Re: VHF radio mic problems

"Richard Crowley" <rcrowley@[EMAIL PROTECTED]
> wrote in message
news:13v0lsj3f4cgt07@[EMAIL PROTECTED]
> "Christopher Jahn"  wrote...
> > "Richard Crowley" wrote :
> >> "Tim Perry" wrote ...
> >>> By placing a right angle BNC adaptor on the lower right
> >>> antenna you will be able to orient the antenna to vertical
> >>> without touching the antenna above it.
> >>
> >> Yes, anything that gets the antenna rods away from other
> >> metal objects is desirable.
> >>
> >>> A non-conductive sleeve such as heat shrink tubing or even
> >>> large soda straws will help prevent inadvertent grounding.
> >>
> >> But note that positioning the antenna rod(s) close enough
> >> to be at risk of shorting is likely not doing your signal
> >> reception much good even if it doesn't short. Anything
> >> metalic that is close to the antennas interferes (for better
> >> or for worse) with the reception. Murphy's Law tells that
> >> close-by metalic objects will make reception worse rather
> >> than better.
> >
> > Well, not Murphy's law so much as physics.

Right, but the poster seem to have little recourse in effecting any change
that might cost $.

>
> Well, if you are extraordinarily lucky, a nearby conductive
> object will form a director or a reflector at just the proper
> frequency and direction to enhance reception. But you'd
> likely have a better chance of being struck by an interstellar
> meteor. Thus my appeal to Murphy vs. more formal scientific
> theory.  :-)

Murphy deserves a special category just for wireless mic systems.

My last big musical the client dumped a pile of cheepo wireless lavs
rented
from a local music store (2 hours before show time - no advance notice) .
These were Gemini / Samson junk. After 20 min of testing I flat refused to
use them. with 2 HT wireless, 4 wired on stands, 3 shotguns, 4 PCC,  4
choir
mics taped to mic stands mics plus orchestra mics for a total of about 26
mics.

The wireless mic I used were Shure ULX mounted in a plastic rack at the
top
with front panel mounted 5/8 wave antennas (rubber coated). The receivers
were located in the pit with the stage monitor mix system.  The antennas
were... you guessed it, one straight up and one sideways :)

Once a year this system is used to broadcast (radio) a major race event.
To
increase the range and maintain 'line of sight' one antenna is taped to an
aluminum speaker/light stand. The stand acts as a ground plane.