Lou, why would a 1:1? input swr raise alarms ?? ?I did notice on the heath SB-220? tuned inputs, the C1 + C2 cap values are very low? vs the L4B.?
IMO, the Q is way too low on every band.?
I gave up on tuned slugs years ago, like the infamous Millen? 69046 slugs.? You have to sit with a box of silver mica caps to get em right on each band..pita.? ?The ferrite slugs will only take such much power.? AC0C burned up the slugs on his highly modified? SB-200 amp...running RTTY.? ?The wire on em is puny as is....ditto if T-50's used...unless bigger roids used.?
If? ?T-50's etc are used, and mating ARCO compression trimmers ( and padded on 160..and maybe 80m).... per KM1H, they are good for 200 watts ssb / cw.?
On these metal tube amps, the pair of air variables and either tapped coil or roller ( 8 ga wire)? u can use any Q u want... always flat swr... and covers the entire 1.8-30 mhz.? Length of coax to ipa / xcvr ..and also? bias / b+ level / drive level, etc, is easily compensated... just tweak both caps for a match.? With the q on the high side, and on 80m, it won't be dead flat across the band.? ? No big deal,? ?I have one setting for the lower 80m portion..and another setting for the upper 80m portion.?
The concept of trying to design and build nine (9)? high powered, and bandswitched PI? ?tuned inputs was the final straw.? Now that's the ultimate pita.?
