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Reviews Categories | Antennas: VHF/UHF+ Omnidirectional: verticals, mobile, etc | Diamond SG-7500NMO (Super Gainer series) Help

Reviews Summary for Diamond SG-7500NMO (Super Gainer series)
Diamond SG-7500NMO (Super Gainer series) Reviews: 20 Average rating: 4.8/5 MSRP: $79.95
Description: 2m/70cm NMO-mount mobile antenna
Product is in production.
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W3RXO Rating: 2/5 Jul 5, 2010 21:50 Send this review to a friend
Not very happy with Diamond, Right now.  Time owned: 6 to 12 months
I rate this one at a dismal, 2, as I have had a few problems, and am beginning to wonder if Diamond might not be having some QC problems, right now.
First, let me explain, I am a darned loyal Diamond user. I run an SG 7900 on my mobile, and on the mobile I keep in my wife's car. I have an NR770HB on my motorcycle, and ran an SG7500 on my work truck, sort of. It has been OFF the truck, more than it has been on the truck. My backup antenna for the truck is an NR77oHBNMO. I also run Diamond antennas for my base (510X) and HT (SRH320A), as well as a few other applications. Yes, I have always been loyal to Diamond, as I have always been happy with their products, until now.
I bought my first 7500, after about a year and a half of great service from my 7900's, and considering that several friends, whose recommendations I value greatly, recommended the 7500, HIGHLY, I decided to get the 7500 for the work truck, as Diamond does not recommend the use of a 7900, on a large commercial vehicle, due to it's length, and the vibrations causing trouble.
The first 7500 I bought, from HRO Anaheim, was purchased new, but when I got it to work, my next day at work, I went to take it out of the package, to install it on my existing NMO mount, and it fell apart, in two pieces, in the middle of the lower coil. I chalked this up to being an anomaly, and a week later, took it back to HRO, for a replacement.
HRO was gracious enough to replace it, and even looked it over thoroughly, saying, "Yep, it was NOT stressed, it was a defect". They gave me another new SG7500NMO, and off I went.
A month and a half later, I am driving down the road, and hear a "clinking" noise, on the catwalk, behind the cab. When I stopped, I looked to see what it might have been, and sure enough, the top section was missing, from the middle of the top coil, up.
Now, this antenna, is mounted high, above the rear window of a 2008 Freightliner daycab, and behind a fiberglass fairing, centered on the cab. For it to have been hit by anything, the fairing would have sustained serious damage, and the trailer likely would have, also. No damage to either.
A month of emails later, between Diamond Japan, me, and RF Parts, their US Distributor, I finally got an RA number, to return it for them to look at it, and "see if it is covered under warranty". I got it back 2 days after shipping it (Great turn around time) with a note that said:
"Antenna was hit by something. Lower element is bent. Diamond Japan is warranty this antenna".
While there WAS a SLIGHT bend in the section between the lower coil and the middle coil, I can assure everyone, it was not from hitting ANYTHING.Could it have been mishandled, or some other treatment cause the slight bend? Sure. But it did not hit anything. Even if it had, do not these antennas have enough ruggedness, to withstand a normal strike, from a foreign object?
While I am grateful that Diamond Japan covered this item, and got it fixed, I am not very confident that anyone will receive proper service, when they turn to RF Parts, for their warranty work, and seriously doubt that Diamond's QC is what it once was. While I have always been very happy with Diamond antennas, in the past, I would look for others, before I settled on a Diamond, nowadays.
Sorry, I must rate it a dismal 2.
KF4ULD Rating: 5/5 Jan 7, 2010 20:44 Send this review to a friend
What a difference from a 1/4 wave 19 incher  Time owned: 0 to 3 months
This thing is outstanding, especially compared to my MFJ 19" mag mount it replaced. I now can turn down my power and hit and hear the repeaters that used to be very weak. I like the fold down feature and find myself using it weekly driving into parking garages in Seattle. Not having to use high power on APRS means I don't hear interference any longer on my Sirius unit when my APRS beacons on 25 watts instead of the former 50 watts with the 1/4 wave. I highly recommend this for mobile or an urban base antenna. The only improvement I would make is to have a set screw on the base you could secure it with after screwing it onto the mount.
KF4ULD / Matt, Seattle, WA
KJ4AQT Rating: 5/5 Feb 3, 2008 11:39 Send this review to a friend
Awesome Antenna  Time owned: 0 to 3 months
I have had this for a short time but it has proven to be an excellent performer, it is mounted on my mirror of my Volvo 770 18 Wheeler and has been through 2 ice storms, it has folded over both times but went right back into position

i would definately reccomend it
KC7KMP Rating: 5/5 Jan 30, 2008 10:37 Send this review to a friend
Excellent Antenna period  Time owned: more than 12 months

Used for 4-5 years now and it still works great (with 5" magmount). Taken a few low branch/parking garage hits with no perceptable performance hit. Looks like its been used for fencing but its still the best mobile antenna I own and would highly recommend it.
KA7OEI Rating: 5/5 Jun 5, 2007 12:28 Send this review to a friend
Solid and well built  Time owned: more than 12 months
I've had this antenna mounted on my Jeep for over a year now, having taken it on some bad roads with low-hanging branches and have not had any problems. Having it on the left (driver's) side of the vehicle has helped, as that puts it farther away from most antenna-damaging trees and bushes.

I did note that the VSWR on 70cm was not flat - about 1.7:1 in the repeater subband, but that is of little consequence, really, as this doesn't put much stress on the finals, and this doesn't amount to much additional loss in the fairly short coax run inside the vehicle.

I have seen problems where others have mounted similarly long-ish antennas on rather flimsy mounts: This will stress the antenna more than a rigid, non-flexing mount, actually - especially if mechanical resonances are set up while driving. I used a modified, very heavy stainless-steel CB-type mount that I redrilled with a 3/4" hole for the NMO and then die-ground out enough of the mount to be able to install the NMO onto the antenna mount's thick metal (which was too thick for a standard NMO.) All of this has paid off with a super-rigid, stable, and rugged mount.

As for its actual performance: It seems to get out and "hear" at least as well as other antennas - what more could you ask for?
KZ1A Rating: 5/5 Oct 4, 2006 13:32 Send this review to a friend
Outstanding Mobile Antenna  Time owned: 0 to 3 months
I to have the UHF mount style of the SG-7500.
It is, by far, the finest VHF/UHF mobile antenna I have owned to date.
Solid construction and solid performance.
KB3MMX Rating: 5/5 Jul 10, 2006 16:46 Send this review to a friend
Excellent performer!!!  Time owned: 0 to 3 months
I have the UHF style base antenna and the performance from this antenna is astounding!
I replaced a Hustler CG-144 BIG 2 meter only antenna which really performed well for 2 M.
I was suprised that the Diamond antenna about 2/3 the size of the Hustler actually outperformed for RX and TX in several spots of my daily commute. I was also suprised to see how far away I could work our "low profile" UHF repeater!!
Excellent product, would definetely recommend it to a friend!!
K8APS Rating: 5/5 Mar 11, 2006 09:18 Send this review to a friend
Best mobile yet  Time owned: more than 12 months
In use for almost five years now on permanent installs and mag-mount installs. Works awesome all around with my IC-2800H. I get much better TX/RX than many other hams with this setup. And parts are available from the manufacturer. I know this because I rolled a vehicle and had to replace the fold-over section and recently after all these years the upper most phase coil broke (this could have occured at a car repair place when it was on the lift). Either way, I've VERY satisfied and will recommend this antenna to anyone. Only drawback is it is very rigid so if you off-road it will hit low branches... not a problem with a mag mount that can tip over but not good on permanent installs. I had a through the roof mount on my Ford Ranger and it was a pain to fold it over every time I drove in the woods. However, now have a Chevy K1500 with mag mount and it I hit branches I just let it get knocked over and I set it back up when I'm done. It has never fallen over on the highway, even at high speeds. Again, a great antenna.
N7KZD Rating: 5/5 Feb 19, 2006 13:06 Send this review to a friend
GREAT ANTENNA  Time owned: 0 to 3 months
Best antenna I have ever used used to like Larson but after numerous problems I tried the diamond brand much better antenna for the price
KI4CDK Rating: 5/5 Nov 25, 2003 04:47 Send this review to a friend
Excellent antenna  Time owned: 0 to 3 months
I've read on the forum that similar models of this antenna have succumbed to joint failure in the couple of joints in this antenna, but this has not yet happened to me. Therefore, my review may change considerably in the future.

However, I'm absolutely convinced this is the best mobile antenna money can buy. The SWR was 1.1:1 and usually even less all across both bands, and I was able to hold long-distance UHF simplex conversations on low power, much to my surprise. I put it on a sturdy magnetic mount atop my truck, so I'm a little concerned about trees, but I never park in parking garages (haven't since I became a ham). Expect to pay a good price, though...
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