| N4UP |
Rating:      |
2012-07-16 | |
| Excellent !! |
Time Owned: 0 to 3 months. |
I've had this for about two months and it works extremely well on 40-20-15-10 meters given that I have it installed in my third floor attic. I did not incorporate the 6 or 2 meter elements.
Easy to assemble, but it takes some time to trim the spokes ( with eye protection ) to the resonant frequencies of interest, starting with the longest wavelength band and then trimming the remaining bands progressively, one at a time. The antenna "starts" tuned to just below each band. Best to trim evenly in small increments, as the trimming is not necessarily linear, e.g., the first 1" of trim may not increase the resonant frequency the same amount as the second 1" of trim. Best to go in 1/4" increments. Important to trim all spokes of a band the same amount ( on both ends of the antenna ), to keep the SWR low. Tedious, but worth the effort. Trimming instructions are not entirely clear or consistent, but even so I had no trouble trimming.
You should keep in mind that where you do the trimming may not result in the same resonances as where the antenna is finally mounted, but the instructions explain this. Worst case you will need to bring the antenna down, obtain extra spokes, and try again. Mine was best case, I was able to mount the antenna exactly where it will operate and do the trimming in place.
Also, in my case, the resonant frequencies ( and trimmings ) are influenced by proximity to other objects in the attic ( like another antenna ), which effectively lower the resonant frequencies.
I used the MFJ-259b SWR analyzer connected at the station end of the feed-line to determine the antenna resonances. So up and down the attic stairs for each trimming. The MFJ-259b made the job easy.
Performance. Wow. Hard to believe how well it performs in my attic with 200 watts ( I have since increased max to 600 watts, but it works very well even at 200 watts ). Only six inches clearance from the rafters and fairly close to another antenna.
In six weeks I have over 800 CW QSOs including 560 DX. It is very rare that someone doesn't return my call immediately.
Of course it would be better up in the open air. And of course it is not going to compete with a multi-element yagi on a tower. But if you have limited space or HOA restrictions, then this is a very good choice.
One final note. The bandwidth on 40 meters is quite narrow ( 50 KHz ). So for me, on 40 meters, it only works on the CW end of the band because that is where I operate the most. In the 40 meter phone band the SWR is rather high. So you have to choose one or the other, or have a better external tuner than I have. |
|
| N7TVV |
Rating:     |
2012-06-23 | |
| Surprising perfomance for a shortened dipole |
Time Owned: 3 to 6 months. |
As others have commented, this compact dipole requres careful assembly. Be sure to check ALL the pre-assembled parts, like the cap. hat brackets, coil connecting fasteners, etc. On mine, several of these were only finger tight!
Tuning takes some time, is a bit complex and the tuning instructions, while extensive, could be more explicit. Using an MFJ-259b it took me several hours with the antenna mounted (as recommended) at about 8' using a tripod to achieve proper resonances on all bands. End VSWR results were satisfactory after the antenna was at it's final height (43'). I am using an ancient HAM-2 rotator which easily handles this antenna's light weight. I also use a differential tuner to match the station to this antenna with good results on all bands. However matching is very sensitive to any moisture (like rain, etc.) which can change resonance significantly.
Performance is better than I expected and is exceptional for a loaded, shortened dipole. It is exceptionally quiet (low QRM) compared to my other antennas, especially on 40m. Directional performance (e.g. gain) is small, but acceptable on 40m, but much better on the higher bands.
The only other annoyance I note is a tendency to detune somewhat when any power greater than about 100w, is transmitted.
After 2 months, I rate this a 4/5 for performance with a few minor issues. |
|
| KF6VMC |
Rating:      |
2011-07-23 | |
| Great Performance!! |
Time Owned: 0 to 3 months. |
A Ham friend and myself assembled this little wonder in about 3 hours. It does require alot of assembly ( lots of small parts ) and It Took awhile to get the SWR we wanted but after that came the big surprise, The MFJ 1775 acts like a much much bigger ant. It's performance sounds like your running power and a serious beam. In just two days I have made DX contacts from my QTH in Canyon Lake Texas to Italy, Russia, Sweden, Croatia, Guam, Belgium, Spain, and The Virgin Islands. Heres the best part all of these were barefoot at 100 watts on antenna only 10 feet off the top of my house. Reports of 5/9 to no less than 5/4! A QSO of 15 mins plus with Germany who sounded like he was in my yard. I keep looking up at this little marvel in total wonder how such a small footprint can work so well. I moved here from my last QTH that had a 75ft tower at 3,000 ft elevation with a Cushcraft
A4 with hats that did no better. I now question if I even need to hook up my 811H? Good Job MFJ I don't know who designed this little wonder but I am totally impressed. I have yet to use my amp and will follow up with those results later. The Radio used is a Yeasu FT-990.. |
|
| KE4QZW |
Rating:      |
2010-04-06 | |
| Good for a small station |
Time Owned: more than 12 months. |
| I've had this antenna for 2 years and I constantly receive 5/9 reports from EUROPE on 20M. I have had no problems with it, it is hard to tune, but once you've done that, look out. I run 300W to 500W to it regularly. I have no complaints. I put it on a 40ft telescopic mast with a YAESU 450 rotor. I had a 3 element RAIBEAM up that came down in a storm, I replaced it with the MFJ-1775. I have no regrets. |
|
| IM0QMA |
Rating:    |
2008-06-02 | |
| Good ? Bad ? |
Time Owned: 3 to 6 months. |
I bought the Mfj-1775 dipole to have also a rotative antenna and I thought that was a good idea.
It works good but has not satisfied me. My old vertical antenna is better in every situation and also the inverted V dipole.
It' s expensive and may be useful only if you do not have enough space for other solutions.
The balun was glued in a bad way and I needded to reglued again.
I think you can spend better your money. |
|
| W6YDE |
Rating:      |
2008-01-27 | |
| Great for small places |
Time Owned: 6 to 12 months. |
I have owned the MFJ-1775 for about 8 months. I use it at a location where there are CC&Rs. I have it on a home made tripod and painter's pushup pole, about 25 feet off the ground, with a Radio Shack rotor.
It is not hard to assemble, but it does take a lot of time and testing to adjust it. Read the directions many times over before you start. Keep notes about your cutting of the rods, and take your time. Once you cut too much off the rods and pass the point of the resonant freq, you can't go back. Also keep it away from items like trees and your home's roof. These items will effect the SWR. I coated the coils with spray on liquid plastic, to keep the rain out of the turns. All the freq. are very low on SWR, less than 1.7 to 1.0 except for 2 meters. I only use it on QRP and stay in the lower 40kc's of each band.
Mine works very well and I am very happy with it, I have worked a lot of DX on CW/QRP with a FT-817ND and received many 569 or better reports. It is great for small lots, I use it just for the fun of getting on the air. It is not for the ham who is short on patience due to its setup and adjusting.
73, Mike/w6yde |
|
| W3XAF |
Rating:   |
2007-11-25 | |
| Bummer!!! |
Time Owned: more than 12 months. |
It's been over a year now that I constructed & installed my MFJ-1775 Rotatable Dipole. So far, I've burned up three different coil assemblies.
Hy-Gain, who now has control over all MFJ antennas, has sent me new coil assemblies because my antenna was still under warranty.
The problem seems to be with the 20-Meter coil. For some reason the fiberglass tube that the coil is wrapped on will eventually burn up and this leaves a rather large hole in the tube. After the hole is formed, my 20-Meter SWR shoots up and I can't use the 20-Meter band any longer.
Hy-Gain thinks that the problem is metallic impurities in the fiberglass tubes.
|
|
| PD9JO |
Rating:     |
2007-04-07 | |
| Great with no rain |
Time Owned: 3 to 6 months. |
I use this dipool for a few months,I bought it new at classic-international. I can say that it performs unbelievable for a mini dipool!!
I worked Indonesia, N and South America en a lot of europian stations. I would like to give this dipool a 5 BUT: There is a BIG problem, the open coils make it so hard to transmit when it rains!!
Even the tuner of my Yaesu mark V can not make it wright, the total swr is gone..... check my story with pictures on www.pd9jo.nl. 73's |
|
| AD5X |
Rating:      |
2006-02-26 | |
| Neat antenna for restricted space |
Time Owned: 0 to 3 months. |
If you have limited space, this may be the answer for you. Mine is mounted at 30 feet on a Rohn push-up mast. While it generally underperforms my ground-mounted Butternut verticle on 40 and 20 meters, it almost always outperforms my Butternut on 15 and 10 meters. And it is a much quieter antenna than the Butternut on 40 meters.
Positives: Covers the popular 40/20/15/10 HF bands as well as 6 & 2 meters. Very light, and verl low wind resistance.
Negatives: Bandwidth is limited to 40-60 khz on 40 and 20 meters due to the short length. And be prepared to spend 2-hours assembling it and 2-3 hours tuning it.
I have a full review on my website at www.ad5x.com. |
|