What about 5 gig
Are you doing long runs and amps at 5gig?
Blair Davis wrote:
We use both methods, depending on how hard the location is to climb....
For locations that are easy to climb, we put the radio at the top.
We've made our radios easy to feild swap on the tower. Four nuts, one
N-connector and an outdoor cat5. This swaps everything except the
antenna and coax. Static protection, grounding, electronics all swap
out as a unit.
For locations that are hard to climb, I use radio at bottom, amp and
antenna at top. Started out using HyperLink amps, now use RF Linx.
Over 7 years, I've had 2 amps fail, and 1 antenna and amp destroyed by a
direct strike. In the direct strike, the amp saved the coax down the
tower and all the radio gear below...
And RF Linx replaced the amp under warranty.....
There is room for both methods and a wise engineer picks the appropriate
one for the location.
JohnnyO wrote:
Jeez Ralph - your post is misleading to EVERYONE that is reading this.
Do you know what loss per 100ft is on 7/8inch heliax on 2.4ghz which can
be had for $1.50/ft ???? What is your loss at 900mhz on 7/8thinch heliax
? How about lost per 100ft at 5.8ghz on 1 1/4inch heliax ?
Scott - here is the following specs for your loss you'll expect... By
all means - if you can afford to leave your radios at the bottom of the
tower - DO SO ! and ignore posts like Ralphs which are nothing but
BS....
Loss on 7/8th Heliax per 100ft
2.4ghz = 2dB
900mhz = 1.1dB
Loss on 1 1/4 Heliax per 100ft
5.8ghz = 2.2dB loss
2.4ghz = 1.5dB loss
900mhz = .8dB loss
You'll need to add .5dB of loss per connector.
Putting your radios at the bottom and using some 250mw Teletronics AMPS
will give you a much better system then if you were to leave your radios
at the top because your AP will also see a 17dB gain on the receive
side.
You will not be creating "noise, interference" if you use the proper AMP
!
Scott - contact me offlist if you need some help deciding what cable /
amp combos to go with.....
The nice thing about running cable up your towers is - once you
weatherproof your antenna and install the proper grounding straps along
the run, you will more then likely never have to climb that tower again
!
Ralph - please enlighten us with the reasons you've stated EVERYTHING
you did.... Opinions are one thing, but false information is completely
different and the only reason JohnnyO decided to take on this mule
headed post :)
JohnnyO
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Ralph
Sent: Saturday, March 17, 2007 8:38 AM
To: 'WISPA General List'
Subject: RE: [WISPA] LMR600, LMR900, Heliax
You can buy them at Tessco, I'm pretty sure. Stick with Heliax (r)
type
cables (hard line) for those distances, and use 1 5/8 minimum. The loss
is
amazing at anything above 450 MHz. Look at any cell tower and you will
see
what you need to use, then count on twice the loss if you use 2.4 or
many
more times that at 5.2 or 5.8 Look at a price range of tens of $ a
foot,
once installed properly.
This brings you to the next obvious issue. Now for the lesson in RADIO.
You have degraded your system so much by adding loss, you can figure
that
your antenna just magically became 0 dB gain instead of what it was.
You
may even totally offset the antenna gain and be upside down (as they say
at
the car dealer down the street).
So go buy the best antenna you can, with the most gain possible. Of
course
now that moves us to the next step. Can't get a high gain antenna
because
now the tower company wants more rent, or the wind load is too high, or
the
pattern is too narrow.
On to the next step- More APs so you can cover the areas that your new
high-gain antennas leave out. Then, more hard line, then more $$$ etc.
Or you can take the illegal, easy way out. Buy Amp. Create noise,
Violate
Part 15 and your radio's certification. Leave yourself open for a fine.
Sounds to me that you are better off doing what most discovered the hard
way: Leave the radios up top, do a great installation job,
weatherproof,
lightning protect, and enjoy the power you paid so dearly per milliwatt
for
in the first place!
Ralph
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Scott Reed
Sent: Friday, March 16, 2007 6:05 PM
To: WISPA General List
Subject: [WISPA] LMR600, LMR900, Heliax
Who supplies pre-terminated (N connectors) cables in the 70 to 150'
range using LMR 600, LMR900 and/or Heliax? Looking to move radios to
the bottom of towers.
--
George Rogato
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