Re: K3: IF output buffer gain modification
Posted by
gm3sek on
Sep 22, 2009; 1:27pm
URL: http://elecraft.85.s1.nabble.com/K3-IF-output-buffer-gain-modification-tp3690284p3693082.html
Dave G4AON wrote:
>
>Bill W4ZV wrote:
>
>>When the mod was first published I asked:
>>"Just checking to see if this is a typo. 13K or 12K?"
>>
>>Bob Friess N6CM (the 1st mixer designer) replied:
>>"13K is a standard 5% value and is correct."
>>
>>I took the 5% tolerance to mean the value is somewhat critical.
>>
>There is about 0.2 dB difference between using one value or the other,
>depending on the accuracy of your model.
>
13K is a standard value in the E24 series, which covers a full decade in
24 steps. Each step is about 10% above the previous value, so E24
resistors have to be manufactured with a tolerance of 5% or better.
http://www.logwell.com/tech/components/resistor_values.htmlBut *standard* values aren't the same as the most-used *common* values.
The ones most used are the well known E6 series (1.0, 1.5, 2.2 etc) or
the E12 series (1.0, 1.2, 1.5, 1.8, 2.2 etc).
Most RF circuits don't operate within 5% margins, so they can get along
fine with E6 and E12 values.
--
73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek______________________________________________________________
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