MFJ-1786 Loop Antenna – My Stealth Antenna Installations
I used / am using this MFJ-1786 antenna at various QTHs from a mountain top overlooking the Great Smoky Mountains National Park, to our beachfront condo 100 yards from the Gulf of Mexico to our current home in Potomac, Maryland 15 miles from the White House and Congress – and from all three locations worked a total of over 100 countries and all 50 states.
MFJ-1786 antenna on a mountain top in Tennessee overlooking the Great Smoky Mountains National Park.
(Now that we live in a single-family home instead of a high-rise condo, I am experimenting most of the time with two longwire stealth antennas so I’ve lost count on the number of actual countries that I’ve worked with which antenna! The number of countries that I’ve worked with the MFJ-1786 magnetic loop antenna is well over 100 but I’m not sure by how much.)
My Super Stealth Bar Stool Tower and Fire Pit Cover for the MFJ-1786.
My favorite is the Bar Stool Tower Approach with Fire Pit Cover that I used on Sand Key Island in Clearwater Beach, Florida. From a distance, the MFJ-1786 looked like a patio chair with an umbrella and came with the added benefit of being rotatable with the Armstrong method.
(Click Fire Pit Cover for the Amazon link for the Classic Accessories Veranda 44-Inch Round Fire Pit Cover. You want the small – not the large – for about $22. The antenna mount that I used was the Winegard DS-2000 Universal Antenna Mount with U-bolts at Amazon for about $20. Click Mount for the Amazon link. Note: This is a very tight fit for the horizontal mounting u bolt holes of the MFJ-1786 but a very sturdy mount that is highly adjustable. )
As you can see from the below photos, I tried a variety of approaches including both horizontal and vertical mounting of the MFJ-1786 loop antenna. All three locations had / has HOA restrictions against antennas and this was some of the ways I came up with to keep a relatively low profile.
(Click on any image for the BIG picture!)
These photos were from three locations with three different HOA communities overseeing everything we did. During a total of six years, so far, that I’ve been using this MFJ-1786 antenna, I have never received a single complaint – or even comment – from any HOA organization or from any neighbor.
Your mileage may vary!
Out of the three locations, my very best results with the MFJ-1786 were from our fourth floor beachfront condo using horizontal polarization. Being only 100 yards from the Gulf of Mexico shore may have had a lot to do with the great propagation we got from our west facing balcony location. Even though Europe and Africa were blocked by our huge high rise, I had no difficulty working those parts of the world almost daily.
The wind load from the MFJ-1786 antenna is so low that we have never had any problem with the antenna toppling over – no matter how strong the winds – including some gale force winds on Sand Key Island.
I use sandbags that are intended to stabilize large photography lamps – with each sandbag holding about 10 pounds of sand. I bought the sandbags off eBay for about $26 delivered for all four bags and got a 50 pound bag of sand from Home Depot for four dollars.
One warning for those unfamiliar with loops…even the low power manual tune ones…there is an RF hazard if you get too close and the hazard index depends on frequency as well as power levels. This is something to worry about even if the MFJ-1786 is 100′ away if it is ground mounted and where children or adults play. Bottom line: Keep a 7-10 foot distance at 100 watts.
The MFJ-1786 Magnetic Loop Antenna works surprisingly well, even when only 8′ off the ground like the current location I have here in Maryland. It will handle 100 watts and is remotely controlled in the shack via motorized control that uses the feedline for voltage.
73 / 72,
K3RRR
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73 de Robert K3RRR
http://K3RRR.com
@K3TripleR
http://YouTube.com/user/K3RRR
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PS: If you’re interested in balcony operation of the loop antenna, be sure and check out this fantastic webpage: “The Balcony Mounted Magnetic Loop Antenna – A NEC Model Comparative Analysis of Physical Orientation and Performance” by Dr. Carol F. Milazzo, KP4MD
http://www.qsl.net/kp4md/balconyloop.htm
PPS: This was the view the MFJ-1786 Mag Loop got 24/7 looking directly west from our balcony with a 170 degree panorama (click image for BIG picture):
Sunset Over The Gulf of Mexico From Our Balcony, Sand Key Island – Clearwater Beach Florida
This was the view the MFJ-1786 Mag Loop (and my ATAS-120 before I bought the loop) got 24/7 from our balcony on a mountain top overlooking the Great Smoky Mountains National Park with a 180 degree panorama (click image for BIG picture):
180 Degree Panorama View From Our Balcony With The ATAS-120. Photo Pre MFJ-1786 By Two Months . The MFJ-1786 Worked Much Better With A Lot Less Noise.
Greetings All !
Enjoyed the pictures and discussions.
I recently converted my 10-30 meter MFJ mag loop by adding 3- 50pf 20kv caps in parallel along with a 300 amp dc switch. This way I have it all and switching in 40 puts me right in the center of the capacitor.
I also use the ANC-4 for 40 typically. I use a CCD dipole, a 40/20 dipole with a 4:1 balun and have it a foot off the roof. It is very quiet due the silver mica caps every 3 feet, 26 of them I believe to keep the current lobes down. It is a shortened 40 dipole with gain due to lower noise.
I might suggest the 40 and 75 meter Isotrons which I have tied together with a PL259 coupling, which are home brew along with my 160 Isotron.
I also use a 8 foot delta kite with RG-174, 300 feet of which (200 feet) is straight up with a 5+ knot wind. I hang a 20 meter dipole vertically with streamers to blow away from the coax and have put 300+ watts into that coax which takes 600 max believe it or now hi. Worked Milano Italy with a S7/8 at 100 watts at 2PM from San Diego from the car with a FT-100-D. The kite is very stable and might be a solution for SOTA/POTA situations for the QRP crowd. Age 73 and having fun with the hobby which I started in 1967 as a sophmore in HS back on the New Jersey shore. When the bands are too quiet I revert to DMR on the Brandmeister network and can work any of over 1500 talk groups around the world, just call CQ and you will be surprised. Have fun – Rich / NJ6F
Greetings!
U-tube has a great mod for the 10-30 meter loop to convert to 40-15 or 30-10 by adding 3 fixed caps which total 200mfd and a vacuum 12vdc switch with separate12vdc cable. I like the vertical config with no worries on ground effect and a bit more directional. You can sit it on a cardboard box and work the world. I really enjoyed the various mounting configurations & black wire harness covering.
Forgot to mention two alternate antennas that work great and take more power as well. The Isotron 40 and 75 I built and run full 1500 watts into them. Very small as well. Both can be tied together full power with a PL259 T. Also built a 160 Isotron. My neighbor in the last home hear my voice coming out of some trees at 200+ feet, as I modulated the ether hi…. they work well at 100 watts as well. I use a CCD dipole with silver mica caps every 3 feet with a 4:1 balun, a shortened (gain) 40 dipole with low noise and low to roof works well due to caps minimizing the current lobes. It takes 1KW max, and instructions are out there on building your own since they stopped making them 10+ years ago. I use a ANC-4 as well which is very effective on 40 if you have noise problems.
Greetings!
U-tube has a great mod for the 10-30 meter loop to convert to 40-15 or 30-10 by adding 3 fixed caps which total 200mfd and a vacuum 12vdc switch with separate12vdc cable. I like the vertical config with no worries on ground effect and a bit more directional. You can sit it on a cardboard box and work the world. I really enjoyed the various mounting configurations & black wire harness covering.
I picked up a used 1786 but it came without mounting hardware. It’s a bit hard to tell from your photos but is your mounting hardware stock or DIY? Thanks for all the great mounting tidbits!
It is a standard mounting kit that came with the mag loop antenna. You might contact the MFJ. Even though they’re mostly shut down, they still have parts and repairs active, as far as I last heard. You might be able to buy just the mounting hardware before they close down completely.
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73 de Robert K3RRR
X/(Twitter) @K3TripleR
YouTube.com/K3RRR
Website: K3RRR.com
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My attempt to order the MFJ-1786 from HRO two years ago didn’t work out. There was no availability estimate after waiting 4 months – so they uncharged my card. This past April ’24 I again ordered, this time through DX Engineering. They don’t charge until delivery is underway. I expect to receive it May 28th, coming from Sparks, Nevada (DX Engineering warehouse) to Florida. With MFJ supposedly not making new stuff anymore, I was surprised it was still available.
I chose the 1786 because we’re well into the solar cycle that favors 10 through 30 meters for the next several years. Thanks for this encouraging thread. Jerry KK4GMU
Jerry, thank you for your comment and congratulations on being able to get one of the 1786 loop antennas. I actually wanted that one instead of the 1788 but the backlog was so long for those I decided not to wait. There are a couple of new competitors out the blade there even more expensive than the 1786. Remember: it’s directional as a vertical and omnidirectional when horizontal. The great news is that if it’s vertical it does not matter how much elevation. You might report back here after you use it for a while and let us know how you like it.
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73 de Robert K3RRR
Twitter: @K3TripleR
YouTube.com/K3RRR
Website: K3RRR.com
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I picked up one for $60 the other day, unused. Somebody had stashed it away and never installed it.
Fantastic grab, Jerry!
What coax do you use? I have a 1786 on order, and plan to run 40 or 50′ of cable at most. I’m wondering since this is an inefficient antenna to begin with, if it is worthwhile to spend $30 or $40 more for LMR-400 over RG8-X to reduce the loss to a minimum? Is the juice worth the squeeze?
Hi Gerald,
I completely agree with you… I only use RG-8X for all of my HF antennas including the MFJ Loop. I do use LMR 400 for all my satellite antenna work. In my opinion, the losses per hundred feet for HF frequencies does not justify LMR400 unless you have a very long run. Avoid the squeeze!
73,
Robert
Can you share your thoughts of which MFJ loop among the 1786, 1788, and the 1780 (Box Fan) relative to best performance relative to cost? I’d like your opinion whether based on your personal experience or what you’ve heard from others.
Sorry, Jerry… I only have experience with the 1786. However, given the choice, I would probably go with the 1788 if I were to buy another one just so I would have 40 m even if I have to sacrifice 12 m and 10 m.
73,
Robert
Nice blog.
I would like to get your book with your Autogram.
Also would like to ask, if you ever used RF chock with the magnetic look?
From you experience do find vertical or horizontal antenna setup worked better with magnetic loop.
Thank you in advance.
Best of 73
I’m not sure which of my books you would like to buy but they are all available on Amazon. Thanks for your interest!
Yes, I absolutely use an RF choke on all of my antennas including my magnetic loops. With a loop, I usually have the choke near the antenna… With my 9:1 and my EFHW antennas, I put the choke near the transmitter – using the coax as a counterpoise until it gets to the choke.
Horizontal gives you omnidirectional… Vertical gives you directional in the direction of the plane of the big loop. This directional behavior is significant and usually works better with the rotator. The good news is that vertically, the antenna does best when it’s only 6 feet-8 feet off the ground. Omnidirectional radiates a lot like a dipole, as I recall… This also means it needs to be 1/2 wavelength – to a full wavelength above ground.
73,
Robert
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73 de Robert K3RRR
Twitter: @K3TripleR
YouTube.com/K3RRR
Website: K3RRR.com
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Can we use magnetic loop antenna to null the RF or EMI noise ?
I would like to see if anyone has experience in implementing the MFJ antenna to block RF / EMI noise from a near by source power line transformer / cell tower?
Any advice would be helpful and if anyone has experience and interested to in consultation & implementation..please message me @ JonBikos@gmail.com
Hi John,
You end up with more noise with a magnetic loop antenna and if you operate it vertically, it is highly directional. I’ve never tried it before but being so directional would probably let you track down the source of the noise assuming that you are set up for portable operation with the magnetic loop.
In specific answer to your question, I would think you could null out the noise if it is outside your home. The problem I see is that you would also be nulling out a whole lot of stations in that same direction that you might have otherwise worked. I also understand how even that compromise can definitely make sense in a lot of cases.
One of the other things you might try with regard to the noise: MFJ 1026. This thing can work wonders but it all depends on how good a noise antenna you use.
Hope that helps!
73,
Robert
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73 de Robert K3RRR
Twitter: @K3TripleR
YouTube.com/K3RRR
Website: K3RRR.com
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Fantastic photos and info about the magnetic loop antenna.
I am glad that you are enjoying your MFJ loop. I recently picked up a W6LVP Magnetic Loop a few weeks ago and put it up about 20 ft on a Channel Master rotator and use it as my receive antenna on my ham station while using a 132 ft Carolina Windom antenna for transmit. I really have found a tremendous difference in noise after going to a loop. I also have a Timewave ANC-4 Noise reducing device that works great in combination with either antenna when fighting noise that is not nulled out by the loop because I am using the loop at times to pick between stations in different locations on the ham bands and also BCB stations. I have a 12 ft noise dipole at 3 ft above the ground for the ANC-4 that I placed right under my electrical power line pole. The combination of a loop and the ANC-4 has allowed me to enjoy listening to Shortwave like back in the 50s and 60s before all of the electrical environment issues we face today.
73s
WD9GNG
Very nice photos and excellent work on using this stealth antenna. Did you have to do any kind of weatherproofing ?
The only weatherproofing I did was to silicone tape wrap the connector….the only maintenance issue that I’ve had is taking the cover off to get the wasp nests cleaned out…seems like they love making the MFJ-1786 their home.
Thanks, Kieran….I had completely forgotten about adding the wire harness in order to cover the shiny aluminum tubing… As you can imagine, it made a big difference for invisibility!
Thanks Robert,
You have given me lots of great ideas. The black automotive wire harness cover is excellent. I’m really happy with my MFJ loop and have worked 93 countries to far. Kieran