[TowerTalk] Beverage Layout Problem

[Edward Sawyer]

You're going to have to explain that some more for it to make any sense.
The total cable loss for 200 feet of RG-213 at 7 MHz is about 1 db.  It
seems to me that you'd have to have some really horrible impedance
mismatches for the difference between RG-213 and LDF4 to even be noticeable.

 

The best clue that something is skewed, though, is your comment that the
noise floor changes a bunch and the signal level not so much. That sounds
like a termination problem of some sort, or more likely some kind of open
shield in the RG-213.

 

73,

Dave   AB7E

 

RESPONSE - That's because its not about loss differences.  Its about the
lossy coax also picking up sufficient noise to be amplified by a preamp and
create noise floor.  If you don't believe it. Lay out 200 - 300 ft of RG8x
or Rg6 on the ground and connect a 20dB preamp to it and see if you hear
anything with a good receiver - mine's a FT1000MP Mk V (and supposedly that
isn't even any good - although I never seem to have problems hearing more
than most other people).  Then do the same thing with LMR600 or LDF4.  All I
can say is - there's a difference.  And when you then connect a long
beverage to it, you can hear more than with lossy coax.

 

Possibly if the pre-amp were mounted on the beverage feeds, you wouldn't
hear as much noise pick up.  But with 5 beverages, that's a lot of preamps
for me.

 

Ed  N1UR