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Coaxial lightning arrestors for frequencies above 50 MHz use the same technology as lower frequency units described above and are all constructed in our standard arrestor housing.  M-302U is for terrestrial repeater or point to point services, commercial broadcast or cellular applications, long distance scatter, EME, etc. Each unit includes high voltage blocking between input and output ports with antenna side of arrestor connected through near dead-DC short inductor to ground(case), draining center conductor of earth connections.


Models Available:            

M-302U, 300w, UHF connector, 50-500 MHz

M-302U-PP, 300w, UHF connector, 50-500 MHz,  power pass version, no blocking capacitor,

             allows for DC control voltage to run through arrestor to power pre-amps, switches, etc.

M-302N, 300w, N connector, 50-500 MHz      

M-304U, 1kw, UHF connector, 50-500 MHz   

M-304N, 1kw, N connector, 50-500 MHz        

M-306N, 150w, N connector, 50-1300Mhz    

Like no other protective device in the world for RF coaxial cable lines, Morgan’s M-300 Series arrestors offer a complete, nearly perfect blocking/shunting system for induced voltages. Whether produced by lightning (directly or indirectly coupled), wind, rain, or snowfall MMI arrestors are continuously active, constantly draining transmission line center conductor to ground. The result? Solid protection for station equipment and related noise.

All M-300 Series units feature heavy discharge toroidal inductors used to neutralize developed voltages on the antenna side of a central high-voltage blocking capacitor. Inert gas tubes are used to limit the natural back-EMF voltages often induced across an inductor when large fast rising input currents are presented to the unit.

Sold and used worldwide, our arrestors are the first line of defense in lightning protection employed by such services as the U.S. Army, Boeing Corporation (Commercial Airplane Division), AT&T, NASA, and a wide variety of Commercial Broadcast, Public Safety, Emergency Relief, Government, and Amateur interests. Our arrestors can be found in the most stark surroundings, from dense African jungles to the vast wastelands of some of the world’s most punishing deserts. You can even drive a truck over the top of the chassis without damaging the contents (actually, you can do that to most MMI products).

Available models cover the frequency range from as low as 100KHz to 1,000MHz. with lots of connector choices. All units feature Teflon connectors. All may be mounted on flat surfaces, grounding bulkheads, or through-mounted using dual stainless steel grounding screws for mechanical fastening. Packaged with an informative owner’s manual.  The arrestors are approx 3X3X2 inches.

Models Available:                                                                                                                Price:

M-300U, 1kw, UHF connector,   .1-54MHz                                                                                                  $62.00

M-300U-QRP, 10 watts, UHF connector, .1-54MHz                                                                                    $62.00

M-300U-PP, 1kw, UHF connector, .1-54MHz, power pass version, no blocking capacitor, allows            $62.00

                    for DC control voltage to run through arrestor to power pre-amps, switches, etc.

M-301U, 1kw, UHF connector,    1.5-54MHz                                                                                               $62.00

M-303U, 3kw, UHF connector,    1.5-54MHz                                                                                               $69.00

M-303N, 3kw, N connector,      1.5-54MHz                                                                                                  $72.00

M-303U-PP, 3kw, UHF connector, 1.5-54MHz, power pass version, no blocking capacitor, allows          $69.00

                    for DC control voltage to run through arrestor to power pre-amps, switches, etc.

Models Available:                                                                                                   

M-309, Balanced line arrestor     1kw, 1-30 MHz

M-308, Single open wire arrestor     1kw    1-30 MHz         

M-309H, Balanced line arrestor     3kw, 1-30 MHz

M-308H, Single open wire arrestor     3kw    1-30 MHz                                                                              

For transmitting or receiving applications using open-wire fed systems in parallel balanced lines, these arrestors use our patented technology in larger housings with insulated terminals. These units are constructed in metallic aluminum chassis cases.

Model 308 is designed for use with open single wire systems such as tuned longwire antennas and random wires added with antenna tuners. It is compatible up to it’s design power rating with a wide variety of input impedances / reactances ranging from about 300 ohms to 600 ohms  Like all arrestor protection units these circuits are designed to be ground-mounted and should be installed close to earth entry point connections for best results.  M-308H is the 3kw high power version, comes in a 4x4x2.5” plastic NEMA box.

Model 309 is designed for use with open wire balanced feed systems. It is compatible up to it’s design power rating with a wide variety of input impedances / reactances ranging from about 300 ohms to 600 ohms  Like all arrestor protection units these circuits are designed to be ground-mounted and should be installed close to earth entry point connections for best results.  Compatible with both split capacitor type antenna tuner and balun output stages common in modern antenna tuning products.  M-309H is the 3kw high power version, comes in a 4x4x2.5” plastic NEMA box.

Morgan Systems now providers of the legendary I.C.E. products!  Morgan was formed in 2005 as a subcontractor for I.C.E., which had a 20-year history of building quality lightning and filtering equipment and accessories for the communications industry.  With the untimely passing of the founder of ICE, Mike Koss (W9SU), Morgan Systems is carrying on the quality reputation of the ICE line and will be able to provide many of the products that professionals and amateurs have come to know.  More Morgan products than listed below are available; email me for information.  Check manufacturer’s website for more technical information.

Unshielded control line conductors used to operate remote switching operations, antenna rotators, and home weather stations are easily charged to thousands of volts potential referenced to ground by overhead lightning discharges, frequently causing severe damage to equipment. In the RF transmitting environment, these same leads often couple into transmitted energy and re-radiate signals at ground level, resulting in interference to nearby equipment tuned to other services.

Model 347 solves both problems in one convenient unit. Easy to install and virtually permanent, this suppressor shunts RF currents and voltages over 20V directly to facility ground terminal connection.  This model is perfect for 12-14v remote switch controls and Alfa Spid rotators.

Model 348 is the same as above but shunts RF currents and voltages over 50V directly to facility ground terminal connection.  Choose this model for most HyGain and Yaesu arrestors.

Model 349 is similar but for 120v AC or DC connections.

Installation is a breeze and takes only a few moments. Each wire (up to 8 conductors on standard models and 12 conductors for the B models) entering from rotating unit or switch box may be attached to any of the 8/12 insulated terminals on the side of the unit. The same wire then continues from that connected point onward to control box destination. Connect the metal case to a ground rod or system and you’re all set. May be used indoors or outdoors, designed for flat surface mounting, includes stainless steel grounding terminals.  Uses metal oxide varistor devices, AC or DC voltage rated, ceramic high-capacity RF bypassing components.  Comes with owners manual.

Models Available:   


M-347, Rotator line/remote switch, 8 wire, AC/DC 20v or less                                                                                         

M-347B, Rotator line/remote switch, 12 wire, AC/DC, 20v or less

M-348, Rotator line/remote switch, 8 wire, AC/DC 50v or less                                                                                         

M-348B, Rotator line/remote switch, 12 wire, AC/DC, 50v or less

M-349, Rotator line/remote switch, 8 wire, AC/DC 120v or less                                                                                

M-349B, Rotator line/remote switch, 12 wire, AC/DC, 120v or less

NEW!  90˚ mounting bracket for M-374/348/349 units, rotates unit so terminal strip is facing up. 

Makes wiring duties much easier; comes with hardware to mount unit to bracket.       

Spade terminals to fit M-347/348/349.  Fits up to #10-12 gauge wire, or 14-16 ga. wire. 

Nylon insulator.  Come in 8 pack or 12 pack, or 20 pack.           


Great protection for your SteppIR control lines!

Most modem electronic equipment devices are subject to interference from electromagnetic signals and noise entering via AC line power cords. DVD and Video cassette recorders, television sets, consumer audio gear and many telecommunications products are now being constructed with transformerless power supply technology, making each piece more sensitive than ever to line variations and interference. AC line filters offer an inexpensive alternative to the risk and unpleasantry of dealing with many types of line problems. MMI’s line filters are a complete package of inductive isolation, over voltage control, capacitive decoupling, and interference control of both common mode and differential mode signals across a broad frequency spectrum range. Several models offer currents to 20 Amps and up to 6 plug-in outlets.

Filters are constructed in a tough, single piece heavy chassis measuring 4″ square, and each includes 6 foot molded line cord, fuse (replaced if necessary from the outside), and stainless steel ground terminal.

All are designed for flat surface mounting and may be used with or without ground terminal connection. Performance improves if local ground connection can be made and if distance from filter body to ground is kept short.  Each unit is packed with a informative owner’s manual and an extra fuse.

** Looking for the M-471, AC Line/appliance filter?  To eliminate RF that is causing problems with a noisy appliance?  Look here.

Models Available:                                                                                                 

M-474-3, 120VAC, 50/60 HZ, 15 amp,  3 outlets with ground, 3 prong cord.                            

M-476-3, 120VAC, 50/60 HZ, 20 amp,  3 outlets with ground, 3 prong cord.             

NOTE:  M-476 uses a plug with one prong horizontal, and requires pictured outlet type.              

Modern television and FM stereo systems are the most delicate ever built and can be easily damaged by voltage transients delivered by outside antennas or commercial cable systems. The only other installation requirement is a ground rod earth terminal connected to the chassis. 

Model M-320 is a DC blocking arrestor that allows RF signals to pass through the unit, with a frequency range of 3MHz to 2GHz.  It uses bleeder resistors to drain static and a gas discharge tube to shunt large surges to earth.  Great for CATV, video systems, receive radio antennas, etc. 

Model M-322 is a DC blocking arrestor that allows RF signals to pass through the unit, with a frequency range of 135KHz to 60MHz.  It also has a toroid inductor from the center conductor to ground, acting as a constant static drain.  This model is ideal for low band receive antennas such as beverages, loops, flags, etc.  Can be used with 50 or 75 ohm systems. 

Model M-325 is a DC passive unit with extremely wide frequency coverage from 0 to 2GHz.  It is compatible with  power on coax systems to provide low voltage power for pre-amp or switching relays through the coax.  This product uses a gas discharge tube as rapid firing entrapment of large impulses and has bleeder resistors to drain static.

Models Available:                                                                                                

M-320, HF/VHF/UHF, 75 Ohms, 3-2000 MHz, DC blocking, F connectors, receive only      

M-322,  LF/MF/HF, 50 or 75 ohms, 135KHz - 60 MHz, DC blocking, F connectors, receive only

M-325, LF/MF/HF/VHF/UHF, 75 ohms, 0-2000MHz, DC pass, F connectors, receive only                                                     


Penetrox-A anti-oxidant connection grease.  For all aluminum to aluminum and aluminum to copper connections.  Prevents oxidation, corrosion and improves conductivity between arrestors and copper (or aluminum) sheet.  Also great for antenna element construction.  Available in 2oz. and 8 oz. containers.

Models Available:                                                                                              

Penetrox-A, 2 oz. container                                                                                                   

Penetrox-A, 8 oz. container                                                                                                    

Models Available:

Clamps for Morgan surge protectors

Attach two Morgan Manufacturing surge units to your ground rod.  Clamps can also be used as a quick and easy “single point ground” before cables enter the building.   Clamps are made entirely from copper and and secure with stainless steel hardware and nylock nuts.   Designed for 5/8” ground rod only.  Click pic for larger version.  Only fits M-300, M-301, M-302, M-303, M-304, M-320, M-322, and M-325.



              online  reviews

                      MORGAN MFG. ARRESTORS

All Morgan Systems arrestors can be pre-installed in KF7P Entrance Panels and shipped ready to go for a complete, ready to use system.  Email for more details, Chris at KF7P dot com. 

HF Arrestors, coaxial
VHF Arrestors, coaxial
Balanced Line Arrestors
Rotator / Control Line Arrestors
AC Line Protectors
Receive Only arrestors: 50 and 75 ohm, LF thru UHF
Penetrox A  Anti-Oxidant Connection Grease
User Reviews:  What are other hams saying about these products?

Chris provides a great product at a great price, surprisingly low shipping costs, and awesome customer service! I'm very glad I found this website, and Chris has certainly added another loyal customer!  [M-302N unit above-Ed.].

Thanks again, Mark KF5VQY






















$  9.00











I wanted to let you know I received the AC line Filter yesterday, thanks.  I plugged my new noisy refrigerator into the new filter and it worked - it removed the hash interference I was receiving on the 40 meter band.  40 meters is my favorite band for listening so it’s great to have it clear again!



All units use toroid inductors and present near dead DC short on antenna side of arrestor, constantly draining feedline wires of static and any developed voltage potential feedthrough breakdown voltage from input ports to output ports 4,000 to 6,000 volts. Arrestor units may be placed anywhere in the feedline at ground level without serious change in tuning, but small change may be detectable due “to small” increase in total feedline length caused by size of arrestor case & circuit.  Models 308 and 309 series all rated for frequency range 1-30 MHz, non-DC continuous through ports, polarized.  Units 308 & 309 are constructed in aluminum cases measuring (HWD) 11/2″ x 2″x 3″. Units include a 3 page owner’s manual.

M-476 requires 20A outlet as shown.

Mounting bracket

Questions? Email Chris@KF7P.commailto:Chris@KF7P.comshapeimage_53_link_0