[Amps] Fwd: Pi-L In-circuit Adjustment Question

[R.Measures]

On Feb 20, 2005, at 6:35 PM, TexasRF at aol.com wrote:

>
> Hi Rich, no, I said "C1 resonates the network" but no matter, we both 
> know what the intent was.

No capacitor in a L-network or a Pi-network (double L-network) 
resonates the network.
> Ê
> While driving up to my eme operating QTH this morning I was thinking 
> about the subject and came to an interesting conclusion: there is no 
> practical way to couple a grid dip meter into network to look for a 
> dip while the amplifier is running key down to produce the needed 
> impedance represented by the plate load impedance calculation. The rf 
> signal present will QRM the heck out of the dip meter!

QRM the dip meter or toast it?
> Ê
> Then the thought; removing the rf enclosure lid to make the 
> measurement makes the LÊandÊ the C change. The only way to get an 
> accurate measurement is to build a remotely operated dip meter into 
> the circuit. This seems like a lot of bother knowing that QRM will 
> negate the reading anyway.

There won't be any reading after the meter is toast.
> Ê
> Therefore, I must conclude that your statement about a Pi network not 
> being resonant just might beÊtrue as it can't be disproved.

An L-network transforms E and I by operating near resonance.  The 
greater the Z-transformation, the closer it operates to resonance, the 
greater the circulating I in the inductor, the greater the E across the 
capacitor., and the greater the operating Q.  However, an L-network is 
never operated dead-on resonance because there would be ° E and ° I.
> Ê
> There is a lot more to be said about this subject as it seems to come 
> up from time to time. I can't tell if you are really serious about 
> this "non resonant network" or just pulling our chain about it.

  On AMPS, those who joke about AC circuit analysis are destined to 
become one.
> Ê
> I would appreciate knowing the answer to this before spending a lot of 
> time building up the remotely tuned dip meter or thinking too much 
> about it.
> Ê
> By the way, I had a grammar slip in an earlier e-mail calling a point 
> "mute" really meaning "moot". I know you saw that and thank you for 
> graciously not pointing it out!

In this neighborhood, grammar is not as important as circuit analysis 
and physics of electricity.
> Ê
> Best Regards,
> Gerald K5GW
>

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org