Brian Gregory [UK] wrote:
wrote in message
...
Because the presently made MLB-1 by Palomar Engineersis a UNUN for a
longwire. The older transformer which I used (may have the original
instruction paper somewhere) was a true BALUN. To build a T2FD we must
use a balun, since it is a broadband dipole.

A long wire balun should not assume you want a common ground connection on
the input and output.

But I've look at the picture and description of the MLB-1 on the web and I
agree it's far from clear what connections are provided.

However if I bought it and found it did have the grounds joined I'd return
it as unacceptable because when using a long wire you want to use a separate
good quality earth which is not joined to your receiver's earth which may
have RF noise on it.


I disagree. Use on an UnUn (autotransformer) puts all points of the
system at ground, provided you ground per electrical code. "Noise" from
the radio chassis (?) flows to ground through the IEC cable. Static
charges from the antenna system flow to ground at the transmission line
point of entry.