Purposed Mud Bay Remote Site Repeater  KL7SRK  [Sitka Ham Amateur Radio Klub]

Mud Bay is an ATT remote site on Kruzof Island, elevation approximately 900 feet, at 14 miles from down town Sitka.

1 - 22 - 2018


The City of Sitka has adopted the NIMS organization methods, and aligned itself with the Incident Command System Organization Structure ICS.
Sitka Amateur Radio Emergency Services ARES may act as a "resource" for the Incident Command System, and within the Logistics Section as a "Communications Unit

Where multiple agencies are operating together, the weakness has been inter organizational communication.
The normal intra agency channels of communications are quickly filled with traffic, and inter agency communications suffers at the Incident Command Center.

The SHARK Sitka Ham Amateur Radio Klub was approached and queried if we could begin taking the ICS courses and also build our systems with the goals of wider more reliable coverage.
The SHARK group responded with a very strong turn out for the first classes and certifications for ICS courses 100, 200, and 700, having several of our local members already experienced in this.

We are thus now investigating the possibility of locating a repeater for this service at the ATT Mud Bay site as it would approximately double our present coverage area for the 440 MHz band.

As our first repeater at higher elevation, we expect this to make us a more valued resource for emergency services.

Since ATT owns and maintains this site, they will become an essential partner, to accomplish our goal, and this will hinge on their decision to allow our repeater presence there.
Amateur equipment is privately owned, and operated as a voluntary service during times of emergency, for which all Amateurs will observe this as priority traffic.
We wish to maintain the high standards of installation of a professional site, and will supply what ever is required to meet those standards.

David Lowrance AL5X


Relocation of existing repeater to Mud Bay "sender cone."   Approximate Lat Lon 57° 9'10.22"N  135°38'46.68"W
Increase range of Amateur Radio Emergency Services ARES coverage to end of Halibut Point Road, and surrounding water access routes to the North, South, and West of Sitka.

Propagation Map

Area Propagation Map


Mud Bay to Sitka  Downtown     14  miles
Mud Bay to Ferry Terminal         10  miles
Mud Bay to Peril Straight            32  miles
Mud Bay to Kanga  Bay              22  miles

Repeater Equipment:

Motorola Radius GR1225  ~ 45 watts ERP
444.000 Mhz +       Tone  167.9
Power 120 vac 5A Fuse
This simple Analog unit has been reliably in service for several years without failures to date.
It recovers reliably from power outages, although has not been configured for battery operation.

Repeater Dimensions

Rear View

Front Pannel Settings

GR1225 Specifications PDF

Unit contains a duplexer slid into the left side from the rear with the cover removed.
An AC power unit, converting to 12 vdc, a cooling fan, and a UHF radio unit.

Technical :

Block Diagram

1)  GR-1225 Rack Mounting Hardware - 19 " rack mounting solution.

Relay Rack Shelf

1 ea 19" Relay Rack Shelf
2 ea  4U extenders

2)  Antenna  Type and Model      Diamond X50NA  [5.6  feet tall,  3-5/8 wave, 7.2 db gain,  rated for 135 mph winds, Type-N connector]  Ordered 1 - 16 - 2018

X50NA Specs

Antenna Photo

Antenna Mounting Hardware for mast.

X50 Resonance Graph

3)  Feed line distances      LMR 400
Repeater  to PolyPhaser  Distance?  [N connectors male male]       
Poly Phaser to Antenna   Distance?  [N connectors male male]

4)  Lightening arrestor     PolyPhaser   N connectors
  [On Site]

PolyPhaser Photo

5)  AC Power Filter -Tripp-Lite  Isobar 2-Outlet Surge Protector  [Ordered 1 - 16 - 2018]
Model - Ultrablock 15A Breaker RF filtered AC power wall plug PDF

Isobar Photo

6)  Laptop with Windows XP for GR-1225 programming, with backup run file, now on site.

7)  Maintain data and photos of remote equipment for technical support.


Sitka Techs:

Todd Dokey   KL4EL   907 - 623 - 7266      justcallmebuddy@gmail.com  [ARES Team Leader]
David Lowrance    AL5X    907 - 747 - 8348    libra_spirit@hotmail.com  [Staging of Equipment 711 SMC Sitka]
Benjamin Downing KL2UF  907 - 747 - 8636  aikiben@gci.net  [Technical]

ATT Tech Juneau:

Jeffrey Deaner  KL7JVD    907 - 723 - 8689  alaskaboy07@ak.net  [Site Logistics]

Sitka SHARK Officers:

President   Darryl Ault  AL7BW  907 - 738 - 4539  darrylault@yahoo.com [KL7SRK Repeater LicenseTrustee]
Vice President   Benjamin Downing  KL2UF  907 - 747 - 8636  aikiben@gci.ne
Secretary Treasurer    April Ault  KF6BMF 907 - 738 - 4559 aaault@earthlink.net [Club Records]

Web Page Admin -   David Lowrance    AL5X    907 - 747 - 8348    libra_spirit@hotmail.com