I've owned the 2K-FA since about the first week of 2012. So far, I'm
quite happy with it. It replaced a TenTec Titan 425 and a Command
VHF-1200. I was getting ready to contribute a write-up on it for the
Contesting.com site, but I wanted to evaluate it for a few more weeks
before doing so. Here are some initial assessments.
1.
It easily puts out 1500W on all bands from 6-160M with about 30W
drive. I have seen the output power go as high as 2,200W out on
some bands when running it in MAX power mode and allowing the ALC to
limit the drive. With 1500W out, you're limited to about 15 seconds
or so key down and then it automatically switches to MID power
mode. (Power was measured with a fairly recently calibrated LP-100A.)
2.
Utilizing the ALC and maximum exciter drive (200W), as recommended
by the manufacturer, in MID power mode, it puts out about 1,100W.
The ALC action throttles the drive to about 40W. Presumably, the
key down time under these conditions is quite long, since MID power
is recommended for RTTY by the manufacturer.
3.
The amp is set up for connections to two different exciters and band
switching can be accomplished automatically through parallel
connections to the exciters' serial ports or via the amps internal
frequency counter. The manufacturer recommends using serial port
switching rather than relying on the frequency counter. Having all
switching done internally in the amp has really simplified and
reduced the number of coax links and external manual switches in the
shack. I think the exciters will also switch automatically with
applied RF, but I've never tried it.
4.
The amp has a port for connection to a Steppir control box for
automatic band selection on their antennas. I haven't hooked this
up yet.
5.
I have run 200W through the amp in standby mode without any
problems. However, because of the internal switching, the exciters
are not connected to an antenna unless the amp is turned on.
6.
In contrast to its predecessor, the 1K-FA, fan noise is barely
noticeable.
7.
The internal tuner seems to work as advertised, but I never use it
since I have all resonant antennas or an external Matchbox.
8.
The only serious problem I've had is that one of the six antenna
ports doesn't work at all. The domestic distributor (Expert Amps
USA) offered to fix it on the spot if I brought it with me to the
Orlando Hamcation. But since I could live without one of the ports,
I decided not to bother. In talking there with the owner and
designer, Gianfranco I0JY, he thought it might be a relay. (It also
might be a cable problem, but I haven't gotten in there to check.)
9.
I don't operate RTTY or contests (seriously), so I've never seen the
internal temperature exceed 50C. I believe that the amp shuts down
if the temperature gets to 76C.
10.
One problem that I have is that there is no service manual.
Apparently, the manufacturer is concerned about protecting his
design. (OTOH, it seems to me that it could be easily reverse
engineered.) Nevertheless, the service guru is a W5 who shows up on
the reflector to answers questions, etc.
I'm not sure that I understand Joe's (W4TV) comments regarding the
antenna issues when operating SO2R, but that's probably because I don't
work contests.
The bottom line is that with the exception of the antenna port problem,
the unit has worked flawlessly so far.
73, Joe
K2XX
On 4/25/2012 9:57 AM, Paul Christensen wrote:
>> I would also be concerned about cooling (and noise) with that much
> dissipation in such a small box.
>
> I have the 1K version of the SPE amp. Nice, compact and reliable design.
> If the League's QST product review is to believed, IMD performance is
> excellent for a solid-state design.
>
> No contesting here but when using CW in say....a 2-3 minute exchange, the PA
> deck becomes quite hot and the fans are running "full tilt," resulting in
> what sounds like a jet engine. That, together with output power that
> changes with PA deck temperature seems to be problematic with most
> commercial solid-state amps. SPE does use a very well designed protection
> system. In effect, a high-speed bus is created to kill bias to the PA
> transistors when one of about a half-dozen faults occur.
>
> I like the amp for its instant-on, compact design, but I would never use it
> as a replacement for a good VT amp. I saw the 2K amp recently at the
> Orlando hamfest and for folks wanting a solid-state amp, I think it's worth
> considering. But if noise in the shack is bothersome issue, ask other
> owners about noise level with varying duty-cycle at full output power.
>
> I believe the 2K version has a vacuum relay option that adds several hundred
> dollars to the purchase price. In my 1K, its T/R frame relays were way too
> loud. I ended up modifying the amp's logic for use with an Ameritron QSK-5.
> The interface between the two units is optically isolated and a schematic is
> shown on my QRZ.com page. Much happier with this arrangement as it's fast,
> silent, and no truncation of keyed elements.
>
> Paul, W9AC
>
>
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>
>
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