Anyone else fried their AG?

LA9AKA Hans Chr. · June 2024

I am well aware of the 6m 800W limit for digital modes for my AG 8x2 switch. Was enjoying an opening on 6m to the U.S. here the other day and was running 750W FT8 for about 1 hour. Suddenly the SWR started jumping around and my PGXL gave me a warning as well. Stopped transmission and went into my shack the next day to check. It smelled like it had been a fire in there. Opened up the back lid on the AG and I could see burn marks on the housing and some copper tracks on the circuit board has curled up. SWR on my 6m antenna is 1,12:1 and my TGXL is in bypass mode.

Why did this happen when I transmitted well within the 800W limit? The only reason I can think of is that I have transmitted earlier above 1KW before the power limit was reduced. And maybe this has damaged the unit.

Pretty frustrating for me as a 6m DX'er to suddely have the power handling reduced on the antenna switch that was bought with an inititally much higher power rating on 6m :(

73 de LA9AKA

Erik Carling EI4KF · June 2024

I do not want to hijack Hans Christian's thread regarding his sad tale (for which I am sorry to hear about).

But it caused me a sudden jolt and I need clarification. I have been waiting for the AG 8:1 to come back into stock at a European supplier. It is advertised as 160m to 6m at 3000W. I have also read the user manual which states

Power handling → 3,000 Watts ICAS (SSB/CW) for 5 minutes @ 1.5:1 VSWR @ 30 MHz
→ 3,000 Watts ICAS (SSB/CW) for 3 minutes @ 1.5:1 VSWR @ 50 MHz

Is the advertising a misrepresentation or does 3000W ICAS mean 800W on FT8 or does the 8:2 switch limit not apply to the 8:1? If would be grateful to be advised in case I need to cancel my pre-order.

Erik EI4KF.

LA9AKA Hans Chr. · June 2024

Erik,

You are more than welcome to hijack my thread! I am quite curious myself if the 6m limitation applies to the 8x1 switch as well. Had a relay issue with mine earlier, 4O3A was supposed to send me a new relay. That was probably over a year ago now. Never received a relay and no replies to emails either. So I'm close to giving up the switch. I have not yet opened a ticket for the latest issue.

Hans Christian LA9AKA

Erik Carling EI4KF · June 2024

I also emailed 4O3A but no reply so far. If no answer here or from the manufacturer I will also give up on the switch. That will mean also cancelling my PGXL order because, as attractive the PGXL is, a switch usable per its claimed specs and with no extra risk on 6m compared to other bands is required owing to the amp not having a one of its own.

Frankly I am totally dismayed, not only at what has happened to you but also at the thinking behind this. Do they think PGXL owners will never do contesting on 6mtrs? Whilst I would never use my 1500W FT8 licence limit on that band, I would certainly want to retain 1000W in 6m contesting which my tube amp with its on-board switch provides. I'd been saving up too…..

Erik.

km8v · June 2024

The difference between a KW and 800W is .. negligible.

Erik Carling EI4KF · June 2024

I do not understand the comment from km8v as it seems completely irrelevant given that the discussion is about actual specification versus claimed. To that end I have learned that ICAS is no longer quoted by 4O3A in their AG specs but that their distributors' advertising and the user manual still quote ICAS without noting any 6m band limitation. 4O3A now use CCS as in constant carrier RTTY / FT8 which is far more informative from my point of view. Maybe ICAS and CCS are the same, I am just a prospective user and not well versed on the nuances. It would therefore go too far so say that the the advertising is misleading but it sure is peculiar. For the 8x2, the 800 watt limit on 6m applies as we know. The 8:1 however is claimed to be "Capable of 3000W @ 1.5:1 VSWR CCS (e.g. RTTY) duty cycle for five minutes" with no noted 6mtr restriction.

I have actually cancelled the 8x1 order, being a little dubious that the spec of the 8x1 really is so superior to the 8x2.

I sincerely hope Hans Christian that you get a satisfactory reply from Flex / 4O3A and that a no cost repair is forthcoming.

Erik.

Lou Laderman W0FK · July 14

I am considering the 8x1 as well, which is why I am resurrecting this older thread.

I only recently learned about the 800w limit on 6M. I have owned an AG 8x2 for 5 years and have had no issues running up to 1500w on 6M FT8. But I fear it's been on borrowed time.

The current specs are as follows:

"160M through 6M bands. Capable of 3000W @ 1 .5:1 VSWR CCS (e.g. RTTY) duty cycle for five minutes."

Should I have any concerns running legal limit through it on 6M?

73, Lou W0FK

Mike-VA3MW · July 14

I would check the path loss at 6M through the AG and make sure you use the ports with the least loss.

I have been running AG's for a long time and I do a lot of 6M digitial work, all without issue. That being said, my max power is 750W as it is a Canadian limitation. Going much above that doesn't really give you much more performance anyway.

Lou Laderman W0FK · July 14

Good suggestion on the least loss path Mike. That said, running 1500w on 6M can make a difference. Getting an additional 3dB (1/2 an S-unit) from 750w to 1500w can make a difference on FT8. The increase can move you from the "can't decode" column to being heard. This is especially helpful on 6M when the signals are light and variable. If the 8x1 switch allows 1500w safely, count me in.

73, Lou W0FK

Mike-VA3MW · July 14

You're absolutely right that 3 dB—especially in weak-signal modes like FT8—can be the difference between a decode and nothing at all. But it's also important to recognize that, on 6 meters, ionospheric variability often plays a far larger role in signal reliability than a static power increase.

Unlike more stable HF bands, 6M is heavily influenced by sporadic-E and other transient propagation phenomena. Signals often fluctuate by 10–20 dB or more in a matter of seconds, which tends to mask the relatively small advantage of doubling your output from 750 W to 1500 W. In many cases, propagation will open or close entirely irrespective of your power level.

Moreover, increasing power also increases the risk of overload, intermod, or RFI—especially if the entire station isn’t equally well-engineered for that higher level. So, while 3 dB can help under some conditions, it’s often not the deciding factor on 6 meters. Careful timing, antenna optimization, and frequency agility usually yield a greater return than sheer output power.

Still, if everything else in the station supports it cleanly and legally, then yes—more power certainly won’t hurt. But it’s not a substitute for propagation awareness and good operating practice.

I can personally saw that I have no issue working the world on 6M with no more than 750 watts.

Good luck.

Ken Wells · July 17

NOTE: The AG's 800 Watt limit for 6 Meters assumes a well-matched antenna system.

If the SWR at the AG antenna port is higher, the power limit should be reduced, since Standing Waves will generate higher RF Voltages within any device in the signal path, which could damage the AG even with power levels below the recommended limit of 800 Watts on 6 Meters.

The same may also be true if using one of the AG ports that has a higher signal loss at 6 Meters, as mentioned by Mike - VA3MW. (Signal loss = additional heat build-up)

In the same way, for example, the Tuner Genius says it is a 1500 or 2000 Watt tuner, and has an approximate tuning range of 10:1 SWR.

BUT: It will not operate at 2000 Watts into a 10:1 SWR. This would generate unbelievably high RF voltages inside the Tuner Genius!

In fact, as the untuned SWR rises at the Tuner Genius, it calculates a maximum "safe" Power output ;eve; and marks that on the Meters of the Tuner Genius.

LA9AKA Hans Chr. · July 25

Note regarding my AG failure: I do have a well-matched 6m system consisting of a 15el 6/4m dualband antenna and the best cables/connectors money can buy. I also used the antenna port with the best match for 6m.
As I said in my original post, what might have hapened in my case is that I have used 1KW earlier, before this 800W limit was official, and this might have partly damaged the relay/circuit board. But when I bought this switch it was supposed to handle this power with ease, so I feel a little bit betrayed. 4O3A was supposed to send new relays, and they also said they would release a modificaion for the switch within a few weeks. This is now a long time ago. No relays, no modification and no replies to emails.
I've given up and I'm using a MicroHam Trio switch with great success now.

Erik Carling EI4KF · July 25

I am really sorry to hear this, Hans Christian. Your failure was over a year ago and for 4O3A to continue to fail with support for its customers, and its own product, is appalling.

I stated earlier that I cancelled my AG order and I am glad I did. In addition to your MicroHam alternative, there is another that I purchased: the Amplitec Antenna Switch. These come in 4-, 6- or 8-Way versions with network control versions or manual control as a choice. Absolutely solidly built and handles 1500 watts on 6m easily (rated to 2KW on 6m and 3KW other bands, even 1KW on 4m for those with that band). Not expensive either, much less than a 1AG.

LA9AKA Hans Chr. · July 25

Erik, thank you for understanding. If I knew beforehand that the AG would not handle more than 800W digital on 6m, I would never have bought it.

The Amplitec is definitly an alternative as well. I have extremely good experience with build quality and customer service from MicroHam, so I am very confident that this switch will do the job. He also said that he would give me my money back if I was not happy. And as you say, these switches also do a great job on 70MHz. So far I've run many hours 1,2KW digital on 6m and 800W digital on 4m with no issues :)

I used to have great communications with 4O3A, but now it's just nonexistent. I really hope that I do not get any issues with my PGXL and TGXL in the future.

Anyone else fried their AG?

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