Thank you, Marty.
I wasn't prepared for a "text only" response to my dimension query. So the hard data exists in the form of statements like "moved the mast from Sta. 176 to Sta. 129.5" ? And Bill Harney then used them as guidance for his drawings?
My opening comment to the page you linked relates to the third sentence under Bell Labs installation: dorsal Vee, which reads: "This length did not include the lead-in wire which exited the aft fuselage through a feed-through insulator and connected to one leg of the Vee at a point a few feet from one of the vertical stabilizers."
I think there's considerable photographic evidence that shows the lead-in wire exited the starboard fuselage through a feed-through insulator in the cabin roof near station 239 and went forward to connect to the apex of the Vee. Two photos in the Purdue collection (b10f7i22 and b12f9i2) show the connection of the lead-in wire to the Vee quite clearly. (I have links to them, but they're each three lines long and I hesitate to dump them into this post--and I don't know what html tags are supported in these posts that would allow me to make them shorter).
It's the second sentence, coupled with the fourth sentence, that prompt my primary comments to Mike Everette's dorsal antenna write-up. These are: "The antenna was, therefore, a total of 46 feet, doubled back onto itself." and "This antenna was, then, already 15% longer than optimum;. . ." He makes like statements about the revised antenna in his research report, substituting 54 feet for 46 feet.
In each case, Mike is comparing the total length of the horizontal V portion of the antenna to a reference antenna length of 40 feet. The problem with that is twofold:
1) The V portion is just that--a portion of the antenna, not "the" antenna". The antenna also includes the lead-in wire (runs from the V to the feed-through insulator), the interior wire from the lead-in to the transmitter, and the wire from the transmitter to the airframe. These latter wires cannot be disregarded.
2) The effective length of this antenna configuration can be much shorter than one might think. To a first approximation, it equals the length of wire that runs from the airframe to the farthest point on the V. As an example, suppose you have two 27-foot legs and a 7.5-foot "feed-line" that runs from the airframe, through the transmitter, and connects to the V at a point 9.75 feet aft of the apex. The approximate effective length is 7.5 + 9.75 + 27 = 44.25 feet (not 54 feet or 54 + 7.5 feet). In this ideal case 17.25 feet of one leg is inactive and can be ignored.
I want to emphasize the use of approximation in 2)--but it's an approximation that may have been used by a technician tasked with sizing an antenna in the late 1930's. I've found two variants of the approximation from the early 1940's. They each differ slightly from the wording in 2), and make for a bit shorter estimate. One measured from the transmitter output terminal; the other from the feed-through insulator. Applying the latter method to the dimensions I'd derived from drawings in Amelia's Shoes gave 40 feet as the estimated length. This may be just an interesting coincidence. (I have no great confidence in my dimensions, a situation I'm hoping to improve via this forum.)
An upshot of all this is that, sadly, the dorsal V as used on AE's Electra cannot be computer-modeled simply as a horizontal V with the source positioned in one leg of the V. Doing that defines a totally different antenna.
Chuck Varney