| WA2TDE |
Rating:  |
2023-09-26 | |
| Poor QC, Poor Customer Support |
Time Owned: 0 to 3 months. |
After reading quite a few favorable reviews, I ordered a HY-Gain AV-640 multi-band vertical antenna from DX Engineering in July 0f 2023. Hy-Gain, which is owned by MFJ Enterprises, was known for well-designed and well-built products in its day but I was not blind to the fact that MFJ has a very checkered reputation for quality but figured that could be dealt with.
The antenna arrived in just a couple of days without shipping damage, and I commenced an inventory of all the parts according to the manual which revealed a half-dozen incorrect and missing parts. I contacted MFJ/HY-Gain and DX Engineering with the list of needed parts. Replacement parts arrived a week later and that allowed me to start assembly of the antenna. The manual is well illustrated but confusing on some points. The manual writers assume you have some experience putting mechanical assemblies together, identifying parts and getting small misalignments corrected. Assembly was relatively straight forward but there are a few errors in the manual that required an email to MFJ/DX Engineering for clarification.
The antenna was mounted on a 16-foot, tilt-over mast which made accurate tuning relatively easy. Unfortunately, the antenna could not be made to tune (low VSWR) on 40, 30 and 20 meters. Resonance was too low in frequency by 400 kHz to 1.1 MHz depending on the band. MFJ did not respond to an email about this condition or that the amount of tuning needed exceeded the tuning range of the capacitive hats which are the main tuning element. All other antenna dimensions were double checked to verify they were correct.
A phone call to MFJ allowed me to talk to a gentleman who told me all I needed to do was adjust the wide range capacitive hats. He dismissed the fact that I had to remove entire capacitive hat rods to get anywhere near resonance.
Frustrated, I searched the internet to find others who had a similar problem but only found one report for the similarly constructed, Cushcraft model R8 Antenna (also owned by MFJ) which was also resonating too low in frequency on 40, 30 and 20 meters. This poor chap received no help and ended up rewinding the three loading coils that control resonance for these three bands.
I wrote another email to MFJ and DX Engineering requesting information about the number of turns for each of the three suspect coils and I received no reply from MFJ. DX Engineering could not get them to respond to this question either. I found a few decent pictures on the internet of the coils for this antenna that allowed counting the number of turns. Sure enough, the coils in the pictures had 4 to 6 fewer turns which implied that the coils on my antenna were wound with a smaller gauge wire which would allow them to fit the allotted space with more turns and inductance, leading them to resonate at a lower frequency.
DX engineering took the antenna back (I disassembled and shipped it back) and issued me a full refund, much to their credit. It pays to have the support of a knowledgeable vendor.
MFJ/Hy-Gain? No more business from me. Caveat Emptor!
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| NB4M |
Rating:  |
2023-04-15 | |
| Possibly the best vertical ever |
Time Owned: 0 to 3 months. |
Having several verticals on the property, I decided to seek out the AV-640 for the 12/17 band options.
Build was time consuming, but followed the directions to the letter. Added anti-ox on all fittings and tried not to over tighten.
Lots of wind in the cow fields here, so decided to make my own support application. Added a precise cut piece of plastic just below the upper mast section to allow for 4 each guy wire (paracord) connections.
Assembled and ready - removed a Hustler vertical from a 6' mast with 4 radials each for 80, 40 and 30 meter, so a total of 12 radials existing.
Installed with an existing 12-turn coax choke at the feed point and went in the contest shack for testing.
To my amazement, all designed bands were perfect according to the analyzer. For the first time in my 26-year amateur career, the manufacturer recommended measurements were spot on! I did see a small peak at 18.100 mHz, but only brief and was back to "perfect" by 18.110.
Performance is also amazing. Connected a rig and quickly dialed up E51, easily making the contact with 100w from here in W4 land. Same with 3D2 and 9K2.
Summary - although I've just installed the antenna, the experience has been excellent and I am very pleased with the purchase. I highly recommend the AV-640 for anyone interested in a new vertical application.
73 es GL
NB4M
(also N4NA at times) |
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| W2SAS |
Rating: |
2023-02-06 | |
| Better than I expected! |
Time Owned: 0 to 3 months. |
Just spent 12 hours inside my basement putting this thing together, checking measurements and rechecking, dropping the #6 screws, dropping nuts on the floor and rechecking measurements and torque on all of the pieces. It was great therapy while it was 2 degrees outside. Got a warm day and hung it outside attached to the back of my shed leaving a foot of air-gap between the shingles & the droopy radials. Tied 100 foot of LMR400 on it and powered up the Rig-Expert and thought WOW this is much better than I expected. Here is what I measured at factory settings:
40M SWR is 1.02 @ 7.330 mhz - 5.63 Midband
30M SWR is 1.03 @ 10.174 mhz - 1.4 Midband
20 M SWR is 1.17 @ 14.100 mhz - 1.32 Midband
17M SWR is 1.26 @ 18.200 mhz - 1.99 Midband
15M SWR is 2.0 @ 21.165 mhz - 2.03 Midband
12M SWR is 1.64 @ 25.036 mhz - 1.72 Midband
10M SWR is 1.40 @ 28.570 mhz - 1.49 Midband
6M SWR is 1.05 @ 52.140 mhz -2.98 Midband
Obviously I will drop it and extend the 40 meter section but otherwise the tuner takes care of any small changes needed. Very happy with my compact 8 band vertical. |
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| N4AK |
Rating: |
2022-09-14 | |
| A very good vertical without the hassle of ground radials. |
Time Owned: 0 to 3 months. |
| This vertical antenna is excellent if you have limited space for radials or simply don't want the hassle of installing them. The SWR can be adjusted below 2.5 to 1 on your favorite operating portion of each band....so your rig's internal tuner can be used! To adjust the SWR initially you will need to raise and lower the antenna several times... so keep this in mind when installing it. All the parts came with my package. Most of my operation so far has been on 40,20 and 17 meters with good results. I suggest you not trim any radials (spokes) initially.....put it up.....take SWR readings....make yourself a chart...then begin adjusting SWR on each band. I am 81 years old and have been on the air since 1957. I did find it convenient to have assistance in raising and lowering the antenna. It was ground mounted at 10 feet using a treated 2 X 2 post and metal articulating bracket. DX Engineering as usual was prompt in shipping. You must have an antenna analyzer to adjust the radials (spokes). I recommend this vertical. |
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| K2QB |
Rating: |
2021-08-31 | |
| Great Choice for a Vertical with no Radials |
Time Owned: 0 to 3 months. |
Similar to another review, this antenna replaced an R7 that had been in storage for 11 years and in service for 10. I thought (story for another time)it had given up the ghost so I ordered the AV-640 as a replacement.
I have always had a beam and other antennas such as loops, EFW's etc but before the R7 never a vertical. The R7 surprised the heck out of me as to how well t worked especially on 30 and 40 meters.
Didn't know what to expect from the AV-640 but I have been pleasantly surprised. Assembly was very straight forward as long as you take the time to read the manual over several times to ensure you understand what's being called for. I had no issues with the assembly except as another reviewer stated the mounting base was actually for the AV-680 and a call to Tom at Hy-gain resolved that.
Once up and running all bands resonated exactly where they were set to except 17 and 40 meters. Before taking the antenna down for adjustment I spoke to Tom once again and he indicated that if you set it according to the manual it will resonate quite a bit lower then stated. Not sure why that is or why the manual hasn't been updated to show the correct measurements for those bands.
After having it up for two days the SWR suddenly went infinite on all bands. Again a call to Hy-Gain and Tom who was extremely helpful in offering some testing tips and once I did those he decided I received a bad matching unit. A new unit was received in a couple of days. Once installed I tested the antenna at the base using an analyzer and nothing changed so again a call to Hy-Gain and the ever helpful and patient Tom. After speaking with him I tried another analyzer and lo and behold it worked! It seems that my analyzer decided to go south in the two days I had the antenna up and running. The original SWR issue was a bad connector at my lighting protection so I not only had a connection problem but a bad analyzer as well.
Since having it up and working I can honestly say it meets or exsceeds the performance of the R-7. I operated in the WAEDX CW contest on 40 meters running 100 watts and was asked by several Euro stations for QTC's which tells me I had a solid signal to them.
Overall I would have to say as others have stated, if you are looking for a vertical that does not need radials this is a great option. Mine is sitting about 12 feet above ground and works great on all bands. |
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| WA4SCA |
Rating: |
2020-12-25 | |
| Works well, but has some mechanical bugs. |
Time Owned: more than 12 months. |
The antenna performs surprisingly well, and has also weathered some heavy winds. However, I have twice turned on the rig only to find virtually no signals.
The first time, the top aluminum bracket which holds the matching box had fractured at the 90 degree bend. The aluminum was thin and brittle, and could not stand the continuous flexing. I added an aluminum angle bracket for reinforcement, which solved that problem. No repeats in 4+ years.
Update: The angle bracket I installed finally broke. This time, I realized that only one bracket was needed for mechanical support. Accordingly, I replaced the top bracket with a copper strap which has enough "give" to handle the flexing in the wind. The current fix has worked for 5+ years, but just to be prepared, I have a replacement strap available.
The second time, when I was examining it, I heard a buzzing noise from the matching box. Then a small wasp flew out of the drain hole on the bottom! I sprayed a good amount of wasp spray into the unit, and after waiting a bit, took it down and opened it. There were several dead wasps and a nest inside.
I cleaned it out carefully, washed out all the residue, and after drying, it was as good as new. Slightly better actually, as I cleaned up some cold solder joints. (Remember, the is a MFJ in all but name, with all the quality control deficiencies that implies!) To prevent a repeat, I cut two small circles of window screen and glued them over the drain holes inside the box. No new visitors with 6 or 8 legs.
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| N8XMS |
Rating: |
2020-12-25 | |
| I'm pleased with this antenna |
Time Owned: 0 to 3 months. |
I’ve had my HyGain AV-640 up for about two months. It replaced an old Cushcraft R7 that had been in use for 27 years! Overall I am very pleased with this antenna and recommend it for anyone who is considering a multi band, no-radial, vertical antenna. I will break down my review into several categories:
Materials Quality = 3: My antenna came with the 20m capacity hat spokes cut one inch too short. And the hardware for mounting the antenna didn’t match the assembly instructions and caused some considerable confusion at first. (See next category.) There is a little more plastic than I would like to see and I don’t think that it will last as long as my old R7 did, but I am expecting to get some good years from it.
Customer Service = 5: A call to Tom at HyGain resulted in a speedy replacement for those 20m spokes. He also explained that the mounting hardware for the AV-640 has been changed to the same as what is supplied for their AV-680 model, but that the manual has not been updated to reflect that fact. So a quick download of the AV-680 pdf assembly manual cleared up that confusion.
Ease of Assembly = 4: There are a lot of parts to this antenna and carefully following the instructions is important. I also recommend double or even triple checking all of the important measurements. I took my time over several days and didn’t have any problem. My son-in-law gave me about 10 minutes of help to actually get it vertical and on the mast. (My antenna is on the same mast that supported my old R7 and it’s base is about 7 or 8 feet above the ground.)
Performance = 5: It’s certainly not a Yagi at 60 feet but it’s really working well for me. The SWR is good on all bands, except it’s just a little bit high on the CW part of 40m. I could take it down and tweak that but for now I’m just letting the tuner in my rig take care of it. I’ve had QSOs on all the bands from 10-40 and have worked some nice DX as well - all CW at QRP or QRPp power levels. (I don’t have a radio for 6 meters and didn’t even install the stud for that band on the antenna.) |
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| KZ5A |
Rating: |
2020-09-11 | |
| Really good DX antenna |
Time Owned: more than 12 months. |
I've owned and used one of these for close to 20 years. i've rebuilt the transformer box twice over the years and replaced washers, clamps, screws, etc. Currently I am setting it up in it's forth and final QTH in Capitan, NM. Its been up for abt 3 months (temporarily??) here at 10 ft above gnd and is working an amazing amount of DX on FT8 with 75 watts from a TS-440.
This is not a NVIS antenna but it is an excellent DX antenna. Contrary to the last MFJ advert I saw for the antenna it is NOT a collection of 1/4 wave verticals in parallel, it is a set of 3/8 wave parallel stubs feed by a 4 to1 transformer (200 ohm), which explains the low angle of radiation.
It is very easy to tune since there is minimal interaction between the tuning of the 8 bands.
i think this is still the best performing most durable multiband vertical on the market, even after all these years. Or really, especially after all these years.
73 Jack KZ5A
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| ZS6VLT |
Rating: |
2020-09-10 | |
| Small footprint with big band coverage. |
Time Owned: more than 12 months. |
I am very Blessed especailly in acquiring this antenna. I found it on a local swop shop form an elderly HAM moving into retirement. The antenna mostly assembled and was delivered for the equivalent of 75 USD in 2017.
Overall the antenna was weathered (aparantly it was on stilts for the last 3 years), fortunatley in South Africa we mainly have sun to worry about which did not seem to have much impact on the appearance or performance.
Given the fact that it was pre-used and tuned for some applications, which seems to have been mainly CW part of every band, and FM portion on 6m.
Even with the AV-640 merely 5m above the ground to comply to local munisipal regulations in Pretoria, the antenna is performing well beyond expectation.
All Bands are either usabe without an antenna tuner or the few that are tuned on the other side of the band easily tunes with the MFJ 939 antenna tuner.
It has been up for more than 2 years and I am very pleased and happy with the performance.
This is my first vertical and my first permanent installed antenna, previously used Diplole, Aplha Military whip and G5RV.
Findings: Maybe this is a general vertical problem but I find the antenna very noisy with regularly experiencing S6 noise compared to a Dipole maybe only S3 noise in direct comparison.
For local operation I was surprised that the vertical has very limited NVIS catecaristics duue to low takeoff angle.
Other than that I am really enjoying DX with the IC7200 at 100w maximum.
Finally I would reccommend this antenna to anyone that are looking for a lekker DX antenna with a small footprint and big band coverage. |
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| VK3XIW |
Rating: |
2018-10-03 | |
| Wrong parts |
Time Owned: 0 to 3 months. |
| Bought this from a local source here in Australia and when I came to assemble it, the carton was still stapled closed, found that one section of tubing was incorrect so that it would not all fit together. Investigations are under way to solve the problem |
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