I just replied to a question I received about my impressions of the PG XL. Thought I’d share my thoughts with the group so below are my edited long-winded comments;
I haven’t had much air time with it, but so far I’m happy with the PG. I did a lot of research before finally deciding to go with it. It was a tough choice between the KPA1500 and the PG. From what I had read they are both excellent amps. I flip/flopped between them several times. Main reasons for finally choosing the PG, in decreasing order of importance to me:
Integration with Flex. This is really neat. All you need are power, Ethernet, and coax connections and you’re in business. Everything except switching power on/off is done from the keyboard. I found it super easy to set up, with one exception. When using the supplied Windows app to configure the radio, a serial number popped up when I selected the radio tab. I thought the amp auto-detected the radio on the LAN, so I clicked on it, but the amp would not track the radio. That serial # turned out to be from the radio of a 4O3A user who tested the amp at the factory. When I manually entered the correct serial number, all was well. If it wasn’t for that the configuration would only have taken a few minutes as others have stated. Another minor problem was trying to change the brightness of the backlighting that shows the amp’s state. Turns out it is a known bug and is in the queue for resolution.
Headroom. Based on comments from folks in this group who have run it all day in digital modes at the legal limit, the PG MAY have somewhat more headroom/efficiency than the KPA1500, maybe (as others have stated) due to the choice of PA transistors, harmonics trap, automatic bias class switching between AB and AAB, and/or vapor chamber heat sink. I haven’t run it at high power yet (except into my dummy load) because I need to upgrade my antenna system surge protectors (which would fire at high power) and coax jumpers. I’m moving stuff around and changing cabling right now.
Engineering for clean signals. Use of diplexed filters, the automatic bias class switching, and harmonics trap are supposed to result in cleaner signals than competing LDMOS designs. Hope this is true. Future test reports will be interesting.
Fan and relay noise. I can’t really compare this to other amps, since this is my first one. I found the noise to be about what I expected from Ria’s comments. There is noise all right, but it’s not objectionable to me either. And if it was, I could move the amp further away since I control it from the keyboard. But I prefer to have it close by because I like to look at what I paid $7K for. Or maybe not! (-: From I read, the KPA1500 is somewhat quieter - it uses pin diodes and has a separate power deck (with its own fans) which can be located further away. I think the bottom line is what is more important to you, headroom at high power or noise level. Cooling at high duty cycles at max power takes a high air flow and some noise is unavoidable.
Compatibility with other radios. I plan to also use it with my ICOMs since the PG supports the ICOM protocols. The KPA1500 does this too.
Tuner. The KPA has an internal tuner. The Flex tuner is not available yet and probably won’t be until early next year. This is not a big issue for me, since I’m getting the Flex tuner free with my 2017 pre-order. In the meantime I’m using my manual ATR-30, which has the best matching range at high power of any tuner I know of.
Other comments. SO2R is not important to me, which is a shame since that’s one of the main features of the amp. On the other hand, if QSK were important to me I would have gone with the KPA-1500 since it supports QSK via faster pin diode switching (4O3A has stated the PG uses slower mechanical relays for reliability at high power and better isolation). Also I somewhat prefer the traditional looks of the KPA, but I’ve gotten used to the clean looks of the PG, especially with that great display!
I’ll be sending the PG back for the 6M fix sometimes soon. That problem was a little disappointing but these things happen and Flex did the right thing and is fixing it promptly. The great support from Flex would be another reason for choosing the PG.
As I said, this is my first amp (50 years since first licensed, geez how time flies!), and I’m having a ball with it playing catchup, time permitting! BTW, hope Ranko/4O3A publishes his long awaited comparison between LDMOS amps sometimes in the near future. Also for more reports from other users.