I've used my PGXL for several weeks now, comparing it to my Alpha 9500 and several homebrew amps. On balance, it is my amplifier of choice. Here I address some of the criticisms and strengths:
1. Fan Noise: The PGXL has several fans which switch on as the temperature changes. The highest speed is like having a threshing machine in the room. One important point: Fan noise is always going to be an issue with solid state amplifiers because the generated heat is very localized and has to be exhausted quickly. The PGXL does as good or better a job at flushing the heat as any solid state amp, but is somewhat louder than a comparable, well-designed vacuum tube amp. Incidentally, the front air vent is for intake air only, and does not blow in your face or contribute to the fan noise. Between transmissions the fans switch off and are dead quiet. Keep in mind also that the PGXL runs 2000-2100 Watts output and generates 500 more watts of heat than, e.g., a KPA1500. It's a very rugged amplifier.
2. Remote operation: Although reviewers have commented on the PGXL's remote capability, I want to make sure that really sinks in. There is no reason the PGXL has to be on your operating desk. It has only one button (operate/standby) on the panel, and that is also operated remotely. (Compare that to the front panel of a KPA1500.) The neat little LCD on the front is duplicated exactly on your computer screen. The ONLY reasons to put the amp on your operating desk are (a) you don't have floor or table space elsewhere, and (b) it looks so cool you want to show it off.
3. Interfacing: With a Flex transceiver, the PGXL is nearly effortless to hook up. All controls (T/R switching, everything) is done via your LAN or an ethernet cable to the transceiver. The coax is the only other connection to radio. If you run SmartSDR, you'll have a new menu on your computer when the amp is running. If you're using an 6600M or 4400M, you'll see a new icon on the transceiver's front panel, plus a menu showing power output and other amplifier parameters. With Yaesu, Kenwood, Elecraft radios, etc.,you'll also need a phono cable to handle the amp relay keying. For those radios, the PGXL hooks up like any other amplifier, except that you'll also have a menu on your PC display that shows a duplicate of the amp's LCD.
4. CW operation: The PGXL is not intended for QSK, but that doesn't mean CW is an afterthought even if, like me, you don't run SO2R. You'll need to set the delay from your transceiver (the time between a key closure and the appearance of RF at the amplifer) to at least 10 mSec. Note that Flex transceivers handle that delay in a completely different way from other brands. Flex radios time-shift your CW by whatever delay time your select, so that the RF never arrives at the amplifier before the amp is ready to receive it. There's never any clipping of the first dit, no matter how fast you send it. On a Flex transceiver, you can set the delay to anything. For fun, I set it at 1000 mSec and listened to my signal on another receiver. I sent "hello" at 30wpm, and waited. A second later I heard my transceiver send "hello," delayed by a second. Fun. What this means is that whatever delay you choose is pretty much irrelevant. You can't do that with any other brand, so for, e.g., an Elecraft, you'd just set it at 10mSec. Other CW features, like independent sidetone volume and frequency, separate headphone and speaker volume controls, adjustable AGC times, (and AGC threshold), bandpass tuning, etc. filter slope and latency, work well on CW. Flex transceivers don't have quite as many CW bells and whistles as a K3 (e.g., automatic zero beating), but it has everthing most CW ops want.
5. Software Design: In my opinion, the software developers at Flex are hands down the best in the industry, and the PGXL reflects this level of sophistication. Pretty much everything is done for you. You can't damage the amplifer by choosing the wrong antenna, the wrong frequency, overdriving it, or overheating it. It's designed to withstand almost any abuse you can think of, which is why its unsurpassed for remote operation.
6. Nits: The PGXL uses fast, German, open-frame relays, and the relays make an audible clicking sound which will bother some users. At the 2000W power level, I don't think pin diode switching is appropriate, but I would have preferred near-silent vacuum relays. Of course if you remote the amplifier or wear headphones, like I do, the clicking is irrelevant. I am told the life expectancy of the open frame relays exceeds that of vacuum relays, but I haven't verified that.
My other nit is the near lack of information about what's inside the PGXL cabinet. There is no circuit diagram provided, nor circuit description, nor even interior photographs. While there's not much point in providing information about the insides of a transceiver, which are just a collection of circuit boards, that's not the case with RF power amplifiers. I don't doubt the amplifier is well-constructed, but like most hams, I would like to know what I'm spending $7000 on. By the way, the PGXL is larger than you might expect for a solid state amplifier. The depth is 19.5 inches, which is the same as an Alpha 9500. So whatever is inside the cabinet, there's a lot of it. I hope Flex will change their policy and be more forthcoming.
The PGXL is my first solid state amplifier. It's a brute and produces 2000W output effortlessly. (I set the maximum power on my transceiver to 55W, which gives me full flexibility for power output.) A lot of thought went into its design, and the more I use it, the more I like it. |