why are these range tests not working anymore?

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10-25-2013, 08:37 AM
klar

why are these range tests not working anymore?

This is the scenario:
range tests are done every year in the same place with a variety of beacons. transmitting beacon is lying on the snow, searching beacon approaches in a straight line until there is a signal. alignment of searching and transmitting beacon is not changed. in the past years this has worked fine, with normal results. this time none of the results can be reproduced, range keeps changing between test runs (with the same beacons), etc. different beacons/ manufaturers all affected the same.

place is on glacier ice, next to a groomer and t-bar. in the past this did not cause noticeable issues. nothing obvious has changed. any suggestions what it could be? (my ideas are WLAN in the resort messing stuff up, recently burried treasure, or aliens.)
10-25-2013, 09:45 AM
Hugh Conway

Is there a dinosaur-tech analog beacon in the mix/could you ad one? It should be less susceptible to interference and/or would possibly give you audio clues to the source of interference if that's the problem. No electronic devices on the person executing the test?
10-25-2013, 10:48 AM
sar13

Power/phone line added to T bar haul cable?
10-25-2013, 10:59 AM
od

Did you or anyone else nearby have a cell/smartphone that was still left on in a jacket pocket?
10-25-2013, 04:26 PM
coldfeet

Trying to video the range tests with a gopro (or any device near the receiving beacon, really) ?
10-25-2013, 04:36 PM
PNWbrit

When you figure it out it might be useful to know what kind of fluctuation/deviation you were seeing and whether it was more noticeable in any particular beacon. Also when you say range keeps changing are you seeing changes in maximum receive distance compared to earlier tests or is distance to transmitting beacon once acquired actually varying on display as you proceed straight toward it?

It sounds to me as if all likely culprits have already been suggested.
10-25-2013, 04:37 PM
bfree

What kind of variation are you talking about? A couple meters or ten or ?
10-29-2013, 06:21 AM
klar

Thanks for the input. I should add I wasn't actually there, I was just asked to help brainstorm. These people do this stuff a lot, in a very routine manner, so they wouldn't have gopros or phones or something like that lying around. The issue was with maximum range, as in "at what point do I first get a clear signal when walking towards the transmitting beacon". Results were different from previous tests and also differed between runs on the same day, with the same beacons. Variations 10+ meters.

Quote:

Originally Posted by Hugh Conway

Is there a dinosaur-tech analog beacon in the mix/could you ad one? It should be less susceptible to interference and/or would possibly give you audio clues to the source of interference if that's the problem.

They tried that and got some vague signals but couldn't identify a source or even a clear direction.

Quote:

Originally Posted by sar13

Power/phone line added to T bar haul cable?

possible. I suspect it will turn out to be something like that, or someone was fucking with them.
10-29-2013, 03:40 PM
theshredder

Were these tests done on the 25th around 15 UT? A solar flare disrupted the ionosphere on that day according to the space weather archives. They can disrupt long-wave radio transmissions and transceivers use the same part of the EM spectrum.
10-29-2013, 06:42 PM
Hugh Conway

How close is it to the drive motor for the T-Bar? Worn motor/new control system?

Or maybe the NSA is tapping euro-beacons in addition to phones?
11-01-2013, 04:30 AM
klar

Quote:

Originally Posted by theshredder

Were these tests done on the 25th around 15 UT? A solar flare disrupted the ionosphere on that day according to the space weather archives. They can disrupt long-wave radio transmissions and transceivers use the same part of the EM spectrum.

The times and date match really, really well and that is a wonderfully freaky explanation. Cool.

Quote:

Originally Posted by Hugh Conway

How close is it to the drive motor for the T-Bar? Worn motor/new control system?

Or maybe the NSA is tapping euro-beacons in addition to phones?

There is a terrain park there and they have one of those airbag things that people jump into. This has a motor which is kinda close but really should still be far away. Also depends on where the cable and the switch is, I suppose. I have heard rumors that the US military has a program working on how to target specific beacons, so they can disrupt the signal if a terrorist finds him/herself in a companion rescue situation. Perhaps they were practicing.
11-01-2013, 07:27 AM
Scottish_Skier

Quote:

Originally Posted by sar13

Power/phone line added to T bar haul cable?

^
Ever since it got converted from diesil to electric my beacon (bca T2) goes haywire if you put it into search mode near the top t-bar at Glencoe.
Remember that when doing a range test the beason is trying to amplify / detect the smallest RF signal it possibly can.
Any small changes in the background EMI noise level could affect results.

3 suggestions / things to consider

1) Background EMI noise could be affecting the range result. For example an electric motor.
2) Does each beacon have 100% battery charge ? Especially in the cold, then it could make a difference ?
3) Frequency drift can also affect range as beacons get older : more so with older analogue models (i.e F1s) that used ceramic oscillators for the 457kHZ.
http://beaconreviews.com/transceivers/Frequency.asp