Welcome to the KB8MFV repeater home page

147.285 MHz + 600 KHz

PL tone 88.5 Hz

(PL is used only when needed)

This page last updated 7-10-2001

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KB8MFV greeting.mp3

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since 1-30-2001

• Satellite links - The KB8MFV/R has several C and Ku band TVRO links for Amateur information services provided by the dish farm here at the main site (six dishes in all!). From left to right in this image from the top of the tower is a 7' Hero, 6.5' solid stainless steel, 10' BUD... (big ugly dish) on a 15' pole, 7' Hero, 3' Primestar (not in use... YET!) and a 5' Wilson solid spun aluminum dish. There are dedicated receivers for NASA select TV for round the clock coverage during space shuttle missions, and the W0KIE network which carries This Week In Amateur Radio and the Houston area AMSAT net. A snow covered 50 watt home brew solar panel is visible in the top left of the image.

Dish farm viewed from ground level

• Nets - The Ohio SSB net is on 3972.5 KHz at 10:30 AM, 4:15 PM and 6:45 PM EST everyday of the year. The KB8MFV/R is linked to the evening net from 6:44 PM to 7:15 PM. Users are encouraged to check-in and sharpen their message handling skills. If you are a Technician class operator, you should give your call sign along with the fact that you are using the KB8MFV/R as "third party traffic". This link was called into question by an Official Observer in December 2000. There ARE several requirements that MUST be met for this to be done on a 2 meter repeater. KB8MFV/R meets those requirements, so the daily net operations were resumed on January 5th 2001. For details on this, the applicable sections of Part 97 of the FCC rules and E-mail copies of the correspondence with the ARRL on this matter, click here.
• The Houston area AMSAT net is heard live via satellite Tuesdays at 9 pm EST. The net is RX only from the W0KIE satellite network on Satcom C3 transponder 24 at 7.5 MHz audio. The net has up to the minute information on the amateur satellite program, bulletins, status reports and also sends slow scan TV images near the end of their hour long net. You can check-in to the net via E-mail or telephone.
• This Week In Amateur Radio (TWIAR) is heard live via satellite Saturdays at 9 pm EST. This satellite delivered bulletin service also comes from the W0KIE satellite network. This is "the weekly news" for amateur radio operators. It is very well produced and deserves our support.
• The Columbiana County Emergency Training Net is rotated among the five two meter repeaters in our county in the following order: 146.700 East Liverpool, 146.775 East Palestine, 146.805 Lisbon, 147.255 Salem and 147.285 Salem. None of the repeaters require PL during the traffic nets. CCETN is held Mondays at 8 pm EST.

• Wx service - The KB8MFV/R has a weather alert monitor that will sound a 5 second alarm and change the courtesy tone to a Morse code "W" for five minutes after the alert is sent. Users can enter a DTMF command to listen to the radio on demand. The six meter remote base is linked in RX only mode to the Cleveland weather net during severe weather. The two meter synthesized remote is RX/TX enabled for the Columbiana County SKYWARN net when the weather really gets bad.

• Remote Bases - KB8MFV/R has several remote base radios available for users to link the repeater to other frequencies. They may be activated individually, or multiple remotes may be active at the same time.
• Icom 2AT synthesized remote. User programmable with PL, 3 watts to a 1/4 wave at 45 feet using 70 feet of 1/2 inch Heliax.
• Icom 4AT synthesized remote. User programmable with PL, 2 watts to a 3db gain at 45 feet using 70 feet of 1/2 inch Heliax.
• Drake TR7 HF remote. 100 watts, 160-10 meters including the WARC bands with Drake L7 2KW amplifier, using tri-band beam at 40 feet, double size G5RV, elevated six band vertical and a double bazooka inverted V for 75-80 meters. A MFJ-984 3KW tuner is also available. Feed lines are RG-8 and RG-8U.
• Yaesu FT-680r 6 meter all-mode. 10 watts to a Mirage A1015G 150 watt amp with a folded vertical at 50 feet and a 5 element beam at 45 feet using RG-8.
• Yaesu FT-736r all-mode with 2 m (80 watt Mirage B108), 1.25 m (25 watts), 70 cm (100 watt RF concepts RFC4-110) and 23 cm (10 watts) modules. All feed lines are 70 feet 1/2 inch Heliax or 1/2 inch hardline.

• Remote RX - KB8MFV/R has a remote receiver just north of Canfield, Ohio at  the home of KC8WY (Dave) at 41.04'.11" North and 80.45'.53" West at 1290 feet above sea level just a few miles north of Canfield, Ohio. The RX antenna is a Ringo II at 120 feet using 150 feet of Times Microwave LMR-400 cable feeding a Advanced Receiver Research 25 db GAsFet preamp. The link TX antenna is a 7 element homebrew yagi. Two more remote receiver sites are planned for the future.

• Phone patch - KB8MFV/R has a 250 number auto dialer phone patch including 10 emergency autodial numbers. Auto patch slots are FREE to all licensed amateurs. Priority is given to SKYWARN spotters that want to use their spotter number for an autodial slot.

• DVR - A homebrew Digital Voice Recorder will be available soon using the ISD family of  "Chip Corder" voice storage IC's. Users are able to hear how they sound at the repeater and stored natural voice messages will be available. Users can E-mail MP3 or wav files to have them recorded as rotating ID slots. Watch the KB8MFV projects page for future updates, information and schematics for this handy feature.  The DVR went on-line 3-1-2001... users are encouraged to send text of their ideas for new DVR messages to [email protected] Above is a view of the OLD repeater equipment rack... a new 6 foot by 3 foot rack (much bigger) was installed on 3-6-2001. Photo will be posted soon.

• RX voter - KB8MFV/R uses a homebrew Doug Hall 4RV 4 channel active voter to select the best main RX signal from the two main receivers currently available. It is expandable up to 32 channels. This is real time true diversity reception that requires no additional effort on the users part to improve signal to noise ratios. A tone generator board will be added in the future to generate a unique courtesy tone sequence for each active receiver site. This way users will be able to tell by the courtesy tone which receiver another user came in on. Watch the KB8MFV projects page for future updates, information and schematics on this too.

• Locations - The KB8MFV/R is located in Salem, Ohio 44460 maidenhead grid square EN90nv. If you like to crunch numbers, that's 40.54'.20" North and 80.51'.00" West. Ground elevation is 1270 feet and the main antenna is up 80 feet at 177 feet above average terrain. The image on the right shows the main tower (13 antennas!) including the ATV, repeater, PBBS, link, remote base and satellite antennas. Guy cables for this tower are NOT optional! The Youngstown area receiver is located at the home of KC8WY (Dave) at 41.04'.11" North and 80.45'.53" West at 1290 feet above sea level just a few miles north of Canfield, Ohio. Future RX sites are planned for the Alliance and Lisbon, Ohio areas

• Tower top views - Here are eight views from the top of the tower here in Salem looking N, E, S, W, NE, NW, SE and SW. They can be arranged to form a panoramic view. Click on each direction to download a high resolution image.

North - Northeast East - Southeast South - Southwest West - Northwest

• Main radios - The entire KB8MFV repeater system including all link RX and TX radios uses the Motorola Mitrek line of radios. All receivers use GAsFet preamps and/or the factory internal preamps. All radios have been modified to be capable of full duplex operation (RX/TX at the same time) for redundancy in case of a failure. The main transmitter is 100 watts output continuous duty. The Youngstown receiver site uses a full duplex 45 watt Mitrek radio and is set to 3 watts feeding a Celwave duplexer. The remote site will in the future be able to be commanded on and off remotely and/or to enable the site as a remote transmitter/receiver with the addition of another VHF duplexer if desired. 

• Controller - KB8MFV/R uses the Advanced Computer Controls RC-850 repeater controller (top) running version 3.42 software. The computer interface board option is not installed. The RC-850 is interfaced to a homebrew controller (below) consisting of a second DTMF decoder with display, a four port remote base interface, a four port rx only link interface, two FC-1 synthesized remote base controllers and a 64 output expanded user function board... all homebrewed on perfboards! The empty space in the homebrew controller is for the DVR  that went on-line 3-1-2001 after this picture was taken.

• Duplexer - KB8MFV/R uses a Sinclair Labs 4 cavity band pass/band reject duplexer. Insertion loss is measured at 1.3 db. 100 watts input produces 75 watts RF output at the antenna port.

• Antennas - The KB8MFV main repeater site in Salem uses a Hustler model G6 vertical with 6 db gain fed with 1/2 inch Heliax. Link RX and TX antennas are homebrew 7 element yagis fed with 1/2 inch hardline.

• Emergency power - KB8MFV/R uses battery back-up for the entire system. A pair of 35 amp power supplies with their control voltages strapped provide operating power and ensure that the battery (stack of 6) stays fully charged at all times. If the AC power mains fail, the batteries take over automatically and the courtesy tone and hang timers are changed to alert the users. The 12 volt battery backed power supply also powers the Packet BBS computer, TNC, disk drive and monitor. Two homebrew gas generators are available to keep the power up during extended outages. The Youngstown area receiver also has battery back-up that will provide several hours of operation without AC power. I am perfecting a control circuit for the generator system that may soon appear on the projects page.

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