[Amps] PI Calculation using G3SEK Excel Spreadsheet

[Jim Thomson]

Date: Thu, 31 Mar 2011 17:25:42 -0700 (PDT)
From: Bill Smith <ko4nrbs at yahoo.com>
Subject: [Amps] PI Calculation using G3SEK Excel Spreadsheet

Are these values correct (in ??) for two 3-400Z tubes at 2500vdc and 800ma Plate Current?
There is so much information there I get lost.

Input Supply voltage E 2500 V

Input Max DC anode current Ia 0.8

Input K factor K 1.6 

Input RF power output W 1500 W ??

Info Estimated RL based on E, I and K 1953 ohms??

Input Efficiency e 56 %??

Info Estimated RL based on E, W, e and K 1458 ohms??

Input Enter your choice of load resistance to be used for the calculations. RL 1900 ohms??

Input 2: Antenna load resistance R2 50 ohms??
Input 3: Operating frequency F 7.2 MHz
Input 4: Overall network Q Q0 12 

5: Strays compensation 
Input Output capacitance of tube(s) Cag  10 pF??

Input Strays local to tube Cs1 5 pF

Cout = Cag + Cs1 Cout 15 



Info Total effective parallel capacitance of tube, strays, RFC etc Cp 25.0 pF??

73,
Bill Smith KO4NR

###  I  have been using the GM3SEK  pi/pi-l   software  for years now....and it's always DEAD ON.   It has been
used on several RF deck designs, from small tubes, to the yc-156 variety.  160-6 m too. 

## It factor's  in stuff that everybody else's  doesn't.    That stray uh..... between anode and PI net  makes a huge difference ! 
This is exactly how we get the bigger tubes to play on 10m.    You will see, that by adding just a tiny bit of stay L...like .5 uh
between anode and input to pi-net.......that ur plate load Z  will  be transformed to a much lower value.

## You can then juggle the values  of this stray L..... and the uh of trhe main 10m coil.... and also the loaded Q... and you will that
you can get almost any tube to work on the higher bands.    You will also see the effect it has on the next lower bands. 

##  Nobody elses  pi  pi-l  software appears to factor in stray Uh  and stray pf.     all those strays can easily be measured with a lcr meter..
including cabinet side walls and top lids etc, 

Ian's software can't be beat...superb. 

Later.......... Jim  VE7RF