well, check on the internet to see what the feed point impedance for that 
sort of loop would be.
Then, bassed on using the latter line, or twin lead, which ever you have, 
you can figure out if you need a balun or not.
I've heard of  G5rv's with both 300 ohm twin lead, and 450ohm latter line.
I don't see a problem with disconnecting the feed line from the G5RV, and 
reconfiguring it into a loop.  Then, you could use regular 50ohm coax to 
feed it...I don't now remember, but a loop has a high feed point impedance I 
believe, so you might need to use a balun.
By my calculations, a 102 foot g5rv, in a loop, would allow you the lowest 
operating frequency of 9.85MHZ.
So you would be good from 30M and up.
You might be able to get 40M if you use your latter line as part of the 
antenna.
Also, and you may want to check, but I don't think you want to have any of 
your loop angles to be sharper than 60 degrees on the inside of the turn.
So if it's a diamond shape, some of your inside turns might be sharper than 
60 degrees.
I think the tightest loop is a delta loop which has 3 60 degree inside 
turns...I remember reading that if the loop has sharper turns than that, it 
no longer functions like a proper loop antenna and you start running into 
SWR, feed point impedance and odd lobe issues.

73
Colin, V A6BKX
----- Original Message ----- 
From: "Michael Ryan" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, July 07, 2011 10:43 AM
Subject: G5RV to Loop


> Hi All:=20
>
> Still trying to figure out what to do with my G5RV not tuning properly =
> with the internal tuner on the Yaesu FT-450.=20
> With regards to converting it to a 40/10M loop, would it be pretty easy  =
> to detach the ladderline component, and move it, resoldering it to one =
> of the corners for feeding?=20
> Right now, the G5RV is like a T with the ladderline section hanging down =
> from the center. I'm thinking of removing this ladderline section, the =
> end insolators, have 20 feet of wire soldered on each end,=20
> closing them up to form a somewhat diamond shape and resoldering the =
> ladderline section to this newly created point for feeding. =20
> Would I have to add my old 4/1 balun?=20
> Would all this work or am I just barking up the wrong tree.=20
>
> 73:=20
>
> Michael De VO1RYN=20
>
> P S=20
> I do plan on rearranging my shack to shortin' up way too much coax and =
> ground wire.=20