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Reviews For: SGC SG-237 "Mini" Smartuner

Category: Antenna Tuners/Matching Networks

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Review Summary For : SGC SG-237 "Mini" Smartuner
Reviews: 41MSRP: $339.99
Description:
Antenna Coupler
Product is in production
More Info: http://www.sgcworld.com/products/sg237/
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00414.4
WS1C Rating: 2020-07-14
Not waterproof Time Owned: more than 12 months.
Tuned well, but not waterproof. In dry spot on boat extensive corrosion. SGC was no help. I managed to repair with many jumpers across corroded traces. Not in same class as SEA.
K7TAA Rating: 2020-04-22
Good coupler for oddball or regular antennas Time Owned: more than 12 months.
SGC SG-237

I have had three of these antenna couplers over a period of 10 years, and I have had good results with two of them, and a recurring problem with one which has been back to SGC. They have never been abused in terms of high power. I have had one or more at a time outside for months with no additional weather cover, in Alaska at -30 degrees F. I have used them in dozens of different configurations in different portable setups, from Buddipole horizontal long elements, to 102' dipole for NVIS on 80 and 40, and on an 80 meter full wave horizontal loop both on all bands directly at the loop and using 450 ohm balanced line.

Most of the difficulty in using them was a lack of understanding on my part as to their limitations, and their instructions didn't help much. The impression I had in reading their instruction manual and their notes for antenna ideas was that if you hooked a piece of wire to them using almost any type of antenna that was 8' long or more, it should always match and radiate on any frequency from 80-10 meters. Quickly. I also used them for several years without a Smartlock locking remote control, since it was extra cost and I usually didn't need a way to prevent the couplers from continuing to try to find a better match when they were already at 1.5:1, which should have been fine. But there are combinations of impedance and reactance that they will not match, like any tuner or auto tuner, and some combinations that cause them to be unstable and try to find a better match on each transmission, which is frustrating.

Also, as others have noted, they are not suitable for a 5 Watt QRP transmitter like the Yaesu FT-817, since they require at least 3 Watts to tune reliably, and the transmitter output protection reduces power output below 3 Watts as the tuner tries different high SWR combinations while searching for an acceptable match.

The SG-237 design primary intent, to match the feed line to the antenna and avoid high SWR in the coax to the transmitter, is much better for "random" and other non-resonant and high SWR antennas than to try to use a tuner at the transmitter.

The SG-237 units worked much better than a newer design remote tuner from another company that couldn't match an almost resonant dipole that was only 2:1 or 3:1 SWR without the tuner, or work with ladder line using a balun.

The SG-237 works quite well for many situations, but I would recommend paying extra for the Smartlock remote control. If the coupler can't match a specific length antenna at a specific frequency, changing the radiator length a little can help. If you aren't using a good antenna analyzer, which is what the automatic coupler is supposed to make unnecessary, then it may appear that the coupler is faulty when it isn't. I got some encouragement and advice from tech support at SGC as I ran into difficulty a couple times.

This is a very useful antenna coupler to have available if you need to use improvised and non-standard antennas.
W3FLH Rating: 2019-11-01
Virtually "disappears" in my mobile Time Owned: more than 12 months.
My experience pretty much echoes that of KK5JY in his first paragraph: I have mine mounted inside the tool box (plastic) in the bed of my truck, with #10 solid copper for the feedpoint and ground connections. It matches a 108" S/S whip easily on 40m and up with little or no problem; it'll match the whip on 80m (even 160m, FWIW), but the efficiency is so low, and since I only run barefoot, I don't venture down there that often.

KK5JY is right about paying close attention to SGC's instructions in terms of the power handling of the unit, but also about keeping the leads as short as possible. If you stick close to the installation guidelines, this little box really plays.

A little off-topic, but worth noting: I also use the AA4PB tune control between the '237 and an IC-706MKIIG, which becomes a seamless set-up in practice. With the tune cotrol in the LOCK position, the coupler doesn't want to re-tune due to temporary SWR changes. It also allows the rig's TUNE button to function as designed. One push of the button, and you're ready to go.

de Tony, W3FLH
73
VK3HAY Rating: 2019-06-03
Faultless over 7 years Time Owned: more than 12 months.
I had the sgc237 installed under the front drivers side guard of my Land Rover defender with a very short run[ less than a foot to a 2 price antenna [6 meters with the wire whip on] for over 70,000 kms of harsh off road/corigated dirt road driving for near 7 years, it’s seen days of snow and days of 110 plus heat tuning both Barrett and codan land mobile 100 Watters , it’s now feeding my 40 meter delta loop and turning flat through 80,40,15 and 10 meters[f licence bands here in Australia ]it tunes all ham bands in loop form ecept 160 meters[not enough wire in the air] only issues I’ve seen are that a nylon nut rattled loose and there was some corrosion on the earth plate where the stainless steel earth lug touches the alloy . Internally ecept for said nylon nut it is spotless
AB0O Rating: 2019-05-03
Excellent Tuner Time Owned: more than 12 months.
This is the second 237 that I have owned since 2005. The first one was destroyed by a lightning strike, but no hesitation to purchase a second one.
These tuners are outstanding. They simply tune whatever signal and antenna that are connected. I have used mine on short and long wires/whips, but 90% of the use has been to feed balanced feedline to multiband wire dipoles or flat tops.
I currently use the 237 to feed a 160-6 meter G5RV-style antenna fed with ladder line. As you key the mic, you can see the SWR work its way down to nothing after about 5 spoken words. Memories are immediately recalled.
It just "disappears" between the rig and the antenna. I did not purchase the SmartLock for either tuner.
N5XJT Rating: 2019-01-26
Very Good Tuner Time Owned: 6 to 12 months.
PROS: Works flawlessly with no issues. Easily and quickly tunes my S9v31 on any band from 80m thru 6m. Quickly recalls memories.
CONS: None really but I have to mention that I dislike having to protect this "waterproof tuner" from the elements by covering it and providing 12v dc power to the antenna 70 ft. away is not much fun either.
KQ6IG Rating: 2017-11-24
Great Time Owned: more than 12 months.
I'm using my SG-237 to tune a military mobile 16 foot vertical that is expandable to 32 ft for stationary operation.

After much difficulty with an LDG tuner in this application, I purchased and installed the 237. It has been flawless. It tunes every HF ham band effortlessly. I am powering it through a relay that is activated by the accessory jack on the radio. I also installed a DC separation filter in the tuner so it may be powered over the coax line.

The tuner comes with many functions that I'm not using, but may be very helpful - such as provisions for remote status lights.

The SG-237 is a rugged, affordable, compact, well designed autotuner. I highly recommend it.
W4DXL Rating: 2014-12-04
Expected more Time Owned: N.A.
I'm on my second SG-237 after the first one wouldn't pass the lightbulb test. Previously I had a FC-800 attached to a FT-840 radio but when I upgraded the radio I had to use a different tuner. This tuner has entire bands that just won't tune. It was mounted in a difficult to reach place, and no matter how much I worked with it performance was lacking. So I finally got tired and went to a desktop tuner which works a lot better and cost less than a third as much. I plan to work with this one to see if there is another use for it. After all it works for other Hams. I'm disappointed, I had high hopes it would work as well as the FC-800, it didn't.

VK4BG Rating: 2014-10-16
Faulty out of the box, nil support Time Owned: 0 to 3 months.
This is the second SGC product that I have purchased, and it will be the last. It was faulty out of the box ( did not work at all ), and emails to SGC went unanswered. The local supplier replaced it, and returned the faulty unit to SGC, who then accused me of damaging it by shortening the external cable to suit my installation, and damaging internal components. This was the worst experience I have had with a supplier of amateur gear. Never again.
KA3RCS Rating: 2014-01-05
Superb autotuner Time Owned: more than 12 months.
I spent years thinking about mobile HF antenna options, with just a Wilson 1000 and a 10 meter radio in the vehicle. Finally decided on the SG-237 to tune the same antenna, and paired it with an FT-857D.

I quickly realized that the matching coil in the Wilson antenna was fighting with the tuner and eliminated it, effectively ending up with a 5 foot whip connected directly to the tuner (which was mounted inside the roof of the vehicle, a few inches from the feedpoint). It would tune virtually anywhere from the top of 160 through 6 meters, though the radiation efficiency was obviously extremely poor on the lowest bands. It worked great on the higher bands.

I have since moved the radio and tuner to a different vehicle, though now feeding a different whip of similar length due to a completely different mounting configuration. It still works very well.

I had wired up a tune lock switch in the other vehicle, but have not yet done so in this installation. I really must do so, as the sporadic retuning events (even while stationary; possibly wind acting on the antenna or similar) can be annoying. I've seemed to the other station to disappear in the middle of a QSO several times. This is not the fault of the tuner, and is very simple to implement. I found that all I needed was a single SPDT center-off switch tying the control line either to +12 volts or ground, or leaving it floating in the center position. I'm planning to build a multifunction control box to accommodate this functionality (along with indicator LEDs), as well as a low power tune button for the radio (similar to the Quicksilver tuner box which worked so-so).

What I found to be quite convenient was to power the SG-237 from the tuner port on the FT-857. This way, the tuner automatically receives power whenever the radio is turned on. I've read comments about overloading that accessory power output causing damage, so I plan to add a tuner power fuse in the new interface box to protect the radio just in case.

In summary, the SG-237 is a rock-solid autotuner which just plain works, and works very well.