[Elecraft] Comparing the K2 to other RIGs

Thu Nov 28 09:02:04 2002

Interesting, Chris, and a little surprising.

I don't recall exact CW filter settings on my K2 but something like 1200,
400, 80 and 60 Hz, I believe.  At the 80 and 60 Hz settings, the filters
seem quite good compared to my IC-756PRO.  If I activate the audio filter,
the K2 sounds more selective than the PRO and as I said in a previous post
it is difficult, if not impossible, to hear anything BUT the single, desired
signal.

On SSB, the filters are excellent and will take out most nearby
interference.  The PRO has the advantage of passband tuning, or rather of
adjusting the upper and lower filter skirt locations.  This can be a great
help at times but takes more "fine tuning" than simply changing filters on
the K2 and frankly, the end result is often a "toss-up."

I have not used a TS-870 so it's difficult for me to make any meaningful
comment there but based on my experiences compared to the PRO, and
comparison reports from the ARRL lab, I wonder if your K2 is working and
adjusted just right.  BTW  my location is also very quiet.  I have done no
modifications to my K2 beyond the extra crystal grounding... which seemed to
have little effect to my ears.

I also find the lack of background noise a little strange, and also thought
some sensitivity must be lacking, but there are the signals, right where
they're supposed to be.  I also had issues with the K2 S-meter readings so I
adjusted it to match the readings on my PRO.  They seem to be more
reasonable and track quite well from band to band (+/- 1 S-unit) on signals,
though sometimes the PRO shows less reading on background noise.

My PRO has been my primary radio for skeds and rag chewing because of its
100 watts out.  I didn't have the KPA-100 set up yet.  The PRO's audio is
routed permanently through a ClearSpeech DSP making any halfway-strong HF
SSB signal sound like 2-meter FM.  You want to hear something awesome... try
that on your K2 with its already low background noise!!!  *I* am kind'a
anxious to see how my use splits between the K2 and PRO when I get back on
the air with the K2/100!

73... Ed, W5EJ

----- Original Message -----
From: "Christoph Rheker" <[email protected]>
To: <[email protected]>
Sent: Thursday, November 28, 2002 1:43 AM
Subject: [Elecraft] Comparing the K2 to other RIGs

> 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
>
>
>
>
> _______________________________________________
> Elecraft mailing list: [email protected]
> You must be a list member to post to the list.
> Postings must be plain text (no HTML or attachments).
> See: http://mailman.qth.net/mailman/listinfo/elecraft
> Elecraft Web Page: http://www.elecraft.com
>
>