Thanks to Col at DX World for the image and to Bernie at the Daily DX - and to both of them for publicizing this holiday style operation that will begin in October.
I'd like to emphasize that this is a vacation, not a DXpedition. All radio ops will be a bit on the spur-of-the-moment but I will be able to pre-announce them on my blog and the POTA website a couple hours beforehand.
The manual for the KX2's internal battery charger (KXIBC2) allows for a variety of input voltages, up to a maximum of 15V, to be used to charge the radio's 2.6AH lithium battery. The manual also mentions that lower voltages (down to 11V) can also be used although the battery will not be fully charged at these voltages.
I was curious to see how a lower charging voltage - ie, a partial charge - would correspond to capacity.
My main interests were:
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With the QMX+ being a kit, any published value of MDS would have to be a range of fluid values since receiver characteristics will depend, not only on component tolerance deviations, but of builder's methods in soldering and the winding of toroids & transformers.
I decided to compare my QMX+ receiver sensitivity with the KX2 and FT-891, using a TinySA Ultra and appropriate attenuation.
As can be seen in the video below, the QMX+ does quite well.
After the video, I "measured" (by ear) the point at which a signal becomes too weak to copy on the other bands. The CP1 directional coupler does not cover 6 meters but I measured -113 dBm on that band, which is probably inaccurate. I will sweep the coupler on 6m with my VNA and post a corrected value soon.
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The mic was initially offered by Dave M0JKS as a kit but they now are sold completely built.
I ordered one the next day.
A search of the mythical Ideal QRP Travel Rig For Vibration-Rich Environments has me, once again, pondering what's out there and coming to the same old conclusion:
That the Elecraft KX2 - manyyears (yes, one word) after its introduction - still has no peer. Eight years old now - a virtual eternity.
Like others, I watch the YouTube infomercials of the latest offerings, hoping to find my unicorn. But lately, rather than compelling me to open my wallet, they reaffirm the value of the radio released back in 2016.
Here's where I'm coming from vs. what's out there - a bit of a backstory (please bear with me):
Nine years ago, I rode most of the off-road motorcycle trail known as the TAT that stretched (at the time - it's longer now) from Tennessee to Oregon, on a single-cylinder Suzuki DR650. Single-cylinder bikes are often called "thumpers" for good reason. I made it to Utah before the obligations of still being employed called me home. That fact bugs me like you have no idea. I almost finished - but didn't.
I had two radios with me: an MTR-3 and an Elecraft KX2. Both performed admirably and survived single-cylinder vibration and the bike being dropped three times on Colorado's Ophir Pass.
Today's activation of IS-0092 Blábjörg Natural Monument was a lesson in Exceeded Expectations 101. Just when you think you can predict certain aspects of this radio stuff, the unexpected happens.
The park is located near the small town of Djúpivogur on Iceland's eastern coast. It's pretty much a straight shot into parts of Europe but many mountains block the path to the US...or so I thought.
I called CQ POTA on 15, 17 and 20 meters and worked both continents on all bands.
Many US stations were quite strong and I worked a number of familiar calls. The QRN that I worried about was non-existent - the bands are quite, propagation over salt water works like a charm and my 10 watts was doing the trick.
Tuesday mornings can offer slow POTA activity but I was pleased with the results anyway from a peaceful little park about half an hour from home.
The weather was perfect and this project served as the perfect excuse to be outside.
In the following video, I made 10 contacts in 20 minutes. Those 10 contacts included 7 DXCC entities - all with a short whip antenna and a single ground radial.
When the bands are hot, amazing things are possible. Earlier this week I was able to work 4W8X on 10m CW from home with the KX2.
This weekend I'll be building a short coil to supplement the CB whip's internal coil with the idea of using the whip on 17/20 meters.
Various online calculators say I'll need 30 turns on a 1-inch form.
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I don't particularly care for the KH1's sidetone for two reasons:
First of all, it sounds terrible and I find it to be reminiscent of a code practice oscillator I built as a kid.
Second, there is no way to zero-beat a station based on how their pitch relates to your own sidetone.
Neither of these reasons matter too much - the KH1 is a utilitarian radio designed for a specific purpose - quick deployment in scenarios where other stations are doing the calling (and therefore the zero-beating).
But I wondered: What exactly are the audio components that produce the KH1's sidetone? Nothing in the KH1's manual gives any indication of how the sidetone is generated.
Spectroid to the rescue!
For comparison, here is my Elecraft KX2, with its sidetone set for 560 Hz:
And here is the KH1's sidetone, comprised of many discreet frequencies between 1000 and 11,000 Hz:
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UPDATE (20 Nov):
Wayne N6KR mentions on the KX Group.io that I must have taken the reading in "SPOT" mode which would include a bit of background (receive) audio in the spectrum plot. So I made another measurement - key-down - not spot.
Here is the plot for the sidetone (and only the sidetone).
Again, the KH1 sidetone is a broad-spcetrum audio signal consisting of tones from 1000 to 11,000 Hz (thus the raspy sound):
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Anyone with a KH1 can verify this via one of the many audio spectrum apps available for smartphones.
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| Set-up for measuring spectral output of 100W rig. Note the 100W dummy load behind the tinySA |
This is an example of where the availability of a new item adds value to something that's been around a while. The new item is the tinySA - many hams now have one of these small spectrum analyzers/signal generators - and the old item is Elecraft's CP1 bidirectional coupler.
Questions I get whenever I post something related to the tinySA are:
I decided to use my tinySA ULTRA to measure the spectral output of my Yaesu FT-891 when operated at full power: 100 watts.
Updated 14 Nov (see bottom of page)
Kevin KB9RLW has posted an interesting series of videos to YouTube recently, exploring the poor SSB performance of his (tr)uSDX transceiver (beginning with this one).
I'm primarily a CW operator and wasn't too concerned about my (tr)uSDX's SSB performance but Kevin's video's piqued my interest and I decided have a look with my SA and an Elecraft Two-Tone Generator feeding a 700 Hz and a 1900 Hz tone into the mic input of the (tr)uSDX.
The purpose of this test is to measure IMD due to non-linearities in the transmitter. In a perfect world, only those two tones would be transmitted.
