[FADCA] TLH VHF Site Coordinates

[Chuck Hast]

Comments below...

On Tuesday 30 April 2002 14:53 L, you wrote:
> At 09:57 AM 4/30/02 -0400, you wrote:
> >OK, have one end of the path, now need the other end.
> >More comments below...
> >
> >> -----Original Message-----
> >> From: Doug Ferrell [mailto:kd4moj@kd4moj.org]
> >> Sent: Tuesday, April 30, 2002 08:19 AM
> >> To: fadca@mailman.qth.net
> >> Subject: [FADCA] TLH VHF Site Coordinates
> >>
> >>
> >> Morning All:
> >>
> >> 	Lost some of my messages during a HD crash... someone
> >> (Russ ???) was
> >> looking for the coordinates for the tallahassee tower. here Goes:
> >>
> >> 	AGL 173.88 Feet
> >
> >Is the where the link antenna will be?
>
>   Yep this is the elevation at the tower

AGL= Above Ground Level, that is the point  above ground level
where the antenna is sited on the tower.
The 173.88 feet is AMSL

>
> >> 	30.29.36
> >> 	084.17.01
> >
> >This is good.
> >
> >Is the below a separate tower? if not I am kornfused over the AGL
> >data...
> >
> >> 	Tower 400 feet
> >> 	42 inch tower face
> >>
> >> 	our antenna (Decibel 308) @ 389 feet
>
>    Tower is 400 feet tall. Antenna is @ 390 feet. Antenna Decibel Products
                                         ^^^^^^^^^^^^^^^^^^^ This is AGL     

> DB304 (Exposed Dipole Quasi-Omni Antenna) is 6.1dBd gain side mounted.


OK, this is going to be for the access point, what is going to be the link, I
am more interested in that info as the link data is what I need to calculate
the path between the two towers. I am assuming that you are going to
use either 220 or 440 for your link. Indeed it is not FADCA standard to
use the 2m side as a link as that is not a accepted way to link the site to
the rest of the network. It can be done so in a pinch but it sure causes a
lot of contention as the local users can not hear the distant switch trying
to talk to the local one.

We are getting there little by little, as soon as I have the link data for
both ends I will draw you all a nice little picture of the ray path with both
the planet curvature and the first fresnel zone. 

I will fire up my software tomorrow and start a radial plot (those are much
faster than the tile plots) of the access point, the contours will be 19 db
and 40 db quieting. 19 db is where a bell 202 starts working pretty well, 
and 40 db gives you a nice fade margin.


>
> {snip}
>
> >What I need are the following to calculate the path between the two sites.
> >
> >Tower 1
> >Lat/Lon (I can get the ground el from the data base if you do
> >not have it)
> >height of antenna AGL
> >To do link budget you can add the following
> >Antenna type
> >Antenna gain
> >Feed line loss or feed line type and number of feet between radio
> >and antenna, along with any cavities/amps or other in line devices
> >Also need the number of connector pairs along the path
>
> Total length of 1/2 (soon to be 7/8") hard line is 400 feet, 4 connectors
> (.5dBd loss per) and one pass cavity.
> 60 watts out to hardline.

What is the loss of that hard line/100ft at the freq you are going to use?
Loss/connector sounds good if they are type 'N' if they are pl-259 it can
be "not good"
What is the loss of the cavity?



-- 
Chuck Hast
KP4DJT
kp4djt@tampabay.rr.com
To paraphrase my flight instructor;
"the only dumb question is the one you DID NOT ask resulting in my
going out and having to identify your bits and pieces in the midst of
torn and twisted metal."