----- Original Message ----- From: "Edward B Richards" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Thursday, June 08, 2006 5:48 PM Subject: Re: [AMRadio] PA set up using ant analyzer
> Hi Dennis; > > I am having trouble resonating the plate tank on the linear amplifier I > just built. When checking for resonance with a grid dip meter using a > 5,000 ohm resistor from plate to ground, should the tubes (4-400 X 2) be > in the circuit? This is not Dennis but the answer is the tubes must be there or a capacitor equal to the total output capacity of the tubes in their place. i.e.28 pf ( 14 each) for a pair of 813's check tube table for output cap. The analyzer should show a 1 to 1 swr from the antenna looking in when it is resonated. The grid dipper technique is differnet. You take the resonate plate load z , plate volts divided by 2 time plate current and divide by disired operating Q, 10 or so for the input capacitor, with the tank cold disconnected. use a capacity meter to set the C1 and then leave it alone, the output cap C2 is the load z ( 50) divided by q, about 2. These give the x sub c value which must be converted to capacity. Then you tap ( short coil till the analyzer shows one to one from the output jack). Hope this helps..For pi-network. check ARRL handbook for pi-l. Mike
