Archive: Author: aa4ga

Like last year, the condx seemed to go down a bit on Sunday compared to Saturday. This year seemed a little worse than last – hard to say though. One thing that was down this year was BIC time – only about 18.5 hours compared to 24 hours last year. I did pick up a couple extra mults compared to last year, but QSOs and points were down slightly. But this was with 25% less operating time, so either condx were actually better this year, or the station was better. I’m voting for the second. The weekend before the contest I put up a full-sized 40m ground plane, with the feedpoint up about 12′ or so. This antenna consistently beat the 80m doublet into Europe on 40m, so it got a good bit of use. Also, on Saturday, during the contest, I put up a trapped EFHW for 10/15/30.

This antenna has generated a number of questions, so in case anyone else is curious, here’s a little more info. The Cushcraft R-series of electrical half-wave antennas has always gotten mixed reviews, but I think overall they are a good idea. But I didn’t want to shell out the money to try one in case they really were dummy loads. So, I figured why not build what I wanted? Since the R-series are effectively half-wave antennas, they have a high input impedance – this is corrected for with the large base-mounted matchbox that comes with the antenna. A similar arrangement exists for the Par End-Fedz 10/20/40. It is a half-wave on 40 that has a broad-band matching transformer used at the base; in the Par literature, they even mention that this matcher may be used for single-band antennas by simply replacing the wire with one appropriately sized for the band of interest. The 10/20/40 resonances all stem from the fact that these bands are harmonically related. My idea was to build an R-3(-ish) antenna with a trapped half-wave element to allow operation on 10/15/30m. 10 and 15 because those are the bands I need to pay attention to for my 5BDXCC, and because my antennas from 20m on down seem to work OK as is…and, I was anxious to get back to the contest and didn’t want to bother with tuning the new antenna’s low band up to 20m.

In March 2012, QST published an article by W6NBC titled “Better Coax Traps”, wherein the author presented an alternative method of coax trap construction that was free-form, rather than using PVC or some other form on which to wind the traps. This looked like an easy method, so that’s what I did, using the VE6YP trap calculator. I used RG-174 to build coax traps, and was aiming for a frequency just below the targeted bands. Not having a way to measure the trap resonance, I just put an antenna together and checked SWR – generally the SWR was OK after trimming the 10m section to lowest SWR, but could be better. I will likely trim the antenna closer to resonance on all bands, and also am planning on trying some different traps. Before doing too much with the traps though, I’d like to buy or build a dipmeter so I’ll have a reasonable way to check the traps’ resonant frequency. Oh, I also fed the antenna through a Par End Fedz 10/20/40 matchbox, as I had one laying around, not in use. There are a number of plans for a similar matchbox on the internet…Google is your friend!

I hung the antenna up as a vertical, with the feedpoint up about 10 feet or so. How did it work? At first, on 10 meters, when the band was just opening, the 80m doublet sounded better than the wire vertical. But, within a half hour or so, the band settled down, and the the vertical was actually better to Europe about 95% of the time, and the advantage was usually at least two s-units – at times, the advantage was 4 or 5 s-units. Performance like that makes the antenna a keeper – I do hope to do a little more tweaking on the antenna before next fall.

For the contest itself, I operated about six hours less, and got a couple more mults, and otherwise, my score was down only slightly compared to last year. The bands seemed a little worse, but with the new antennas, it was pretty hard to tell.

Here’s the band breakdown:

Band QSOs Mults
80:   30   26
40:   85   47
20:   91   51
15:   87   44
10:   58   35

Tot: 351  203 Total Score = 213,150

Down a little less than 5%, with only 75% of the operating time – I’ll take it!

KX3 at 5 watts, 80m doublet at 45′, 40m Ground plane fed at 12′, and 10/15/30m trapped EFHW, hung vertically.

The Four State QRP Group (representing MO, AR, NE, and OK) sells a number of neat QRP kits including the K8IQY MagicBox, a T/R controller that lets you connect a QRP transmitter, receiver, antenna, and key and gives back full- or semi-QSK, RX muting, and sidetone. It provides an easy way to interface all sorts of little transmitter and receiver projects so that they can be easily used on the air. The Four State website goes into greater detail.

I got my kit from someone on QRP-L who decided not to build it, and found that the kit was well documented and went together easily and quickly. I tested it and made a QSO using a Tuna Tin 2 I’d built up Manhattan style. The board is designed such that no enclosure is needed and uses PCB-mount jacks for all connections, so it was easy to try without an enclosure. Which was great, because for a lot of us, finishing the project by mounting in an enclosure is the hardest part. It certainly is for me, and I had a bare MagicBox for months.

 I left it at work, thinking I’d be able to get one of our shop guys to help me with it, but that never happened. I finally conned NA4SO into helping me drill the holes, but we did run into a problem with the drilling template. It was a little off, although I thought I’d confirmed it was OK (measure twice, cut once!). Not too bad though, and the easiest solution was to pull the BNC jacks off the board and use panel-mount jacks.

 I set mine up with a power LED, a semi/full QSK switch, spot switch, and tune pushbutton. The only problem with any of this was with the spot switch – the early kits were supplied with a “bleed-through” resistor that was too large a value – I paralleled a 100 Ohm trimpot with this resistor and now the spot function works as it should…with the added benefit of being adjustable…this could even be routed to a pot for front-panel control if desired.

Right now, I’m using my old Drake R4 for an RX, but eventually hope to build something up from scratch.  All-in-all, I think it’s a great kit and well worth looking at if you need to interface QRP “seperates”.

Not an argument extolling the virtues of the radio – it does that pretty well by itself.  Instead, a physical case for carrying the KX3.

I still haven’t taken my KX3 out in the field to speak of…although I did carry it to NA4SO’s shack last week, and apparently while in my pack, something banged into the RIT knob and cracked it.  I only had the rig in a thin neoprene shell, and there were a couple of heavy crimpers in the pack, one of which I’m guessing banged into the KX3 – glad it didn’t hit the clear bezel!

So, I’m trying to get back to deciding what case would be best.  I’m looking for something that protects well, but I don’t need – or want – a bunch of extra compartments for carrying “stuff”.  I just want good protection for the radio itself, and for that package to be as small as possible for SOTA hikes.

Here are some possibles:

 This case is being used by W7GJ.  I think it would be great for carrying the KX3 along with more stuff…but that’s not what I’m really looking for.  This bag doesn’t look ideal for using in conjunction with a backpack, which is what I need.  Although, I’ve had a number of LowePro bags over the years and always like them, so I’d say this is definitely worth considering if you have the need for this type of case.

Here is a better candidate for my needs, and one I’m giving serious consideration.  It has a better form factor, and while having some extra compartments, the bag isn’t grossly over-sized.  I learned about this one from G4ILO, who apparently learned about it from N6KR himself, so it’s got to be a good candidate.

Obviously something like this Pelikan would offer great protection, but it’s far from petite, and the case alone weighs in at 2.5 pounds, so it’s not exactly backpack friendly.  But I’m still looking at the weight vs. protection tradeoff and may go for it.

If anyone has any good ideas, let me know via email at the address listed on qrz.com

Courtesy K3ZM:

If your signal level is mentioned in the Frequently Asked Questions section of ISITLOWT.COM, you might be running QRP. 

If you have come to learn that “QRL?” means, “It is time for you to QSY now, OM,” you might be running QRP. 

If it seems unusually cold in the shack, you might be running QRP. 

If the methane from the cattle on your neighbor’s farm has a larger carbon footprint than your transmitter, you might be running QRP.

If you go through a contest hitting the F4 key 400 times more than the F1 key, you might be running QRP. 

If you feel like the invisible man, you might be running QRP. 

If you can hear great without your noise canceling headphones, you might be running QRP. 

If you work a local station and he says the line noise is louder than your signal, you might be running QRP. 

If the night light in your bathroom dissipates as much heat as your radio, you might be running QRP. 

If you can copy your brother’s attic long-wire in Florida better than he hears your full-sized array, you might be running QRP. 

If you are going head to head against KR2Q in a DX contest, you might be running QRP. 

If your score is rising more slowly than global temperatures, you might be running QRP. 

If your father’s pacemaker produces more energy than your transmitter, you might be running QRP. 

If your QSO total is approximately equal to the combined points in the latest Knicks-Lakers game, you might be running QRP. 

If you have the winning score in the Stew Perry TBDC and your name is not Al, you might be running QRP.  

If getting beaten to an ordinary DX station becomes as commonplace as finding AA1K on 1820.5, you might be running QRP. 

If you are having the most fun ever per watt of output power, you might be running QRP.

Conditions this year seemed a bit down compared to last year….which is unfortunate, as this does not bode well for the remainder of this solar cycle.  It’s starting to look a lot more like 20m and down will be where you’ll need to concentrate antenna efforts for the next, oh, 30 years or so!  I’m writing this during the ARRL 10 meter contest, and that band is totally deceased.  I’m only a few short of 100 QRP countries on 10 and 15 – I need to get those knocked out this winter for a 5BDXCC, or it may be a really tough nut to crack!

I did have less butt-in-chair time this year, but that was most likely due to the worse band condx.  I also spend a bit of time comparing the FT817ND to the new KX3.

I definitely need to do some antenna work!

I’ve been using a Yaesu FT817ND for just over 20 months as my primary rig.  It is pretty good for what it is:  a portable 5 watt radio that covers from 160 meters through 432 mHz.  It’s really not a bad radio, but like most rigs, it has its own set of quirks.  Even after using the rig for a while, the menu system is a bit cumbersome.  The LCD display is small.  It’s a good battery-powered portable rig, but draws a surprising high amount of current for that type rig.  The receiver is OK but not great – I’ve added a 300 Hz CW filter which helps, but the front end does kind of fall apart during contests, especially on 80m.  And for casual use, that narrow a filter can be uncomfortable to listen to for a lot of folks…even me, and I like a fairly narrow bandwidth.

Early this year, ND4V was kind enough to loan me an Elecraft K3, and I discovered it is the finest radio I’ve ever used.  A little pricey, but compared to top of the line rigs from Yaesu/Kenwood/Icom, it’s really a bargain.  Around about the same time, Elecraft started shipping its KX3 – their latest portable rig, and it promised to be head and shoulders above the FT817 and any other commercially available QRP rig – either built or kit.  Many referred to the KX3 as a “mini K3”.

I had had a chance to put my hands on a KX3 and knew that it “felt good”, and was even able to operate one for about a half hour or so at the QRP gathering at the Huntsville Alabama hamfest this year and it seemed, at least ergonomically, to blow away the Yaesu.  Then in August, Rob Sherwood tested the KX3 and added it to his table of Reciever Test Data.  Wayne, N6KR, one of Elecraft’s principles had mentioned the year before, pre release of the KX3, that he was certain the rig would be near the top of Sherwood’s chart…and it was – it came in at number 1 of all receivers tested, even ahead of the K3!  Now the ranking is done based on dynamic range, which is only one measurement of reciever performance, but it is certainly one of the most important criteria, if not the most important.  It was plain from Sherwood’s testing that the KX3 was something special:  Superb receiver performance that you can hold in the palm of your hand!

Bottom line is that I wanted a KX3 to evaluate to see if it was a worthy replacement for the FT817.  I felt sure it probably was, but I didn’t want to just “drink the Elecraft KoolAid”.  So, events transpired that I was able to acquire a KX3 just a few days before the CQWW CW contest…a perfect test!

The first night of CQWW usually goes a bit slow for me, especially now that I’m limiting myself to 5 watts and only have an 80m doublet up about 40 feet or so.  I figured it would be a perfect time to A-B the KX3 and the FT817.  I used a BNC-Tee to split my antenna between the two rigs.  I had an earbud in one ear from the Yaesu, and one from the Elecraft in the other.  I used the 300Hz filter in the Yaesu, and set the Elecraft’s bandwidth to 300 Hz also.  I was pretty amazed at the differences.

First, the KX3 just sounded better.  It was cleaner – the Yaesu has always had a bit of hiss that the Elecraft really didn’t have.  Additionally, the filter response of the Elecraft seemed much tighter than the Yaesu’s – the skirts seemed steeper.  The Elecraft seemed about the same as the Yaesu as far as sensitivity goes, which means the rig wasn’t the sensitivity limit, the band noise was.  But the KX3 could separate signals so much better than the FT817! I listened to a loud station CQing, and in the Yaesu, there was another loud station about 500Hz above that was easy to copy in the Yaesu, certainly loud enough to cover up weak stations – I couldn’t even tell he was there in the KX3. Listening to the lower side, the Yaesu seemed a bit better, but still not as good as the KX3. In fact, I heard stations calling the CQer that were covered up by stations below the CQer in the Yaesu – in the KX3, I could still detect the QRM, but it was suppressed enough that I could copy the caller when it was impossible to do so in the Yaesu.

Ergonomically, the KX3 seems to do everything right – very little consultation of the manual has been required.  Most of that has been for setup of rig that is a bit out of the ordinary – and it’s all pretty much set and forget stuff.  But the KX3 uses the same LCD display as the K3, so it is plenty readable.  The knobs all seem to do what you’d expect, and the alternate functions make sense.  All the buttons are plainly labelled.  The radio is very easy to use.

Now, for other niceties:

Dual Watch – very impressive and highly useful when calling DX stations that are working split.  I’ve found it so useful that I’ve dedicated one of my programmable function buttons to activate and deactivate this feature.

Output Power Adjustment – It’s easy to dial in whatever power output you desire from 100mW up to 12 watts, no menu hunting needed

CW Delay/QSK – see output power adjustment

Bandwidth Changes – see output power adjustment – and you can crank the bandwidth down to 50 Hz – and it still sounds good that narrow!

Sidetone Level – see output power adjustment – sense a theme here?

Alternate VFO B Display – the biggest problem with this one is deciding *which* alternate to use.  For SOTA expeditions, I can see the clock, battery voltage, and current all being useful…but in that case I think the clock will win most of the time because of paper logging.  And at home, I’m sure the VFO B frequency will win.

I/Q Outputs – it’s very easy to set the rig up an have a panadaptor type display: just connect a stereo cable from the rig to the sound card input on the computer.  I’m using NaP3 right now, and it actually displays frequency, and can control the KX3 as well when using a USB connection between the rig and the computer.  And do all the DSP if you’d rather use it for that instead of the KX3.  I’ve also just discovered LP-Bridge, which will allow the panadaptor display with proper frequency indicated and rig control via separate logging software.  Pretty dang neat.

There is a lot more that this rig will do that either doesn’t interest me, or that I just haven’t discovered yet (I’m about 18 days into owning it).  But I can say without hesitation, it is the finest radio I’ve ever owned.  The only nit I can pick with it is that the speaker is small, and it can be pushed into distortion/rattling.  But I’ve found that if I need to be listening that loud, I should probably be on the headphones – problem solved!

How does this radio do so much, so well, in such a small package?  It’s pretty simple really:  it’s all in the software.  You see, the RF part of the rig is really a direct conversion receiver.  That’s about as far as my true understanding goes, but basically the signal is directly converted to audio and split into two signals that are out of phase(I and Q).  From there, the software works its magic – the radio is really an SDR – software defined radio.  What’s different from the way many hams think of that is that the processing part is built into the radio’s hardware rather than in a separate computer.  It allows for easy change and update of the radio’s basic function with simple software upgrades (note that “easy” and “simple” are from the end users’ perspective!).

The KX3 has performance that rivals and even exceeds all of the top of the line radios for considerably less money with one exception:  power output.  But, if you’re a dedicated QRP operator, that isn’t a limitation at all, and in fact, you’re not paying for something you won’t use.  Elecraft is working on an external power amp for those who are interested in using this radio at a higher power level, but it hasn’t been released as of this writing.

My FT817ND will be for sale soon.