December 2004 - January 2005 hunts for 146.91 problems
Paging on 146.31. TOI. One of the freq's is 47.68mhz. Theory, Lebonon
Mountain, Hancock. Heard at the Pittfield Airport.
Re-tranmission: Middleburg 146.61(123pl) re-transmitted on 146.31.
Suspect un-identified link transmitter pointing towards Syracuse?
Kerchunker: No details here, call me at home or on 146.58.
More details after the hunt is complete.
May 10-15, 2003 A Hunt for the 146.91 Interference
Some time in March we started hearing paging interference on 146.91.
During the winter without access to Mt. Greylock the only thing we
could
do was guess at the source. I did a PC signal compare to several paging
companies in the area and discovered 157.74 was the page we were
hearing. I went to three of the 157.74 sites in our area and heard
nothing on the 146.31 input frequency. So my guess was that maybe we
had
another case of third order intermod in the 146.91 front end like we
had when 144.39 packet was interferring. We still could not get to Mt.
Greylock to even try that theory so the problem just persisted. No way
to prove anything until the mountain opened. Then on a weekday of the
eneding May 3/4 Sigurd (KJ1K) and Ed (N1FGY) made a successful trip up
greylock in a 4x4 pickup truck. They took out the pre-amp and the noise
was still there! They also hooked an HT to the repeater antenna and
found that they could hear the interference on the repeater input! So
now the hunt was on! On May 10th Sigurd and I (Tim/KE3HT) went up
greylock again and got some confusing bearings until we got on top of
the mountain by the monument. We got a nice 55-60degree bearing from
there. I used a three element tape measure beam (see our equipment page)
and a home brew switched attenuator. I even combined them with body
sheilding (the process of using your body as an additional reflector to
narrow the beamwidth of the Back side of the beam) to get as narrow of
a
bearing we could. Sunday May 11th I drove out to Greenfield, MA in
order to get another bearing. I just wanted to see if the direction was
NH or Maine. I got two bearings 345 from the east site and 330
from the west site. These two did not intersect with each other. This
meant that one or both of these readings was not to good. In any case
the signal was Not in Maine. when you look at the Mt Greylock line and
its intersection with these you could see the signal source was
probably
within in 10 miles of a town called Marlboro. It was probably a one day
trip. I took Thursday off and Ed joined me to take a closer
look at the source of the interference. Some of the many reports we had
on the interference said they thought it was near Bennington so we took
off along Rt 8 and stopped in Searsburg. We had nothing to the
west towards Bennington but we had a good signal towards the east at
80degrees. Looking at the map we now knew that our four lines all
surrounded Marlboro. We picked a site that was the target of one of our
Hounds hunts, it was called the HogBack Mountain. We figured we could
have a nice clear line of sight signal. When we got there we discovered
that we could not get a bearing! We were on top of it! Even with 96db
of attenuators switched in and No antenna I could not tone down the
signal. We did discover that as we drove away from the site with no
antenna we could get the signal to drop off so we measured the distance
away from the top we went on each side of the hill before the signal
dropped off and found the top to be at the center of our measurements.
We did see a couple of other towers on another hill top to the west of
us on the Hogback shi area. So with the attenuator on 96db and no
antenna we went towards the other towers and the signal dropped of. So
we are pretty sure of the source of the 146.325 signal. Turns out this
hill has a 157.74 transmitter on it! This hunt took a few days of
work but it was fun to use our skills to find a real interference
signal. This information and maps were e-mailed to both Mt Tom and Mt
Greylock repeater clubs presidents. The source: N42 51.230 by W72
47.684.
Click on these maps for larger versions.
Don (N1ISB) was called around 8:30am and was asked to see who might be
available for a search and rescue mission involving a plane crash at
5:30am. At around 11am Don was calling us back and asking for us to
make
the trip to the Williamstown Fire department. Ed (N1FGY), myself Tim
(KE3HT) and Don (N1ISB) all made it there and signed in. Three officers
and three hams were the first search parties to start looking for the
plane. The State police might have been looking to get a helicopter in
there after the clouds cleared but after awhile it started to look like
the day might stay overcast. Thats when the first foot search parties
went in. We were escorted with sirens and lights by MASS state
enviornmental police to a back road just east of Berlin mountian. Ed
and I took our search gear and mounted ATV's with two of the
police officers. My portable 5 element beam was a bear to handle and
still be able to hold on to the frame of the ATV. The trip up the
mountain only had a few obstacles to overcome. The first was a bridge
out which required the ATV's to make a river crossing along some rocks
then climb the other side of the river bank. What a neat ATV! I took
the chicken way out and crossed on foot. We had a couple of trees in
the logging trails to go around but we did not have to stop till we
were facing a up hill slope that the ATV's could not climb. We were
three teams but split up in the woods. Ed took the south ridge, I took
the center ridge and a police officer with no df equipment took the
north ridge. Ed heard a rise in the noise, which is trade mark in AM
signals, to the north of him. I was to close to the shadow of my ridge
to hear anything but I confirmed the position of Ed and my police
officer used his compass to figure out which way was north of Ed. The
officer to our north went further north of us when he picked up the
scent of Aero-fuel. That lead to the helicopters circling him and the
plane was found. The police did not really want us on the scene but my
officer (Sgt. Terry, id=S18) was very poilte and concerned for my
safety. He really did want to help get us into a position to DF the
plane. The State Police should be commended for such fine officers. The
only thing that might have gone better if that we should have started
earlier in the morning to hear the ELT (Emergency locator transmitter)
before its battery ran down. The signal got weaker to the point of
dissappearing by the time they actualy got to the plane. Ed only got
one
bearing on the signal and as he got closer to the ridge got closer to
the shadow of the hill and of course lost the signal. You can view the
news broadcast of the story from WNYT and see how
things were interperted by the news crews. Nov
15, 1999 update: A nice thank you from a friend of one of the pilots of
the plane. He also sent a set of pictures to be seen here.
September 26th, Greylock, lost day hikers at night !
We had a real hunt this evening as well. Right
after the NOBARC club meeting N1FGY,KJ1K and KE3HT were up at Greylock
looking at the split pipes on the tower when the call came in that
there
were lost hikers on the mountain. The hikers had Motorola FR50 radios.
We had some trouble figuring out that channel 14 was 447.7125mhz. With
good weather the hikers were able to signal a hellicopter with the
exact location so our attempts at DFing them were not successful. I was
totaly unprepared for the event. I also never heard that I should stand
down from the hunt. I think the ground crews were successful in
extracting the hikers but it was so late a night that the net control
just stopped when they were done. I am not sure. I would like to be
more prepared next time. Two areas of preperation are needed.
#1 We should be prepared to hunt for lost hikers
or hunters that may have radio's even if they are not ham radio's.
#2 We should be prepared to hunt for people that
interfere with the operation of any emergency event. There are $20,000
fines for emergency interference. In some cases there are also rewards
to catch the jammers.
SOLUTIONS:
#1 We are looking at the idea of putting some of
the more useful frequencies used by hikers and travelers up on this web
site somewhere so we can get fast access to them should the need arise
again in the future. When you see them posted, print them out and stick
them with your ham gear. I also have a plastic carry all box that I
keep
my dop scan stuff in, I just added the list and a scanner so I can scan
for out of ham band signals.
#2 Everybody likes to monitor the frequency when
there is a real emergency. Many do not say anything unless they have
something useful to say. Would you like to help without being to
involved or leaving the house on a cold winter night? PLEASE when you
hear a jammer on a real emergency event, CHECK THE INPUT, and report it
on another repeater or simplex. You can do this without leaving your
easy chair. For instance if a WX problem is going on on 146.91 try
449.426(-)(pl162.?), 147.03 or even 146.52. If I hear anything
happening
I plan on being out there with the dop scan and I need the help of
everyone sitting at home. Please press the REV (reverse) or MONI
(monitor) buttons available on almost every ham radio. If you hear the
jammer, note the Signal level and call it in on one of the other
frequencies.
To return to return to the NoBarc home page click here.
This page was last updated 20
January, 2002 20:45 -0500
