Hello. I spent a night building a portable longwire out of scrap acetal,
stainless steel wire and a few other scrap parts. It works well but not as
fast to use as I'd like, and the shape for stowing means it's not a circular
coil and there is no guide to keep it winding easily without overrunning the
edge of the former.

To make something that can be set up and taken down so easily I could do it
at a run, I looked at two existing widgets that might do very well: Centrepin
fishing reels, and kite winders. I settled on the kite winder as being
slightly cheaper, more durable, etc.. eBay listing 270879102395 shows the one
I'm interested in. I haven't bought it yet, because a question remains...

Assuming I start at some tree on open ground and run the wire to where I want
to set up the receiver, I will usually leave some wire on the reel. The reel
is about 28 cm wide, about 25 mm along axis, and entirely made of stainless
steel. Is the metal attached to the antenna wire in this way going to affect
its ability too much, even if I take care to prevent electrical contact with
the ground?

Alternatively, I can lay in an plastic channel inside the reel to insulate
the wire from the rest of the reel, and modify the guide to contact the wire
while insulating it from the bulk of the wheel, which in turn might make a
convenience of a connector mounted on its chassis, so the bulk metal becomes
part of the ground, but then the question is this: Would the capacitance
formed across that insulating channel be enough to adversely affect the
longwire performance, bearing in mind that as well as LW I'm also interested
in using this method to listen to HF up to around 20 MHz too?

Another question.. I'm considering a similar (but less demanding) idea for
laying out radials for a temporary ground. For ease and speed these would
have to be laid out on the ground, and the receiver will be battery powered,
so this would be its only electrical reference to the ground. Is this ok, or
is there some better way to make a portable ground? Meaning, something I can
carry on foot for miles with little effort.