Technical Committee Meeting Notes Feb 24, 2018 - Printable Version

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Technical Committee Meeting Notes Feb 24, 2018 - NA7CS - Curt - 03-06-2018 07:42 PM

Technical Committee Meeting
February 24, 2018

1. What is on the air as of today.

a. At CACC two GE MASTR II's and the Arcom RC210 controller are on loan from Bob, W8RH. One is on 145.210, PL 162.2 (On the air); the other is on 449.125, PL 136.5 (Down but ready to go as soon as the hardline is ran).
b. At T-bird water tower one Fusion repeater on 446.300 PL 100.0.

2. What has been done as of today.

a. Tuned the 2M cans, as somehow they were knocked off frequency at CACC.
b. Tuned the 449.125 can at CACC and made it ready to go on the air.
c. Tuned the 446.300 can at T-Bird as best as possible until the proper jumpers can be ordered.
d. Preamps have been installed on the repeaters at CACC, and ordered for T-Bird.
e. Two - 260 ft spools of 1/2” hardline and Type-N connectors have been ordered for CACC to run from the tower to the repeater room.

3. What needs to be done.

a. Pull two runs of hardline at CACC for the 2M and 440 repeaters. ASAP! Once done put the 440 repeater on the air.
b. Order the correct jumpers for the T-Bird duplexer.
c. Modify the Fusion repeaters for cooler operation and circuitry protection.
d. Add the preamp inside the case of the Fusion at T-Bird.

4. What can/will be done?

a. CACC will be removing their microwave equipment from the tower and repeater room in the coming weeks. They will (hopefully) leave the two extra runs of LMR400, the extra rack and maybe the UPS. The extra rack and UPS will remain the property of CACC and will not leave the room.
b. There is a strong WiFi signal in the repeater room that we can use via VPN to connect one, or both repeaters to VOIP networks. DMR, YSF (Fusion), P25, D-Star, EchoLink and/or IRLP. Depending on the network(s) chosen, the repeaters might not be able to be linked.
c. If no VOIP networks are to be used, do we want the repeaters at CACC permanently linked? If not what would be the appropriate schedule for automatically linking them?
d. Do we want to create a link from/to T-Bird from CACC?
e. Do we want to link other repeaters from the CACC site? i.e. Mt. Lemmon 6M, Tucson 900Mhz, etc. If so, what repeater and permanently or on demand?
f. Raise the antenna at the T-Bird site.
g. Anything else I know I missed?

5. What do we want to do?

As this affects the entire club it is open for discussion and a final decision by all club members.

RE: Technical Committee Meeting Notes Feb 24, 2018 - NA7CS - Curt - 03-14-2018 08:27 PM

Here are coverage predictions of all the repeaters; and HAAT for the T-Bird repeater

[Image: Current_2_M_improved.jpg]

440 At CACC
[Image: Current_440_Repeater_improved.jpg]

RE: Technical Committee Meeting Notes Feb 24, 2018 - NA7CS - Curt - 03-14-2018 08:33 PM

Here is the current T-Bird prediction

[Image: T_Bird_Site_Coverage_Pretty_Picture_at_40ft.jpg]

Here is the prediction at 55ft.

[Image: T_Bird_Site_Coverage_Pretty_Picture_at_50ft.jpg]

RE: Technical Committee Meeting Notes Feb 24, 2018 - NA7CS - Curt - 03-14-2018 08:42 PM

Now for some clarification on the T-Bird predictions, and why it should be raised.

It all comes down to Height Above Average Terrain (HAAT). At the antenna's current height the HAAT, or antenna is 3.9M (12.8 ft) below the average terrain. This measurement is 360 degrees out to 20 km taking an average of terrain heights every 45 degrees at 1km increments in relation to the antenna.

[Image: T_Bird_HAAT_40ft.jpg]

The HAAT for an antenna height of 55ft is 0.7M, or 0.7M (2.3 ft) above average terrain.

[Image: T_Bird_HAAT_55ft.jpg]

For optimal coverage the antenna should have a positive number on the HAAT measurement. Raising the antenna to 55 ft, or as close to it as possible will give it the positive HAAT number.