¿ªÔÆÌåÓýThis board does not use band pass networks.? My friend ran them through and found they are only low pass chebychev Filters.? He sent me the graphs. I can post them tomorrow.?
This board is only low pass with each band having a sharp cutoff to prevent harmonics.? It also only provides as tested about 30 to 40 ohms of matching.
This should work for a 50 ohm tube.? Remember,? the L is fixed.? You can only adjust the caps.
For other tubes where you need more matching range, I think an adjustable L/pie would be best.?
I ordered new t68-2 cores.? I will wind a new 40 with one when they arrive and report back. I am at a loss as to why the cores he sent with the correct wire and turns has double the L.
C
On Jan 16, 2024 4:25 PM, "Jim VE7RF via groups.io" <jim.thom@...> wrote:
Ok,? I just checked my own manually tuned, tuned input, which cover 160-15m.? Tuned for 3750 khz, (1:1 sq swr) ,? swr rises at 4 mhz...and also 3.5 mhz.? And rises even more the further I go below 3500...or? above 4000 khz.? ? Same deal on all bands. This is for the hb 3x3 amp. On my L4B's.... flat input swr at 3750 khz..... which rises at both band edges.....and again rises even more, the further above or below the band edges.? ? Just got off the phone with scott.? He previously tested the new manually tuned, tuned input on 160-15m.? Same deal..... forms a bandpass response.? ? That WD7S (paul hewitt, now sk)? setup has always worked in the past.? ? Dunno what the deal abt measuring a toroid? (in this case a powdered iron, red core with a mu-2...... or the yellow cores with their MU=6)? ?with a lcr meter is.? I never had issues in the past.? ?? ? Those powdered iron cores are all colour coded.? Red / yellow / blue.? ? One thing to check is,,,,? put watt meters on both sides of the tuned input.......and make sure u are not losing anything.? ? Something is amiss somewhere.? ?IMO, 22/20 ga wire is on the small side....for the amount of current flowing, but that's a non issue right now.? Those tuned inputs should work, and also show a bandpass response on each band.?? This kind of stuff drives me nuts.? |
