[Elecraft] Comparing the K2 to other RIGs

[Christoph Rheker]

Comparing the K2 to other RIGs. There were some very interesting
emails during the last days!

Here are some observations from QRM Hell, that means 
Central Europe..))

I have listened many hours on lazy evenings with my K2 (#2143) 
and my TS870.

The K2 has the RFC11 mod and the TS870 is an early modell,
ser # 7x. Later models (ser # 8x) have a modified front end
which gives better IMD behaviour I think.

I am using a Force12 C3SS Yagi, a Vertical for 10/15/20/40m
and a full size Inverted-L for 80m. I live on the edge of 
a small town with little man-made noise.

*** CW Filters:
The TS870 filters are much better. It is obvious to hear and 
also clearly visible if plotting the filter curves when using
SpecLab (a software similar to Spektrogram).

My K2 is set for 1200, 1000, 700 and 300 HZ filters and the
filter skirts are not as steep as in the TS870. WHen sitting 
close to a strong S9++ signal at night on 40m, the signal totally
disappers on my TS870 but is still audible on the K2. There is
no or little S-Meter activiation on the K2 but is is noticable.

Here the TS870 wins.

*** SSB Receive audio:
The TS870 sounds better BUT I haven't done any of the SSB filter
mods yet, and I have not ordered the new XTAL set. This is one
of the things on my list for another lazy winter evening..))

Currently the TS870 wins.

*** TX audio:
I like it.. even without the filter mods it sounds good!

No winner because the TS870 has also nice TX audio.

*** RX performance, sensitivity, IMD behaviour:
That's a funny story... My TS870 sounds in most cases like
there is some kind of life on the bands. For example, during
evenings on 15/20m there is always some kind of background noise.
When I switch to my K2, there is no such thing! That made me
think my K2 is deaf. OK, it was deaf because I made some mistakes
during construction.. but even after fixing it, I thought the
RX is deaf! So... now how do I verify if there is someting wrong
or not? Many times, I have tuned a weak signal which was just
readable on my TS870 and switched to the K2. ALWAYS was the signal
readable there as well. The K2 is NOT deaf, it just sounds much
more quiet compared to the TS870. For example, a few days ago
I was listening to a weak VE7 on 20m SSB. He was 100% readable
on the TS870, but there was always noise audible. On the K2
this guy was readable without the noise.

Another example is 40/80m. Here in Central Europe 40/80 is really
bad because there are lots of commercial stations running a little
more power then we HAMs do ..-)) I was listening to DJ9TK working
JA's on 80m SSB a few days ago. These JA's were just audible on the
TS870, no matter what I did change on the RX settings (filters, 
Pre-Amp off etc..). On the K2 the JA's were often readable, not just
audible. The difference in background (QRM/noise/intermod whatever is was) 
was quite clear.

Here the K2 winds, no questions. This is a very important win I think.

One problem with I don't like is the S-Meter activation issue. With my
antennas I often get S7 S-Meter readings without any "real" signal
present. Yes, I have done the RFC11 mod. No, I have not done the mod
to the front-end band pass filters. Another item on my list.

Conclusion:
TS870 CW Filters are better.
K2 Receiver behaviour is better.

I find myself using the K2 when searching for weak DX
signals, like on a noisy 80m SSB band. For serious DX work the K2
is just good. I like it.

I find myself using the TS870 for general operation, like talking
to locals on 40m, scanning the 20m band looking for some good, easy
to work signals. The 870 is easy to use and has some nice features.

Hope this is interesting.

73, Chris DL4YAO