Random vertical antenna
 

Hi there,

i'm thinking about build from scratch on the roof of my house a lightweight
random vertical antenna (with small pvc tubes or fishing rod) feeded by an
automatic ATU. The same antenna with some kind of leverage will be erectable
from 0° to 90° (plain to my *plain* roof) to avoid & prevent lightning but
this is a mechanical history... so:

Many posts about the Rybakov antenna reports the use of a 4:1 UN-UN. I'm not
sure about the real needs of this kind of un-un... you readers what have to
suggest about height and un-un if you have to build a random vertical to
cover 80-6 meters with a decent efficiency ??

TIA,
-.-. --.-

Random vertical antenna
 

"-.-. --.-" wrote in message
...
Hi there,

i'm thinking about build from scratch on the roof of my house a
lightweight random vertical antenna (with small pvc tubes or fishing rod)
feeded by an automatic ATU. The same antenna with some kind of leverage
will be erectable from 0° to 90° (plain to my *plain* roof) to avoid &
prevent lightning but this is a mechanical history... so:

Many posts about the Rybakov antenna reports the use of a 4:1 UN-UN. I'm
not sure about the real needs of this kind of un-un... you readers what
have to suggest about height and un-un if you have to build a random
vertical to cover 80-6 meters with a decent efficiency ??

TIA,
-.-. --.-

forget the un-un, just feed it direct with coax and put as many radials
under it as you can. most of the efficiency questions are then due to the
tuner.

Random vertical antenna
 

"-.-. --.-" wrote in :

... you readers
what have to suggest about height and un-un if you have to build a
random vertical to cover 80-6 meters with a decent efficiency ??

Most of us would understand efficiency as you have used it to mean the
ratio of radiated power to antenna system input power.

An unloaded monopole system that is long enough to be reasonably efficient
at 80m (say 13m) will have a radiation pattern that is most unattractive
at 6m where you would depend on low angle performance for most contacts.

Owen