OVERVIEW:

I have a 43 foot vertical monopole antenna.

Originally I matched it to the transceiver with a substantialmatchbox/antenna tuner located in the shack. Theconventional wisdom is one can more effectively andefficiently match these big sticks at the feed point with aremotely located matchbox/antenna tuner. To this end, I purchased and installed the MFJ-998RT Automatic RemoteAntenna Tuner.

For some time, I had shortened my monopole toapproximately 32.5 feet in height, and converted it into arather effective and efficient 40 m ground plane antenna,where it exhibited an impedance of approximately 38 ohms,and showed an SWR ratio of approximately 1.3:1. It alsohad good measurements on its first odd harmonic, located inthe 15 meter ham band. As good as it was as a quarterwave ground plane on 4o meters, I longed for its originalmulti-band performance, and wanted to restore it to itsformer 43 foot height which would give me multi-bandperformance, and, perhaps, allow me to work 80 and 60meters, as well as multiple bands higher than 40 meters.

MFJ makes the following claims, inter alia, about theMFJ-998RT:

• Remote IntelliTuner handles legal limit power CW/SSB. It’s the perfect match for Ameritron’s ALS-1300, AL-80B, AL-82, AL-1200 and AL-1500 legal limit amplifiers

• MFJ’s 1500 Watt remote automatic antenna tuner is built into a weather-tight ABS plastic cabinet top with a stainless steel bottom.

• Includes MFJ-4117 BiasTee Power Injector to send DC/RF down the coaxial line.

• MFJ-998RT weighs 9.5 pounds.

• Large and in charge -- tough ABS plastic cabinet and stainless steel metal chassis measures 13 3/4W x 6 3/4H x 17 1/2D inches.

• The MFJ-998RT Full Legal Limit 1500 Watt IntelliTunerTM takes you to the final level in automaticantenna tuners. With a capability of 1500 Watts SSB and CW, coupled with automatic tuning, your high-power station can now operate essentially hands-free even when frequency and band changes are made.

• Fast Automatic Tuning -The MFJ-998RT instantly matches impedances from 12-1600 Ohms using MFJ’s exclusive IntelliTune, AdaptiveSearch and InstantRecall algorithms with over 20,000 VirtualAntenna Memories.

• When you key your transmitter, MFJ’s InstantRecall checks to see if that frequency has been

REMOTE ANTENNA TUNER PROJECT

used before. If so, tuning is instantaneous. If not, MFJ’s IntelliTune algorithm (based on MFJ’s efficient SWR Analyzer technology) measures the impedance, snaps the necessary components in place, and then fine-tunes the SWR.

• If the antenna impedance is outside the tuner’s measurement range, MFJ's AdaptiveSearch algorithm measures the frequency and determines only relevant component values -- which are then searched for fast tuning.

• MFJ’s new VirtualAntenna Memory system has 2500 memories.

• MFJ-998RT has one coaxial antenna and a binding post for end-fed long wire antennas.

• Download and Upgrade Remotely - Field upgradeable firmware via the serial port -- download and upgrade your MFJ-998RT as new features are introduced!

• MFJ-998RT is protected by MFJ’s famous one year NoMatterWhat limited warranty. MFJ will repair or replace (at our option) your tuner no matter what for a full year.

INSTALLATION NOTES:

--1 -- Upon first inspection, I discovered a loose screwrattling around inside. A mounting hole in an RF shieldappeared to be missing a screw, and, finding no othercontender, I put it there. It is a bit unnerving as I hateguessing about these things.

-- 2 -- The supposedly “weather tight” steel and plasticcabinet is hardly up to the task of protecting it from harshMichigan weather. It lacked a proper rubber or siliconeseal or gasket, and MFJ did a sloppy job drilling holes forthe mounting screws. A couple were off center andenlarged, which would allow water to enter the cabinet. Itis more of a top cover, than a weather-tight cabinet.

Right Way: Wrong Way:

Therefore, I resolved to house the device within another, perhaps more weather tight enclosure, and upon the suggestion of my young bride, settled upon a plastic landscape feature which looks for all the world like a large field stone! The rock cost about $30.

I hand cut L-shaped mounting brackets from 1” x 1” aluminum “angle iron.” (Kind of an oxymoron... “aluminum angle iron...”) and mounted (suspended) the entire tuner unit inside the rock. I used various 1/4 x 20 nuts and bolts with 1 inch fender washers to attach the frame to the rock. I was

This is a properly made hole. It is smaller than the screw head and hasa marginal chance of keeping water out of theunit.

This is a poorly made hole. It is deformed and larger than the screw head, and would likely allow water to enter the unit.

worried the rock would dull the tip of the drill bit... ;-) ... but it was easy to drill four 5/8” mounting holes in the rock. I made all fittings from a single 3 ft long piece of angled aluminum stock, which cost about $3.

FINISHED PROJECT:

Perhaps not the most elegant solution, but it does have “wife approval,” and provides additional protection from bad weather. It disguises the installation and minimizes the visual impact of the remote tuner, hiding it from the curious or others who might mess with it. Mr. Robin is Master of all he surveys from his new throne.

James - K8JHR