Thursday, December 31, 2009

2010 Resolutions & Wishes

My 2010 New Year Resolutions
1. I will work CW: No, seriously. I really mean it this time -- I can no longer take it when I hear people bragging about their QSO with Holyshite Reef, South Fubar Island, or Siddown & Shuddup Rocks on CW with only 10 watts and a coat hanger. I want in on this action!

So... I've been spending a lot of time listening down at the low end of the bands lately and have an iPod Shuffle loaded up with W1AW code practice MP3s, trying to get my speed up above my current retard level. I don't phant'sy I shall ever achieve contester/DXer proficiency but I figure if I can recognize my own call sign and "5NN' at 30-35 WPM I can fake the rest and blame QRM and QSB for all that I miss.

2. I will work QRP: This resolution closely related to the one immediately preceding. Time to break out the KX1, head out to Whiskey Hill with a 300' roll of bell wire and see what happens. I might even try for WAS on PSK running only 5 watts.

3. I will concentrate on single-band WAS: All-band/all-mode WAS is in the bag, and I just need HI for the PSK endorsement. Only 5 QSLs left to complete WAS on 20m, then I swear to Baby Jesus I'm through with that infernal band (contests excepted). With solar conditions improving I expect to be spending a lot more time on 17m and 15m. And of course 40m is always a lot of fun even with only 100 watts. If I can finish 2010 with WAS on 40m and either 17m or 15m, I'll be happy; if all three, I'll be delirious.

4. I will upgrade to Extra: I've been putting this off for too long. Never did it because I never really needed the lower 25 kHz, but now that Resolution #1 is in effect...

5. I will buy an amp: Because even though QRP is fun, it ain't gonna help me earn any awards on 80m or 40m. That ALS-1300 looks soooo nice.

6. I will build more equipment: Been itching to dig into another kit or two, perhaps a K1 or a SoftRock. If I can muster the dough, I'd love to build a K2 that I can dedicate to QRP CW and PSK31. At the very least I will build and install the 80m/30m option for my KX1 that I have in a box somewhere.

My 2010 Wish List
1. PSK ops will refrain from using RSID: I love automatic ID for oddball modes like Throb and MFSK, but do we really need it for garden-variety PSK31 transmissions? I end up turning RSID off after a few minutes.

2. PSK ops will develop some DXing skills: For God's sake, people... stop sending "My Station" macros and weather reports when working DX. Unless the DX station starts chatting you up, work him like it's a contest -- people are waiting. And trust me, the DX doesn't care what kind of radio or computer you're using or when you were "created". Try this macro instead:
hisCall TU 599 599 Name myName QTH myQTH BTU DE myCall
If the DX wants to know anything else, he'll ask. Betcha' a dollar he won't.

When the DX station signs, just give a quick "73" and leave it at that. Wishing him and his family Merry Christmas in six different languages is not required; neither is informing him that "PSK31 QSO #261 has been logged at 0351 UTC on 12-December-2009", nor that he can find more info about you on And if the DX ends his last transmission to you with "QRZ?", don't say anything else -- just log the QSO and move on. Remember: "QRZ?" is short for "OK, you're in the log, now shut yer pie-hole and let me work someone else!"

This is all so "DXing 101" that I'm embarrassed to have to mention it, but the PSK band segments are clearly overpopulated with noobs who need some gentle Elmering. I'm here to help.

3. Sunspots will return: 'Nuff said.

4. More hams will use LOTW: Yes, I know it sucks... but it's really not that hard to figure out or that much of an inconvenience to sign and upload your logs -- certainly much less hassle than filling out a couple hundred cards, stuffing them into envelopes, fixing stamps, etc. And a whole lot cheaper, too; this alone should appeal to the cheap bastards that all hams are known and well documented to be.

With that, I now sign off for 2009 wishing all a Happy New Year and all the best DX in 2010!

Friday, December 18, 2009

The Noisy K3

or: How I Learned to Stop Worrying and Love the RF Gain

The latest kerfuffle currently brewing on the Elecraft reflector concerns the "Noisy K3 receiver" and, predictably, the commenters have broken down into two opposing factions: the "Me Too!" group is posting comparisons with other receivers that supposedly have less background noise and less listening fatigue, and the "Not Here!" group which swears that their K3 is so quiet that they sometimes think it has been damaged.

Whether any or all of the complaints about background noise are valid, and/or whether these people have radios that are somehow defective or simply misadjusted is beyond my ability to discern. I'm not picking sides here, the guys who think their K3s are noisy may have real issues, and if so I'm confident Elecraft will address these issues as they have done with all others in the past. Perhaps we'll all end up with better, quieter K3s in a few weeks as a result of this discussion.

That said, what really fascinates me is that some of my fellow amateurs apparently believe the RF Gain control to be an archaic, vestigial appendage left over from ancient days of vacuum tubes, and that it has no place or purpose in a modern receiver. To wit:
"Bill has linked to and quoted Eric's paper which quite frankly seems way too complicated to me. IMHO, a modern DSP, microprocessor-controlled receiver should figure all of this stuff out automatically and do it for me ... If the receiver has a properly designed AGC system then there are only two variables that are potentially the operator's responsibility: 1) Preamp On/Off and 2) Attenuator On/Off. With the smarts built into modern radios, why can't the radio do, for example upon band switching, a little routine of turning each of these on and off and measuring the resulting SNR and then setting them accordingly?" -- N7WS
"I'm used to leaving the RF gain wide open on the MkV, leaving the audio gain pretty much alone, and maybe switching between SLOW and FAST occasionally. I don't seem to have any trouble hearing the weak ones under the strong ones. Now I have to fiddle with the RF gain (a small knob hidden amongst the others) while running a pileup. Not enough hands (or enough brains)." -- VE7XF
Seriously? Not enough hands? No offense intended to these guys, fine gentlemen both, but we've long suffered complaints about how the K3 doesn't have the all front panel controls one "needs" at his fingertips to tweak a signal to perfection. Now, a single RF Gain knob is too many controls to tweak in order to deliver a good sounding signal? And what N7WS is asking for falls under the general category of "Artificial Intelligence" -- I think we're going to have to wait a few more decades before we start seeing that offered in consumer electronics products!

The fact is, if you run the K3 or any other radio with RF Gain flat out, the result will be a higher level of background noise than if you "ride" the RF Gain. Whether analog or digital, a receiver's AGC cannot magically discriminate a desired signal from noise. Instead, it will adjust the gain of the IF stages in response to the entirety of what it detects -- that is, signal and noise. The purpose of the RF Gain control is to allow the operator to limit the range of the AGC to some degree in order to compensate for this lack of intelligence. RF Gain is like a transmission in a car, and just as an automatic transmission may work well some or perhaps even most of the time, it doesn't always put the car in the right gear for every road condition. Similarly, the AGC doesn't -- and cannot -- always deliver the optimum results under all band conditions. The RF Gain control is the radio's stick shift. Use it.

Advancements in DSP technology have made it somewhat possible for a processor to detect speech or CW from random noise and perform the requisite voodoo to pass the wanted signal and suppress all else, but this technology still isn't perfect. I don't pretend to understand it all, but lot of math is employed to come up with what is still essentially a "best guess" as to what is, or isn't, wanted. In my experience, it doesn't always guess correctly; operator input is still required. The reason there are so many different possible settings for the Noise Reduction (NR) on the K3 is so you can choose what works best for you. But if you can't be bothered riding the RF Gain a little bit, you surely won't want to mess with the NR parameters.

Is my K3 unusually "noisy?" Honestly, I don't know for sure. I don't think it is; when I first got it I did comparisons with the JST-245, a rig which had a pretty damn quiet receiver. At the time I thought the K3 compared quite favorably. However, these tests were not scientific and the antennas used at the time were fairly crappy. Now I have a slightly better antenna... but alas, no more JST-245.

I did a brief A/B test with one of my NRD-515s on 40m SSB switching between both radios with the same antenna, each feeding identical NVA-515 speakers. It was a hands-down win for the K3 even with NR and AFX turned off. Tweaking both radios for best results, the difference in signal quality and intelligibility was pretty significant. Not exactly a fair fight, though... the NRD-515 is a 25 year old design.

Maybe I'd notice this perceived noisiness more if I had a quiet antenna and QTH. Unfortunately, I contend with a constant S7-8 background noise that I attribute to environmental factors (the QRN of suburban hell) and the fact that I have a vertical antenna, by nature more susceptible to electrical noise. In any case, I've never experienced how the K3 behaves on a quiet band. Under my typical conditions I can tweak the RF Gain, AF Gain and NR to maximize the quality of signals at or above the high noise level while reducing the background hash to a very acceptable level, but there is no single setting of controls that works on all signals. If I optimize for a relatively strong signal, I can reduce the background noise to practically nil but then weaker signals then become much less readable. Tweaking to separate the weakest signals from the noise is possible but that brings up the background noise as well -- all the more so the weaker the signal and the closer it is to the noise floor. Every situation is different, so I'm constantly adjusting RF Gain and other controls to match the conditions much the same way I must downshift my Jeep when I climb a hill or drive through the twisties, or upshift when I reach cruising speed on a highway -- no one gear works well all the time.

Once I find the best RF Gain setting for a particular signal, any noise that is still bothering me is handled extremely well by the NR (which, it cannot be overstated, is the whole purpose of having a NR function in the first place!). The K3's NR has been greatly improved since trusty ol' #216 arrived on my doorstep in January 2008. The original NR worked well for me as an SSB op, but the CW guys were not satisfied; so Elecraft changed the DSP voodoo to accommodate them. All of a sudden, I (and many others) found the NR didn't work as well on SSB as it did in previous firmware versions, it made the output sound too hollow. So after we bitched and moaned about this, the boys in Aptos doubled the number of NR settings from 16 to 32, restoring the SSB-optimized NR settings and giving operators enough variety in NR level and aggression to satisfy everyone. I generally prefer very light NR, so I most often use the least aggressive setting in the 8-1 to 8-3 range to make copy comfortable to my ears; rarely do I use 8-4, but occasionally I will try the 7-x range on stronger signals. With the K3's exceptional noise reduction I find myself adjusting NR more and RF and AF Gain less than I did in the pre-NR days with my JST-245, JST-135 and TS-930.

I hadn't touched the AGC characteristic settings since the K3 was delivered, but today I decided to experiment with the AGC Slope and Threshold parameters just to see what effects they have. I found that the threshold (AGC THR) parameter makes a big difference in the amount of background noise amplified by AGC during periods of no signal. After a few hours of playing around the settings I ultimately settled on (for now) are:
  • AGC HLD: 0.20
  • AGC PLS: NOR (default)
  • AGC SLP: 012 (default)
  • AGC THR: 002
  • AGF-F: 100
  • AGC-S: 020 (default)
Thus configured, and with noise reduction off, AGC set to Fast, and both AF and RF Gain controls set to 12 o'clock position, I've found my sweet spot for tuning around under typical conditions. When find a station, I may switch on NR and/or adjust the AF or RF Gain until what I hear sounds right to my ears.

What it all boils down to is, using the RF Gain isn't a burden, nor is it rocket science -- it's how I've always operated a receiver. Along with NR, Notch, Width and Shift, it's simply another tool at my disposal to recover the most intelligibility out of a signal. Reaching for the RF Gain comes as naturally to me as it does for the AF Gain or VFO. The idea that some ops feel put out by having to tweak the RF Gain control is beyond incredible to me.

Tuesday, December 15, 2009

Why Are Radios Horizontal?

This thought has been keeping me awake at night. Yes, I know I probably need psychiatric help... but that still doesn't answer the question, now does it?

Radio manufacturers appear to be locked into a belief that radios must be horizontally oriented. I don't get it -- this takes up more desk space and offers no discernible advantage over a vertically-oriented rig. Why not flip radios on their side?

The closest thing we've got to vertical radios are some commercial rack-mounted systems, but even then, each of the individual components in the rack are horizontal. The cubish Flex-5000A comes close, it is almost as tall as it is wide, but is still technically a horizontal rig. (Actually, it has no knobs so it's not a real radio anyway. Never mind.)

Desktop PCs used to come in horizontal cases; now they are all happily ensconced in tidy, attractive vertical towers. Has anyone complained? I don't think so...

Tallness projects power and demands respect -- you never hear people marveling over the world's widest building, do you? I believe the first radio maker who ventures out into this brave, new design direction will come to rule the market.

You heard it here first, folks.