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Reviews Categories | Antennas: HF: Vertical, Wire, Loop | MFJ-1786 Super Hi-Q Loop Help


Reviews Summary for MFJ-1786 Super Hi-Q Loop
MFJ-1786 Super Hi-Q Loop Reviews: 58 Average rating: 4.4/5 MSRP: $379.95
Description: High Efficiency 10-30 MHz Continuous Coverage Magnetic Loop
Product is in production.
More info: http://www.mfjenterprises.com/Product.php?productid=MFJ-1786
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You can write your own review of the MFJ-1786 Super Hi-Q Loop.

Page 1 of 6 —>

N9WHH Rating: 4/5 Aug 13, 2017 11:43 Send this review to a friend
Not a bad portable antenna  Time owned: more than 12 months
I purchased mine directly from MFJ, so I had to wait a month or so to get it. It came in the winter months, so, when it did finally arrive, there was snow on the ground and it was too cold to comfortably try it outside. I just hooked it up in the shack to my K3 and tried it out on 20m. I had it situated vertically, next to me in the shack. I made several east coast contacts, just playing around. I was impressed! (I am in SW Illinois)
Fast forward to a special event our club was running in a high location. Not the best situations, as we tried both vertical and horizontal orientations, only 6-8' off the ground. Nothing! We could hear but no contacts made.
A year or so later, I needed a semi-permanent installation, inside a garage. I simply hung it off a bicycle hook from the ceiling. Not too bad. Was making regular contacts in club nets on 40m about 50-75 miles away. I had signal reports that were about the same as other club members who were running verticals. Nothing to write home about, but pretty good for a quick and easy set up.
As has been reported by others, it is very narrow banded, and extremely touchy about tuning. One needs to be quick on the fine tune "up" and "down" buttons. It would be nice to slow the fine tuning down a bit. Otherwise, have no complaints regarding the often reported build quality issues...yet.
Over all I am happy with mine, for what I wanted: a quick and easy portable antenna, with some directionability, and loop quietness. Fun to play with.
 
W9MT Rating: 4/5 Jul 9, 2017 18:21 Send this review to a friend
Liked it so much the first time, I swapped for a second one...  Time owned: 0 to 3 months
I owned an MFJ-1786 about 10 years back and liked it a lot. Hi-Q critters like this antenna provide (like other reviewers have said) a potent, efficient antenna in a very small footprint. It's a great antenna, therefore, for HOA Nazi controlled QTH locations, like mine. I found other ways to stealth my HF operations (Force 12 Sigma 5) and I put my loop away until a work colleague asked to buy it from me from his similarly storm trooper controlled location. So, I sold it to him for a reasonable price...and regretted it afterward.

On Field Day weekend of this year (2017), I saw an on-line classified from another ham who wanted to either sell or trade his MFJ-1786. I contacted him. We struck a trade deal. Our parcels waved "hello" to each other as they passed in shipment. The huge box arrived a few days hence. I did not get a chance to remove anything but the control box until this weekend.

I pulled the loop out of the box yesterday and removed the ty-wraps freeing the smaller, long box with all of the mounting goodies, user manual, and AC power pack. This antenna had never been unpacked, nor ever used. It was NOS in the box !!! Also in the smaller box was a 2013 MFJ catalog. So, this puppy was purchased new in 2013, some four years ago.

I put the antenna horizontally across two plastic chair backs, connected up coax, power packs and my MFJ-259, and tried her out. Fast Up and Fast Down worked fine. The motor quietly tuned the variable cap in the loop housing from 9.85MHz to just above 30MHz. "Slow Up fine tuning" also worked great. Blink-blink-blink went the Up yellow LED...

Not so with "Slow Down fine tuning", though. Both yellow LED's flickered weakly together rather than just the Down yellow LED. Bad sign...Slow Down F-T just didn't work at all.

Taking heed from many other reviewers, I then figured out how to disassemble the covers on the tuner box to have a look inside. The assembly construction of the 1786's tuner box is a bit odd. (Open one up. You'll understand what I'm saying.)

I also did not know until I opened it that there were empty battery holder cases inside (two of them) each holding 4 AA cells for portable operation.

I downloaded its schematic off of the Internet (it's not in the User Manual) and tried to reason out what could be wrong. Nothing I probed made sense.

So, while figuring I may be calling Starkville, MS tomorrow morning (Monday), I got the inspiration to remove the circuit board and look at the opposite (non-component) side. Carefully doing this, I saw trace cuts and several white jumper wires...and even a resistor tacked across one cut runner. Remembering the wise words about MFJ's poor QC, I put on my "ant-burner" magnifying visor and had a look at the workmanship. There at one cold looking pcb solder connection I saw it... One of the white wires of two going to the same node was connected, and the other not connected !!! I got out the Weller solder station and made it pretty again.

It was really that easy. The tuner now fully works. I would say "works again", but this was an NOS, unused antenna that was approximately 95% working, with a DOA "Slow-Down, fine tuning" function. As new, if tried out in 2013, it would have never completely worked.

I'll chime in with the others who say MFJ has great ideas and products, but not the greatest execution. If I didn't have to fix it, it would really have been a "Raving Five" rating for this antenna system.
 
W5VQE Rating: 4/5 Jul 2, 2017 09:42 Send this review to a friend
Great Promise, but...  Time owned: 0 to 3 months
I give it a 4 initially because while other reviews are great, I assume mine will be too - as soon as I can figure out why it won't tune except intermittently. Instruction manual says open coax is the likely cause of this problem. I have tried 4 different coaxes that I have and have checked all of them end to end for zero ohms resistance. One of the coax that works occasionally is RG-8U only 3 feet long. Another is 6 feet long. Sometimes they work, mostly they don't.
 
K7TXO Rating: 5/5 Mar 18, 2017 14:05 Send this review to a friend
DX a breeze w/MFJ-1786  Time owned: more than 12 months
Today I had QSO contact with Germany, Italy and France on 20 meters. In round numbers, we will call that 5,000 miles from Idaho. Last weekend I logged multiple contacts in Brazil, Costa Rica, Alaska, Ontario, Uraguay, Japan and Dominican Republic. All of these at 100 watts from TS-590SG w/HEIL HM-12 mic feeding the MFJ-1786 mounted horizontally with LMR400, 32 ft up on a short Rohn 25G tower. 1:1 match per Elecraft W2 wattmeter and TS-590Sg meter.

Over a year experience with this antenna, it ranged from pretty good while 6 ft off the ground, vertical to rather outstanding in it's present height and omni directional polarity. VERY quiet antenna! I have three HF antennas in the air. I prefer trying to use this loop first. I programmed PF key on TS-590SG to send 5 watt carrier (a must have as a standard radio feature in my book) for quick MFJ controller tuning. I can run the linear on the other antennas but why do that when this MFJ loop works so well at or with less than 100 watts.

Of course I can do better with antennas with gain and directional including my Hex Beam, especially in pileups. This loop will be at the rear of crowd in pileup situations when clawing my way through the better-db gain, directional antenna bunch, often with amps on the radios.

In most all other cases this is an incredible DX performer for me, in a 3 ft diameter "hula hoop" bolted up not that high in the air. And this tower and antenna are right next to the house with standard composite shingle roof merely 15 ft below. The house siding is steel lap siding. No issues with the house or anything on the ground (e.g. snow), wet or dry grass/ground. It just flat works great all year round! Gene / K7TXO
 
M0CRN Rating: 2/5 Dec 18, 2016 04:44 Send this review to a friend
Now a good antenna  Time owned: 6 to 12 months
When I first got my HF licence back in 1998, the very first antenna I used was a badly battered example of the CAPCO magnetic loop. I completely rebuilt it and used it to great effect with a Trio TS120V with a power output of just 10 watts, and for the next 12 months I literally worked the world - and then I rather foolishly parted company with it. After some thought,I recently decided to dispose of some of my antenna's and replace with a system which would be easier to maintain. One of my choices was a magnetic loop, and I purchased the MFJ-1786.

The antenna duly arrived, and after examining everything I started to set it up. One half of the cover was removed to gain access to the feed loop and the antenna was mounted on a short post stuck in the ground while I made adjustments. Upon examining the tuning capacitor I noticed that the shaft coupling connecting it to the motor hadn't been tightened, and there was a dry joint on the feed loop. After sorting out these small issues I soon had it tuning up with an SWR of 1:1 on all bands, but after 'tweaking' resistor 'R26' to further slow down the up/down tuning buttons a bit - the resistor blew. The control unit was dispatched back to the supplier, and the repair took a full month before I finally got it back. Upon its return I tried again, and finally got it sorted. I replaced the covers and got the antenna erected above my shed roof.

I got on air and tried the loop out for the first time, but to my horror the SWR climbed out of band at a truly alarming rate, it wouldn't even have been possible to put out a call before it was out of tune. Down came the antenna again, and I opened it up to examine the capacitor. I discovered that the shaft had about 1/8th inch play in either direction before the motor engaged. This tiny amount of play isn't much when viewed at the shaft, but when you rock the capacitor plates it is actually an alarming amount of free play. The tension spring mounted on top of the capacitor directly to the shaft isn't fit for purpose, and it does nothing to keep the shaft under tension. The slightest breeze on the antenna was sufficient to move the capacitor and knock it out of band.The free movement of the plates was actually larger than the whole of the tuning range for the 20m band!

The solution I came up with was to drill through the plastic nut on top of the shaft and insert a small 2 inch length of fibreglass rod running at a right angle to the loop. I shortened the tension spring by about 1/3 its length and attached it to the end of the fibreglass rod. The capacitor is now kept under permanent tension and there is no drifting out of band. Another modification I made was to rip out the feed loop and the small circuit board to which it was attached. This was replaced with a gamma matching system - which I find to be a much-better arrangement. The motor is still fed through the control-box, but I don't bother running the coax into the back of the box.

The antenna is now working superbly, I use my FT 450D with it at 25 watts, and even under current conditions I have no problem making good contacts on it. I have given the antenna such a low score because after paying over 500 for it, I shouldn't be expected to have to make changes to the tensioning spring on top of the capacitor. It is a poor design feature, and is never going to work properly.
 
VA7PIO Rating: 4/5 Sep 23, 2016 21:59 Send this review to a friend
Good Antenna  Time owned: 3 to 6 months
I'll give this antenna a 4 out of 5, itdoes a great job of DX, I'm located not far north of the US/Canada border,49th Parallel, with this antenna I've received a far south as Central Mexico and North to Alaska on 20m. I have it mounted horizontal as I was unable to get anything with it mounted vertical. I agree with the holes not being aligned properly which is why it's not getting a 5 rating, also I have to tune this at various frequencies on each band. If I tune it below 14.150mhz I have to re-tune it above 14.250mhz otherwise my SWR goes up. Other than that I'm quite impressed with this 3 ft loop.
 
WC6Q Rating: 2/5 Sep 18, 2016 08:24 Send this review to a friend
Doesn't tune in the cold  Time owned: more than 12 months
The Good
So on the plus side it does what a magnetic loop should do and that is receive and transmit on a narrow bandwidth. It does it rather well I might add. This is one of the few MFJ products I actually kept.

The Bad
This thing absolutely will not tune under a certain temperature. I haven't quite nailed down what temperature that is but it's somewhere around 50 degrees F and below. You press the button and nothing. Wait till afternoon and the sun has warmed things up and it works.

I thought it was the motor so I replaced that in hopes it would fix it but that was a fruitless attempt.

Build Quality
Like most MFJ Products the build quality is a joke. Holes are misaligned making this unit a real treat to mount.

Overall yes it's a mag loop. Will it work 100% of the time? No. And keep in mind I live in Southern California, so we don't get that cold here but are mostly a warm climate. I wouldn't recommend anyone in the other continental United States buying this as the weather will ruin you ability to tune.
 
KK4A Rating: 4/5 Jun 17, 2016 17:45 Send this review to a friend
Typical MFJ quality but it works  Time owned: 0 to 3 months
I am writing this review from the perspective of an antenna challenged Ham, i.e. I live in a neighborhood with restrictions against outside antennas. I currently use a 150 foot long wire mounted on stand-offs on my 6 foot high wooden privacy fence. The wire is fed by a remote SGC tuner mounted on the fence. Its not a great antenna but it gets me on all the HF bands....its better than nothing.

In an effort to improve my antenna situation, I decided to try the MFJ-1786 in an indoor (attic) installation. I live in a two story house with a cavernous attic space so I was able to install the loop on a mast in a horizontal configuration at about 25 feet above the ground. The instructions say that it must be at least 20 feet above ground to work when mounted horizontally.

So, without making this an overly long review I will say several things: First, it performs very well compared to my fence antenna and has improved my ability to hear and to be heard. Second, it is over-priced in my opinion. For the price, it is too cheap looking as is most MFJ stuff. Third, I did not have any of the quality control problems described by some other reviewers. I did remove the plastic cover from the antenna itself to be sure there were no capacitor issues as some others have had, but all was good under the hood. Fourth, the tuning nulls for minimum SWR are extremely sharp and it takes a little practice but you get used to it quickly. The loop in my attic is very close to the wood framing of my roof but the antenna loads nicely on the bands that it is intended to operate on (10 thru 30 meters). Fifth, the state of tune is affected by the attic temperature and if you stay on one band all day it requires retuning 2 or 3 times in a day as the temp rises and falls. Sixth, (and this is not the antennas fault) my shack is on the second floor of the house so I am in closer proximity to the RF field than I was with the fence antenna so I was initially getting RF in my computers that I use for digital operation. I was told that RF usually comes into a computer on USB cables so I remedied this by putting clamp-on toroid cores on all USB cables and the problem went away.

So, I could ramble on but I'll finish up by saying that I would have given it 4.5 stars but you can't do that. I simply can't give it 5 stars due to the cheap look of the antenna and the control box. That being said, it works very well for a stealthy antenna and I would do it all over again if necessary, in spite of the price.
 
2E0MEN Rating: 5/5 Feb 13, 2016 21:35 Send this review to a friend
Great DX antenna  Time owned: 0 to 3 months
I have mine mounted vertically on a 3 foot pole in a 2m x 2m wooden shed in the back garden and Im making transatlantic contacts from the Midlands, UK on 50 watts. My best so far is Cuba.

It tunes in brilliantly, the auto tune gets it below 1.5 on mine, then I tune it to nothing with the fine tune buttons. This is with the exception of 10MHZ where it wont tune below 1.4, and the auto band select wont lock on, but ive read and seen on youtube that this is a common issue, but still useable though. SWR is non existant on all bands above this upto 10M.

Fine tuning is a bit tricky on 30-20M but alot easier above this, you get used to it though. Ive also found that I dont need the auto band select (lock on), I just hit the tune button and listen for the signal to rise then I stop it tuning instantly, removing the need to TX on tune. You will need to TX for the final fine tune though.


A great antenna overall, and my only option where I live. As a very rough comparison it compares well to a half size G5RV at about 15-20 feet up with a good ground when its on a 3 foot pole in a small wooden building and no ground. You could do much better with a wire higher than 20 feet or any high gain antenna at a decent height. But when none of those are possible this loop is the best you are going to get. If you could get it on a mast though who knows how good it could be.
 
AF7ON Rating: 4/5 Jan 27, 2016 09:00 Send this review to a friend
A good magnetic loop antenna  Time owned: 0 to 3 months
I acquired an MFJ-1786 for portable operation from my RV and to get some experience with mag loops in general. I first bought a returned unit, but found the controller to be DOA and then bought a new one.

Perhaps MFJ's quality control is improving - the replacement arrived in good shape and everything works as it should (although the mast bracket still needs a bit of filing to fit!). The all-welded construction appears to be low resistance and works well. I feel that the construction and materials are a bit sub-par for an antenna at this price bracket (~$450).

For testing, I set it up vertically on a speaker tripod stand at a height of 5-feet on the patio outside my shack. I have made contacts on the 30, 20, 17 and 15 meter bands and have been pleasantly surprised by its performance. Contacts from Arizona include Japan on 15 meters and the Netherlands on 17 meters. It is perhaps an S -point lower than my 40-foot high wire loop, but much, much quieter. I have been able to contact every station I called with 75 watts.

An excellent choice for a stealth or portable antenna for 10-30 MHz. I would give the performance a 5, but marked it down overall to 4 because of the construction quality.
 
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