MFJ-834 Coax In-Line RF Ammeter
SKU Part Number: MFJ-834
Connect the MFJ-834 Coax In-Line RF Ammeter between your antenna and tuner/ transmitter/amplifier and measure antenna feedline current in 3...
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£89.95 £74.96
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Connect the MFJ-834 Coax In-Line RF Ammeter between your antenna and tuner/ transmitter/amplifier and measure antenna feedline current in 3 calibrated ranges.

Use it . . . for tuning your antenna tuner/ transmitter/amplifier for maximum radiated power, for determining antenna feedpoint impedance, for comparing antennas and tuners, for trouble shooting . . . and for checking for changes.

Tuning for maximum feedline current for any given antenna always gives maximum radiated power!

Any adjustment - transceiver or amplifier tuning/loading controls, antenna tuner settings, whatever - that increases feedline current improves power transfer and gives you a stronger radiated signal.

Radiated power increases rapidly because power increases as the square of the current.

Minimum SWR does not always mean maximum radiated power -- your tuner or lossy coax may be dissipating power -- and you may not get peak output power even if your tuner or amplifier is properly tuned.

Use the MFJ-834 to determine best antenna tuner settings and to compare various tuners.

Calculate your antenna feedpoint impedance by dividing your applied power by the square of the feedpoint current.

Your antenna can change when you apply power -- insulators break down, traps heat up, capacitors leak -- and your feedpoint impedance may be drastically different from your SWR Analyzer measurements.

MFJ RF ammeters are rugged, read acc-urately over 1-30MHz in three linear ranges (.3, 1, 3 Amps) and barely perturb the antenna.

Uses SO-239 connectors. Measures 6" W x 3 ½"H x 4 ½"D

Large 3-inch lighted meter.


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If you have any equipment that needs to be returned to Martin Lynch & Sons, please fill out the form below:

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Upon receipt of goods you have 14 days to return goods however the goods must be returned in original packaging and care must have been taken with the goods you wish to return. Under distance selling regulations you are not entitled to any refund on carriage charges or modification charges made at your request.

Warranty Terms and Conditions

Outside of the 14 faulty return period, returned items cannot be accepted, unless covered by manufacturer's warranty. We will repair as much as possible on site however in exceptional circumstances products may have to be returned to the manufacturer of distributor.

For repairs/replacements under manufacturer’s warranty for any item please download a ML&S return form from the link above and return to ML&S with the faulty product.

International Warranty information

Warranty service for items we sell is available in the U.K. only, unless otherwise noted. It is your responsibility to pay freight for returned items to the U.K. and back to you for desired warranty coverage. All of our NEW products come with a minimum 12 month warranty, (Yaesu & Icom 24 months), with up to 90 days on second-hand equipment. Items returned for service must state "returned goods for repair" on the return air waybill or U.K. import customs duties apply and will be added to your invoice. For more info about returning items please contact our customer help desk, [email protected]