if it matters, than your best bet is to forget finding a period electric one. they're long gone, unless you can find an NOS (new old stock) one sitting around collecting dust.

that leaves you with a manual antenna. you should be able to get a decent bosch manual one from a dealer i should think. or try maximillian imports (800-950-2002)

if originality doesn't matter, then try radio shack. i heard they have a pretty nice electric one that looks pretty close to an old hirschmann (more commonly found on mercedes, but still found on the occassional E9 -- mine, for one.)

(personally, i always preferred manual antennas. they electric ones inevitably get all that crud in them and jam up.)

i'll measure the distance from my antenna to windshield in the next day & post the distance.

best,
doug
73 E9