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Reviews Categories | Antennas: HF: Vertical, Wire, Loop | MFJ-1788 Super Hi-Q Loop Help


Reviews Summary for MFJ-1788 Super Hi-Q Loop
MFJ-1788 Super Hi-Q Loop Reviews: 41 Average rating: 4.2/5 MSRP: $429.95
Description: High Efficiency 7-21.5 MHz Continuous Coverage Magnetic Loop
Product is in production.
More info: http://www.mfjenterprises.com/products.php?prodid=MFJ-1788
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VA3TKO Rating: 4/5 Mar 18, 2014 08:56 Send this review to a friend
Initial findings of my MFJ1788  Time owned: 0 to 3 months
MFJ 1788
Recently purchased the a new MFJ 1788. When the box arrived from the supplier, I noticed one side of the box had been opened and re- taped with clear tape.
I first mounted the antenna on a 8 FT galvanized pole away from any objects in the back yard. I carefully read and followed all the instructions from the operating manual provided. Yes....I had to widen the holes on the vertical support brackets so the hardware would fit properly. That took 10 minutes with a cordless drill.
When I first powered up the control box, I could not get my " FAST" DOWN LED on the right to illuminate. First thoughts were of the quality control at MFJ. AFTER TRYING OVER AND OVER, and failing to get the antenna tuned on 20 meters I decided to take a look inside the plastic covers of the loop itself. I had read some blogs suggesting the checking of solder joints if the antenna was not working. So off the covers came. Within a few minutes I noticed one side of the internal loop wire had a cold solder joint. The end of the internal loop could be moved in and out of the solder joint freely. I resoldered the joint, remounted the antenna and presto.....all LED's were now working. I managed to somewhat tune some of the 20 M band but the SWR at best was 2:1. I had read in another blog that if your internal loop was turned out on one side compared to your 36" loop you may improve your SWR.. I tried it and WAALA," got an SWR OF 1:1 at a full 100 watts. Now the test...( I live in Florida) I heard a station about an S9 on 20 meters. I retuned to that frequency and attempted contact. Immediately I get as response back ...a clear 59 signal to Richmond Virginia. Happy I had made a contact I wondered what the antenna would do closer to the ground. I placed the antenna on the top of a plastic garbage can ( approx 24" in height) in the vertical position from ground. I went back to the radio found another station on 20 meters, retuned, gave out my call and again got a 59 response. He also was located in Virginia. When I told the contact about my antenna and that it was sitting on top of a plastic garbage can he laughed and said I can't believe it. ....that I was a little stronger than another Florida station in FT Lauderdale that was running a beam pointed at him. He was quite excited and started talking to others in his group asking if the could copy me as well.
Pretty cool. In closing despite the few hiccups...I am glad I purchased the antenna.
I just wish MFJ would place some emphasis on Quality Control. Oh yes one other thing.
I called the MFJ Technical Support number listed on the instruction manual for the 1788....A lady answered and told me that I had the wrong number and that MFJ has a new number and has for some time.
She seemed a little irritated.
Anyway, I hope this review helps. 73. VA3TKO
 
W9JY Rating: 5/5 Nov 19, 2013 10:22 Send this review to a friend
Great for Small Spaces   Time owned: more than 12 months
I have both the 1786 and the 1788 from MFJ. They are the same design but they cover different bands. I have them each mounted on MFJ 1918 antenna stands.

I live in a townhouse in the city. I've tried lots of compromise antennas. I've tried verticals. I've tried indoor random wires with tuners. I've found that nothing beats the magnetic loop in terms of performance and convenience for small spaces.

The loops are about 3 feet in diameter. They don't require any radial wires like a vertical antenna does. They are easy to set up and put away when not in use. The tuning is semi-automatic using a control box. I found the tuning procedure easy to master. The tuning box sends the control signal over the same coax as the rf signal. This eliminates the need for a separate control cable. The control box requires power. It comes with a wall wart power supply. It also has an internal battery holder for AA batteries. I use the wall wart power supply when I'm operating from inside. When I'm outside I use AA batteries in the control box.

I've made contacts using PSK31 on HF all over the country as well as internationally with these antennas.

The only drawback to the design is narrow bandwidth. If you move up and down the band you will have to retune again. Retuning is pretty easy, though, so for me it is not a deal breaker. It is a small compromise to make considering the convenience and performance of the antenna.
 
AD0BL Rating: 5/5 Aug 20, 2013 09:10 Send this review to a friend
Works great - small learning curve.  Time owned: 0 to 3 months
First off - my antenna and control box was received in perfect condition. I didn't need to do any "fixes" to anything. My antenna must not have been made on a Monday.

When I first received the antenna, I set the antenna on the floor, connected the coax, and went through the tuning instructions. I couldn't get the control box to "beep" (indicating a tune). After reviewing the troubleshooting guide, I realized that the antenna must be mounted correctly for it to tune (duh). I mounted the antenna vertically on a 4 foot mast and stand in the house. I was able to tune the antenna 1:1 or very close on all bands by transmitting a CW tone at 5 watts. I set the antenna on the stand on my deck outside about 10 feet from the house at about 8 feet. I started working PSK using 45 watts. I worked several European stations on 20m. I could see on WWW.PSKREPORTER.INFO that my signal was being received well into eastern Europe by 10 stations or so. This is much more potent than my 40' end fed wire at 35 feet.

Here's what I learned:

1. Mount the antenna correctly and it will tune.

2. The antenna takes a little bit of practice to tune. You can tune the antenna 1:1 or very close using low power and a CW tone.

3. The antenna puts out a potent signal.

I plan on mounting the antenna on a chimney. I have a place that is both high up and unobtrusive.

I'm delighted that I now have such a capable antenna!

 
W5XE Rating: 5/5 Jul 29, 2013 10:19 Send this review to a friend
excellent  Time owned: 3 to 6 months
I purchased the 1788 in March and installed it
on a fence at the 6 foot level. Worked very well
even at my normal qrp level of less than 5 watts.
I use it mostly on 30 and 20 where it does an
outstanding job. Wanting to see how well the
performance was at a higher level, I moved it to
25 ft over the top of my mobile home. I saw no
difference in performance or signal levels, so
relocated the antenna to the fence location.
I hear many dx stations when the bands are open
and it hears as well as my vertical and dxcc
dipole. Well satisfied.
 
G6YEK Rating: 5/5 Jul 28, 2013 22:18 Send this review to a friend
GREAT  Time owned: 0 to 3 months
Owned now for only 3 days,FANTASTIC only 6 feet above the ground.
Des G6YEK
 
VE3MCA Rating: 5/5 Jan 15, 2013 11:39 Send this review to a friend
Great low profile antenna  Time owned: 0 to 3 months
This past weekend (Jan 12/13, 2013) I installed the MFJ-1788 outside in my yard about 7 feet above ground on a metal pole. The antenna is setup vertically with the loop ends in a NE/SW direction. The antenna is about 15 feet away from the main house and 8 feet from the carport (brick, vinyl siding with some metal trim). Coax cable run is about 50 feet of RG-213. During the installation, the only issue that came up was when I was attaching the brackets to the base of the antenna. The taps were slightly off and it took some time and patience to get the bracket to screw in flush and straight. Once that was done, the rest of the install and setup was a breeze. Ensure you read the instruction manual, especially when it comes time to tune the antenna. It takes some practice and patience to get the tuning down. First few attempts to tune, I was wondering why is it taking so long to tune and I would stop short of a proper tune thinking there was something wrong with the antenna or the location of the antenna. It is normal to wait 30 seconds or longer to see the SWR needle begin to drop (guess I was used to automatic tuners that only take a few seconds to tune). I have also posted a video on youtube on the tuning procedure to help others out. Once I got the antenna to tune, I was on the air making PSK31 DX contacts in no time. Some of the contact made within the first day..from my QTH in London, Ontario, Canada -- Czech Republic (OK1EP); Austria (OE9PCJ); Estonia (ES3RM); Sweden (SA7BWV); Dominican Republic (HI8CAR); Slovenia (S52UF) and many local North American contacts. Signal reports were mostly 599 to lowest 469. Running between 30 to 80 watts using Kenwood TS-480HX. Overall, I am pleased with the performance of the antenna. The workmanship on the head unit is fine, everything works and cabinet is square and set well. Again, the only issue was when attaching the brackets/screws to the pre-drilled holes which were slightly off making it a chore to set the bracket straight. Considering the size of the antenna, the performance is awesome and a relief for me as I am in an antenna restricted neighbourhood. I have tried the MFJ apartment antenna with the base coil and clips, and Buddipole antenna (vertical config.) with only satisfactory results. Sure, the price of the MFJ-1788 is on the high end, but that includes a tuner which provides easy calibration to an antenna that is a fraction of the size of many other HF antennas and it gets out with great signal reports.
 
WA6MJE Rating: 2/5 Jan 12, 2013 20:00 Send this review to a friend
Variable Capacitor Mis-Aligned  Time owned: 0 to 3 months
I just purchased the MFJ 1788. And of course I had to drill out the mounting holes like everyone else. After ten years of manufacturing this same product, MFJ has yet to address this minor but annoying issue.

Here is the real problem. The loop will tune 15 meters and the bands below until it gets to 40M. At that point it will tune down to about 7.125mhz as shown on my antenna analyzer, but no lower. I need to go all the way down to 7.0 mhz to work CW and JT65.

So then I moved the loop all over my yard, and put it higher, and lower to see if this problem was specific to my location, and nothing made it tune lower. Then I took off the lower covers, and played with the inner loop configuration from round to oval and back again as the manual suggests, which changed the SWR at 7.125 but did not allow it to tune lower than 7.125 mhz.

I then took off the upper covers, and noticed that the variable capacitor plates are not aligned properly. The variable plates are closer to one side of the fixed plates than the other. In other words, on a scale of 1 to 100 with 50 being the center line between the plates on the fixed bank, the variable bank is about at the 80 position, very close to one set of plates on the fixed side, and very far from the other set. It should be half way (50 on a scale of 100) or equidistant if it were within design specifications.

At the low end of the tuning range, the plates are fully meshed, but the misalignment would likely produce less capacitance than when properly aligned, and this likely explains why it will not tune below 7.125.

I see no way to adjust the alignment of the capacitor variable and fixed plates to that it will tune the bottom of the 40 meter band as advertised.

I was hoping that this would be the exception to the lack of MFJ quality control rule, but sadly here I am again in MFJ hell. It will be awhile until this is worked out with them.
 
KB8BO Rating: 5/5 Sep 7, 2012 11:54 Send this review to a friend
Exceeded Expectations  Time owned: 0 to 3 months
I received my MFJ 1788 two and half weeks ago. Everything worked fine out-of-the-box. I have been pleasantly surprised how well it works. I have had other mag loops made from 1/4" copper tubing that are far less efficient than the 1788. I have made a/b comparisons with my inverted L antenna. On 20 m and above, the 1788 is usually better than the inverted L. On 30 m, it is almost an S unit down from the inverted L. And on 40 m it is about an S unit and a half down from the inverted L. For its size, I am pleasantly surprised at its performance. By the way, I haven't yet put it outside. It is standing vertical in a spare bedroom on the second floor.

The only downside is that it is more noisy than the inverted L. This is consistent with the other mag loops that I have owned. The literature says that mag loops are quieter than most other antennas, but my experience has been just the opposite.

Overall, I would highly recommend the 1788 to anyone who has antenna restrictions. Be careful of where you place it, because metallic objects do have an effect and moving it or turning it can make a drastic difference in the SWR. Here again, this is consistent with other mag loops that I have owned.
 
STAYVERTICAL Rating: 5/5 Aug 7, 2012 03:07 Send this review to a friend
Antenna restricted no more  Time owned: 3 to 6 months
The lure of a small yet effective H.F. antenna is the holy grail of many hams.
The MFJ1788 I have is a nice piece of MFJ engineering, and works like advertised.

The ABS cover does not seem waterproof but I think it is thick enough to do its job of protecting the insides from most of the weather.
In fact I simply put a plastic cover over it, have not found it affects performance, and solves the weather problem.

When I first received the loop I had to do the usual final finishing which others have described.
Widening the holes on the mounting brackets to avoid putting in the bolts at an angle and cross threading the nuts inside.
I would suggest first putting in the bolts with the brackets gently by hand and if there is any binding - stop and widen the bracket holes.

The control box was in good condition except that the reflected power needle was off zero.
After opening the box and gaining access to the meter, a simple adjustment set this right.

Apart from those two things the unit was ready to go and has performed very well on 40m to 15m.
It is annoying to have to do some final finishing, but being used to building Heathkits and fixing old radio's it was not too onerous.

It is expensive, but it is not simply a loop but also a cross needle power/swr meter and controller.
Overall, not a bad package - and if you are a ham without space for a big beam or have HOA restrictions this little giant can save your H.F. operation.

Well done MFJ.
 
KF4FM Rating: 5/5 Jun 8, 2012 07:50 Send this review to a friend
Great antenna  Time owned: more than 12 months
My MFJ-1788 loop is a fantastic antenna and works flawlessly when properly tuned. Tuning can be a bit tricky at first, but becomes easy with use. I find that tuning to the strongest receive signal first, makes it quicker and easier to fine tune to the lowest SWR. That practice also eliminates fine tuning to a frequency you decide not to use because it's busy.

My 1788 is horizontal at 22 feet and I've worked South Africa from east central Florida with very good signal reports both ways. I was very careful to install it away from too much metal as instructed in the manual.
 
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