IW3GHD
| Joined: | Sun, Feb 6th 2011, 20:24 | Roles: | N/A | Moderates: | N/A |
Latest Topics
| Topic | Created | Posts | Views | Last Activity |
|---|---|---|---|---|
| Delta loop 4NEC2 model | Nov 28th 2012, 21:27 | 2 | 7,962 | on 29/11/12 |
| 4CX250B cathode driven input impedance | Jan 6th 2012, 15:30 | 1 | 7,393 | on 6/1/12 |
Latest Posts
| Topic | Author | Posted On |
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| Delta loop 4NEC2 model | IW3GHD | on 28/11/12 |
| I'd like to post a full parametric 4NEC2 model of a single element (just for now) delta loop antenna which includes a gamma match. If you run the optimizer for example one can find the minimum SWR and/or the resonance condition (min Xin) by playing with antenna perimeter, wire diameter, pigtails parasitic elements, gamma rod length or spacing as well as the gamma capacitance. IW3GHD |
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| 4CX250B cathode driven input impedance | IW3GHD | on 6/1/12 |
| Dear forum, I'd like to design the matching PI input network for my 2x 4CX250B homebrew cathode driven HF amplifier and furthermore get into a deeper understanding on the optimal energy transferring from the RTX to the amplifier. I couldn't find any helpful in databook or SPICE models of such tubes. May I get use of the PC-EL software somehow? What is the cathod impedance in a grid grounded configuration? Someone said 120 Ohm per tube with 15 pF or so in-parallel capacitance, but I don't have any datasheet confirmation on that. Thanks indeed 73 IW3GHD, Stefano Italy |
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