Or would it be easier to replace one or both
>or the tuned input capacitors?

**  C-out and L need to be adjustable.  When you arrive at something that 
works, replace the adjustable C with a fixed unit.
>
cheers, Rick


>----- Original Message -----
>From: "rlm" <2@vc.net>
>To: "Ed" <edw3nr@nexband.com>; " AMPS" <amps@contesting.com>
>Sent: Sunday, March 09, 2003 7:00 PM
>Subject: Re: [Amps] Tuned Input
>
>
>>
>>
>> >I want to make sure I am right here. Tune the input for best SWR
>>
>> **  Yes, provided the minimum is under 1.2 to 1.  If it's not, the Q of
>> the tuned input needs to be pumped up,
>>
>> >and maximum
>> >Grid current or ????????? ...........73
>> >
>> **  Tune for max RF out with whatever drive level produces the rated max
>> anode current.  Max out always results in a reasonable amount of
>> grid-current because if too many electrons are diverted to the grid,
>> fewer electrons arrive at the anode and output drops.
>>
>> cheers, Ed
>>
>> -  R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
>> www.vcnet.com/measures.
>> end
>>
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-  R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, 
www.vcnet.com/measures.  
end

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