Posts Tagged ‘KX3 QRP CW Morse-code Morse Elecraft’

BLT+ Balanced line tuner at Excalibur

Another portable test of the BLT+ tuner

KX3 operating on internal battery.  What a fantastic portable rig.

I took the BLT+ balanced line tuner out to the Excalibur antenna site to try it out on the doublet antenna that we put up last Saturday.  This was the first test of that antenna (40m and 80m using a common feedpoint).

I didn't have much time today and after the first QSO it started to rain so I packed up and left before getting as much documented as I would have liked.  I apologize for not recording the actual tuning process and the subsequent QSO.

BLT+ connected to open wire line (under the gloves) going to ta 40m Doublet at 65ft
I had the KX3 operating using its internal batteries and outputting 2w. I was running 2 watts because that is the most efficient PA mode for the KX3.

I used the BLT+ to tune the 40m/80m doublet.  Balanced line antennas perform better with a tuner designed for balanced line and this was a good test for both the tuner and the new antenna. 

Portable shack, courtesy of three plastic chairs

I quickly matched the doublet using the BLT+ using the lowest impedance setting which is also the most efficient.  I was glad to see that the BLT SWR LED indicator is bright enough to be seen in direct sunlight.  I was wondering about that but you can definitely tell when it dims even in direct sunlight.


After quickly tuning up I sent my call two times and was promptly answered.  The other station was running a Flex 6500 into a KPA500 and a OCF Windom at 50 feet. 

He reported me as 559, while he was a 599.  He was running a new KPA500 amp at 500w so we were a bit mismatched on power.  

Interestingly the difference in 2w and 500w exactly matches the 4 S-Unit difference in our reports if you do the math (each increase in an S-unit requires quadruple the power). 

AA4OO sitting back and listening to the QSO

Paul AA4XX kindly snapped some pictures while I was listening to the other operator.  This is the Excalibur antenna site but the shack is outside the photo. 

The Doublet's feed line has not been brought to the shack yet so I was just sitting under the antenna.  The open feed line is running along the ground for a bit which certainly didn't help the signal but we haven't installed the posts to carry the feed line over to the shack and I was too lazy to move the chairs far enough away to keep the feed line in the air.

In the foreground is some saw-grass common on the NC coast.  I'm not sure why it's growing this far inland.

Portable shack at the Excalibur antenna site... The Doublet is 65 feet above my head
Waiting my turn in the QSO... holding the Palm Single Paddle.  BLT+ tuner in the chair to the right


Here is a brief video showing how the BLT+ is connected to the Doublet...


The little BLT+ performed great with both balanced line antennas I've tried.  It is easy to use and allows me to use my KX3 with balanced feed line antennas now.  I encourage you to build the kit from Pacific Antenna / .

That's all for now

So lower your power and raise your expectations

Richard, AA4OO

Get a taste of the RF coming and going

Elecraft CP1 - A tasty RF treat

I had some time this afternoon to assemble another Elecraft mini-module kit.  This time it was the Elecraft CP1 directional coupler.

Elecraft CP1 Kit

Couple what?

Ah, so if your new to this like me you might be asking what does a coupler do?  Well it sorta listens in on the signal going out (forward) and reflected (back) and is able to send an attenuated sample of the signal to other devices.  It attenuates the sample by either 20db or 30db depending on how you build the kit.

The 20db version is good for signals 25 watts and less so that's the way I built it.  It was easy to build but my glue under the second toroid wasn't strong enough and you can see it popped up a bit.  Also the Elecraft instructions had one confusing instruction concerning mounting the toroids.  The instructions say "... When wound and mounted correctly, the enamel wire will emerge from the top of each core and connect to the top hole at each inductor location".  Well when you wind a toroid only one of the wires can "emerge from the top of the core" while the other comes from underneath.  This confused me for a minute until I finally just went on with the install.  Anyway, if you're a stickler for following instructions that one may cause a moment of pause...

The switches for the two outputs forward, reflected (J3, J4) are in the up position when they are not in use.  When the switch(es) are in the up position the 50 ohm 3 watt resistor(s) take the place of the switched off output.  Don't disconnect an output and leave the switch in the bottom position.  I'm not sure what will happen... maybe nothing, probably a bit of a mismatch on the SWR, or maybe it could be like "Crossing the streams" in Ghostbusters.  Your mileage may vary.

My uses for a coupler

My old Ten-Tec Century 21 has an analog VFO dial that gives me a good guess at where I'm at but I use an external frequency counter to give me more information.  I had it sorta rigged my frequency counter to sample the signal from RF leaked on the shield but I didn't really know how much power I was sending to the counter so this coupler allows it, as well as other devices, to be safely connected to the transmitted signal.

I also plan to use the coupler for IMD tests using a oscilloscope and other projects.  It's  handy device to have in your collection.

My confusion

I will admit I am still such an idiot when it comes to understanding how this stuff works.  After I built it I was testing continuity and saw that input/output (J1, J2) both showed a short from ground to center pin on both BNC connectors.  I thought I'd mis-soldered something and spent the next two hours unsoldering components and trying to trace the fault...

There was no fault.  The way this thing works is a bit of mystery to me but as best I can tell it simply reverses the phase of the signal coming in one side (J1) and leaving the other (J2) and as far as continuity tests go, EVERYTHING has almost zero impedance.  I'm still bewildered but it's AC not DC so my continuity tests don't mean much.

But in the end - It works

I finally just resoldered it, scratched my head and thought I'd give it a try.  I connected the coupler between my radio and a dummy load and transmitted a watt and noted that the SWR on the radio was fine.  Then I hooked up my frequency counter and it worked like a charm sending an attenuated signal to J3 for the frequency counter.

My MFJ watt meter doesn't seem to be all that accurate but I did a power test with it both in-line and absent.  My MFJ watt meter measures 300w / 30w so it isn't very accurate at QRP levels.  But I noted a slight difference in power reported when the coupler was in-line.  If I had to guess by "Mark-One-Eyeball" I'd say the coupler was stealing about 1/2 watt.  Maybe a bit more so that's something to consider.  I'll know better once I build my Elecraft watt meter since it's accurate down to a tenth of a watt.

That's all for now

So lower your power and raise your expectations

Richard, N4PBQ

DX seems to operate in the fast lane

DX for new CW operators

How to copy those high speed ops?

EA8TL's Hexbeam in the Canary Islands
As a relatively new CW operator my copy skills are still relatively weak, especially at higher speeds.  DX stations seem to send their calls at 25wpm or faster so I often can't copy them without listening to them over and over and usually there are so many other stations working them that it gets confusing.

Well this morning I wasn't having much success getting an answer to my calls on 40m, and 20m seemed dead.  So I popped up to 17m and there was a good signal coming in that no one else was answering.  I listened over and over and finally copied EA8T (op name Jorge) located in the Canary islands off the coast of Africa.  I replied to him and worked him at my relatively slow 18wpm sending speed.  I wasn't very graceful in my response and he got my call wrong on the first go 'round but resent it correctly after that.  The entire time no-one else answered him even though there was plenty of activity elsewhere on 17m.  Are the Canary Islands considered blasé as far as DX?

Anyway I was happy to get the response.  I know (or surmise) that my 80m Windom has some fairly pronounced gain nodes in different directions on the higher bands but I didn't know which directions they pointed.  I guess one of the nodes points toward Africa (yaaay!)
Path from N4PBQ to EA8TL in the Canary Islands
My copy speed is slowly increasing as I've been operating CW for about 3 months now, but I wonder if there are DX stations on some segments of the band plan for slower speed operations.  I spent about 20 minutes sending my call at 18wpm down to 12wpm on the QRP segment of 17m (18.096 MHz) but no one answered.  I know I was getting out given the previous contact.
Do DX operators just not want to bother with newbies such as myself?  I wonder.  I'd appreciate suggestions in the comments section.
That's all for now

So lower your power and raise your expectations

Richard N4PBQ

The Perception of Power

Power... or lack thereof

I had a good afternoon playing radio on 40m, 30m, 20m and 17m

I like 30m because that band seems to be more laid back and I seem to have some of the longest ragchews there.  One of the QSOs began with a fellow in CT using a K2 at 80w while I was running 5w.  

As the QSO progressed he was surprised by how well he could hear a QRP station.  This seems to be repeated often enough to me that I asked him to lower his power and see how it goes.  

He lowered his power from 80w to 50w and I gave him a signal report that didn't differ from his original.  Then he came down to 20w and I dropped him a point. Eventually he lowered his power down to 5w while I went to about 1w.  We continued to have our QSO although QSB started to make copy difficult but the main thing was that he was very surprised that he could come down to 5w and have me hear him and that he could still copy me at 1w.  We were both using wire antennas and he was about 500 miles north of me.  Solar Flux was only 107 today so it wasn't particularly stellar (pun intended) and it wasn't grey line by any means.

I think QRP operators should encourage QRO operators to try lowering their power just as an experiment.  After all we are supposed to use just enough power for communication, rather than all that we can generate.  I generally start at 5w and if a station is having difficulty or gives me a 339 I'll turn it up to my scorching 12w.

Save power, save the planet.  Maybe we can design a CW key that generates enough power to run our milliwatt rigs.

So lower your power and raise your expectations

73 es 72

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