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Elecraft K3 Review

KBPF3 Option - General Band Pass Filter

I ordered the KBPF3 General Band Pass Filter option because I'm a Navy MARS operator and you need it to allow for RX on many of the frequencies that MARS uses. The other nice feature that it enables is the ability to listen to the broadcast AM band. My Icom 746 Pro will not receive the AM broadcast band at all, however the Yaesu FT-897d does. The KBPF3 coupled with the built-in 8 band RX EQ and a decent set of stereo speakers makes for a very nice AM listening station.

Main Speaker & Headphone Output

Since I'm discussing RX functionality, this makes for a good spot to talk about the main speaker output. First a warning: The manual comes with a paper insert that warns you about setting the speaker configuration to stereo or mono. This is important! I know someone who learned the hard way by using a mono speaker while the rig was set to "stereo" and they shorted out the speaker PA!

I've learned that this rig is fairly sensitive to the impedance of the main speaker that is used and wants something around 8 ohms impedance to obtain a reasonable output volume. I use the term "reasonable" because the overall output volume range of this rig is fairly low compared to any other rig I've used. I saw some complaints about the speaker output volume on the Elecraft mail list, so I decided to do some tests for myself.

I currently have the K3 hooked up beside the two other rigs I mentioned earlier (Icom 746 Pro and Yaesu FT-897D) with the speakers outputs running into the W2IHY iPlus so I can switch all three rigs between the Icom SP-21 speaker. Listening to the same station on the same antenna, I can switch between the three rigs and observe the output volume range. Both of the other two rigs have a MUCH wider volume range, including total output volume over the K3. The K3 is generally fine, but you do have to crank up the volume knob to a much higher level to get the same output level and you can never achieve the maximum volume levels that the other rigs are capable of. While not generally an issue, I have had a few weak stations that I needed to put on headphones to copy well. A good powered stereo speaker set would obviously solve this. The headphone volume is a stark contrast to the speaker output. You have no problems achieving more than enough volume with either mono or stereo headphones.

Audio Effects (AFX)

One interesting feature that can be activated with either stereo headphones or external speakers is the "Audio Effects" function that is activated by the AFX button on the front panel. This function activates a DSP audio effect that simulates stereo reception. You can also tweak the way this function works by the configuration menu to suit your tastes. I find this function most useful while using stereo headphones because it makes the output audio seem like it's coming from the rest of the room instead of blasting right in the center of your head. It certainly helps with listening fatigue

KAT3 Antenna Tuner

If you followed my build pictures, you also saw that I ordered the KAT3 Antenna Tuner option that includes a second antenna port. The tuner is rated to be able to tune up to a 10:1 SWR. I can tell you with certainty that it works beyond those specs because I can tune up 30 meters on my Alpha Delta DX-CC with it which has a 15:1 swr for me normally. It also remembers the last tuner setting on each band which is helpful. This is an option that is definitely worth purchasing.

More to follow...
Memory Management

The memory management implementation in the K3 is a little different than most other rigs. If you read some of the other blogs or posts in the K3 mailing list, some people feel fairly passionate that this functionality is pretty poor. I have a more moderate view: I don't think the memory management is the best, but it's not completely horrible, either.

To program or retrieve memories, you primarily use the two top right buttons shown in this picture:


To store a memory, you just hit the V>M button, spin the VFO A to select the memory number to write and hit V>M again. If you wish to give the memory a label, you can do that as well by using VFO B. To recall a memory, hit M>V, select the desired memory with VFO A and then hit M>V again. It's pretty simple.

You get 100 general purpose memories, but you also get 4 additional quick memories for each band. The buttons labeled M1, M2, M3, and M4 are the quick memories and are specific to the current operating band. You program and recall those in the same manner, but instead of using VFO A, you just press the M# button that you want to set for that band.

Most other rigs that I've used have a dedicated memory mode that is activated when you press the memory button. Once you're in the memory mode, turning one of the knobs cycles through the memories. The K3 implements this a little different, and it's done using a technique the manual calls "channel hopping". When you label a memory with a starting asterisk (*), the radio sees this as a "channel hopping" memory. If you recall a memory like normal and then later decide to turn VFO A, the radio will cycle through any of the memories stored with the asterisk in the label. The catch with "channel hopping" is that it only works on the current band setting, though. The other problem is that while, the radio will change the mode saved with each memory, it does not change the other settings like the offset or PL unless you remember to hit the M>V button again after the "channel" is selected. It's an annoying little nuance.

The 0-9 buttons on the face of the rig also act as quick memories that are recalled by hitting M>V and then the number. Another somewhat useful feature is that you can set these buttons to act as band selectors using one of the set menu items. When you have this feature turned on, you program a frequency for the band in each of the 0-9 memories, but instead of recalling the specific frequency, the radio will recall the last used frequency in that band. The only problem you'll have is remembering which band you programmed each memory for!

By default, when you're recalling a memory using the VFO, the rig will change bands as soon as the VFO stops moving. This causes a slight delay as the necessary relays are activated. I find that this behavior slows me down quite a bit and it was actually a little annoying to me. Fortunately, there is one other setting that you will probably want to change that makes the rig wait to actually change band until you hit the M>V button for the second time. I find this setting to work much smoother.

Memory Software
The easiest and fastest way to program the memories is to use the Elecraft K3 Frequency Memory Editor for Windows that Elecraft provides free on their website. It works very well and also allows for you to use your PC to recall memories on the rig with a click of the mouse.
TX/RX Equalizer Follow Up

I recently read another K3 review where the author complained that the RX equalizer was in effect for every mode of operation. If this was true at the time that review was written, it is no longer the case.

I have verified on my own rig that both the TX and RX equalizers have three modes. The RX equalizer remembers an individual setting that applies to CW and another setting that applies to voice modes. In data modes, the RX equalizer has no affect. The TX equalizer remembers a setup for standard SSB, and the other for the wide voice modes: ESSB, AM, and FM. CW and data modes are not affected by the TX EQ.

For digital soundcard modes, the fact that the rig turns off the RX EQ is especially important because you want a flat audio response. I suspect that the complaints of K3 operators caused this behavior to be implemented in a firmware upgrade at some point. The current implementation of both the TX and RX equalizer works just like it should.
Q1: As I understand it, the K3 has superior receive compared to any radio on the Ham market presently. Like any radio - none are perfect. What do you feel are the flaws that it has? How would you upgrade their next model?

Q2: The Flexradio I have can do things with software/'SDR' that many radios cannot without an external panadapter.
Does the K3 have a software program that change functions in the software environment on a PC/laptop? Screenshots?
Q1: As I understand it, the K3 has superior receive compared to any radio on the Ham market presently. Like any radio - none are perfect. What do you feel are the flaws that it has? How would you upgrade their next model?

The inability to put the rig into a pure "memory mode" that actually allows you to dial through all the memories and have it instantly change ALL the settings associated with the memory as you scroll. If you forget to hit that M>V button after you land on the memory you want, you're doing it wrong and will have unpredictable results. This seems like something that could be corrected in a firmware update.

The PSK31 and CW decode on screen is neat, but the size of the screen is too small to make it real useful. This could be remedied in firmware also by just having 1/2 of the stuff on the left side go away when you turn on the decode so that it has more room to work with. The rig will translate CW you're sending into PSK31 if you want, but this type of functionality is a gimmick. If they only gave us a USB port (instead of a DB9 serial), they could have made PSK31 work with keyboard input instead. I'm sure I'll have more suggestions as I continue on with this rig.

Q2: The Flexradio I have can do things with software/'SDR' that many radios cannot without an external panadapter.
Does the K3 have a software program that change functions in the software environment on a PC/laptop? Screenshots?

The rig lacks any type of built-in basic band sweep/scope. However, it's clear that Elecraft's strategy is to allow those that want this functionality to do it better by purchasing the KXV3A option. This option gives you a receive antenna, IF out, and transverter interface. The IF out would be used with your choice of panadapter.

Unlike FlexRadio, you cannot change the firmware code yourself, which I'm sure disappoints the hacker types. There is a simple application that allows you to configure the rig from your PC if you like. It is written by N2BC and is available for free from K3_EZ. Of course, Ham Radio Deluxe and the other rig control applications all support the K3
Tim, Have you had a chance to use/play with AM Mode any at all?


Yes, although I have not done a ton of transmitting on AM yet, I've done enough to get a good feel for it. I will concentrate on fining some good AM stations to talk to over the upcoming week to get some more feedback. Remember, you need the optional 6KHz filter to use AM mode effectively.

I no longer have an oscilloscope, so much of the TX opinion will be fairly subjective, based on my and others' ears. One test is easy though, and that is a simple peak to carrier power ratio test using a good peak reading meter. When I tested this, I set the power output level to achieve a 25 watt carrier into the Bird 43P meter with 100 watt element into a dummy load. When I modulate, I see right at 85 watts of peak power or 3.4:1 peak to carrier ratio. I have never been able to achieve anything that close to the "standard" 4:1 ratio on most of my other rigs (the Icom 706MKIIG was pretty close to 4:1 also), with the others like the 746 Pro achieving somewhere around a 2:1 ratio. Unlike most ham rigs, the K3 uses fully modulated double side band (DSB). Most rigs just use a single side band with carrier applied, causing the resulting audio to suffer. That, coupled with the RF clipping and TX EQ built in, will allow you to achieve very nice sounding audio which is quite obvious when you plug in a good set of earphones to monitor yourself. One improvement that could/should be made in firmware is the ability to invert the phase on the input audio if necessary to ensure that you always have voice phase positive depending on the mic/audio input used.

The AM reception is VERY nice, IMO. The K3 has the ability to turn on synchronous detection which helps with signal to noise ratios for low signal levels. It also helps significantly during selective fading and can result in less distortion. When the synchronous detection is turned on, you can also enable automatic VFO tracking, which will auto tune your VFO across the span of a few Hz to find and lock onto the other stations carrier. Pretty cool.

As I mentioned before, listening to broadcast AM is really very enjoyable with this rig.
Out of Band Transmit

The modification for out of band transmit needed by MARS members is handled by a very simple Windows program called "K3_Band_Limits" that Elecraft Tech Support emails to you. You just run the program and tell it to unlock the frequencies, and it does it in firmware. You can set the TX range back to normal if you were to sell the rig at a later time.

After modification, the frequency ranges that are blocked are 7.650-8.990 (where the first IF is located) and 26.961-27.409 (CB band). Between 7.550 and 7.650Mz you are limited to 12 watts or lower, also to protect the IF.
Soundcard and TNC Interface

I hooked up the rig to the sound card tonight and got that working. The only reason it took me so long is because I had to pick up some longer cables to route around my desk.

This picture shows the built-in sound card interface:


The Line In and Line Out are transformer isolated to prevent any ground loop hum. All you have to do is connect the ports using standard 1/8" cables to your sound card, hook up your serial cable (with USB converter) and you're ready to go. If your PC program requires settings for RTS, DTR, or CTS, set those settings to OFF.

I always try to figure out how to use any feature on a rig without reading the manual. I feel that this is a good measure of how easy a rig is to operate. For the soundcard interface, I got about 90% of it figured out before I had to go to the manual :)

There are a couple of settings that you need to enable to make both the sound card and mic work together seamlessly. The default Mic Gain for the Line In is zero, or no gain. The rig will not hear any audio sent to it when set like this. So the first thing you need to do is select the Line In as your main mic input, then raise the gain while sending a signal from your PC. It doesn't take much gain to drive the rig properly. The next setting you need to change is the "MIC+LIN" to "ON". This allows you to either key your mic or use the soundcard without changing options. If you're a MARS operator, this will be an important setting. That's pretty much all you need to do!

I made several PSK31 contacts tonight, including one to Russia. This rig is truly fun to use with soundcard modes and the exceptional receiver design makes it a true joy.

I did find a limitation with the rig tonight. Many of the other rigs in this category have more than one line in/line out port. Usually they are labeled ACC or TNC or something like that. They are almost never isolated, though. With the multiple in/out ports you can hook up both a sound card interface AND a TNC. The TNC interface might be important if you have a reason to use ARQ modes like Amtor or Pactor.

Here's the scenario where you might need to use both the TNC and soundcard modes at nearly the same time:

It wasn't very long ago that it was quite common on our MARS nets to pass traffic in both Soundcard (MT63) modes and then again in ARQ (Amtor or Pactor) for stations that needed it. Under this scenario, the operator must be able to address the net by voice and quickly change to the other modes as needed or requested, and then back to voice; there is no time for fooling around with menu options to switch mic inputs. I can see this also being necessary for any operator that needs to operate MARS digital nets using both a Pactor III modem and Winmor (soundcard tnc) modes.

On my Icom 746 Pro, I have more than one AF in/out on the rear panel, so having both a TNC and soundcard hooked up and using them both within seconds of each other is trivial. This is something that is not possible with the K3 out of the box. You could use the rear headphone and mic in ports for the TNC, but you cannot use those while the front mic is activated. There are external mic/speaker sinks to accommodate multiple line paths using the rig line in/out but that is something you will have to do on your own.

I admit that this is a very narrow application that applies to only a few people, but I thought I'd point out my discovery.

Last night after playing with PSK31 and making several contacts, I decided to head over to a 75 meter frequency where a bunch of locals hang out at night, most of whom have very good audio properties. The idea was to play with the ESSB functionality and obtain a little feedback on the air.

First, I have to reiterate again how quiet the receiver in this rig is. When I first switched over to 75m, I thought, "Wow, the band is pretty quiet tonight". Well, it wasn't bad, but then I switched rigs, back to the 746 Pro for comparison. I couldn't BELIEVE the difference. The 746 Pro had such a higher noise floor that it was a night-and-day difference...and I was doing this with the Noise Reduction turned off on both rigs.

Back to the ESSB stuff...

The K3 comes with the ability to widen your SSB TX audio up to 4Khz wide. I turned ESSB on and set it to 3.3 Khz wide using the menu setting like this:


I got nothing but good audio reports from the other stations, especially from those who had their RX widened up to hear the difference. Turning on or off ESSB is a matter of going into the Config menu, dialing around with VFO A and setting the options. It's not something that is quick to do. For this reason, you would probably create a macro to turn it on/off and set it to one of the programmable buttons. Which leads me to my next topic on the rig's macro capabilities...
Soundcard and TNC Interface

Thanks for the review.

I was looking at the K3 for MARS but it doesn't seem like it will be as easy as I thought connecting up a SCS, doing Winmor, and Voice all in quick succession--bummers.
Thanks for the review.

I was looking at the K3 for MARS but it doesn't seem like it will be as easy as I thought connecting up a SCS, doing Winmor, and Voice all in quick succession--bummers.

You're coming to the same conclusion I have. I think the only way to do it would be to hook the SCS up to the rear head phone/mic jacks and then create a macro programmed to a front button to switch between the front mic and rear mic quickly. FWIW, this same scenario is a problem with many other rigs.
The 746 Pro had such a higher noise floor that it was a night-and-day difference...and I was doing this with the Noise Reduction turned off on both rigs.

Tim, can you do another Vid with audio to allow us to listen to the RX on both rigs? I would be interested in hearing them switched and the audio difference.

Tim, can you do another Vid with audio to allow us to listen to the RX on both rigs? I would be interested in hearing them switched and the audio difference.


I'll see what I can do but it will probably be a few days before I can get it done. I was thinking the same thing when I was comparing them other night. Too bad I wasn't set up for it.

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