K3 receiving AM?

[David, K3TUE]

The other American made radio that does a respectable job on AM is the Elecraft K3.

Woa... the K3 is up there with the worst of them. Sounds like complete garbage.  the K3 is a CW radio, that happens to do SSB.  Nice radio, But I cant imagine anyone buying one and using it on AM.

I have heard several K3s on AM and I thought they sounded just fine

I get great reports on my K3 on AM.   Even with no external "processing", using some "gentle" tweaking of the transmit EQ, and a Shure SM58 microphone, I have had several reports that the K3 "sounds like a plate modulated rig".   I usually set the K3 to about 12 watts carrier output, and run it into an AL811h running about 150 watts carrier.   Great reports and it looks good on the monitor scope.

I have been wondering, and it sounds like some people have experience with it, how is the Elecraft K3 at receiving AM. I have heard a lot about people's opinions on its ability to transmit AM, but I rarely hear about their opinion of it for receiving AM. As far as modern equipment goes, I'd be comparing it to my Drake R-8B, which seems hard to beat in the opinion of many who do not mind something more modern.

[WA3VJB]

Always a good question, David, I like to present it as "the other half of the transaction."

People spend more time on the transmit half, getting it to sound good, and then neglect whether they can hear the efforts of others along the same goal.

[W1AEX]

Hi David,

I have listened to a couple of different K3 transceivers and found the receiver to be pleasant to listen to. I have heard complaints from some owners that it sounds harsh to their ears after extended listening periods, but there are a lot user adjustments in the menu and my guess is that they might not have optimized it. At the link below you can hear (and see) Tim WA1HLR being received on an Elecraft K3 during one of his famous "antenna tests" in a QSO with John G3YPZ on 15 meters.

http://www.youtube.com/watch?v=ngDOgKq0JAY

To my ears Tim's signal on the K3 sounds smooth but it also sounds like the bandpass is set fairly narrow. If I have read the display on John's K3 correctly (the video is 720p HD so watch it in full screen for best clarity) it looks like the receiver is set for 6 kc. I don't know offhand what options are available for receive bandwidths with the AM mode but I would want to be able to go out to at least 10 kc.

As far as how the K3 performs on the transmit side you can listen to a friend of mine as he launches into an old buzzard with his K3 on AM one Saturday morning as we chatted on 75 meters. It sounds fine to my ears but you can draw your own conclusions about how it looks on my scope. His signal was fairly weak and conditions were definitely not optimal, but I think you can get a pretty good idea of how a K3 sounds on AM. Toward the end of the <4 minute video you can hear another station's BW 5100 for comparison.

http://www.youtube.com/watch?v=FdPYQgQlo6E

73,

Rob W1AEX

[wa2dtw]

It receives fine on AM, as long as you have the 6kc "roofing filter".

[KZ5A]

The K3 is like some other receivers in that the "RF" gain control can not be simply left wide open.  For one thing it is actually "IF" gain not RF Gain as labeled.   The correct usage is to set the audio gain to a typically comfortable level and then to regulate signal strength with the RF gain.   Normally I set the RF gain to the point where it moves the "S" meter up a bar or two above the noise level observed with the RF gain at max. 

AGC setup also has a big impact on how well the rig sounds, particularly in roundtable situations.   I found some good info on the internet, but don't remember where at the moment.

Another factor is the the RX EQ setup.   I had originally set mine up for contest audio a long time ago and forgot about it.   When I started listening to more AM the audio sounded pretty thin compared to my 75A4, which is hardly a paragon of fine audio.  However, after I went in and reset the RX EQ for more bass it sounds much better than the 75A4.

So I don't want to sound like one of the "Elecraft Koolaid Drinkers" that frequent the Elecraft reflector, but if you have the 6kc filter and your K3 audio sounds less than good, you either have a setup issue or a crappy speaker.

The  TX EQ also has a big impact on the TX audio as one would expect.   The catch is that the response is not flat when the TX EQ is set flat.   You pretty much get contest audio with the TX EQ set flat.   You have to put in some counter-intutive settings to get "good" AM audio out of the TX.  It takes a lot of low frequency boost to get decent bottom end.  Tom W8JI (I think) did some testing and published the actual settings to get "flat" TX audio.

Another good AM feature is the built in Synchronous Detection.  It also has "auto-tracking" for the synchronous detector which is supposed to enable it to track roundtables but I have had weird results with that, it will work for a while and suddenly QSY to 6 meters.  I don't use this much and haven't looked into it, but suspect it a reaction/conflict  with some of the rig control software in use here..

73 Jack KZ5A

 

[sndtubes]

With the 6KC roofing filter, you can only open the bandwidth up to 5 KC.  You need the 13 KC FM filter to open up the IF bandwidth more than 5 KC