[NLRS] 1296 antennas

[jcplatt1@mmm.com]

Some quick thoughts Jim in no particular order:

   I've used DEM loops on 902, 1296, and 2304 for some time with good
   success.   The loops on 902 are a bit big and do have the bird probl=
em
   if you mount them loops up.   I do believe that the antennas are rob=
ust
   (electrically and mechanically) and provide good performance even wh=
en
   banged up a bit.  My recommendation is to stay with the loopers and =
that
   your problems are elsewhere.
   To prevent bird damage which is more severe on 902 with its big loop=
s,
   hang them upside down or, loops down.   I have a small horizontal
   H-frame with one 902 loop on one side and a 1296 loop on the other .=
....
   on the 1296 side, mounted above it and in the loops up position is m=
y
   2304 looper with its small loops that are bird proof.   This has bee=
n up
   for several years and the loops have stayed round.
   I don't think your problem is antenna related.   I suspect the probl=
em
   is somewhere between the RF port on your rig and the N connector on =
the
   antenna.   Water in the feedline, a middle pin on an N-connector tha=
t
   isnt making proper contact, deer eat your coax ?   Sometimes its han=
dy
   to have a 100' run of LMR400 around to switch in to see if the probl=
em
   goes away .... can you steal a feedline off of another antenna just =
to
   see if the SWR changes ?
   Also, how is your antenna for clearance with respect to trees, are y=
ou
   in the clear, or do you have trees.   Based on my experience, starti=
ng
   at perhaps 432 but definitely by 903, that tree foliage does suck up=
 RF
   ..... if you are shooting into trees you have a problem there.   Fol=
iage
   on 2304 is big.   Worst case is when its 20 to 200' in front of your=

   antenna.    Also, aiming is somewhat more critical on 903 and up,
   especially if the signals are weak.

Hope this is helpful.   Good luck on getting your system working as I a=
m
looking forward to working you on 1296 myself.

73, Jon
W0ZQ



                                                                       =
                                                               =20
                      Jim Johnson                                      =
                                                               =20
                      <jimj@uslink.net>        To:       NLRS <nlrs@mai=
lman.qth.net>                                                  =20
                                               cc:       (bcc: Jon C. P=
latt/US-Corporate/3M/US)                                       =20
                      06/10/02 11:16 AM        Subject:  [NLRS] 1296 an=
tennas                                                         =20
                                                                       =
                                                               =20
                                                                       =
                                                               =20





What does everyone reccomend for a 1296 antenna? I am using a 45 elemen=
t
loop yagi now but I mounted on top of the 15' mast "elements up" and I
suspect the birds have bent the elements? The reflected power is real
high where it was almost flat when I put it up last year. I am thinking=

about changing it out for a M squared 23CM35EZ 35 element yagi I have t=
o
tip the tower to fix the old one so replacing is a option since it will=

be accesable. Granted paths are differnet but when Bill K0AWU hears
W0GHZ 5.9 on 1296 and me being 7 miles away I cant even detect him ther=
e
is something really wrong there. I used new 7/8" andrews up the tower
and a short 9913F jumper for a rotor loop to 1/2" heliax to the antenna=

so feedline should not be a issue. I have tryed 2 different transverter=
s
here still have both and neither one hears any different.

Suggestions? Comments?

The 45 element loop is a Directive systems antenna 2345LY
45 element Loop Yagi, 1270 - 1300 MHz, 20dBi, 16=B0, 11'9" boom

M2's antenna claims 18.4 dBd so compairable gain between the 2
www.m2inc.com

I think the differance was what -2.3 dB between dBd and dBi right?? The=

isotrophic radiator has less gain than a dipole some say 2dB I have
heard 2.3dB I think ?

Basically same gain for the 2 antennas from what I figure. Is there a
advantage? one over the other?

73
Jim
KB=D8CIM  EN37

_______________________________________________
NLRS mailing list
NLRS@mailman.qth.net
http://mailman.qth.net/mailman/listinfo/nlrs


=