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Reviews Categories | Antenna Switching, Phasing, Controllers | MFJ-4712 2 Position Remote Antenna Switch Help


Reviews Summary for MFJ-4712 2 Position Remote Antenna Switch
MFJ-4712 2 Position Remote Antenna Switch Reviews: 8 Average rating: 3.3/5 MSRP: $79.95
Description: MFJ 2-position remote antenna switch uses single coax feedline to feed two antennas, DC power and control signals -- no power/control cable needed. 1.8 MHz-150 MHz. 1500 Watts/50-75 Ohms. 4Wx25/8Hx11/2D inch Outside Switch Box is fully enclosed, weather protected. Teflon(R) SO-239 connectors. Stainless steel 11/2” tall bracket with U-bolt for masts up to 11/2 in. O.D. Inside Remote Control is 21/4Wx21/2Hx11/4 in.
Product is in production.
More info: http://www.mfjenterprises.com/products.php?prodid=MFJ-4712
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WV2M Rating: 2/5 Mar 15, 2014 20:54 Send this review to a friend
Where is QC?  Time owned: 3 to 6 months
I purchase the remote antenna switch to remotely select among 2 receiving antennas. The instructions indicate that the antenna 1 connection would be selected with no DC power applied and antenna 2 connection would be selected with DC applied. Turns out that the markings on the body of the switch are reversed! Ant 1 is really ant 2. I spent hours trying to figure out why my antennas did not exhibit the expected polarity (one is vertical and one is horizontal.) After checking all coax cables and connections, I disassembled the remote switch unit and the circuit board clearly indicated the antenna markings and they are reversed to those printed on the case! I then used a VOM to determine that indeed antenna connection 1 is actually antenna connection 2. Once I reversed my coax's, performance was what I expected and the switch works fine.

Come on MFJ - where is quality control?
 
KC9XG Rating: 1/5 Jun 25, 2013 12:44 Send this review to a friend
Shoddy workmanship  Time owned: 0 to 3 months
The MFJ-4712 arrived with the top 2 front panel screws loose. Could not re-tighten, as they were stripped. Certainly not water tight with these screws not fastened.

A simple visual inspection would have revealed this issue.
 
KD8IIC Rating: 5/5 Apr 9, 2013 20:39 Send this review to a friend
Works Well  Time owned: more than 12 months
As a word of caution, Do Not run the ant 1 line to a transformer balun or anything that shows as a DC short.That will over heat and open the inductor coil in the DC Injector as well as the slide switch.The ant 2 position has no DC on it and will work fine.Learned the hard way on that one. 73
 
N4UFO Rating: 5/5 Apr 9, 2013 16:21 Send this review to a friend
No problems works great!  Time owned: 6 to 12 months
I bought it for a project that I ended up not being able to use it for... but then used it to add a 160m/80m vertical out 'beyond' my HF beam. Worked great all winter and performed flawlessly. I just removed it from service the other day as I am adding more antennas and upgraded to an Ameritron 4 port switch. I would say, 'If MFJ made a 4 port switch, I'd have bought it..." but if you think about it... that's what I did. X^D

Mine was mounted a foot or so high on a piece of iron pipe driven into the ground. Made for a good grounding point between all the toroid chokes I put on each line going in and out of it. Which I highly recommend... both to help keep lightning out as well as filter out common mode noise.
 
KE4PTM Rating: 2/5 Dec 11, 2009 10:44 Send this review to a friend
Have a good supply of 1N4148s!  Time owned: more than 12 months
This switch is a great fit for small environments and is priced moderately. Unfortunately, I must have gotten the bad one from the factory because is eats 1N4148 diodes. When it blew its fuse the first time I took it apart and found that the diode for the #2 antenna relay had already been replaced once....on a supposedly brand new unit. I finally got tired after the second disassembly and diode replacement and placed 4 1N4148s -- two in series and in parallel with another series pair -- in order to keep from having to take the thing down and apart every six months.
 
N9ZA Rating: 5/5 Jul 30, 2009 10:59 Send this review to a friend
Does the job without upsetting SWR numbers.  Time owned: 0 to 3 months
The only rub with it was the plug in 12 volt power supply that went dead after about a month's use. But then I also had another similar supply plugged into the same outlet, and it too went dead at the same time. I guess a ghost must have gotten into the AC line that day, and killed them both off showing no mercy.
 
KF6IHL Rating: 1/5 Sep 5, 2007 10:50 Send this review to a friend
Not what I expected.  Time owned: 0 to 3 months
As I was designing my antenna system, I placed my tower in what felt like an ideal location in relation to the cabin at my ranch. This position required me to have a reasonably long run of coax from the cabin to the top of the tower. At the top of my tower I installed an A3 beam for 10, 15, and 20 meters and a Alpha Delta sloper for 30, 40, 80, and 160 meters.

I began the process of deciding how I was going to feed the antennas, and I settled on a reasonably expensive 9913 coax to preserve as much of my signal as possible. I had originally planned to do 2 runs of 150 feet, when I encountered the MFJ-4712 remote antenna switch.

The switch was very convenient. It easily bolted to one leg of the tower. It ran the DC voltage down the coax so I didn’t need to run control lines along with my coax. I installed the switch at the top of the tower, and connected the A3 to the Antenna 1 position and the Sloper to the Antenna 2 position.

I operated with this configuration for about 2 months and I was very pleased with the performance of the antenna system, and the coax and the antenna switch.

After I became comfortable with the setup, I scheduled a contact with my buddy on 40 meters and went up to my cabin for a long weekend. When I set the station up for my contact I smelled a strange smell in the air.

Turned out that the control box as an inductor to filter RF from the 12 volt power line and that the inductor was red hot. The fuse on the line didn’t blow (1 amp) and while the switch was in the antenna 2 position (energized) a short that had developed someplace in the switch on the tower was causing a high current condition that was heating up the inductor, but not pulling enough current to blow the fuse.

I am not sure if this is a common situation with the MFJ switches, or if I found a unique failure of the device but I wanted to make sure I shared my experience with others to help them choose a switch that meets their needs.

I was running an IC-730 barefoot on the line, and was not keying down when the situation developed. I plan to contact MFJ and see if I can exercise the “no matter what” warranty on the switch. I am not sure I will reinstall the switch on my tower after it is repaired.
 
NI0C Rating: 5/5 Apr 2, 2007 09:36 Send this review to a friend
Very useful product  Time owned: 0 to 3 months
Comparable remote switches offered by Ameritron, DXE, and Array solutions switch four to eight coax lines, and most of these do not send the control voltage through the coax, thus requiring an auxiliary control cable.

I don't have a contest station-- I'm an ordinary ham trying to improve my DXCC Challenge score from a suburban backyard antenna system, sans tower.

My antenna system has been limited by a single coax feedline which crosses my driveway through 3/4 PVC conduit that passes through a slot in the driveway. This switch sends a 12VDC relay control signal through the coax, allowing me to switch between two verticals in the backyard.

The remote unit is very compact and weatherproof. Mine is mounted with connectors facing down (protected with coax seal) on the side of a wooden fence post.

The unit is rated at "1500 watts, 50 Ohms," which leads me to suspect the rating is not conservative, i.e., the antenna had better be well matched if you want to safely run full legal limit through this switch. However, I routinely run 800 watts, with no problems.

In summary, this unit has allowed me to use two backyard antennas, instead of just one.
 


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