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Reviews For: AlphaDelta ATT3 G50 Static Discharge Protector

Category: Lightning & Surge Protection/Supression

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Review Summary For : AlphaDelta ATT3 G50 Static Discharge Protector
Reviews: 12MSRP: 54.95
Static discharge protector for VHF/UHF
Product is in production
More Info: http://
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
N1OKL Rating: 2023-07-15
Seems effective Time Owned: 0 to 3 months.
Recently installed an A-D ATT3 arrestor, 200w UHF connector version, on a coax line to my VHF GP antenna. Within several hours of installation, there was an unexpected thunderstorm, and I had yet not disconnected and grounded the antenna. A nearby lightening strike caused the gas tube to discharge with a characteristic "snap". No damage to the new IC2730, so I think I got my money's worth! Though, as other users have stated, the best practice is to disconnect and ground all antenna coax when not in use.

Here are several additional comments. I actually wanted to buy the 2kW version of the ATT3, but could not find one in stock. DX Engineering did have spare, 2kW Arc Plugs in stock, and a conversation with the hams there suggested that the low and high power Arc Plugs are interchangeable, and that there is no difference in the body of the ATT3 between low and high power versions. So, I also ordered a 2Kw Arc plug, in case I want to use the ATT3 with my HF rig and 500w amp in the future. I would be interested to know if anyone here can confirm or refute the suggestion that changing the Arc Plug can make a 200w ATT3 into a 2kW version? Several messages asking this question to A-D via their website contact form have gone unanswered. And, no one answers the phone at A-D.

Also, I looked closely at the gas discharge tubes in both the 200w and 2kW versions, to see if I might be able to order spares of the GDTs only. The answer is Yes. Both are available from Mouser and other parts suppliers, for significantly less than the $15 cost of the tube and plug. Both are supplied as axial lead devices. To use in the Arc Plug, just snip the leads off as close to the body as possible, being careful not to damage the tube end caps. Here's the info on both GDTs--

200W - EPCOS / TDK EC350X - Mouser p/n 871-B88069X810S102 - red, positive markings on part are: EPCOS EC 350 YY o where EC = Series, 350 = nominal voltage, YY = year of production, o = non radioactive. Cost is about $1.50 ea.

2kW - Littlefuse CG2 1000 - Mouser p/n 576-CG21000LTR - black, positive markings on part are: LF logo CG2 1000 YY and a small, black square, where CG2 = Series, 1000 = nominal voltage, YY = year of production, small black square = ? Cost is about $3.60 ea.
AB6RF Rating: 2022-07-28
Needs better quality control Time Owned: more than 12 months.
I'm using two ATT3G50 surge protectors at my home QTH, and those two protectors have been working fine.
I can't comment on their effectiveness on protecting the rigs from lightning damage (very few lighting storms in my location), but at least they have not caused any RF problems.

But recently I took one "new old stock" ATT3G50 with me to be installed at a remote station. The ATT3G50 was unused, but few years old.
Long story short, it turned out that this ATT3G50 was faulty. The brass tube that connects the two SO-239 center pins together, was loose on one end, and caused a sky-high SWR.
This was a real issue since I didn't have a spare unit with me, and had to take the ATT3G50 apart, and do my best job at soldering the brass tube back in place with the less than ideal tools I had at the remote location.

I guess the lesson is, even simple devices can have quality problems, and anything "mission critical" has to be tested first, and you better have a backup for EVERYTHING.
KN0JI Rating: 2018-05-16
Can't even tell it's there Time Owned: more than 12 months.
Mine are the TT3G50UB-HP, the 2 kW UHF model. Never had one of these blow, so I don't really know whether they can withstand an outdoor-sourced discharge, but so far, so good. Contrary to what a few others are saying, when I've run at max (800 watts SSB or CW for me), never had a problem. SWR with and without the TT3G50 is 1.3 on 14.2 MHz at lowest, 1.8 on 7.2 MHz at lowest.
W9RAC Rating: 2018-02-03
Low Power/SWR Time Owned: more than 12 months.
At first I considered this to be a good idea. I have 5 in line. 20/40/60/75/160, all separate antennas, all renasant. I run a Kenwood ts990s/Alpha 8410/Palstar auto tuner. The 60 meter has held up fine at 100 watts. The 40 has not been a problem of which I use mostly for CW, 100 watts, Yaesu FT2000. The 80 and 160 started acting odd. I generally talk within my swr range of 1.5 OR less. On a occasion I have moved to a lower OR higher area to talk with friends. I live within the forest rural area so I was mostly concerned with nearby storms creating static being my antennas are all in the trees. I'm using a Georgia Copper busbar. I generally run 1kw OR less. I started noticing a bit of movement from my auto tuner, it would on occasion try to retune for a instant on 75 and 160. I also noticed a slight bit of SWR occuring when this occurred detected by my Alpha 8410. After I disconnected the static discharge unit the oddity stopped. Took me a while to track it down but that's what it was. I'm thinking, like the others have stated that if you run much power and out of the low SWR portion of your antenna they will fail. I use a DX engineering CC-8A switching unit to change antenna and a Alpha Delta-4 switch inside to change rigs to radios. These both go to ground when off so I am not using the static discharge units any longer. Bottom line, low power and use within low SWR range. I was a fairly expense lesson and one that I would recommend you not do. I have always disconnected my antenna lead in coax so that's how I do it.
W3HKK Rating: 2017-09-24
HIGH QUALITY GAS DISCHARGE UNIT Time Owned: more than 12 months.
Bought one of these babies 9 years ago for my HF antennas.

Often when sitting in the shack when T storms would pass nearby I heard the distinctive "crack" or "crack-crack" as my antennas would discharge their high voltage induced charges through the gas discharge tube to ground. Probably heard 30-50 such arcs, but the latest one did in the gas tube, but protected my gear keeping it damage free.

I ordered a replacement GDT from DXEngineering and had the unit back working again in 2 days.

The AlphaDelta GDT specs talk about how effectively it limits line voltages to 300-1000 volts, but acts so quickly that only a very small joule amount gets into your equipment, not enough to do any damage.

Pretty neat to see it in action, and to come out unscathed.

Two years ago I added two Array Solutions high end static discharge units at the inputs to my IC7600. I had forgotten about the lowly AlphaDelta GDT that was in the line from my remote antenna relay box and the shack. But it came through with flying colors. An impressive GDT unit!
K2IZ Rating: 2014-11-21
Every station should have them. Time Owned: more than 12 months.
Installed ATT3's for every antenna I have in the air, , everything is well made, up until last year I never had any lightning protection, guess I got lucky, with these installed I don't have to rely on luck to not get damage to my equipment.
DXSHORTWAVE Rating: 2013-08-30
Works great at 2 kW Time Owned: more than 12 months.
The previous reviewer must be using the 200 watt model. The 2 kW model is ATT3G50HP. We use them here at this commercial station at 2 kW carrier with no problems. Have used them for years.


Earlier 5-star review posted by DXSHORTWAVE on 2007-07-02

At our commercial HF monitoring and point to point transmission site, we provide services for several commercial and government entities. We get to work ham radio too during off hours.

Some months ago, we replaced our "DC blocked" Polyphaser units with Alpha Delta TT3G50 surge protectors. We did this because several of the Polyphaser units failed during 1000 watt continuous duty transmissions over a 1 to 2 year period. We discovered the capacitors in them failed during high power operation. We asked for the rating specs but received no response.

We tested both types of designs with our high voltage, current limited pulse generators to characterize surge protection performance. We found the Alpha Delta units provided the same nanosecond (approx 80 nsec, as verified by an outside lab) "response time" as the others and the discharge protection is as effective.

The Alpha Delta units have no internal capacitors to break down and the reliability has been flawless. We have changed our systems in the U.S. and Asia to the TT3G50s and have been very satisfied with the performance. The Alpha Delta folks have been very responsive to our questions.

As always, we use commecial grade grounding techniques (single point grounds, etc.) because no protectors can do the job by themselves. We have sustained no equipment damage or failures at this point, and some of our HF antennas are quite large.
K0KS Rating: 2013-08-30
Works Well with Reservations Time Owned: more than 12 months.
These work fine at low power levels but will not handle 2KW @ 3:1 SWR. Mine breaks down at 800W CW with a 1.9:1 SWR. A Polyphaser IS-B50HU
did not but this is a more expensive unit. This would rate a "5" except for QRO above 500W.
K6USN Rating: 2012-08-14
Prudent Insurance Time Owned: more than 12 months.
I live in central Wisconsin. Lightening is a way of life here. For many years I have used a variety of Alpha Delta products (antennas, lightening arrestors and coax switches) and find them to be of high quality. I've had several near misses where the surge took out the TV's, the phone system and the garage door opener but my ham station came through fine.
I have a number of Alpha Delta Static Surge Protectors - one for each feedline- and ground them per the electrical codes in my area. (An 8 ft ground rod with #8 copper wire as a minimum.)

W5DGM Rating: 2012-03-02
Absolutely essential Time Owned: 6 to 12 months.
I have these devices on every coax line at the base of my tower. Along with a very good single point ground system, this is essential for station protection. All transceivers perform as they should with the protectors in line.