| KK4GMU |
Rating:  |
2024-07-21 | |
| Very good |
Time Owned: 0 to 3 months. |
Update July 21,2024:
Jimmy at MFJ suggested I send the tuner box in to be checked out. So I did. A couple weeks later I got it back and tested it. The buzzer sound was now unmistakably present. They said that a couple of guys in the shop listened to it. The younger guys heard it; the older guys did not. The fix was to lower the frequency of the buzzer, which is what they did.
Operationally, I made several dozen contacts across the country using JS8Call. Tunes more easily than I thought it would. The "flashing light" issue that I thought I had was just lack of familiarity with how it works.
I'm using it in a compromised location surrounded by a chain link fence and a metal arbor with the bottom of the loop ranging from 5 to 8 feet off the ground. It is not as directional as I thought it would be. I understand its directionality kicks in at a greater height, but the lack of it could just be its environment.
Overall, I'm glad I have it.
Original review early June 2024:
Received and set up on June 1. No rotator installed yet. Able to get 1.1 on most bands, no worse than 1.3.
However, the buzzer will not sound when fast tuning passes the "dip" as item 9 on page 10 of the manual says it should. I checked the internals and the buzzer is connected and jumper is in place. I do hear a faint "click" when the dip is passed.
Additionally, the up/down fast tune lights do not consistently light when the up/down fast tune buttons are pressed. They light most of the time, but not consistently. Not sure if it is some form of unknown operator error, or defective operation of the control box.
I called MFJ and spoke with Jimmy. Only solution is to send it in. Initially not sure if I wanted to do that for a buzzer. I have no trouble operating without the buzzer.
But a second call with Jimmy he did suggest I send it in. So I did. MFJ is picking up the shipping tab.
I'll update as new info comes to pass. |
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| HB9DTC |
Rating: |
2023-12-17 | |
| Super und unterschätzter Winzling |
Time Owned: more than 12 months. |
Unglaublich aber wahr, ich besitze diese Antenne schon mehr als 20 Jahre und sie war bis vor zwei Tagen noch nie in Betrieb. Meine Antenne, die ich zuvor hatte, war eine 7 Band Cobweb von einer polnischen Firma. Leider wurde diese Antenne durch enormen Schneefall derart beschädigt, dass ich sie irreparabel abbauen musste. Als Provisorium montierte ich die MFJ-1786 Horizontal, auf dem 13.5 Meter hohen Alumast. Leider war die Masthalterung zu klein, so dass ein Hilfsmast aus einem Schiffs- Ruder gebastelt werden musste hi! Erste Feststellung sie ist deutlich schlechter als die Cobweb. Zweite Festellung, dass 15m Band ist nur bis 1:2.5 abstimmbar. Dritte Festellung sie geht trotzdem, für ihre Grösse, erstaunlich gut. Ich konnte auf dem 30m Band bereits ZL und VK auf dem Long Path erreichen, dass sind mehr als 20'000 km von der Schweiz aus und man bedenke, hier hat die Antenne den kleinsten Wirkungsgrad, von nicht mal 30%.. Die effektiv abgestrahlte Leistung dürfte so um die 5-10 Watt gewesen sein. In den paar Tagen die ich sie benutze, habe ich schon viele QSOs und DX QSOs gemacht und obwohl ich in den digitalen Betriebsarten meist schlechter ankam, kann ich die MFJ-1786 bedingungslos weiterempfehlen, da mehr in dem Winzling steckt, als von mir zuvor angenommen wurde.
73 &: 55 HB9DTC |
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| AI0C |
Rating: |
2021-11-24 | |
| Not the best, not the worst. |
Time Owned: 0 to 3 months. |
I received my MFJ-1786 one day short of four weeks after ordering it from HRO.
Having read the manual (which, BTW, is NOT included with the antenna) more than once in eager anticipation of receiving my new antenna, I read this sentence on page eight of the manual: "This antenna can be used inside a wooden or non-metallic building with some reduction in performance." I assumed the "reduction in performance" might be related to radiation pattern disruption from the antenna not being out in the open.
Living in a "wooden" house, I thought, well I can set this up in my shack for testing and did just that. The initial tests outlined in the manual went perfectly. Time to feed it some RF. Yikes! The antenna would not tune up on ANY band! Geez, I got a lemon!
I read through the troubleshooting section of the manual. The only troubleshooting step that seemed to apply was, "Check the mounting of the antenna (too close to a building, or other improper mounting, etc)." Too close to a building? Like inside a building? That seemed at odds with the "This antenna can be used inside a wooden or non-metallic building with some reduction in performance" statement earlier in the manual.
OK, so outside we go. I was able to get the antenna out in the open, 25 feet or more away from my house and other antennas, and six feet up in the air on a temporary steel mast attached to a steel fence post. That did the trick! The antenna now tuned up great on all bands.
Some observations...
As many before me have mentioned, tuning the loop is a bit of an acquired skill. But, I got the hang of it pretty quickly. The only oddity, and one that I'll be calling MFJ tech support about, is that there is a three second delay between when you press the slow tune buttons and when the tuning begins to change. You can plainly see this on the band scope display, if your radio has one, like my IC-7300 does.
Seeing the antenna "passband" moving across my band scope made me realize that I could pretty much rough tune the antenna without transmitting RF and fine tune it using RF and the "Slow Tune" buttons, so that's what I've been doing.
The build quality, as MANY before me have also mentioned, leaves MUCH to be desired. Following the suggestions of numerous eHam.net reviewers before me, I opened the case and had a look inside. The capacitor plates are VERY unevenly aligned between the stator and rotor. In some positions, some of the plates are almost touching. I'm a bit concerned about arcing when running 100 watts. I'll be talking to MFJ about this.
And the case. Oy! Whoever put the case together on my loop must've used a sledge hammer! The top half was pushed WAY down over the bottom half. So much so that many of the screws were pulling themselves out. I plan to fix this by installing J style clip nuts and drilling all new holes. MFJ will get some feedback on this.
As for the antenna as an antenna, I only have my old Cushcraft R7000 40 to 10 meter vertical to compare it to. Below 15, signals are just as strong on the loop as they are on the vertical. On 15, signals are about 2 S units lower on the loop and on 10, signals are about four S units lower. That's not too good. But, I plan to do some additional testing using my old Heathkit HW-9 as a signal source to give me a strong and steady signal.
I'll post back with a follow-up later.
Here's the promised follow-up:
In my earlier post I made note of two issues. First, comparing signal S meter levels on my Cushcraft R7000 to my MFJ loop, I noticed on 15 and 10 that signal levels were lower on the loop.
I did some further testing and determined that the loop receives signals on 15 and 10 at the same level as the R7000. The differences I saw earlier, and still see on some signals, is due to the fact that the loop is somewhat directional. Broadside to the loop is a "null zone" about 15 degrees wide, in which received signals can be up to 10 dB lower. So, my thinking is that the signals I saw on 15 and 10 that were lower on the loop was due to those signals arriving broadside to the loop.
Second, I mentioned a three second delay when engaging the slow tune up/down before the bandwidth began to move across my band scope. This turned out to be a mechanical issue. The motor used in the loop to turn the tuning capacitor is a 0.5 RPM geared motor. There is some play in the gear works and that combined with the low RPM causes this delay. I determined this visually. You can hear the motor turning, but the capacitor doesn't begin to move for two to three seconds. I asked MFJ tech support about this and they replied that this is "unfortunately normal."
Another follow-up:
I've been using the loop for several weeks now and have to say I am quite impressed with its performance in terms of emitting and capturing RF. Running FT8 I see stations from just about everywhere. Africa, Japan, China, Australia, Croatia, England, Germany, Israel, all at the same time!
Something else I noticed is that I don't get the best match when using the SWR meter in the MFJ control box. I noticed that my Daiwa CN-901HP meter did not agree with the meter in the MFJ control box. When I tuned using the Daiwa meter, I got a better match and the signals were noticeably stronger.
So I checked the MFJ SWR meter against my Diawa SWR meter and my Oak Hills Research SWR meter. Using my Heathkit HW-9, I fed a signal into my Siglent 'scope and adjusted the carrier level to provide three watts of output. I then fed the three watts to all three meters. The Daiwa and OHR meters read three watts. The MFJ meter read FIVE watts. I then fed the signal backwards through all three meters to check the reverse sensor and readings. The Daiwa and OHR meters both read three watts and the MFJ meter read 7 1/2 watts, off by more than 100%!
I now tune the MFJ loop using my Daiwa SWR meter. The Daiwa meter RF sensor is in a shielded box. The MFJ meter RF sensor is not shielded and looks like something an inexperienced ham might homebrew.
I would recommend this antenna only to an experienced ham, with the caveat that "final assembly" will more than likely be required upon receipt.
Also, after having read reviews where wasp nests were later found inside the antenna clam shell body, I bought some one-inch wide coax seal and sealed the seam between the two clam shell body halves and also sealed all other openings. I created a half-inch screened drain/weep hold in the bottom of the clam shell body.
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| G5MAT |
Rating: |
2021-08-27 | |
| Poor build quality, failed after a couple months |
Time Owned: 0 to 3 months. |
I enjoyed this for the first 2 months of ownership and it tuned up nicely. After just 2 months outside though, in summer, in the UK, it started having trouble tuning. As of today it tunes intermittently but only really on 20m. I struggle to get better than 3:1 most of the time.
Opened it up to try and fault find with an expert friend. Half the screws and nuts were loose, some had rusted in just 2 months, the soldering was not great either, so we refreshed that. Current suspected culprit seems to be the motor but can't really be sure without changing it. Online searches cite a number of reasons, many of which seem to be "just got a bad one". Will keep trying to resolve. :)
Sure has put me off MFJ products, great start with a disappointing end.
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|
| WA6OVP |
Rating: |
2021-04-01 | |
| Good antenna |
Time Owned: more than 12 months. |
Have had the antenna over 4 years - worked over 20k digital contacts - Antenna tuning is easier with practice.
First hour that I used the antenna was on 20 meters, using 15 Watts and FT8 ... worked a station in South Korea / some stations in the USA / then a station in Spain.
The antenna was in my backyard 12 feet above the ground, mounted onto wood mast attached to a water filled plastic portable picnic table umbrella base.
The antenna has even made lots of contacts, when used inside my home.
My 1786 was well made and trouble free - works great both inside and outside the house
Expensive but worth the price |
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| KI0TI |
Rating: |
2019-08-18 | |
| Works well. |
Time Owned: 6 to 12 months. |
| Don't count this little loop out! I have mine mounted horizontal at 19'above a metal garage. When you first get it you should open it up and check the alignment of the large capacitor plates as well as check the spacing through a full rotation. Then while the cover is off check the tuning on each band and make sure you can get 100 watts through it with a low swr. You may need to change the shape of the feed loop to accomplish this. I have the 1788 as well and had to do this with each loop. You will be surprised at how well these little mag loops will do. |
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| W4HTP |
Rating: |
2019-04-13 | |
| Relatively portable and great in attic |
Time Owned: more than 12 months. |
| Works good. Compact. I use it in conjunction with a 80-6M OCF and Butternut HF9V. I mostly use the loop on the receive port of a IC-756 Pro III. Seems well made and reliable. |
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| K7TXO |
Rating: |
2019-01-28 | |
| Submarine service ng |
Time Owned: more than 12 months. |
If you can keep the electronics dry, this antenna does indeed work well. I suggest you mount it only in the vertical plane so that rain storms can drain out around the SO-239 at the bottom of vertical mounting.
My MFJ-1786 has been mounted horizontal for two years. This Winter it stopped responding to 12 volt DC motor control through coax from the included "Remote Control". With a bucket lift to get at and take down the antenna on a 30 foot tower, the first thing I noticed was getting drenched with water as I unbolted it from the mast. Flipping the antenna vertical, something like 1/24 to 1/2 gallon of ice cold water came out the seam of the molded enclosure. Pretty sure I know why the antenna was not responding to the control box down in the shack...
Once I got it down on the ground and opened the two halves of the molded enclosure, I drained the remaining water and ice chunks. Also removed five wasp nests and a lot of dead wasps that did not seem to enjoy the ice water swimming pool so much.
I could see the water line where one of the two lever "snap" switches used to control the limits of the variable capacitor rotation had been submerged. The other components were damp with moisture but otherwise appeared ok. Drying everything out and electronic cleaner used, I left it to sit until next morning inside my shop. Next day I found some winter groggy but still live wasps exiting the ends of the loop, oh boy.
I contacted MFJ Support to try ordering the easily replaced lever switches but the person could not seem to find the switches only. He indicated he would email me back later that morning when he found the switches to ship to me but that never happened. I ordered a pair of OMRON long lever arm equivalents through MOUSER 653-V-163-1C4R.
After a thorough drying out of all parts inside the enclosure housing, I replaced the faulted lever snap switch and the other one too since the latter switch surely had condensation inside its sonic welded housing. I bench tested the antenna with new switches in place with the mating control box and my HF radio on a number of different bands and frequencies. The antenna has been restored to like-new operation.
Some people have sealed up the two piece molded enclosure with silicon. I chose not to do that originally and still not after the wasp and water issue. Air has moisture content and trapping it inside the MFJ enclosure without a truly 100% perfect seal likely would still cause issues over time. A silicon seal would in my mind only be good enough for wasp/most bugs control. I have chosen to place the antenna in a vertical orientation now, 12 feet above ground with a TV rotator. I am devising a rubber seal to go around the SO-239 enclosure hole. I will add something like a weep port found on some modern truck, tractor and car air cleaners on the bottom end of this now-vertical enclosure as a high moisture content drain. And some sort of miniature version of a rubber car trunk seal along the enclosure-halves-rim. That should mitigate major moisture, dust and bug entry but still allow some limited breathing to the interior. I don't want a solidly sealed black colored, thinly molded enclosure to cook the electronics while it warps itself open anyway and then lets wasps or other bugs in anyway along with rain, sleet snow here in the Winter.
Love the antenna for its excellent performance. Worked two South American and one Asian and one European country in ideal conditions in one day with it so yes, it does indeed work. Otherwise it cannot compete with my Hex Beam with its decent signal gain and better S/N ratio and fair side and rear rejection.
You will marvel at the performance of this 3 foot diameter thick wall aluminum hula hoop for barefoot rig operation. Especially if you have space or HOA restrictions. Just know that you must rematch from the control box for roughly every 3 kilocycles you move away from the last matched frequency. Signal db levels drop off considerably until you rematch from the control box. Pros and cons of only 3 foot physical diameter of an otherwise nice, heavy duty loop/lightweight electronics. Hide some sort of long wire receive only antenna and you will have quite a pair on 30 through 10 meters with this particular MFJ-1786 model of hula hoop. Gets a 4 for some great attributes and what you can work even if I am miffed about the electronics enclosure itself. Kind of a bargain really but just know you may have to decide how you mount it and deal with your local year round wx conditions if installed outdoors.
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Earlier 5-star review posted by K7TXO on 2017-03-18
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 |
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| N7JS |
Rating: |
2018-10-01 | |
| Amazing |
Time Owned: 3 to 6 months. |
| These antennas are amazing for their size. If you can, mount it horizontal at least 20 feet off the ground or above structure and you will have an antenna you can be proud of. I use my multi band vertical to listen where I want to operate and then dial this antenna in for the contact. They make a great team that won't piss off the neighbors and the wife. |
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| K5TED |
Rating: |
2018-09-01 | |
| Good antenna |
Time Owned: more than 12 months. |
Works fine. Unfortunately mud daubers and other wasps love it. Take the cover off and stick a sponge in there. Saturate it with wasp spray. Close it back up.
That'll keep you from having to replace a motor due to wasps building a mud nest on the capacitor.
Easy to tune once you get over the fact it requires some ear/hand coordination, manual dexterity and motor skills. Kind of like driving a car..... |
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