Elecraft K3?

[n1eu]

Has anyone measured the tx bandwidth and modulation % of the Elecraft K3 in AM mode, with either/both the 6KHz and 13KHz filters?

seem to remember the tx bandwidth being fixed at 6KHz (3KHz audio) but not sure

Thanks & 73,
Barry N1EU

[N2DTS]

I think that is right, about 3 Khz, and the KX3 is about the same.
People also report the audio on the K3 as harsh with a nasty sound, at least on the early radios, there was some circuit change but it may not have helped.

Its a shame those guys do not get into AM...

[w1vtp]

Elecraft K3 specs

Gotta get an extra 6 KC filter or you will sound like you have a "sock in yer mouth 

Al

[n1eu]

IMHO, the sub-par receive audio rap for the K3 has been undeservedly carried forward from the earliest days of the K3.  Elecraft made some changes early on (first year of production) that fixed the issues.  There is a 4KHz low pass audio filter permanently in-line, so don't expect to get wider rx audio, even with the 13KHz filter.  You'd have to demodulate the if output to get wider (e.g., LP-PAN/NaP3) audio.

It's a shame that they didn't carry over the ESSB 4KHz wide dsp tx audio into the AM mode.

It's funny because the Ten-Tec Orion also does 4KHz tx audio in ssb and only 3KHz in am.

[W1AEX]

A good friend of mine has a K3 and loves it on SSB but it seems to be fairly limited for AM. As you said, it is a 3kc + 3kc setup for AM, which does not leave you with much to work with. My friend uses a broadcast type mic with his K3 but in spite of many attempts to EQ it the AM it produces sounds kind of peaky to my ears. I attached a recording I made of his K3 on AM. I agree that going out to 4kc + 4kc would have added a lot to the clarity but I'm still not sure it would help with the lack of smoothness in the audio. It would not be my choice for an all-in-one multi-mode radio but that's just me!

73,

Rob W1AEX

[n1eu]

Thanks Rob.  The spectral plot of that xmsn doesn't look good - really drops off above 2500hz.

[Steve - K4HX]

The IMD performance of the K3 is suspect. I've heard quite a few of them that were quite W I D E on SSB. It's strange that they would be so worried about AM.

[w1vtp]

Steve

I can confirm your comment from watching a good friend of mine almost on a daily basis with his K3.  There is definitely some "extra stuff" showing on his K3 - I don't think it's an adjustment thing either

[flintstone mop]

The high end is definitely cut off hard. No matter how much someone tries to force through.
The low end was weak and when the eq was reduced; it got weaker. Basically comm quality TX audio.
The hi-tech stuff coming on the market with micro circuits and tiny components will make it very hard to break thru with hi-fi audio.
I can see why the Kenwood TS850 was an easy candidate for ESSB and VERY hi-fi AM. Just connect your source audio right to the balanced modulator chip and a jumper wire to 'fool' the on board processor to think a filter was installed, when it isn't and cycles to kilocycles audio here we come.

Fred

[N2DTS]

The Elecraft guys are CW ops, and qrp ops, and voice is likely just there to make the radio's sell.
Not sure about the new radio's but even flex limited the bandwidth on the 3000 and 1500.
And no other out of the box non sdr radio has great audio in stock form.

I have had most of the Elecraft radios, and they all had hard to listen to audio.

[n1eu]

Well, they added ESSB mode with 4KHz wide SSB audio as well as an 8 band TX EQ to the K3.

As I said, I'm skeptical about "hard to listen to" rx audio comments, at least on the K3 with s/n over 3000.  To each his own however.  But I did find an AM recording I made 6 years ago on the K3 (listen with stereo headphones): http://n1eu.com/K3/75M_AM_9Nov08.wav

[N2DTS]

Sounds different but not bad, and nothing like the K2 or K1 radios.
I worked someone running a K3 once and thought it sounded good, but I am no judge at all, no high frequency hearing left at all.
I can hear distortion though, and that sounded clean to me.

I would rather have a flex 6500 though...

[flintstone mop]

Well, they added ESSB mode with 4KHz wide SSB audio as well as an 8 band TX EQ to the K3.

As I said, I'm skeptical about "hard to listen to" rx audio comments, at least on the K3 with s/n over 3000.  To each his own however.  But I did find an AM recording I made 6 years ago on the K3 (listen with stereo headphones): http://n1eu.com/K3/75M_AM_9Nov08.wav

The audio clip is really pretty nice!! I'll be slightly critical and say that the high end is really cut-off (no sibilance at all), but still sounds very decent. The clipping sounds in the bass is from recording??? or the TX is over modulating?? I get the same response from my TS850 around 2kc audio frequency going over 100% neg.

I thought ESSB was 6khz wide?

The Elecraft line is definitely a favorite with the CW ops. Probably why the entire audio scheme for TX and RX is lacking.
Fred

[n1eu]

Other than SDR's, how many radios on this planet can do 6KHz wide SSB?

[W3RSW]

With a little tweaking of where the phantom zero freq. is through the 8kc four pole crystal filter, and setting IF selectivity wide on the other bandpass filter, the TR-7 is capable.

--but like some others I can't hear much above 3kc anyway. If I valve-salvo  my ears (pop your eardrums with pressure) I can hear above 5kc for a little while but deafness returns her age adjustment and "pay-backs" all too soon.  

Oh also meant to say, on SSB (non-essb) I run a k3 into a used Alpha 89.  No one's complained but then I don't usually ask.  Running a Shure SM-7 into the rear panel of the K3, used hi-gain/no phantom pwr. setting through back panel.  Use the k3's internal EQ's as follows:
50  100  200  400  800  1.6k  2.4k  3.2k  Hz
-16  -6    0     +5    10    13    14    10     set

Also use the built in EQ on the SM7 switches, low roll-off, high boost.

The booming bass of many SSB signals heard irritates me. -not natural.
I listen to my own signal via the QS1R with low power settings into dummy load.  Since there is latency, the "echo" of my speech is delayed sufficiently to hear the actual signal without the internal head bassiness. 

Way better than the internal monitor of the k3 which reflects your speech in real time along with all the boominess.
 
Back in the day I'd run a tape recorder of mois through the xmitter into a dummy load and listen on a portable receiver while walking away from my house until local overload effects, if any, disappeared.  Great way to monitor own audio if the recorder is low distortion.

[WA1LGQ]

Wow, I guess I don't want a K3 anymore, except for CW. Joe did not sound very good in that recording Rob. The recording of Steve was good, except for the clipping and the lowpassed high end. Thanks for the insights into the K3. I wonder how the Ensemble RXTX performs on TX.
Larry


PS: Off topic Barry, just wanted to report that I heard you on 10 this morning on AM working somebody in Finland I think it was. Could not pull out all of your audio and you had QSB though. Using vert here in East Hartford.

[n1eu]

Backscatter not working so much this morning but condx into EU fairly good.  I've been playing on a borrowed ANAN-200D, revisiting whether an SDR suits me or not  ;-)

[n1eu]

Sorry, I need to correct something I said previously.  I hooked up the panadapter and found that the Ten-Tec Orion is doing 4KHz audio (8KHz RF) in AM, not 3KHz.  Yay.

73, Barry N1EU