HR2.0 - RF-Kit RF2K-S Amp - Ham Radio Amplifier, Legal Limit, Hamvention 2022

Let me add one more thi g. I considered the KPA 1500. It sells for $6500 compared to the RK 2KS. It’s also a 3 to 6 month wait for the kpa1500 amp

The kpa is a 2 piece box. Power supply is on an umbilical. Takes up loads more space …

the kpa 1500 was tested right there at Dayton and when the fans kick in, it sounds like a Hoover vacuum cleaner, no shit.

The RF2KS is dead silent. QSK cw is silent. No fan noise. No relay clatter. Just a steady 1.5kw output. For me that was the selling point.

5 grand is a lot for ham radio gear but very price competitive vs competition as others have stated.

Yes it could depreciate. But I don’t want to analyze fun purchases too much. I’ll get tons of enjoyment and life is short.

 

One Year!

 

From the specs and reviews I'd bet an RF2K-S, KPA1500, or an SPE 1.5K-FA would all be excellent amps, possibly with a bit of tweaking needed or minor tradeoffs. I used to have an SPE 1K-FA which was a great amp, only issue was one of the fans ran loudly all the time, so I put a resistor inline to reduce the speed and noise to more like that of a typical PC fan and that fixed that, and it still ran very cool. A similar mod could be done to any other amp if needed. Seems RF-Kit figured out from the start that having a big fan and running it at a low speed cools things just fine, whereas other mfr's just drop in a 12V rated fan and supply it with 12V - not realizing it would cool things just fine at 6V and at a 10x lower noise level. I run things conservatively and don't do CW at full power so don't need Hoover-style cooling capacity in an amp. Had to sell the 1K-FA when moving to a new house 2 years ago, and the 1K-FA is discontinued and a bit on the heavy side and a bit dated, thus was thinking to upgrade at some point to a 1.3K-FA but seems from reviews those may have some reliability issues, whereas the 1.5K-FA have high ratings and are only 24 Lbs., 5" x 11" x 17" - significantly lighter and more compact than the RF2K-S which are 35 Lbs., 7" x 12" x 17". The KPA1500 is also pretty light and compact, 39 Lbs. total, 4.5" x 13.5" x 12" with a power supply of the same size, which is in fact a smaller footprint than the RF2K-S. The problem with all these amps however is availability. I prefer to buy used when possible to save a few $ + sales tax and support other hams, and happened to find a KPA1500 in like-new condition at a good price just last week so hopefully it meets my requirements but if not any of these other models look like they would be fine as possible alternates in the future on those rare occasions when they're actually available.

Also note that RF-Kit is increasing the price on the RF2K-S from $4990 to $5490 effective July 1. Which is hardly a surprise considering all the globalist-created supply chain issues and inflation running at 8%+ thanks to money printing and gov. spending continuing at utterly ridiculous levels.

 

............
Allegedly, you can run a Kilowatt out from a 2N2222.... IF you keep it submerged in liquid helium.

 

Yeah I believe the power supply and Low Pass Filter will give out before you get close to 3KW.

 

Which amp did you ultimately go with ?

 

Yep, LDMOS amplifiers are about 80% efficient, unlike bipolar mosfets or vacuum tubes that are in the 60% efficiency range. So assuming 53V at 60Amp (its a server grade power supply) it can supply 3180 input watts continuously and these are spec'd at 10% above that on a current peak, that would provide 2540 watts (output) or nearly 2750 watts PEP (output). Way above PEP legal limit of 1500W. I like that it can be run from 120V or 240V making it nice for travel too.

I looked at the Mercury III. The mercury III can provide 1200W PEP (not quite legal limit) on a single LDMOS device. Of course, the Mercury III is not QSK with pin diodes which was my hesitancy as I do lots of cw. Mercury does not include an antenna tuner built in so requires a bit more coin to do all that ($800 for their just released Mercury antenna tuner, and $500 for a QSK box from a 3rd party). So all in, that would be $4100 for the mercury III with a tuner and QSK versus $4999 for the RF2KS, The $900 bucks to get to legal limit ++ seems like a reasonably good tradeoff.

Once in-hand, I'll let you know how it works and my honest opinion (no sugar coating).

 

Canadian legal limit .... ..

 

1.5kw is not the highest pep or a global limit.

Somalia has higher. Canada has 2.250kw, at the antenna feed point.

So no, 1.5kw is nowhere near the global highest limit.

Somalia has their ratings based on ssb output (over 1.5jw) and carrier, for carrier based modes.

Interestingly enough they do not have a pep limit on carrier based modes, enabling you to legally go over their pep rating when using AM.

--Shane
WP2ASS / ex KD6VXI

 

No one said it’s the highest legal limit. It is the limit here in USA.

As for Somalia. Ah yes. Ham radio Mecca that it is.

So both hams there can order an amp

Ya. That’ll sure keep Reinhard and his company in business and going strong

 

I think there's less than 10 active amateurs in that country
There's a lot of HF and VHF being used, but it's not for amateur radio.... ..

 

Umm, yes they did claim 1.5kw was the world limit.

"but of course our legal limit is 1.5KW (as is the highest legal limit globally in ham radio"

Not hard to see there.

I brought up Somalia as a for instance. Just like Canada. Just like other countries.

The fact thatbits not a bastion of ham radio operators doesn't matter. It's the fact someone stated 1.5kw was, globally, the highest limit allowed. I posted two examples that it wasn't.

--Shane
WP2ASS / ex KD6VXI

 

Who posted that. What message number ? I didn’t see that anywhere. Only a usa limit of 1.5kw

 

Your call is literally in the quote.

You state the legal limit is 1.5kw. Then add '(as is the highest legal limit globally in ham radio) '

If you aren't stating that the worldwide legal limit is 1.5kw, wtf are you saying?

--Shane
WP2ASS / ex KD6VXI

 

Oh, I got you now. I mis understood your comment. Yes, my error. 1.5KW is USA limit. There are many places that are less...very few that are more. And even fewer of those places that legal limit exceeds 1.5 KW where anyone would sell such an amp in any volume.

Which amp did you buy?