¿ªÔÆÌåÓýThank you, Jim. I¡¯ve had to reverse engineer other people¡¯s results in the past to find out that we were actually talking about the same thing. I have learned one thing in my 40+ years as a professional Electrical Engineer ¨C nomenclature is king. And, everybody needs to be on the same page. Avoids a lot of meaningless arguments. ? Respect, for all that work. ? John VK6JX ? From: [email protected] <[email protected]> On Behalf Of Jim VE7RF
Sent: Tuesday, March 12, 2024 12:15 PM To: [email protected] Subject: Re: [ham-amplifiers] High Temperature in Toroid of the PI-L network (Alpha 78) ? Finally got it all figured out.? It's a bit of a complicated mess.? There is a total of 5 different? 'Q's'? involved on the GM3SEK? PI-L spreadsheet.? ? The short of it is.... I had to maladjust the 'total network Q' (line 39) to '7.74' ......so that the 'PI network Q'? (line 82, called? 'Q0PI' ) = 6.0? ? The 'PI network Q'? ? is what Peters is using to enter his Q of 6.? This is the PI-net portion of the PI-L.? On the GM3SEK sheet, only line 38 can be changed.? It spits out everything else.? INPUT Q? ? =? 4.4? ( Line 83)? ( called Q1) Input Q + Output Q =? PI network Q.? (4.4 + 1.6 = 6.0)? ?( PI network Q on Line 82) The L NETWORK? Q? = 1.7? ?(line 75) ( called QL) OVERALL NETWORK Q? ( called? Q0) =? ?PI network Q + L network Q ( 6.0 + 1.7 = 7.7)? I also used Peters 200 ohm image Z, and 1100 ohm plate load Z.? ?Then the main coil? comes out to peter's 29.0 uh.? ? I did have to maladjust the plate choke to 141.5 uh? to get the main C1 tune cap = to peter's? 350 pf.? ( the plate choke value has a big impact on the C1 cap...as the 2 are in parallel electrically.? Software spits out 1487.2 pf for the C2 cap.? ( close to peters 1500 pf) Software spits out 7.66 uh? ( close to peters 7.65 uh)? ? Short of it is I'm entering...? 'overall network Q'... ..while peter is entering .... ' the PI net Q'? ? BTW, coil current in the main coil is? INPUT Q x dc plate current.... and not PI net Q? x DC plate current.? ? (I verified this via actual measurement).? 4.4 x 2.75 dc amps? = 12.1 RF amps in the main coil.? ? ?Same deal with the simple PI network ( INPUT Q x DC plate current = coil current.) So it's semantic at best.? On 40m, min OVERALL NETWORK? Q that can be used with a PI-L? is? 8 ...........? ?(This is all based on having the MIN C1 being at least 14 pf).? ? The lower Q concept works on 160+80m...... but not 40-10m.? The Tube C is just too great.? ? |
