Phil,KB0NES writes: "Over the past two months the City of Burnsville has been having our main repeater site water tank painted. Typically this is a project they undertake every 8 to 10 years. This time around it was easier as they didn't have to blast the tank to bare metal for preparation. The old paint was in decent shape so they were able to simply pressure wash and paint. There were some structural and mechanical improvements made as well.
One issue that made this project differ from prior painting projects was that the workers were wearing RF exposure monitoring alarms. These devices will alert the worker if they get into a strong RF field near a transmitting antenna over an operating range of several MHz to several tens of GHz. The greatest dangers when up on the tank are from the highly directional cell phone panel antennas which operate near 100% duty in the low microwave range. These have pretty high power density and it wouldn't be good to have your head in the beam path. Our antennas have an omnidirectional radiation pattern. They operate at low frequency; power and duty cycle so in comparison they are much safer. During past painting projects we never shut off our equipment. But this time even our low power-density signals would set off the worker’s safety alarms.
So for this project we had to shut off the systems daily during the hours that the workers would be on the tank. The two main concerns we had with the shutdowns were the IronMan bicycle ride and any Skywarn alerts that may occur. We managed to work out the schedule with the contractors to allow us to be up for the IronMan and luckily we had no Skywarn alerts. Of course in the case of bad weather most likely the workers would get off the tank and with a few phone calls we could have likely resumed operation. All of the systems could be controlled remotely so the hassle was not so bad.
They wrapped up the project a few weeks ago and the tank once again looks shiny, white and clean. For the first time in my memory they have applied "Burnsville" decals to the tank(s) to give them their own distinctive look. With luck we won't have to go through this again for a number of years."
The long awaited 100 Hz CTCSS tone (PL for you Motorola fans) is now on the 147.21 repeater. This means you must transmit a 100Hz subaudible tone in order to open up the repeater.
Kevin is also experimenting with a PL "wakeup" mode which would require a 100Hz tone every 5 minutes. This will allow a conversation with someone without a tone as long as the other person has a tone.
Kevin is also experimenting with a dtmf wakeup mode where transmission of a * (lower left corner of your keypad) would be required every 5 minutes.
Posted by w0kf on: Sunday 14 September @ 18:51:54 Read More... |
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Four Repeaters on Four Bands!
Which organization is the only one to have FOUR REPEATERS ON FOUR BANDS? The Twin Cities Repeater Club, of course!!
We have repeaters on 6 meters (53.37MHz, 100Hz tone), 2 meters (147.21MHz, 100Hz tone), 1.25cm (224.54MHz, 100Hz tone), and 70cm (444.3MHz, 114.8Hz tone). Give them all a try.
No, you don't have to be a member of the TCRC to use our machines. However, at $25.00 per year why not join us?
Posted by w0kf on: Monday 11 October @ 23:05:58 Read More... |
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