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Reviews For: Elecraft KPA-500

Category: Amplifiers: RF Power - HF & HF+6M

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Review Summary For : Elecraft KPA-500
Reviews: 124MSRP: 1999.95 Kit Form
Description:
KPA-500 Solid State Amplifier 160-10M Plus 6M, Auto Band
Switching via RF sense or cable connection.
Product is in production
More Info: http://www.elecraft.com/
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
251244.9
K5AND Rating: 2011-05-06
Really great addition to any shack. Time Owned: 0 to 3 months.
Like Rick has already done (above), this amp (SN31)has become my 'every day amp', saving my bigger amp for heavy-lifting chores. The KPA500 is quiet, switches from band to band extremely quickly, QSK is a joy, built-in wattmeter, and like other K-Line products, let's you configure many functions thru easy to use menus. Since much of my operating is on dxpeditions, it should be SO much easier to transport. Looking forward to adding more to these comments later on.
IK4AUY Rating: 2011-04-26
Small, autoband change, fully protected, fast pin diode T/R Time Owned: 0 to 3 months.
After presentation by Eric WA6HHQ at Montichiari Contest University meeting I had the opportunity to get one for a weekend from Carlo Bianconi IK4ISQ, Bologna, an early production unit he has on display in his laboratory (he services Elecraft and other radios). Small in size and fully autoband change by RF sensing input it delivers the 500W on all bands from 30 to max 45Watts in. All relevant parameters are on display, and a multy segment (20) led wattmeter and SWR is also on the front panel. The T/R switching is made by silent and ultra fast pin diodes with an inside 270V to minimise forward attenuation. The equipment would be for that totally silent but it cannot be, of course, for the cooling requirements of the 2 VRF2933 Mosfets (working at about 60V under load delivered by a toroidal transformer PSU) and the relative small size inside warm dissipator. The blower in the rear is taking out the warm air and it is on very often but with multy step changing speed by temperature. The low pass filters, one per band, ensures more than 50dB of harmonics attenuation. The 2T IMD products 3,5,7,9 is average for a solid state amplifier and tipically at least 10 - 15 dB less than a good tetrode tube like 4CX800A, but small size, automation and full protected, qsk - cw very fast T/R pin diodes, make this unit a joy to operate fixed or portable. There is a brief report .pdf file in my website at http://ik4auy.xoom.it/ .
Best 73 de Sergio IK4AUY.
N6XI Rating: 2011-04-07
Work Pony Time Owned: 0 to 3 months.
My field test KPA-500 exceeded all expectations. I have been watching the market for high power, solid-state amplifiers for several years, refraining from buying because of the rampant complaints of failures, mainly of final transistors and power supplies. Elecraft promised to be different and they seem to have succeeded. This was one of the smoothest field tests in which I have participated. Problems were few and minor even though I did make casual (and unsuccessful) attempts to break it. I experienced no failures and only a few glitches. The amp was solid from the start and production units will be even better.

Why do I, an avid contester, like this little 500 watt amplifier? In a nutshell:

* Instant-on
* Instant-band change
* No-tune
* Reasonably load-tolerant
* Four-level fan control - just the cooling (and noise) you need; no more
* "Smaller than a bread-box" -- i.e. portable

Like Elecraft's K3 and P3, the KPA-500 is microprocessor controlled. This lets them introduce new features and adjust many aspects of rig performance without hardware modification. It's simpler than a transceiver or SDR, of course, so I don't anticipate as frequent updates.

I have used it extensively for casual operation where instant-on lets me grab DX without waiting for an amplifier to warm up and a pileup to gather. For casual operation, you can actually leave it on all the time because it is silent.

I have also used it in a number of contests on both CW and SSB. It just sits there and does its job without complaint. Even during runs, the fan rarely ran above Level 1 of four levels. It's almost inaudible through my headset at that level. In search and pounce duty, the fan only came on occasionally. I have been getting better than rated power out of mine (on all bands where that's legal) with no more than 40W of drive.

The amp senses input frequency and changes bands during the first part of the first dit or syllable, almost instantaneously. However, I also tried connecting it to my K3 ACC port so it tracks band changes BEFORE I transmit. That's nice, too, but I wouldn't hesitate to use the KPA-500 with other rigs that might not output the standard BCD band data that pre-switches the amp.

The LED Power and SWR bar graph meters are fast and convenient. You can opt to see peak power as well as instantaneous output. Faults are displayed on an alphanumeric LCD so you don't need to look up binary codes in the manual. The amp is reasonably tolerant of moderate reflected power and other detected problems or even higher bursts that don't last long. The "soft fault" feature wherein the amp flashes a light and cuts back gain is very handy. Major sins result in rapid "hard faults." The rig goes into Standby and you have to press the Operate button to get back on line. This is a good combination of convenience and protection.

The KPA-500 is now my default amp for casual operation and my Rig 2 amplifier for contesting. The no-tune, instant band changing is ideal for snaring multipliers wherever they pop up. Sure, I wish it were more powerful - two of its amplifier modules in one box would deliver over 1KW, only 1 dB down from the US legal-limit. I hope Elecraft does that some day. But for now, I have found that 600W cracks most pileups just as fast as full power.

The KPA-500 is another Winner from Watsonville.

I forgot to mention the outstanding full-break-in (QSK)operation of the KPA-500. It's very smooth and I leave it on all the time unless there is a lot of echo on the band or I'm running SO2R and want computer-sent messages to be muted.
VK4FD Rating: 2011-04-06
Great Amplifier Time Owned: 0 to 3 months.
I have been using this amplifier for over a month now and it has performed flawlessly. The RF sensing band switching in less than 20msec is faultless. Silent switching and superb QSK feature is a dream to use. The simplicity of operation makes life so much easier.
The ability to be able to be able to run this baby with any radio, auto bandswitch and not require an interface box is a bonus. The KPA-500 can be connected to to most modern radios via and interconnect cable to allow auto bandswitching to follow the radio is also a feature.

I have run the KPA-500 in CW, SSB, SSTV, RTTY with absolutely no issues.

For those who suffer from senior moments and key the KPA-500 with excessive drive power (over 40W) the KPA-500 drops to standby and alerts you to the fault condition as well as displays the fault on the LCD screen. Same thing if you switch to an antenna with a high VSWR.

Elecraft have again produced a solid performing product with the amateur operator foremost in mind.

I will update my review in the future, but for now this is one brilliant US designed and manufactured amplifer.

73's
Gary - VK4FD