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Q: RX performance KX1, K1

Hi all,

I am thinking about building one of these. How are the RX of the 1-models performing compared to the K2? Two cents anyone?

Thanks and 73
Bernhard DL4CW

In reply to DL4CW:
Hi Bernhard,

Thanks for the QSO yesterday, I was using a KX1 at the time, I use a K2 for the smaller summits and a K3 at home.

The receive performance of the KX1 is not quite as good as the K2. The KX1 is however, a very good lightweight radio for portable use. I have the 40, 30 and 20m bands (haven’t got round to installing the 80m band yet.)

There has been quite a few comments about the lack of AF volume. It is recommend to use sensitive earphones for best results. I use the Koss earbuds for portable use and the Beyerdynamic DT231 for the shack and find they work well with plenty of volume. The only gripe I have with the KX1 is that the sidetone is linked to the AF volume, I wish it was seperate as I have pretty good hearing.

The ATU option tunes up a wire or doublet well considering it doesn’t have the range of the K1 or K2. I was using a 44 foot doublet yesterday when I worked you without a balun.

The variable filter in the KX1 works OK, I tend to keep it fairly wide most of the time. For the size, the KX1 performs very well, but more expensive than some of the other portable rigs available.

Hope that helps and I’ll be happy to answer any further questions.

73
Roger MW0IDX

In reply to DL4CW:
Hi Bernhard

I have a 2 band K1 but sadly no K2 to compare directly. However the RX of the K1 on 80m and 40m is better than my Icom 706 II G.

I also have the Hendricks PFR-3 that I built specifically for SOTA use which is very good although the RX is not quite as good as the K1 (on 40m).

The PFR-3 is also slightly better value than the KX1 in my opinion. However the Elecraft service and support is more responsive so you get what you pay for.

73 Marc G0AZS

In reply to DL4CW:

Both the KX1 and K1 use NE602/612 mixers. These have well-known performance limitations. The K1 appears to have a better receiver than the KX1 - possibly because is has a more complex filter and uses a VFO as opposed to a cheap DDS. Both are entirely adequate for portable use and the K1 would make a good QRP home-station radio. I have used both for SOTA.

I have no direct experience of the K2 but that is a far more sophisticated radio with a high-performance receiver and I would expect it to outperform the KX1 and K1 in all departments. The differences are probably only apparent in more demanding applications though.

73

Richard
G3CWI

In reply to DL4CW:

Compared to the rigs at the local radioclub, i have noted better receiver performance on my K1 than a japanese plastic box with tons of knobs and buttons rig worth 1000 € or more…

When finished the build of my K1 for a couple of years ago I borrowed an professional service instrument at my work which is used for checking mobile network radio equipment, and could easily align and check performance both on TX and RX and confirm that they meet the specifications or even better given by Elecraft.

In reply to G0AZS and DL4CW:
I have also built K1 and KX1 several years ago and I am very satisfied considering technical characteristics. My K1 has the 4 bands module and covers 40m to 17m bands which is a good setup in these years of low solar cycle !, and the KX1 has the 30/80m option (which is a difficult add-on to install, considering its size and geometrical interferences with the main bord components).

Both behave as intended, without surprise for elecraft products … despite its size, my preference goes to the K1 for portable operation : I have built a special container in a marge plastic box (30x15x10 cm)which contents all necessary equipmemnt for a portable operation : cables, a tuner (the T1), earphones, 2 sets of NiMH accus (2700 mAh), a key, and a 2*13m doublet with 10m of 450 ohms ladder line. The KX1 is smaller but general performabnces and power are a little bit under the K1.

But my most prefered QRP rig for portable is the ATS3b : it is a very small 5 bands CW TXRX using only SMD components; output power is 5 watts and it compares very well with the K1 except on QRM coming from strong BCL stations which overload the first RF mixer ; unfortunately it is no RF attenuator. The main advantage is its size : the PCB is 805418 mm (with the changeable band module)!! it is contained in a small pill box !! You can go to my small home page for more details : go to QRZ.com and follow the link in the 8th line in the main page; a google translation tool is available (with some strange results in english).

72/73 de

Chris / F6FTB

Gentlemen, many thanks indeed for your input and comments. I guess the ideal solution for me would be a “try before you build” option since I am already using a Blue Cool Radio as well as an ATS3B which both are a “big bang for the buck” and great radios for their intended purpose. I was curious if any of the #1 Elecraft radios would outperform them, as the K2 certainly does. Maybe I should handle it like Ansel Adams who once had been asked which his favourite Camera was. He replied “the largest one I am just able to carry” (in this case large being equal to quality) - says it all. Under this point of view I might consider to go for the K2 instead since this would also be a great rig for the shack.

Thanks again!

73 Bernhard DL4CW

In reply to DL4CW:

Bernhard,

I have both a KX1 and an FT817 that I use for SOTA and other outdoor use. The first out of the bag is always the 817 and its gell cell. This is mainly for ease of use and multiband & multimode capability. However for the bigger climbs the KX1 wins on weight and the FT817 stays in the car.

I am very pleased with my 3 band (40,30,20) KX1 and it performs well but does overload on the main station antenna on 40m (not tried it since the Broadcasters went away on 40). Its other advantage is I can use it on the gell cell for long after the 817 has cried ‘enough’ on battery volts! The internal ATU matches my doublet well on all 3 bands so I don’t even have to carry the Elecraft T1 which the 817 needs to match. For lightweight trips it is the answer.
Many of my friends have K2s and have taken them out /P but they seem to be at the upper limit of what is easily portable.

73

Mike G4DDL

In reply to G4DDL:

I am very pleased with my 3 band (40,30,20) KX1 and it performs well
but does overload on the main station antenna on 40m (not tried it
since the Broadcasters went away on 40).

I find that my 817 also overload when many station (with strong signal) are calling. It sould be better with the attenuator on, but not easy to catch it with the menu system, so I never tried it.

73 Alain F6ENO

In reply to F6ENO:

I find that my 817 also overload when many station (with strong
signal) are calling. It sould be better with the attenuator on, but
not easy to catch it with the menu system, so I never tried it.

73 Alain F6ENO

I agree with you Alain. I found that last year when in DL. I usually have the IPO on (eg preamp off) but don’t always have the ATT on and it is difficult to find when everyone is calling. On CW the narrow filter on the 817 is quite good for seperating signals but does not solve the overload problem much.

However both rigs are quite good and easy to carry. I take the batteries out of the 817 and use a gell cell. The gell cell and the inernal batteries keep the KX1 going for hours!

73 Mike G4DDL