KA7BTV Repeater/Remote Base information

443.450+/PL 100hz(1Z)

Echolink Node # 211274

Coordinations: Oregon Region Relay Council (Region 7), E.C.O.R.G.

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This system is located in Klamath Falls, Oregon. Originally designed & built in the summer of 1982 in Reno, Nevada, it was moved to Klamath Falls in the spring of 1983. It was then operational until mid 1988, at which time it was taken off the air for approximately 16 years. From mid 1983 thru late 1988, this repeater operated in the 2 meter band, first on 147.38/98 and later on 147.20/80. For a time in the 1980s, it was located atop 8036 ft. Pelican Butte in Oregon, and provided very wide coverage.

In July of 2004, the system was un-mothballed, redesigned, upgraded, modernized, and changed so as to operate on 70cm rather than 2 meters. It was placed back in service on 04 August 2004 and now operates on 443.450+, with a PL tone of 100hz (1Z). No tone is required for access via Echolink nor the remote bases.

The system provides good handheld coverage within most of the city and south suburban areas. Coverage is spotty inside some buildings when using low-power handheld radios. Average mobile radio coverage is +/- 25mi. of Klamath Falls, using 10-25w mobile radios.

Primary purpose of the system is to provide full-time UHF & VHF gateways to Echolink, an HF Remote Base, and to provide a platform for further experimentation in the areas of computer control, Internet Linking, & remote bases.

The system sports several functions, and features voice identification & selected announcements by a local professional radio announcer, Carolyn Hope of Wynne Broadcasting. (Thanks Carolyn!).

This system is somewhat pioneering in that it is totally controlled by a dedicated PC computer, with custom control software written specifically for this application only. The system is known to its users as C.O.R.A., for Computer Operated Repeater Application. 

This system is open to all licensed Radio Amateurs, with some restriction in regard to transmitting on the HF remote base so as to comply with FCC rules. Please feel free to use it anytime you wish. Access codes for the various functions are shown below.

All operations are confirmed via system voice a few seconds after each command entry. 

Echolink

Code

Function

Remarks

(Desired Node Number)

Connect to specified node

 

# Plus 0 (Zero)

Disconnect

  

Autopatch

Code

Function

Remarks

* Plus 74 or *74 Plus Desired Telephone Number

Activates Autopatch & dials desired #

Local Calling Only

#

Disconnect Autopatch

  

Time & Weather Functions

Code

Function

Remarks

05

Current Local Time

  

06

(Reserved for future use)

  

07

Current Local Weather 

  

08 + Desired Zip Code

Current Weather For Supplied Zip Code

  

09

Current Temperature Only

  

10

(Reserved for future use)

 

2-meter Remote Base Functions

Code

Function

Remarks

201

Select 2m Remote Ch. 01

146.460 Simplex

202

Select 2m Remote Ch. 02

146.490 Simplex

203

Select 2m Remote Ch. 03

147.510 Simplex

204

Select 2m Remote Ch. 04

147.530 Simplex

205

Select 2m Remote Ch. 05

147.560 Simplex

206

Select 2m Remote Ch. 06

 146.610 Repeater

207

Select 2m Remote Ch. 07

 146.740 Repeater

208

Select 2m Remote Ch. 08

 146.790 Repeater

209

Select 2m Remote Ch. 09

 146.850 Repeater

210

Select 2m Remote Ch. 10

 147.160 Repeater

211

Select 2m Remote Ch. 11

 147.180 Repeater

212

Select 2m Remote Ch. 12

 147.200 Repeater

213

Select 2m Remote Ch. 13

 147.280 Repeater

214

Select 2m Remote Ch. 14

 147.320 Repeater

215

Select 2m Remote Ch. 15

 147.360 Repeater

216

Select 2m Remote Ch. 16

 147.380 Repeater

Activate/Deactivate Codes

    

217

Activate 2m Remote Base (Monitor Only Mode)

  

218

Activate 2m Remote Base (Full Transceive Mode)

  

219

Deactivate 2m Remote Base

  

6-meter Remote Base Functions

*Note: 6m Remote Base is not yet operational*

Code

Function

Remarks

601

Select 6m Remote Ch. 1

52.525 National Simplex

602

Select 6m Remote Ch. 2

53.020 National Simplex

Activate/Deactivate Codes

    

617

Activate 6m Remote Base (Monitor Only Mode)

  

618

Activate 6m Remote Base (Full Transceive Mode)

  

619

Deactivate 6m Remote Base

  

HF Remote Base Functions

Code

Function

Remarks

401

Activate HF Remote Base (Monitor Only Mode)

The HF Remote Base is only available on the UHF (443.450) Repeater

403

Deactivate HF Remote Base

  

Mode Selection

    

410

Select LSB Mode

  

411

Select USB Mode

  

412

Select AM Mode 

 

413

Select FM Mode  

 

Frequency Selection

    

4* Plus Desired Frequency

Select Operating Frequency To Within

1  Khz.

Example: 4*7240 Selects 7.240 Mhz

4* Plus * Plus 100hz Digit

Select Operating Frequency To Within

100 hz

 Example: 4*7268*5 Selects 7.268.5 Mhz

Antenna Selection

    

431

Select HF Dipole (or G5RV) Antenna

Use this antenna for most applications

432

(Reserved for future use)

 

HF Autotuner Commands

    

433

Activate Autotune mode 

These commands are not often used. They

434

Deactivate Autotune mode

 are provided mainly for manual tuning and

435

Store tuner settings in memory

 diagnostic purposes.

436

Deactivate (Bypass) tuner 

  

437

Activate tuner

  

Misc. Functions

Code

Function

Remarks

#88

Activate Custom Courtesy Tones

50 Random Silly Sounds :)

#89

Deactivate Custom Courtesy Tones

Use Normal Courtesy Tone

 

Technical Description & Pictures

For those of you who are technically curious about the repeater itself, here is a brief rundown of the equipment and software in use.

==========

The primary 440mhz repeater consists of a Motorola Mitrek UHF radio, converted for repeater use. It transmits with 30w of power, and shows a receive sensitivity of .22uv for 20db of receiver quieting. The Mitrek radio is an excellent choice for repeater use. These units provide legendary reliability, great audio, and incredible flexibility. 

The 440 Duplexer is a Motorola T1500 series unit.

The 440 antenna is a Phelps-Dodge model PD201-6 Stationmaster®. It provides 6db of omnidirectional gain. Height is approx. 65ft. above ground. This antenna is fed with Andrew FHJ4-50B Low-Loss 1/2" Heliax® coaxial cable.

The UHF control link & backup antenna is A Decibel Products model DB-411 4-Bay Dipole, fed with Belden 8214 coaxial cable. This is a semi-directional antenna, aimed to the west. 

The 2m remote base consists of a Motorola Maratrac synthesized programmable VHF radio. It transmits with 35w of power. Receive sensitivity has not been measured.

The 2m antenna is a Hy-Gain model V2R 5/8-wave 6db gain collinear vertical at 35ft. on the south side of the tower. This antenna is fed with Belden 8214 RG-8 type coaxial cable. In the spring/summer season of 2009, this will be upgraded to Andrew FHJ4-50B Heliax® as is used on the 440 system. 

The HF remote base consists of an Icom model IC-725 all-mode 100w HF radio. This unit is ideal for remote use because it is a basic and rugged radio and is easily computer controllable via the Icom CI-V specification. HF receive audio is taken directly from the HF receiver’s detector so as to keep the audio frequency response flat across the audio passband. This is to allow for clean rx audio, and the ability to copy digital modes such as RTTY,  PSK, SSTV, etc. through the 440 repeater. HF Transmit audio is taken directly from the discriminator in the UHF receiver for the same reasons.

The HF antenna is a 140-ft inverted vee with the apex at 65 feet. It is fed with RG-59U 75-ohm coaxial feedline. Antenna tuning is accomplished automatically via a model AT-200PC autotuner by LDG Electronics. This tuner is controlled by the main repeater computer.

12vdc power for the radios and other circuits is provided by (2) commercial-grade 30-Amp continuous duty power supplies - one power supply (Motorola) supplies power for the UHF repeater and 2m remote, while the other (Aerotron) supplies power for the HF remote and other circuits.

The control system consists of a dedicated IBM PC compatible computer, with a special homebrew interface between the computer and the radios. All parts of the system are controlled by the computer. The computer has a PentiumII 233mhz processor, 256mb of RAM, and a 4gb. Hard disk. A backup Hard Disk is installed and contains an exact copy of the primary HD, but is not powered up unless needed. Uninterruptable power is provided by a Best Power Technologies model LI-660 600-watt UPS unit. Three Soundblaster soundcards handle audio routing and DTMF decoding.

The computer uses Windows XP Professional, and runs both the Echolink software and a custom control program for the various repeater and remote base functions. The two programs are tightly integrated via an API interface. Internet connectivity is provided by a 5mbps cable connection from Charter Communications. It is estimated that this connection can handle 8-10 simultaneous Echolink connects.

Some pictures of the system are shown below:

Equipment Cabinet, Closed & Open:

 

#1 tower & some of the antennas:

 

Not shown: #2 tower, 40-10m HF vertical, 6m antenna.

Future Plans

The 6m remote may or may not get completed, as there appears to be no demand in the area. At some point, it is planned to make the system accessible from the Internet. Also, the main HF antenna is to be replaced with either a Carolina Windom or a G5RV.