Homer, do you think you have enough accumulated info on the 5/8 to draw a decent comparison to a .64 if you resurrect it by increasing it to 23'? Actually it should be right about 22' 10" for .64 @ 27.375 to offset the average diameter of the tubing.
You might want to feed it with a 10 turn coil at ~2" diameter and close to center tapped, though you might find resonance a little closer to the ground side, perhaps even only 2-3 turns up.
I'm sorry to hear about your radio melt-down, what happened?
I found this on ebay and have to share it, it's all you'd need for awesome SSB performance. (AM receive is incredibly good but AM TX operation requires a VERY tinny sounding mic to get decent performance without bass overdrive, such as an Echomax 2000 which works very well, especially w/o the echo crap.)
ICOM IC-751A HF XCVR - eBay (item 160497880786 end time Oct-31-10 14:26:54 PDT)
You could possibly get it for well under the average closing bid of $500-$600 due to the loose shaft possibly scaring away less courageous bidders.
The VCO(VFO) knob Shaft is easy to tighten.
I had to help a friend tighten his up, just remove the knob with a small allen wrench in the hole under the rubber grip and the other knobs, and screws along the edge of the face plate, then you'll find one more screw to remove behind the VCO/VFO knob.
REMOVE THE FACE SLOWLY & CAREFULLY BECAUSE THERE ARE WIRES GOING TO THE SWITCH-BUTTONS TO THE IMMEDIATE RIGHT OF THE VCO KNOB!
Simply tighten the hex nut on the shaft. It's really quite easy and should require about 10 minutes for the entire procedure including reassembly.
You'd love the incredible receiver clarity, and my TX sound quality with a Yaesu MD-100 desk mic constantly gets me unsolicited but highly complimentary audio reports.
Here are test results which show it scoring higher in some ways, such as 10KHz rejection (one CB channel) than even the newer Yaesu FT-2000 and Icom 7800:
Drake ICOM Yaesu receiver dynamic range measurement
I preferred, and kept, my Icom IC-751A while letting go of my Kenwood TS-940SAT & Yaesu FT-990, even though those are also very nice radios.
73
