The RAM Polar Cafe Site
147.36 split +0.6 PL=103.5 IRLP Node 7254
Updated May 6, 2016

 

 

Raising the Antenna

April 22, 2014

On the roof, left to right, Keith Andrews KL1CC, David Rutter KL3GA, and Thomas Ilmar (AL7X's non-ham son), raise the antenna on the roof of the Polar Cafe.

A hinge at the base of the mast vastly simplified the raising. Once up, it was clamped.




Picture Copyright 2014, Ramon Gandia

The Finished Antenna

Here it is up in Place. Once the antenna was raised, it was clamped to the two Unistruts on the building gable.

The antenna is a Diamond X-200A; the coax LMR-400, the pipe as full 21 ft length of 1.5 inch schedule 40 water pipe. At the top it was bell reduced to a specially hand crafted mount that brings the coax cable inside the pipe.

The base of the antenna is ten feet higher than the roof of the Federal Building penthouse, and thus has a clear line of sight in all directions; North, South, East and West. It should perform well. The base of the antenna is about 50 ft above ground level and 62 feet above sea level.

Besides the ham radio antenna is Ramon's AL7X microwave antenna dish bringing the internet 4.3 miles to his home at the base of Anvil Mountain. This also works to administer the 7254 node. Works perfect.




Picture Copyright 2014, Ramon Gandia

Putting It Together

May 4, 2016

This is the famous "Frigipeater" updated in 2016. It replaced the older Kenwood TKR-720 that suffered a burnt out Power Amplifier. These old defunct refrigerators make good cabinets!

At the very top is a cooling fan keeping the cabinet at reasonable temperature. The Kenwood TKR-751 VHF 25 watt continuous duty repeater is at the bottom of the freezer compartment. It will do sixteen channels; the information is on the white card taped to its front panel.

Underneath is the silver Duplexer, a Sinclair Q2330E, 6-cavity, close frequecy spaced unit allowing for the new RAM frequency with standard 0.6 mHz split.

The small device in front of the Duplexer is a dual isolator, to eliminate signals flowing down from the antenna to the transmitter. This ameliorates any intermods generated by us.

Left of the Duplexer, sporting a bright blue LED, IRLP node 7254.

On the very bottom, under the duplexer shelf, is an APC Backup 750 PRO. Providing 117 Volts AC. The internal battery has been removed, an a 100 AH external battery connected. It is visible to the right of the refrigerator. Running time estimated 20 - 24 hours.

Normally Node 7254 connects to a default reflector. Every half hour it will check to see if still is, and if not, reconnects to that reflector, probably probably 9006. For changes or updates, check the center pane of www.xalaska.com




Picture Copyright 2015, Ramon Gandia AL7X

Finished Product

May 4, 2016

Here is a picture of the finished product after the door to the Frigipeater was closed.

It operates on 147.36 mHz, split is STANDARD +0.6 mHz split. PL (CTCSS) 103.5 tone is required.

The courtesy tone has double beeps if the transmission came over the internet; but a single beep for local transmissions.

You may steer the IRLP node on this computer to any node or reflector you want. Be aware that every half hour, on the hour and 30 minutes past, it will close your connection and reconnect to the default reflector (As of this writing, default is 9006 except 9AM - Noon = 9109 Alaska Morning Net).

Initial Range Test

Rolland KD8JOU and Ramon AL7X drove 24 miles east to the Safety Bridge in 2014 and tested it there. Fully quieted on HT's 15 miles east to Cape Nome; faded away rounding the cape; then came back "Mobile Strength" all the way to the Safety Bridge. "Mobile Strength" means you can access it with a mobile radio but not with an HT. This was the expected coverage.

Quality and Impressions 5-6-2016

This repeater is a pleasure to use. Audio quality local or on the internet is Kenwood excellent.

Note 1: The repeater and the entire internet feed is on battery backup which received a significant upgrade on 5/4/2016.

Note 2: Repeater affiliated with Nome, Alaska, ARES.

Picture Copyright 2014, Rolland Trowbridge.



Page Last Updated May 7, 2016