[Boatanchors] Optimum L/C ratio chart(s).

[Al Klase]

Ken,

You said the magic words: "Crystal Set."

See my site:  http://www.skywaves.ar88.net/xtal/xtal.htm

And my Aeriola Jr. video here:  
http://www.rtm.ar88.net/Radio%20Listening.html

BTW, the capacitance of a typical back-yard inverted-L is on the order 
of 200 pF.

Al

On 4/14/2010 7:58 AM, KEN wrote:
> Hi Al,
>
> What a suprise! You must have been rummaging thru old files!
> I have acquired an old, and I do mean OLD Variometer used
> back before the appearance of the AM BCST operations, in
> the maritime services down on 500 Kcs. and workig frequencies
> just below that no doubt back in spark transmitter days!
>
> A long planned research is to use this variometer along with a
> "straight line frequency variable condenser" which I also have
> found. By jockying both and measuring output of signal I
> should be able to determine the "optimum" values of L and C
> for the various frequencies on the AM Band. Now, the
> task is to find the correct coupling between both L & C
> to have them "track" across the AM BCST band.
> I have the Sencore "Z" meter so measuring the L & C
> should be no problem.
>
> I am an ardent Crystal Radio Receiver fan and have been
> since the early 30's  when I built my first one.
> Take care,
>
> Ken   N5CM
>
>
>
>
> ----- Original Message ----- From: "Al Klase" <al at ar88.net>
> To: <boatanchors at mailman.qth.net>
> Sent: Tuesday, April 13, 2010 11:51 PM
> Subject: Re: [Boatanchors] Optimum L/C ratio chart(s).
>
>
>> Ken,
>>
>> The classic values are 365 pF and 250 uH.  This comes about because of
>> the high distributed capacitance of old fashioned coils like close wound
>> solenoids.  The issue is being able to reach both ends of the band.
>> Things get a lot easier with modern iron-core inductors.  Charts and
>> equations won't help much if you can't measure the self-resonate
>> frequency of the coil.
>>
>> Al
>>
>> On 8/3/2009 12:15 PM, KEN wrote:
>>> Fellows,
>>>
>>> I am searching for a chart that will give me the optimum L/C ratio 
>>> for the frequencies of the AM Broadcast Band.
>>>
>>> I seem to recollect there was one in the large book, "Gharardi Radio 
>>> Physics Course" (Not sure of spelling).
>>> But, can't locate my old copy - may be gone!
>>> Any help appreciated&   take care,
>>>
>>> Ken   N5CM
>>>
>>>
>
>
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-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/