[NCARC] 145.115 shutdown

[ab0sf]

Steve Henry wrote:

>Howdy-
>
>Unfortunately we've run into an interference problem with the 145.115
>repeater output signal.  Great Western Railroad contacted us a little while
>ago with this information (courtesy of Jim, N7VDR and a relay from K0OJ).
>This has been confirmed by several hams who hve listened on Great Western's
>repeater frequency of 160.620 and heard the output signal from the 145.115
>
>It's likely we have an intermod problem, but it is also possible that the
>recent repeater realignment may need to be examined.  In the meantime as of
>9:00 pm this evening 1/4/04 we will shut down the 145.115 repeater.   Our
>plan is to solve the interference problem as soon as possible and then get
>the repeater back up and operational.
>
>Here's the general outline of the plan we're following, and how you can
>help.
>
>1.	George, AB0SF is working with Jim, N7VDR of Great Western Railroad (glad
>we have a ham working at Great Western!) to see if there are hours where we
>can make the repeater available for general use where Great Western Railway
>won't be using their repeater equipment for train communications.  At a
>minimum, we will find out times where we can run experiments to track down
>the issue we are facing.
>
>2.	At specific times, we will be running a series experiments to isolate
>whether this is intermod problem (likely) or a spur problem from the
>repeater:
>
>a)	Rule in or out spur problem:   use a spectrum analyser that we can hook
>to a directional antenna and determine what the signal looks like coming
>from the 145.115.
>
>b)	If it is a spur problem, George AB0SF can realign the repeater.
>
>c)	If it isn't a spur problem, we need to track down where the mixing is
>occuring creating the intermod output on 160.620.
>
>d)	Long distance DFing:   Hams with directional antennas and receivers that
>are capable of being tuned to 160.620-- we will need your help during test
>times to see if we can determine if the intermod mixing is occuring up at
>the Horsetooth site (likely) or somewhere else in the area.
>
>e)	Short distance DFing:  Hams with good experience at DFing will need to go
>up to the Horsetooth site and we will need to discover if some piece of
>loose hardware or something else is generating the output signal.
>
>If you can help, we would sure appreciate it.  Please email Steve Henry at
>steveh291 at comcast.net if you can volunteer in any/all of the following ways:
>
>1.	A few volunteers who can do long distance DFing:  requires receiver at
>146.620 and a directional rotatable antenna.  We will set up a time where we
>will run an experiment and do some triangulation.
>2.	Several volunteers who can do short distance DFing: requires skill (or
>willingness to learn the skill) as well as antennuators, directional
>antennas, etc.  Also-- a willingness to go up to the Horsetooth repeater
>site.
>3.	A volunteer who has access to a spectrum analyzer and who know how to run
>it. Preferably someone with a directional antenna who can run this
>experiment very soon.
>4.	2 volunteers with 4 wheel drive vehicles, chains, and skill at going up
>(and coming down from) the Horsetooth site.  We will choose a time with
>reasonable weather and less than 1 foot of snow on the trail.
>
>If you have suggestions to this plan, please email this reflector
>'NCARC at mailman.qth.net' so that all can benefit from your suggestions.
>
>
>'73
>
>Steve Henry  N7GN
>President, NCARC
>
>George Salzmann,  AB0SF
>Technical Committee chair,  NCARC
>
>
>_______________________________________________
>NCARC mailing list
>NCARC at mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/ncarc
>
>  
>
Thanks, Steve. Just one point to clarify regarding this matter. The 
frequency we are interfering with is 160.260, not 160.620.

George