Showing posts sorted by relevance for query kx3. Sort by date Show all posts
Showing posts sorted by relevance for query kx3. Sort by date Show all posts

Sunday, January 8, 2017

My TenTec Eagle sounds better than my Elecraft KX3

Your eardrums will thank you

Coming back to the hobby in 2015 I re-entered as a CW / QRP operator and I searched for a good QRP radio.  The Elecraft KX3 certainly qualified and it has been a great radio to use, especially when portable.

Elecraft KX3 -- stellar radio for portable QRP operations

But a few months after getting my KX3 an old TenTec Century/21 found it's way onto my desk and through numerous blog entries you may note that for some reason I kept gravitating to use it rather than my KX3 when I operated from the shack, even though the KX3 beats the old C21 technically in absolutely EVERY regard.  I just enjoyed operating CW with the old radio more than the KX3. I couldn't explain why.

Fast forward to late March of 2016.  I purchased a used TenTec Eagle from my friend AA4XX and began using it as my primary radio when I wasn't portable.   Here again the KX3 trumps the Eagle in nearly every technical aspect and offers dozens more features.  I just kept gravitating to use the TenTec radios rather than the Elecraft.

I used the my KX3 for Field Day in 2016 and after I packed up and brought it home the KX3 stayed in my backpack and only came out for portable outings.  It did not go back on my desk.  The KX3 cried little electronic tears while the Eagle gloated...

Ten-Tec Eagle -- compact / simple HF transceiver

Why no love for the KX3?

Time passed, and over the new year break I got to thinking about what I missed about having my KX3 on the desk; like its RX/IQ output for HDSDR and the ease working DX splits using it's dual watch capability and it's integration to logging applications like the ability to trigger CW macros from my logging software.  The list of "nice-stuff" goes on and on since the KX3 contains multiple kitchen sinks...  So I re-organized my desk to make room for the KX3 again and operated with it exclusively over the past few days...

I was getting ear fatigue and my ears rang in the evenings.  This was not the sort of ringing in the New Year that I wanted. I had been previously operating the same amount with the Eagle over the past month without the earaches.  Something was amiss.

Had I finally discovered why I keep going back to my TenTec radios?

Audio, Audio, Audio

So over time, even when I switched back and forth between radios there was a subtle "ouch" occurring when I used the KX3.  I enjoy CW and digging out weak signals can be fun... or it can be painful.  I guess when I sat down to use a radio and my hand hovered between the "Oh-so-feature-rich" KX3 and the "Nice-personality" Eagle my brain was saying "choose the nice personality" you're happier that way.

But there was a underlying reality to the choice I was making.

Just the facts mam

I used an audio frequency analyzer to capture audio from each radio by sandwiching the microphone in my headphones.  It hears what I would hear.  And the graphs tell a tale.

Below is one graph for each radio.  The RED graph line in each chart is the averaged "peaked" frequency output audio during the same QSO.  Ignore the green line as it was just the instantaneous  audio at the time I froze the display between takes.  The CW sidetone on each radio is set to 620Hz.

I re-ran this capture for each radio a few times during a lengthy ragchew between two stations.  The signal strength was around S5-S7.  It wasn't a strong signal which is typical of what I work, especially as the Solar cycle winds down.

I tried the captures with and without noise reduction on each radio.  The RF was rolled off as evenly as I could determine for each and both were set to a DSP filter bandwidth of approximately 400Hz.  Both radios were using the same antenna and everything was as similar as I make it.  RCVR EQ was set flat for the KX3.



Elecraft KX3 CW audio (ignore green graph line)
Ten-Tec Eagle CW audio (ignore green graph line)

The CW audio output from each of the two radios is distinctive

KX3 audio demonstrates
shoulder noise
Eagle has clean audio
There's clearly a CW signal peak around 620Hz in each radio but the KX3 shows a significant shoulder of audio just 9dB down from the peak below the center frequency 

Whereas the Eagle has a clear peak presenting a narrow tone range at the sidetone pitch with narrow shoulders down to the filter width.





Confirmation of my subjective tests

When I saw this I literally said "Aha!"   

This confirmed what my ears and my subconcious had been telling me.  The KX3 is more fatiguing to listen to than the Eagle because it presents more noise in the audio or at least a wider audio signal given the same DSP filter setting.  I've always remarked about my TenTec radios that their CW seemed to float above the noise.  I believe it's related to the cleaner audio filtering. The TenTec Eagle just has cleaner audio out of the box. It has no audio adjustments beyond AF and NR, no menus for fine tuning.  My old TenTec Century/21 sounds the same when using its 500Hz selectivity setting. 

In my opinion Ten-Tec just got CW right.

Yes, I have tried using the KX3 RCVR EQ settings to reduce that lower frequency noise and the problem IMO is that the EQ is more for SSB audio.  I think the Q for each setting is too broad and when I try to reduce the low frequency noise IMO it just makes the audio sound mushy.  I just can't get as "clean" sounding CW tone out of the Elecraft as I can the Ten-Tec.

OK, "sound" is a subjective thing.  No two people will hear the same thing the same way and frequencies that bother me may not bother you, but it seems pretty clear from the graphs that the CW audio from the KX3 doesn't match the Eagle.

Summary

Admittedly, my test involved a very small sample size of one radio from each manufacturer.  It's just that I'd put the KX3 back on the desk after a many month absence and my ringing ears got me to investigate the cause a bit more scientifically.  

I will continue to use the KX3 for portable ops because it is a great self-contained radio and when I work portable I usually operate for much shorter periods so the audio doesn't become an issue.

Man, I hope Ten-Tec can come back from the grave. They sure made some fine radios for CW operators.


That's all for now...

So lower your power and raise your expectations

72/73
Richard AA4OO


Sunday, March 26, 2017

More power to you with the Elecraft PXA100

When 5 watts is not enough

Gasp!  My blog is called "HamRadioQRP"... so what sort of heresy would lead me to post a topic on using more than 5 watts...
Will I have to turn in my QRP card?
I bit the expensive bullet and bought a used PXA100 amp for my KX3 this past week. There, I've got it off my chest.  I've come out of the closet. Go ahead and unfriend me and unsubscribe from my blog...

Normal Elecraft KX3 -- Notice the RF scale goes from 1w up to 12 watts

Elecraft KX3 with a PXA100 -- note the RF scale now goes up to 110 watts

OK, for those still reading...

This is my first time into the bottom of a solar cycle running QRP

If you've been operating for the past 6 months I'm sure you've noticed the band conditions have been getting pretty poor, and while I continue to try and make contacts and have ragchews using QRP power levels sometimes I feel bad for the other fella who is not QRP struggling to copy me.

I enjoy the challenge of making contacts at QRP levels but I also enjoy exchanging more than my call and an RST.  When the other station gives me a 559 or worse, or the QSB is getting bad I want to give them a few more dB to work with.  

I've written before that QRP operators can be compared to certain persons with dietary habits.  Sometimes vegetarians will eat dairy but if your vegan then you're abstain from anything that didn't grow from a root.  Well I'm more of a QRP vegetarian who will occasionally put a slice of bacon on my sandwich if I think it will improve the taste.  I'm certainly no vegan when it comes to operating QRP alone.   I've used my TenTec Eagle and TenTec C21 to go beyond 5w when the mood struck and in the case of SSB I've rarely operated at QRP levels with success so there I'm usually running well over QRP levels but I'd pretty much stuck to QRP for CW until recently.

Elecraft PXA100

Elecraft makes some very elegant equipment.  The KX3 by itself, running on internal batteries and with a built-in auto-tuner is an amazingly portable and full featured QRP rig.  With the newest version of firmware (MCU 2.70 / DSP 1.49, 2-27-2017) the KX3 will produce up to 15 watts of output on 80m, 40m and 20m when used with an external 13.8v power source, but if you want more than that you need an external amplifier.

I've been reading lots about the Hardrock 50 external amp and had even bid on a couple of Ten Tec 405 QRP amplifiers (which I lost) recently.  The Hardrock 50 was compelling for the price because it could be built with a full QSK option, whereas the old TenTec 405 did not have a full break in option but both would get my output up to 50 watts which is about 3-5 dB more output than the KX3 on it's own. 

But my normal operating mode is to begin at QRP and if that's insufficient I turn up my power.  In the case of most external amplifiers I would be over driving them if I kept the KX3 at 5 watts input to the amp.  It would require dropping my KX3 input power to the amp and fiddle with the output until I was at the power level I wanted.

On the other hand, the Elecraft PXA100 is fully integrated with the KX3 and I can simply turn up the power knob of the KX3 and when the power exceeds what the KX3 is capable of on its own the PXA100 electronics take care of adjusting the KX3's input into the amp to give me a smooth power output up to 100 watts.  Additionally, when using the internal tuner option with PXA100 I can use two antenna outputs from the PXA100 and switch between them using the ANT button on the KX3 while the PXA100 tuner maintains independent tune memories for each antenna. It is a very slick package but an expensive one.  Purchasing a used KX3 and PXA100 together puts you well over the $2k mark which you can certainly find more full featured 100w desk radios in that price.  So for price conscious hams this is not a sensible option.  I won't argue that this makes sense from a financial aspect, but I did it anyway.  Given the vibrant used market for ham equipment I wouldn't pay new prices for these but it still comes out to be a pricey desk rig even when purchased used.





OK, back to the PXA100.  One absolutely brilliant aspect of the PXA100 when using the internal tuner option is that its tuner seems every bit as good as the KX3's internal tuner.  I think it will tune a spoon on 160m (admittedly I haven't tried that).  It has no trouble tuning my ladder line fed attic Doublet which has some serious impedance mismatches on certain bands, so being able to quickly switch between my attic doublet and my outdoor Windom has been a real boon that I don't think other desk rigs can match with their internal tuners.  I could be wrong, but Elecraft's tuners and super fast matching algorithms are pretty much legendary in the industry.



Another nice thing about the KX3/PXA100 combo is that full break-in QSK is maintained and there are no fans. My shack stays very quiet (I hate fans).  The amp has a massive finned heat sink on top that while getting quite warm to the touch has not become overheated even on extended transmissions at 100w into non-resonant loads.  I still haven't delved into digital modes but I'm confident that while the KX3 struggles to maintain its cool when used for full cycle modes at 5w and above, when used with the PXA100 this combo avoids that problem because the KX3 is only running between 2-3w intput into the amp and can dissipate its heat at that level with no problem.

So for the past week I've been using this combo and I'm quite pleased.

Here is a video that I made today in a contact on 30m where I started at 5w and moved up to 25w and switched antennas during the QSO.



So lower your power and raise your expectations, but when expectations fail, use an amp

Richard AA4OO
http://hamradioqrp.com

Saturday, February 4, 2017

Over the waterfall

Situational awareness 

After reading all the hoopla surrounding the ICOM 7300 with its nice touch screen and waterfall/spectrum display, it got me to thinking that I was missing out on something.

HDSDR display on 40m tonight

When I first got my Electraft KX3 I hooked it up to HDSDR running on my PC and played around with the panadapter display. I admit it is very cool to visualize signals on the band.  That 44kHz view shown in HDSDR covers a large portion of the commonly used CW band segments.  I'd click on a signal and bam there it was tuned right in. I'd listen for a while and click another, and another. It was like shooting fish in a barrel (although I admit I've never tried shooting fish in a barrel).  After a while the novelty wore off and I went back to just tuning around the band.

There seemed to be more magic in stumbling upon someone calling CQ than looking at the bandscope and choosing the strongest signal.

Taking it all in


But I'm starting, just starting, to be more interested in working DX and potentially doing some contesting this year and for that I can definitely see an advantage to using a panadapter with the radio to see what's around me at a glance. 

However, as you may have read, I prefer using my TenTec Eagle over my KX3 at the desk.  But my Eagle is an older model made before the panadapter output came standard and even before they offered a provision for hooking one up.

My friend AA4XX uses a separate SDR with a input splitter and a DX Engineering RTR-1A receive interface to switch the SDR out of the chain when transmiting. The advantage of his solution is that it works with any transceiver but the relay in that unit is quite noisy and I appreciate the quiet full QSK offered by my radios.

Using a SDR as a receiver
protected during transmit by a DX-Engineering RTR-1A

One option for an older Eagle like mine is to take the input for a SDR straight from the input of the Low Pass Filter. That line is switched out on transmit by the Eagle to protect its own receiver so no separate switching circuit is required.  There's a tiny coax that would need to be spliced into which Paul assures me is doable mod with the right equipment. I would still need to buy an external SDR and it should be a good quality one or there's little point.

So I've been operating my KX3 at the desk this week using its built in RX/IQ to feed HDSDR to see if I like the idea enough to spend the money on doing this for the Eagle.  It's been over a year since I had this setup and I've switched computers so I had to go throuth the setup again and I thought it was worth documenting in case there are others that want to do this with their KX3's.

HDSDR is a really nicely done program, doubly so because it's free. It can be fed from an SDR or from your sound card. It interfaces to the control the radio using Omni-rig software.

So the setup is in two parts, configuring Omni-rig and secondly configuring four your sound card.

Omni-rig

Omni-rig is freeware CAT control software.  In the case of the KX3 it interfaces using the USB control cable that comes with the KX3.  Simply choose the serial port that your computer assigned to the KX3 and match the baud rate settings in the KX3. 

omni-rig settings for my KX3

HDSDR configuration

Download HDSR.

Configuration for the KX3 is mostly straightforward. Click the options button HDSDR.  The only part that trips me up each time is configuring the CW offset in [RF Front end configuration]. Make note of your side tone Hz setting on your KX3 by pressing and holding the CMP/PITCH button. Also be sure that you haven't inadvertently set CW reverse on some bands because that will really have you pulling your hair out as you try and figure out why the signals line up on some bands but not others.

So to set your CW offset correctly put your sidetone Hz as a negative number in CW_L and subtract your sidetone from 1000 Hz and put that value in CW_U as shown below.  Everything else should be set as shown.

RF-front end configuration screen

Choose the Omni-rig configuration as shown below to match your station settings.

CAT to radio settings

Lastly make sure RX/IQ output is turned on in your KX3 by setting MENU: RX I/Q to ON.  Run the KX3 RX/IQ cable to your mic input on your PC.  Then  choose your sound card bandwidth setting in HDSDR.  I'm not sure what the available bandwidth from the KX3 RX/IQ actually is but on all the PCs I've tried it with a bandwidth of 44100 seems to work best.

soundcard bandwidth

That's basically all there is to it. If you see a bunch of "lines" in the waterfall display that do not correspond to signals and if there is a thick signal line right at your input frequency then your station grounding is insufficient.  See my article on grounding.  When I first set this up I had insufficient station grounding and saw a lot of artifacts in HDSDR that were due to bad grounding between my PC and the radio.  So it will let you know if you have grounding problems.

So if you're lusting after that pretty display in the IC-7300 and don't want to shell out for another shiny toy, you can at least get a pretty display out of your KX3 without buying a PX3.  Just use HDSDR and the built-in RX/IQ.


That's all for now...

So lower your power and see the signals in technicolor

72/73
Richard AA4OO

http://hamradioqrp.com

Friday, January 8, 2016

Just stand up

The "Nifty Accessories" KX3 stand

Nifty Accessories KX3 stand

The Elecraft KX3 is naturally at home in the wild

My Elecraft KX3 is an incredible radio in many ways.  It's small size makes it a marvel for portable operations.
The upward facing display of the KX3's short legs is ideal for remote, portable operations

But on the desktop it's short stuff

But for desktop operation the short rear legs make for a laid back angle that makes the display difficult to see and the buttons awkward to operate.  I home brewed a stand that I've used for the past few months.  It angled the radio more vertically but it was still low to the desk. 

The KX3 on my homebrew stand

The KX3 "Iron Throne"

I finally felt it was time to give the KX3 some love and give it a proper throne chair for its little princely demeanor.  The KX3 now has some height and sits more vertically.  Access to the face of the radio is much improved.


Here's a closer view...

If you have a KX3 and use it on a desk in the shack the Nifty Accessories stand is a solid addition to improve the ergonomics of your little jewel.  It can be ordered with enough space to clear an attached paddle or lower to the desk if you prefer but I wanted the additional height to get it above some of my taller keys.


One Suggestion... replace the paper clips

The stand comes with big paper clips to hold the KX3 to the stand.  They are a a bit difficult to properly attach with all the cables exiting the KX3 on the left hand side and they look ugly.


I replaced the two paper clips with a small bungee cord which I attach as a loop across the top of the stand.  The bungee cord connects to itself underneath the stand...



The feet of the KX3 then slip under the bungee cord.  It seems to hold it sufficiently and is easier to attach and remove the radio.  It looks nicer as well...




That's all for now

So lower your power and raise your expectations

72/73
Richard, N4PBQ

Sunday, May 15, 2016

Listen to the music

Comparing CW audio 

The Elecraft KX3 and the Ten-Tec Eagle

The bands were very poor today from my home and finding stations to operate were few and far between, especially at QRP power.  So I thought I'd take a break from operating and create a brief video demonstrating the CW audio differences between the Ten-Tec Eagle and the Elecraft KX3.



The radios

The Elecraft KX3 and Ten-Tec Eagle don't have much in common apart from having DSP architectures and both being from American radio manufacturers.  The Eagle is devoid of bells, whistles and has no-menus.  On the Eagle, what you see is all you get, as opposed to the KX3 which has multiple kitchen sinks stuffed into it's tiny enclosure. 


Setup

Both radios have their pre-amps off and DSP bandwidth set to 500 Hz.  I have the RF gain reduced by about 15dB on each radio since turning up the RF gain on a noisy day like today just makes for white noise.  

During the video I operated the NR (noise reduction) button on the Eagle to demonstrate how it makes a signal pop and in the same manner operate the APF (audio peaking filter) on the KX3.  I end the demonstration by reducing the DSP bandwidth down to about 100 Hz on each radio.  The Eagle has both 600 Hz and a 300 Hz IF filters so it gets a bit of insertion loss when I pass through the 300 Hz setting.  There were no adjacent signals so the IF filtering wasn't doing anything for either radio in this case.

The audio from the Eagle is coming from its built-in speaker, while on the KX3 I'm using an iHome external, self-powered, speaker.  The KX3 has an abysmal internal speaker and there's little point in trying to listen to it compared to a radio with a real speaker.  In my opinion that speaker is one of the few serious flaws in the KX3.  

After I shot the video I realized that there was a bit of a bias against the Eagle's audio because the microphone in the camera was below the top of the Eagle's case and thus wasn't directly hearing the cabinet speaker, whereas it was in direct view of the external speaker connected to the KX3.  The Eagle's audio sounds crisper than this in person when your ears have a straight shot to the speaker.

Subjective listening

Audio is a very subjective thing because people can hear the same thing very differently so I won't comment on my opinion on which I prefer.

I would however be curious to hear other's opinions.


That's all for now

So lower your power and raise your expectations

73/72
Rich, AA4OO

Tuesday, October 10, 2017

CW tone comparison C21 to KX3

The old ways are sometimes best

This is a short one.  I haven't found much time lately to enjoy the hobby, but the past few evenings I've been firing up the old Ten-Tec Century/21 and just listening to CW while I tend to other duties.   Tonight, I managed to find time before dinner to have a brief ragchew with fellow SKCC member WV8DH (Dave in West Virginia) using my old rig.  It reminded me how much I enjoy the sound of CW coming out of that radio.



I was too lazy to set the camera up to capture the QSO, but after the QSO I dropped down the band to find a good ragchew going on and grabbed my smartphone and shot a quick comparison of the CW tone presented by the 40 year old TenTec radio and my new, modern, Elecraft KX3. 

After listening to the video I realize that a lot of wonderful sound, including harmonics are not captured by the microphone on the phone and can't be heard in the video.  Nonetheless, I think you'll agree that the older rig has finer CW audio. It's certainly more pleasant to listen to for long stretches.  The KX3 audio still wears me out if I operate more than an hour.  I wrote a detailed post comparing the KX3 to the Ten-Tec Eagle last year that pointed out what I believe the culprit of the tainted audio on the KX3.  The Eagle is presently off the desk and if anything the older Ten-Tec Century/21 sounds even better than the newer Ten-Tec Eagle.

But here's the brief, badly made smartphone video comparison of the C21 and the KX3...

Comparing CW tone from TenTec C21 to a modern Elecraft KX3

That's all for now.  I'm going to be reviewing a nice bug that a friend has loaned me soon.

That's all for now...

So lower your power and raise your expectations

72/73 Richard  AA4OO

Sunday, January 15, 2017

Have KX3 - will travel

Porch Portable

During a break visiting relatives in Western NC I went outside and threw my end-fed antenna up into a tree and sat on the front porch swing and worked stations in Maine, Kansas and Cuba.


Elecraft KX3 -- Palm Single Key -- and Index cards for logging 


Portable Ease

The Elecraft KX3 is such a fabulously portable radio.  It is very totable with sidekicks panels and cover, the only exposed part during transport is the BNC connector.  I just make sure that's pointing "up" in the backpack.  I didn't take the time to put the internal batteries back in the KX3 so I carried a small 3ah gel cell battery, good for hours of operation.  My antenna is a 9:1 balun fed insulated wire.  I get it up in the tree using a throwing weight and heavy line, then untie the weight, attach the wire and pull it up.  The coax serves partly as a counterpoise, and I clip two more wires cut to different lengths for additional counterpoise.  

The KX3's built-in auto-tuner will tune a spoon so it was no problem tuning the end-fed

Operating

The North America QSO party was in full swing and I was looking for casual ragchews so I headed to 30m and heard a number of QSOs but signals were not strong.  Checking RBN from my smartphone I saw that I wasn't getting very good reverse beacon reports.  

Reverse beacon reports while operating portable

After sending my call out manually a few times I put the KX3's built in keyer memory to work sending out my call and eventually I received answers to my calls.

I only had about 90 minutes to operate but I had a good time working a few stations and listening to other QSOs.  Packing up the radio,  key and pulling the wire down didn't take long.  

I'm still thrilled to have the Elecraft KX3 for such opportunities.


That's all for now...

So lower your power and raise your expectations

72/73
Richard, AA4OO

Tuesday, September 8, 2015

Two keys at once on the Elecraft KX3

The Two Keys to Success

In my past 5 weeks of getting back into Morse Code I've found that I like to use my paddles with the radio's internal keyer and switch to my straight key or vice versa.  But the Elecraft KX3 standard key input (KEY1) on the side of the radio can only be configured for one Key type at a time.  

All Keyed Up
The KEY1 input also requires a stereo plug.  So even if you use a straight key it needs to be wired to a stereo plug with the tip and ring of the plug shorted.  Without a menu change this presents as squeezed paddles to the keyer.  So I can't just plug the straight key after unplugging the paddles because the KX3 sends the input to the keyer and I get the iambic dit-dah-dit-dah... 

I have to go into the menu and change the setting for KEY1 back and forth between it's iambic KEYER mode and HAND mode.  This requires pushing the menu button, rotating the selector to the proper menu item, then rotating a different knob to choose KEYER or HAND mode.  That's just too much effort during a QSO.

I've seen key switching solutions where a rotary switch is used to select from a collection of keys but that still doesn't help switch between a straight key and a paddle unless I purchase an external keyer for the paddles.  But the KX3's internal keyer is quite nice having a dedicated knob to quickly change keyer speed as well as front panel operated memories with repeat, so I really don't need or want to buy an external keyer.

There's an easier and cheaper solution...

The Elecraft KX3 has another key input (KEY2) which has a separate configuration from KEY1, This allows one input configured for a straight key and the other for a keyer.  The tricky bit is that the input for KEY2 uses a 2x2 pin configuration recessed into the front side of the radio.  This is intended to be used by the proprietary paddle attachment for the KX3 which mounts on the front of the radio.  When I searched the web I couldn't find anyone who makes a ready-made adapter for this port to a stereo jack.  So I decided to make one.

The nice folks at Elecraft sent me the schematic for the KEY2 input and I ordered the 2x2 header from them used in their proprietary paddle kit.

KX3 KEY2 pinout


So when you wire your 2x2 header here's the key (pun intended).


Looking at the side where the four pin header is located: 

  • Upper right is ground 
  • Lower right is "dit" 
  • Lower left is "dah" 
  • Upper left is "halt-catch fire"
 By the way.  While I'm mentioning Elecraft let me just say I think they have one of the finest customer service groups of any company I've dealt with.  They respond to emails in record time and provide you with any information you may need concerning their products.
The recessed port for KEY2 is too tight to fit a header covered in shrink tubing so what I have done is connect the cable to a header and then plug that header into the Elecraft proprietary header that has a right angle set of pins coming out. The Elecraft header seems slightly deeper than a standard header and has the right angle pins.

So sacrificing a male to female stereo cable we have the following:

Proprietary header KEY2 connector connected to a stereo cable
I plan on using some hot glue to cover the exposed pins and give some mechanical strength to the connection but this works fine on the desk for now.

So now I am free to use either key as the mood strikes.

That's all for now...

So lower your power and raise your expectations

73
Richard
N4PBQ

Friday, November 20, 2015

Rock 'N Radio -- QRP Style

Operating QRP
Can mean operating from a "Quiet Restful Place"

I had the day off today and it was a beautiful morning.  I decided to spend part of it at Lake Wheeler Park in Raleigh, NC operating QRP from a stone bench under a tall oak tree.
rock 'n radio
I was operating the Elecraft KX3 from its internal AA batteries for the two hours I was there running 5 watts and it worked well.  I had brought an external battery but didn't need to connect it.

I threw a line over a tree using a throwing weight.  I hit my mark the first time, untied the weight, tied on the end of the antenna, and hoisted the 31 foot end-fed up exactly where I wanted it with the feed point a couple of feet off the ground.
31 feet of wire end-fed by a 9:1 balun.
A kite string winder holds the throwing line
A metal stake with a bit of rope anchors the balun and the other end of the rope

Another view of the end-fed with 9:1 balun, stake and coax
The 20 feet of coax serves as the counterpoise so hookups couldn't be simpler.  The KX3 simply has the coax attached to one side and the morse key and headphones in the other.
QRP operating position
The morning was very pleasant, if a bit windy, clear with a temperature of 55 F.

The KX3 will match the end-fed wire on about any band other than 160m but on 80m you could likely throw the radio farther than the signal travels.  The KX3 auto tuner is pretty amazing and I believe it could tune a piano if you hooked it up correctly.

I worked stations on 20m, 40m and 30m.

I called CQ on the 20m QRP calling frequency (14.060) and had a brief QSO with a lot of QSB (fading).  I didn't hear much activity that early in the morning on 20m so I dropped down to 40m and worked the QRP calling frequency (7.030) and had my call answered right away.  After that QSO another station jumped in there calling for a specific station so I moved on.  40m was busy.  Every time I thought I'd found an open frequency someone would jump back in or if I called QRL? I'd get an R R.

So I went up to 30m, and had a very nice long ragchew that lasted nearly an hour.  The internal AA batteries on the KX3 were getting a workout operating at 5w for that entire time but I never saw the transmit wattage drop below 5w and when I finished up the internal batteries still showed 9.8 V  The cutoff is 8.5 V so there was plenty of juice left.  I may just stop carrying the external battery on these brief jaunts.

My long ragchew was with a station in GA about 400 miles away and he gave me a report of 599 so I was thrilled with 30m this morning. Coincidentally, this end-fed antenna, balun, coax-counterpoise combo is nearly resonant on 30m and I've had some of my best reports when operating this portable antenna on 30m. 

Key wise, I was using the Palm Single Paddle.  It is a great little key when you don't have a table to operate from and you don't want to strap something to your leg.  I get strange enough looks from passer-by's without them wondering why I have some mechanism strapped to my thigh and the Palm Single is very inconspicuous.

The Palm key has a clip-on, magnetic base which I use to temporarily attach it to my clipboard when I'm not sending.  When I'm ready to send I simply pull it off the clipboard and hold it in my left hand. As I noted in an earlier review of the Palm Single Paddle it can be used as a straight key if you turn it on its side.  The long ragchew I had on 30m was with a gentlemen who sent me his SKCC number in the first exchange so I quickly turned off the electronic keyer in the KX3's and turned the Palm Single on its side.  That station sent me a nice compliment on my straight key FIST; so the little Palm Single key can serve duty as a paddle into a keyer or (in a pinch) as a straight key.  I far prefer to use my Kent Hand Key if I'm operating manual key but it's too big to bring along for portable operations and I can't quite picture myself trying to hold onto the giant Kent Hand Key with one hand whilst operating it with the other like I can the Palm Single.

The Palm Single Paddle works great in portable operating positions
I made a silly little video of my trip to the park...


So enjoy some nice fall weather if you still have it and have a Rock 'N Radio adventure.
What could be finer than to be in Carolina in the Mooo-oor-ning

Enjoying the last nice days of our Fall... birds singing and morse code beeping
That's all for now...

So Lower your power and raise your expectations

73/72
Richard N4PBQ

Saturday, August 8, 2015

Finding the right QRP radio

So many radios... so little time


YouKits QRP rebranded as TenTec
When I was learning CW I had borrowed a friend's inexpensive Ten-Tec QRP radio.  I'm glad I had the opportunity to borrow it while I was trying to decide what type of radio to purchase. There are many, many options for QRP radios.  


I began by looking at the very inexpensive, simple radios kits like the Rockmite and TunaCans but decided my acumen with a soldering iron was likely insufficient for even something as simple as those kits.  I will probably look into building one of those eventually for fun.  Then I started looking at the more expensive pre-built QRP radios like the Ten-Tec 4030/4020 and Patriot but the more I listened the the little Ten-Tec the more I realized the limitations of these lower priced radios.  Just a couple of items to mention... the AGC (automatic gain control) was harsh.  Strong stations would pop into your ear like a needle before the AGC brought them under control.  If you turned on the attenuator that led to the problem of there being no independent adjustment for the sidetone.  So if you had to turn up the volume to copy a quiet station (with the attenuator on) the sidetone would then blister your ears.  It would do the job but it wasn't pleasant.

Some kits are more capable than others.  This Elecraft KX1 is a very capable radio built from a kit
Ten-Tec Patriot

I think it could be fun to use these inexpensive QRP radios as an added challenge but I didn't want an impediment to my entry to QRP and CW so I decided to spend more money and go with a better quality radio.  
Ten-Tec Argonaut V
Elecraft K1

Show me the Good Stuff

I kept seeing a couple of recurring themes in radio reviews to look for in a radio that is to be used primarily for CW: a smooth QSK and a quiet receiver.  In the past when I had my Yaesu and ICOM radios they used a mechanical relay to switch to transmit.  So when I would send CW the relay would audibly snap shut and when I'd pause it would snap open.  When you're sending CW it's polite to be listening between your words to see if a station wants to break in or answer.  This clatter of the relay in the radio during QSK becomes annoying (to me anyway) such that I ended up setting the delay longer and longer so that it didn't trigger.  At that point I was basically key-down until I finished transmitting which isn't terribly friendly in CW land.  So I wanted a radio capable of full-break-in QSK without relays.  That type of QSK seems to be standard on TenTec and Elecraft radios but isn't offered on "big brand" radios until you've worked into the very expensive models.

Another other aspect of a good radio for CW is a quiet receiver.   That's a very subjective topic but I kept reading rave reviews of the "quiet" receivers in TenTec and Elecraft radios.  I am in no-way an expert on receiver design but TenTec and Elecraft seem to design their receivers differently from the "big brand" radios, and in most cases include front-end filters narrow enough to filter out the noise around a thin CW signal.  There are other niceties like having physical knobs to control keying speed or message sending, etc. without having to enter a menu.  That is standard on most TenTec and Elecraft radios but is normally a menu controlled item on "big brand radios" which makes it hard to change during a QSO.  

You can see where I'm heading here.  My choices were narrowing to TenTec and Elecraft brands (coincidentally, both are American radio companies).   Both companies make QRP radios although Elecraft has more QRP offerings.  Of the current TenTec radios I believe only the Argonaut and Patriots are QRP.  The Argonaut receives very positive reviews but there were not many available used and I didn't want to pay for a new radio so that sent me toward Elecraft.

Elecraft KX3
Most of the Elecraft models are offered as kits.  I'm not competent enough to correctly solder hundreds of components and wind toroids for a radio so I was looking for used pre-built rigs for sale on a major auction site and eham.net classifieds.  Most of the good deals on eham.net classifieds seemed to be quickly snapped up.  I bid on a number of radios on the major auction site but the bids consistently went higher than I was willing to pay.  At first I was bidding on only Elecraft KX1s, then Elecraft K1s, then I moved up in price to Elecraft K2s then to Elecraft KX3s.  I lost all those auctions.  I revisited eham.net classifieds and saw an ad that had just been posted for a KX3 with the options I wanted that was much less than the going price on the auction site.  I sent an email and a week later my KX3 arrived.

The KX3 has been a joy to use.  All the controls I need access to are very accessible without menu diving.  I've made more CW contacts at 5w this past week than I made in all my time with my QRO radios and I made one SSB 10w contact (just to speak with an old acquaintance on the Corn Cob net).   It's internal auto tuner has been able to match my 40m Carolina Windom at 1.0-1 on every band except 160m and 30m.  On 30m it can match at 1.7-1 and 160m it just clicks.  It matches better than my manual MFJ Versa Tuner.

It matches my end-fed dipole 1.1-1 on every band from 40m-6m.  I don't recall trying 80m on that end-fed antenna yet.

The KX3 has internal batteries that I operated at 3watts transmit for a few hours on outside (only a couple of QSOs).  I was operating from my front porch with a 31ft wire thrown up into a tree.  So it's an eminently "Porch Portable" or picnic bench radio.

I have a little 3ah 12v battery left over from a UPS.  I operated with it for a couple of hours and it only dropped from 12.5v to 12.2v when I was done so that's a nice option to have for longer portable operations.  My 50ah UPS battery, while not terribly portable, should allow me to operate off the mains for a week or more! 

The radio, antenna, paddles, and external battery all easily fit in my backpack.  I can't say I could do that with my ICOM 746-pro.

My only limitation on portability presently are my Bencher paddles which weigh twice as much as the radio !!!  But I have a Palm-radio paddle on-order so that should be taken care of shortly.

Bencher Paddles 3lbs 2x the weight of the KX3 radio itself

Elecraft makes a fine radio.  I'd like to operate a TenTec Argonaut some day as well but that will need to wait.

73s and 72s
N4PBQ

Friday, March 25, 2016

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.

Performance

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

Video

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


Summary

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 / QRPKits.com .

That's all for now

So lower your power and raise your expectations

72/73
Richard, AA4OO