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Reviews Categories | Antennas: HF Verticals and Wire | MFJ-1792 80/40 top-loaded vertical Help


Reviews Summary for MFJ-1792 80/40 top-loaded vertical
MFJ-1792 80/40 top-loaded vertical Reviews: 14 Average rating: 4.8/5 MSRP: $169.95
Description: 40/80 Meters vertical antenna
Product is in production.
More info: http://www.mfjenterprises.com/products.php?prodid=MFJ-1792
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You can write your own review of the MFJ-1792 80/40 top-loaded vertical.

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PE1PYC Rating: 5/5 Jul 31, 2009 03:54 Send this review to a friend
Great Antenna but....  Time owned: 3 to 6 months
I own the 1792 for about 4 months now and all i can say is that it works great from the back of my small garden.
Only thing you have to keep in mind is that you reli need to guy it, it wont come down with the first gale but it does bend if you dont watch out.
Just put down AT LEAST 4 33ft radials or a couple of elevated radials, and let he dx come in!
BTW, QC at MFJ must improve because i also had to drill a couple of holes myself.....
Great great value for the $$$
 
KD0BVK Rating: 4/5 Sep 14, 2008 19:38 Send this review to a friend
Great value, some difficulties  Time owned: 6 to 12 months
I mounted the 1793 (same as 1792 but with a 20m radiator included on fiberglass offsets) on a rooftop tripod (20' up) on a ranch style house with three pairs of guy ropes. It has buckled twice in straight line winds, always on the same section, so it must have had a defective tube. After cutting about 6' out of that section it has stood up to the severe weather since, though of course it is now de-tuned on 40 meters.

Performance is acceptable on 80, 40 (with tuner now), 30 (tuner) and 20 meters. Noisy as heck but that's no defect in the antenna, that's just how verticals are in urban environments.

As happened to others it arrived missing parts, and MFJ sent a lot of extra parts that I didn't ask for (including some that obviously didn't belong to this antenna hi hi) but that's alright. In the end I had everything I needed without having to buy any extra hardware, waited about 2 weeks.

Overall I'm ok with the purchase 6 months on, not bad at all for the money. Needs much better quality control though, so one point less for that.

73
ai1p
 
K2CG Rating: 4/5 May 10, 2008 11:05 Send this review to a friend
I am pleased and surprised  Time owned: 3 to 6 months
I have bought a lot of MFJ equipment in the past so my expectations were not too high. Almost everything I have purchased from MFJ previously required a small bolt or screw and or required either fixing a solder joint or removing loose pieces of solder floating around inside with components. I figured with MFJ’s Guarantee and the very reasonable price it was worth a gamble.

Before assembly I completed an inventory, I was missing a few bolts and one large “U” bolt assembly. I notified MFJ and the missing parts arrived 45 days later, even then some of the parts they shipped were not the ones I told them I was missing. I bought the missing parts from Home Depot and assembled the antenna after waiting one week for the parts to arrive. I knew from past experience that continued correspondence would be an exercise in frustration and the additional cost was minimal.

I was initially not impressed with the thickness of the aluminum tubing; however during the assembly it became apparent that the tubing is very good quality. I have had the antenna up about 4 months now and it has survived several very high wind storms 40-60 MPH winds and one CAT 4 Tornado that passed one half mile from my house, http://www.clarksvilleonline.com/2008/05/03/tornado-strikes-south-clarksville-fairgrounds-pavilion-demolished/ the antenna has held up and demonstrated very nice performance. The 80M Coil and Top Hat was not that heavy but when raising the antenna up from the horizontal to the vertical position that little weight was apparent. Had the Mast tubing been thicker, raising the antenna could have been an even bigger challenge. I followed the guying recommendations and the antenna has handled the winds nicely.

I made some small modifications based on observations from Bill Zurilla, NZ5N.

First, step 18 on page 9 of the manual calls for, and my antenna came with, a 1/4 - 20 x 1 3/4" bolt to secure the fiberglass rod to the base mount. There is no way that a 1 3/4" bolt will work. I replaced it with a 2 1/2" bolt to get the job done.

Second, with respect to step 29 on page 11 of the manual, the 10-32 x 1 3/4" bolt goes through Tube 6 but does not go through the fiberglass rod around which the 80 meter loading coil and the capacity hat are attached. I drilled a hole through the bottom of the fiberglass rod. Completed the assembly with the bolt threaded through Tube 6 and securing the Fiberglass rod to eliminate any possibility of the Top Hat rotation during high winds and possibly placing stress on the connector wire of the 80M coil.

Next, I replaced the connectors on the 80M coil with a larger connector to permit a more solid connection under the Tube 6 Bolt as opposed to placing the original connector under the hose clamp. I covered all connectors with Heat-Shrink wrap.

I used “Penetrox” every place the tubes overlapped and on all connections. I used “Loctite” on all bolts and nuts.

I replace the top wire on the matching unit, again to permit the wire to connect under the bottom bolt rather than under the bottom hose clamp.

I used a DX Engineering Radial plate for the Radials. I buried twenty 35’ radials. I checked the antenna for resonance with my MFH-269 and was very pleased with 1:1.1 on the CW portions of the bands on 80M, 40M and 30M. The antenna is connected to my radio with 120’ of “Bury Flex” COAX that is buried in a PVC pipe.

During regular operation my K2 antenna matching unit has shown 1:1.0 on 80, 40, and 20 Meters. A quick menu check shows that the match was possible without using any CAPS of COILS from the Unit. I have also observed very reasonable matches on 30, 17, 15, 12 and 10 between 1:1.1 to 1:1.2.

I have been able to make some very nice DX contacts to Central and South America. I have also been able to hear stations in Japan, Eastern Europe and Africa that I could not hear on my Horizontal Loop that is up 45’.

Overall given the price, quality and performance of the MFJ-1793 I am pleased.


K2CG Chuck Gehring
 
G8KSM Rating: 5/5 Feb 26, 2008 09:25 Send this review to a friend
Modded MFJ1793 is FB on DX  Time owned: more than 12 months
I originally purchased this as the 1793 model that has the optional 20m radiator and operated it for a short time with a good earth and was impressed by the results. I quickly added 8-off 10m radials that comprised 8mm copper microbore heating tubing about 1-2 inches below the grass and got a huge improvement in performance, especially on 40m. This antenna is essentially a quarter-wave 40m vertical, so it needs a good earth and once its got that, you can throw away the ATU and works some real DX, on 40, that is.
80m also gave good results and the bandwidth was exactly as predicted - trouble is, the low-angle radiation means that it's not really very good with stations up to around 150 miles away, but it is very, very good with mobiles - I consistently get much better reports to/from mobiles on 80m than people using conventional dipoles etc.
20m operation was OK, but nothing special and certainly not what I'd call 'DX'y' but then what do you expect from a quarter wave ???

I operated this antenna for about 6 months from my old QTH with better-than-expected results but when I moved to my present location I decided to do some mods that I think really improve the performance. Firstly, I was never really very impressed with the 20m performance - the SWR bandwidth was surprisingly narrow and the 20m element was very flimsy; a good strong wind often wrapped the element around the main mast or whipped it into a distoted shape. Having said that, the main mast with top-loading coil / capacity-hat, although weak-and-weebly, had survived a couple of gales without damage, but I put this down mainly to the use of kevlar guys.
I threw away the old 20m radiator and made-up a new one using 10mm diameter aluminium tubing with a new bottom bracket and three insulated spacers at approx. 1m intervals up the mast, all made out of bits from the local B&Q hardware department.This new 20m element provides a wider bandwidth than the old one although not quite the full 350kHz, but good enough, anyway. As I'd got some tubing left over, I decided to have a go at adding a 17m radiator as well, in the same format as the 20m one and this pretty-much covers the whole band at an acceptable SWR. This gives me very good coverage of 4 bands without the need for an ATU, unless I want to go lower on 80m. Again, 8 radials were installed under the grass, using microbore copper and the whole thing cabled back to the rig with about 30m of Westflex 103 coax.

My very first QSO was with a VK on 40m and he gave me 57. This was followed over the next few months with a very encouraging log full of DX on 40 and 80 with occasional forays to 20 and 17, where SWR under 1.2:1 is available over the majority of the bands. 40m coverage is for the full 200kHz without any significant SWR and I've set my 80m up for the top end of the band where I get unde 1.5:1 over the range 3.73-3.8 Mhz, which is just what I wanted. An unexpected bonus is that, although I need an ATU to match it, I get really good results on 30m as well and have done about 120 countries in 6 months without really trying.

I really recommend this antenna - sure, the main mast is a bit flimsy and you really do need to take some care putting it up. In particular, you really need to use good-quality lightweight guys and the guy rings need to have some additional padding / tape under them to reduce the chafing on the main mast. Most important is to have a decent set of radials, and here it is size of the conductors that matters, not necessarily the quantity. Please, please, use decent waterproofing on all connections and joints - dont just leave bare or use cheap PVC tape - it's not worth it in the long run. The only other thing I might consider changing is the method of holding the six capacity hat rods - these are secured to an aluminium ring using stainless screws and whilst I've had absolutely no problem with them, I'm just not totally convinced that continual visits from birds using it as a roost might not eventually take its toll.

In the last 12 months we've had a significant number of nasty gales and we have a fairly exposed location high-up on the moors and the aerial has hardly batted an eyelid. The top guys are fairly well down the mast, and when the wind is really hammering, the top section does whip about a bit so I'll be checking the effect of the guy ring carefully before finally deciding, however, this is an antenna that is simple enough to replace bits if needs-be and easy-enough to tune-up that I can see me keeping it for a very long time.
 
ZS1TTZ Rating: 5/5 Dec 5, 2007 04:06 Send this review to a friend
A good product  Time owned: 0 to 3 months
My main concern before assembling and installing this antenna was, how is it going to stand up to to the kind of weather we get here in the Cape?, extremely high winds are not infrequent.

I didn't have to wait long to find out, by day two quite a severe storm started up. Driving home from the office I was alarmed to observe a fellow ham's crank up tower "cranked down", the first time I had ever seen him do this, so I almost daren't look up when I turned into my street, but look up I did and was relieved to see it still standing.

I checked and adjusted the guy tensions, then sat outside, sheltered on the patio and observed it for about an hour, the wind was strong with severe gusts, it was moving about "quite a bit" at the top, seeming to pivot about the top guy ring and corresponding slight bending midway between the two guy rings.

When all was calm again, albeit for only a brief period, everything was still dead straight, and over the next two weeks it was subjected to many more similar batterings, all with no ill effect, and now, apart from regular guy inspections I don't worry about it at all.
So, it passed that test, and the other test it passed is that the xyl thinks it looks great !!

As for performance, same as everybody else has said, it works very well, dx on 40m is definitely easier than with my wire doublet, and the top loading on 80m is a definite plus over most of the competition. On 80m I tuned for the bottom end, being a CW operator, but using a Kenwood hybrid I can still tune the phone section with the loading cap just about fully open, without the need for an external tuner.

I think if I had attempted to build something similar myself, and saw it swaying around like that in the first storm, my first instinct would have been to call for help and get it on the ground asap, so there's certainly a "peace of mind" factor included in purchasing an established product, coupled with the hassle-free assembly benefits of buying a kit, everything you need is in the box, it was fun to assemble and rewarding in performance, it's going to score well at this qth.

If I have one criticism it would be with the instruction manual, where it states that one set of guys is the minumum, I would cross that out, two sets of guy rings are provided so you might as well use them, two sets of guys are the minumum, this review might well have been completely different had I just installed one set.

73 de Adrian / ZS1TTZ
 
NZ5N Rating: 5/5 Apr 1, 2007 15:12 Send this review to a friend
Why aren't more people using this antenna?  Time owned: 0 to 3 months
See http://www.eham.net/forums/TowerTalk/9944 for my comparison of this antenna with the Butternut HF2V, and the many comments. I've been getting out from Australia to Kuwait with my ground-mounted 1793 and just thirty 30' radials. Also working great on 17 and 15 meters with quarter wave monopoles (11' and 13' pieces of wire running parallel to the main antenna). There's also a homebrew 160m mod available. For $200 including shipping from HRO, it's hard to go wrong with this nice antenna.

There are some quirks. One of the screws is the wrong size, and the antenna as shipped is over 2' long for resonance on 40m phone (mine resonated at 6.8mhz at the factory length). The antenna arrived with one piece missing, but I called MFJ and they sent it UPS.

In view of the lack of info about this fine antenna, I have just started a yahoo group, http://groups.yahoo.com/group/mfj1793/ for anyone who wishes further info.
 
K5GUS Rating: 5/5 Nov 7, 2005 13:58 Send this review to a friend
Easy and Good  Time owned: 0 to 3 months
Have had the 1793 (w/20m element) up for about a month now. Planted it in the ground and placed 10 evenly spaced 33' radials around it for now, will most likely add more as cooler weather sets in. This past weekend was the CW SS contest and without any trimming of this antenna, it was perfect from 3.5 to 3.65Mhz which allowed me to work both the far NW and far NE which I hadn't been able to work on my low dipole very well. On 40m I have the entire band below 1.5:1. I had to add about 15" of my own aluminum tubing to get 20m resonant in band as it was sitting around 15Mhz with the supplied materials. Assembly time took about 2hrs of casual assembly. Mounted the antenna on a 1.25" dia TV mast set in some concrete filling a 5 gallon bucket stuck in a hole in the ground. Erecting and guying took about another hour. Prefabbed some 33 ft radials with ring terminals on each end. Mounted one end to the u-bolt thread at the base of the antenna and used some large heavy nails to go thru the ring terminals into the earth on the other end. Mower glides right over them without a wimper!
During the SS contest I did many A/B tests on both 40m and 80m comparing this antenna to my dipoles that are approx 40ft off the ground in both N/S and E/W configurations. In almost every instance I saw approx 2 S-unit difference on 40m. On 80m, the vertical is tuned at the bottom of 80m where my dipoles are tuned about 3.8Mhz, so a fair comparison was difficult, but using the tuner to bring the vertical up to 3.8, I still noticed that the vertical did at least as well on short hops and a bit better on longer hauls (as you may expect)..
As someone else said, for $160 you could hardly build something with that was as solid a mechanical design and easy to put up. An aluminum vertical is what it is, but this implementation and packaging made this very enjoyable to build and use.

73,
K5GUS
 
K8DXX Rating: 5/5 Jul 27, 2005 19:05 Send this review to a friend
Great, So Far  Time owned: 0 to 3 months
This 1793 (I got the version with the 20 meter stub) replaces a GAP Voyager IV that I enjoyed very much over 12 years. Reason for the change was vandalism; 8 guy rope cuts over a 6 week period. As a reference point, the GAP was quiet and broadbanded (100 KHz on 160 and full band on 80-20). Also, the GAP appeared to require more than it's share of maintenance, having collapsed 3 times in 12 years.

My 1792/3 went together in 2 hours (plus site preparation). It features a sturdy ground mount with a walk-up/hinge base. The 80 meter top loading coil and capacity hat appear to be of qood quality but are heavier than expected. Coax attaches to an SO-239 connector and matching coil in the base. The 20 meter stub is made of aluminum rod and fiberglass standoffs.

Having had several other quarter wave verticals in the past, I decided to minimize radial connection/reliability problems by purchasing the DX Engineering stainless steel radial plate (really, the way to go). To date, I have 20 radials for 40 and 4 for 80. Incidentally, I lay my radials on the lawn, pull then taut and peg them to the ground with lots of landscape staples (available from Home Depot). Within a month, they become part of the lawn and present no mowing problems.

Thus far, the results have been positive. Bandwidth on 40 and 20 is full band with an SWR below 1.3:1 (at the end of 75 feet of RG-213, slightly higher at the base on an MFJ-259 antenna analyzer). On 80, 2:1 bandwidth is about 110 KHz. As delivered, the antenna resonated at 3470 (almost exactly as predicted in the manual). Tuning is accomplished by cutting capacity hat spokes. It took the XYL and I 3 trips up and down to bring the resonant frequency to 3875. Thus far, I have put 1 KW into the antenna with no problems.

I have had no problems making 80 and 40 meter contacts, despite noisy summer band conditions. I've worked some DX on 20 but prefer my Force-12 beam on that band. On receive, it seems a bit noisier than the GAP Voyager but that is clearly subjective.

What else... The manual is good. MFJ may have provided one incorrect part that proved to be of no real consequence. This antenna does require guying. MFJ recommends 3 sets of guys at about the 15 and 25 foot levels (guy rings included). Raising and lowering the antenna is a 2 person job; one to walk up and the second to secure the guys. Walking up and holding this antenna is no problem for a short 54 year old.

At $141 (plus radials and physical labor), the MFJ is a good value in an 80-20 meter antenna. On the bands it covers, it is probably more efficient than a Hustler 'BTV.' It is less expensive than a Butternut (of which I've had 2). I would buy another.

73 de Bill / K8DXX
 
EA6LP Rating: 5/5 Apr 21, 2005 15:23 Send this review to a friend
giving me satisfactions  Time owned: 3 to 6 months
It is easy to build. But take your time doing all the possible to make his performance last, by adding Penetrox to every tube connection, then seal it with elastic rubber. Seal every wire connection with silicone. You better build some
kind of protection against weather where the
coaxial connects to the antenna base, (I made it
with a little 90 degrees PVC tube attached with some dacron line an plenty silicone). I don´t like to build my antennas in 3 hours, because his
performance is very soon gone away (in EA6-land)
due the proximity of sea.
The radials, if you want DX-performance, get ready to put 20 / 40, or even more,..... , his length 1/4 wave = 20 meters, then the antenna works fine, having punch, and accepting the power
of the lineal amplifier.
I have modified mine to work 30 meters, by suplementing the thinner sided tubing, with good
practical DX results. I am planning to work 160 meters, by conecting an horizontal wire to work like an L and adding 40 meters radials,??. Funny.
 
KC2HZW Rating: 5/5 Jun 29, 2004 21:28 Send this review to a friend
Great Antenna at a Great Price!  Time owned: 0 to 3 months
I purchased this antenna for Field Day use to get our club on 80M. I have to say it exceed our expectations! We easily worked the West Coast on 80M with good signal reports on 100 watts.

The antenna is easy to assemble and the parts are well made. Tunning (with an MFJ 259B) was very easy to accomplish and took just a few minutes. While light weight, it does require 2 or 3 people to erect it and get it guyed. Ground mounted with 8 radials (33') we got full coverage on 20 and 40 and with the tuner in my rig, we easily worked 80 CW and 75 phone. For long tem exposure to the elements, I think I would like to see the matching network and coax connector in some sort of plastic case (along the lines of the Cushcraft verticals.)

This antenna is so simple I don't see any long term problems with it. It looks like MFJ has a winner here!
 
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