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Reviews For: Ten-Tec 238A

Category: Antenna Tuners/Matching Networks

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Review Summary For : Ten-Tec 238A
Reviews: 16MSRP: 485
Description:
2000 Watt Roller Inductor Antenna Tuner
Product is in production
More Info: http://www.tentec.com/HIGH.HTM#model238
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00164.1
W2ATO Rating: 2001-09-06
Very Good Tuner Time Owned: more than 12 months.
I have been using the 238 and 229 Ten Tec tuners for several years on my Alpha 87a, Alpha
89, Ten Tec Titan and Ameritron AL1500 amplifiers at full legal power with no problems.
My antennas consist of a double extended zepp for 40 meters feed with ladder line, 280 foot
center feed double zepp for 160 meters feed with ladder line and other coax feed antennas for
operation on bands 20 thru 10 meters.
Thesse are excellent tuners and tune any frequency within these bands.
AB6GS Rating: 2001-08-16
Needs work Time Owned: 6 to 12 months.
I bought my 238A and Titan II just before the CQWW 160 Meter contest. The first thing I noticed was the SWR/SET/200/2000 selector switch was intermittent. Maybe a bad solder joint or it got overheated when installed. I returned the tuner to Ten-Tec and they had it back to me in a couple of weeks in time for the contest.

Everything worked great during the contest, but later as I used the tuner on other bands I ran into problems. I was using the tuner to trim up a vertical antenna on 10 meters. The antenna's native SWR is only 1.5:1 and I had trimmed it up to 1:1 for the amp. While running about 1200watts I heard a crack and my SWR shot up.

I took the tuner apart and found that one of the capacitors (C11) had exploded. The schematic shows only one cap, but C11 is actually two 120pf 1KV caps in parallel not a single 220pf as shown on the schematic. It amazes me that Ten-Tec would put a 1KV ceramic cap in a 2000-watt tuner, but having read that other hams had also had problems I knew this might happen.

Rather than send the tuner back to Ten-Tec under warranty so that they could install another 1KV cap that would later explode, I ordered two 120pf 5KV ceramic doorknob caps from www.rfparts.com. I retrofitted these two caps on the board and everything was working great.

I later decided to run the 10-10 summer phone contest and again the tuner failed. After about two hours of operation (running about 1200watts) my SWR shot up again. This time when I took the tuner apart, I could find no damaged components. I replaced the two 5KV caps on general principles and still nothing. So I started tracing through the circuit with a meter and discovered that one of the wires from the roller inductor was just sitting in a hole in the PC board. As it turns out, when the tuner was assembled they had done a lousy job of soldering this wire on and with the tiny amount of solder that was sticking it to the board and the heat generated by the RF it just popped loose. I resoldered the wire and again all is well.

In general I like the operation of the tuner very much. Its L network design is more efficient than most Pi network tuners. Numerous threads can be found on the Internet complaining about the C11 cap problem so be prepared to replace them. If you don’t like to get your hands dirty, this might not be the tuner for you. I’m sure if you never run more than 500 watts the tuner would work flawlessly, but Ten-Tec’s 2000 watt rating is totally inappropriate if they are only going to install 1KV caps.

If your primary need is to run balanced line, the circuit is not designed to provide good output balance. You can improve balance by putting a current balun on the input connector of the tuner, make sure the tuner is not grounded to anything, and is at least six inches away from all metal station equipment (capacitive coupling). This trick can be used on most tuners that foolishly have their internal balun installed on the output side (almost all commercial tuners). If you have other coaxial lines connected feeding grounded antennas, you will have to disconnect the coax while running the balanced feeder for this trick to work. Make sure a good ground exists on the Radio/Amp side of the balun.

In summary, I expect more when plunking down $450 and I hope Ten-Tec takes notice of these shortcomings and improves their design.
K9FTB Rating: 2001-06-10
It's What I Expected Time Owned: 0 to 3 months.
After reading several Eham reviews and looking at the TenTec reflector archives, I decided to purchase this unit. Lots of good info about the tuner and heritage. It looks good cosmetically, but I was somewhat disappointed with the movement of both the capacitor and inductor control knobs. Kind of hard to move and you must overcome some resistance. They adjust fine, but it was a disappointment. I saw the same tuner at Dayton last month and checked the capacitor and inductor controls and both were smooth with no resistance. Maybe I've got a warranty issue here.

Anyway, the tuner tunes my multiband dipole just fine, except on the high end of 75m. For $461 shipped to your door, I'd say the features certainly are there (4:1 balun, 3 antennas), SWR / Power meter built in (looks like it came from MFJ). I haven't connected 12Vdc yet for the meter, but I plan to.

The quality of construction inside is consistent with other folks opinions (good), except for the control knobs I mentioned.

I especially like the L network which is broad enough that I don't end up retuning very much.

I've set up a chart for my antenna and simply go to that "third" of the band and I'm all set.

Was considering a Palstar 4K, but the bucks didn't justify the value in my mind. I've got equivalent capability (for my use at least). I'd buy the 238A again.

Dean, K9FTB, Fairport, NY
KF7SN Rating: 2001-04-10
Could use additional Tuning Capacitor. Time Owned: 0 to 3 months.
I`ve had the tuner going on a week. I use it on a G5RV flattop Antenna. It will take the power as I have put a 1000 watts in to it and not a sound. My amp. is a Health SB-200. The only two drawbacks are the metering and the lack of additional tuning Capacitor. Note I think that the Differential T tuners are better at tuning random lengths of wire. Ten Tec needs to add another tuning Cap. and get away from L type tuners. The only reason I see them making this model is that there are less parts so that keeps the cost down. But for $461 to get to your door its not to bad. Also forget tuning 160 unless you have lots of wire.
KF8IO Rating: 2001-02-18
Good Time Owned: 0 to 3 months.
For cost vrs. performance this tuner is a good choice. Solidly built with enough beef to resist a meltdown... on the minus side the SWR/power meter is something of a joke. I would have preferred they OMIT the meter rather than include this mickey mouse one. It's a insult to the purchaser. If you need a tuner only, it's good. If you need a tuner AND a meter keep shopping.
NA2AA Rating: 2001-02-06
Very solid tuner! Time Owned: 0 to 3 months.
I recently had the displeasure of knocking my trusty old MFJ962B into orbit by loading it up on 80M with 1KW. Bright lights. Stopped working. So, after doing a little research, and a reality check, I bypassed the PalStar $4K and went with the TenTec. I was very pleased with the telephone support of W4PA and he expedited shipping to ensure I'd have it for the CQWW 160M contest. Although it took me some time to hunt for the proper tune positions, once tuned (and recorded on a cheat sheet) it was rock solid. It has been a pleasure now running my TL922A full tilt through the 238A without a single concern. My only negative comment about the unit is that the SWR/Wattmeter is a little stingy for a $400+ piece of equipment. I did like the metering on the MFJ better. That being said, I wouldn't part with this tuner!