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Re: [Amps] W6PQL Designs

To: Ken K6MR <k6mr@outlook.com>, "amps@contesting.com" <amps@contesting.com>
Subject: Re: [Amps] W6PQL Designs
From: WT2P - CJ Johnson <fredwt2p@gmail.com>
Date: Sat, 29 Apr 2017 00:04:02 -0500
List-post: <amps@contesting.com">mailto:amps@contesting.com>
That's an interesting way of doing it... Have you run into problems with the rapid switching that occurs when you're doing SO2R? (are you using it in a SO2R rapid switching environment?)

There's some data to be gathered (on my end) but it's still interesting...

On 4/28/2017 11:51 PM, Ken K6MR wrote:

Yes. I have two KPA500s. I use the splitter to drive both of them on the same band, and the combiner to put the two outputs back together. I also have a set of relays that switch the assembly between the two K3s. I have an Arduino that handles switching band data, keyline, etc.. It uses the Tx Focus from the u2R to make the amps follow the active radio. The amps are in the closet, I just watch them using the Elecraft remote programs. Ditto for the tuners, one per radio.

All of my antennas are fine on cw/rtty, but the 80m antennas get squirrely above 3650. I hardly ever operate phone so it doesn’t affect me. The tuners will make them tolerable up to 3750 or so. The KAT500s are good to 1000W at 3:1. Good enough for me.

As long as the tuner will handle it, the feedline losses are so low on 80 that it’s not worth changing anything. 3 or 4 to 1 isn’t going to break anything even at 1500W with normal sized coax.

Ken K6MR

*From: *WT2P - CJ Johnson <mailto:fredwt2p@gmail.com>
*Sent: *Friday, April 28, 2017 9:18 PM
*To: *k6mr@outlook.com <mailto:k6mr@outlook.com>; amps@contesting.com <mailto:amps@contesting.com>
*Subject: *Re: [Amps] W6PQL Designs

Ken-

Did you get the Combiner/Split for an existing amp?

I'm looking at obviously not duplicating the 4O3A design in SO2R amps, and have been resigned to the fact that i'll probably operate two amps for SO2R... but I am looking at building at least *one* amp that is SS for my shack. That is the pinnacle here, of finally operating an amp that performs well in a contest and being able to say "I built/assembled it myself". And being able to troubleshoot any faults that may occur.

There's been a lot of talk about LDMOS amps, and I'm genuinely curious... I have resonant ants for 40/20, but on 80, my seasonal antenna is fairly resonant but narrow bandwidth (3.5-3.68) before the SWR jumps. I've seen some videos of the LDMOS variant amps taking a 3:1 rating (obviously not at RTTY levels) but it has piqued my interest. Even my 76PA has "appeared" to tolerate my momentary excursions up to 75M, but I know that the reflected power is just eating away at the tubes. Probably even more so with transistors.

I know the answer is to get resonant antennas, which I have done.. I'm impressed with my Alpha 76PA in the fact that it has dealt with me at 3AM mistuning the thing and it still works like a racehorse.

On 4/28/2017 11:00 PM, Ken K6MR wrote:

    I bought the combiner/splitter assemblies made by W6PQL for my
    dual KPA500 project. High quality boards and they work great. The
    amp pallets look like they are the same high quality. I’m just too
    lazy to take on a project like that.

    He did an update on the filter design that has better harmonic
    suppression for the high power model.

    Ken K6MR

    *From: *WT2P - CJ Johnson <mailto:fredwt2p@gmail.com>
    *Sent: *Friday, April 28, 2017 8:37 PM
    *To: *amps@contesting.com <mailto:amps@contesting.com>
    *Subject: *Re: [Amps] Amps Digest, Vol 172, Issue 92

    Can we get back to the topic(s) at hand, namely building/repairing
    amps?
    I, for one, am very curious about the new SS amp line(s) coming
    out and
    researching as much as I can about the W6PQL designs and would
    like to
    hear more about the merits of that design and some advice for budding
    builders who want to experiment along that path.

    Or is this going to devolve into an online version of 7.200?


    Thanks,
    WT2P
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