Author Archive
A visit with a QRP contest station
March 13th, 2016 | 
Author: 160m Spring Stew Perry Contest - QRP style
I had the opportunity to visit with Paul Stroud AA4XX as he worked the early hours in the 160m Spring Stew Perry Contest. Paul is an avid CW operator dedicated to QRP and QRPp operations. When he works contests he often participates using the Knightlites club call WQ4RP (Note the QRP in the call). |
| AA4XX operating as WQ4RP during the 160m Stew Perry Spring Top Band contest |
160m Top Band
160m (top band) is challenging due to the physical logistics of a suitable antenna. I had the opportunity to assist with a portion of raising the 160m vertical loop antenna at the "Excalibur antenna site" and installing the 24 elevated radials that help make this antenna so effective. There's a lot of wire in the ground system. The antenna site is located in the woods, off grid, and away from electrically noisy homes.Power to the remote shack is supplied by a quiet Honda 1kW generator operating a couple dozen feet from the shack. Due to the lower power requirements of QRP Paul can run the generator on eco-mode allowing its small fuel tank to provide 8 hours of operation between fill-ups.
Paul uses a Ten Tec Argonaut VI, running 5 watts output into the Excalibur 160m vertical loop. He uses N1MM+ logger software and a WinKeyer interfaced to the software. He also employs a SDR (software defined radio) feeding CWSkimmer signals across the band. An antenna splitter simultaneously feeds the SDR and the Argonaut. The SDR receiver is switched out during transmit by a DX Engineering RTR-1A Receive switch. His CW key is a N3ZN ZN-QRP model.
The N1MM+ logging software keeps track of which stations have already been worked and the CWSkimmer interface displays calling stations on the band being heard by his antenna.
 |
| The remote QRP station setup for contesting |
In the Stew Perry contest the only information exchanged was grid squares. I'm still relatively new to CW and watching Paul casually copy grid squares sent at 30wpm was impressive. I would have had to ask the caller to re-send their grid squares 5 times but Paul makes it look easy.
Instructions for the newbie
Paul explained to me the in's and out's of operating in a contest. Speed and timing the openings were important, as was persistence. The integration of the software and receiving tools optimized his operating but experience and skill seems to be the biggest factors to success. I could have sat down there using the same tools but I would have been dumfounded with the logging controls and the speed the other stations were sending information. However, not all stations were sending at mach speed. When Paul worked a station sending at a slower or faster speed he would use the interface to Winkeyer to speed up or slow down the sending simply using the Page-up / Page-down keys. He would change frequency to a new station in the skimmer display by clicking on it.
Due to the limited amount of information exchanged during the contest most of the sending is accomplished via macros programmed into the contesting software. Paul rarely had to touch the CW key during the time I was there and his primary physical interaction with the radio seemed to be changing bandwidth or bandpass settings (he tends to keep bandwidth at 500Hz).
 |
| Paul demonstrating the contesting software and usage |
Why QRP?
This contest was not a QRP-only contest although there were multipliers for working QRP. There were plenty of big gun stations operating and the Reverse Beacon spots showed some of them with 56dB SNR reports pounding the ionosphere with their big amps.
The strongest signal spot last night for WQ4RP was 35db with the average at around 18dB. Paul has worked QRO in the past but the challenge of QRP operation is now in his blood. During a previous 160m CW contest this winter he and Dick Hayter N4HAY worked 3 stations in Hawaii with Excalibur which thrilled them given the current propagation on 160m. QRP adds a bit more challenge and those multi-thousand mile per watt contacts on the top band make it all the more special
 |
| Finding the next station to work. (N3ZN QRP CW key in the foreground) |
Why contest?
As a new CW operator I'm still getting my feet wet and enjoying the process of improving my CW copy skills doing more ragchews than adding stations to the log or chasing DX. I casually contest with the SKCC weekend sprints and it can be fun to see how many stations I work but I'm not ready for real contesting.
During the time I observed, I could sense Paul's excitement seeing the propagation progress across the band and when a distant station in Russia was heard he looked forward to the challenge to getting that one in the log using QRP. He let the stations running big amps get their fill before jumping in. Ultimately he wasn't able to work that station but he later worked a GW3 station in Wales which was a first for him on 160m. The rewards of contesting seem to be in the accomplishment of something difficult and achieving something new. I can understand that.
What's next?
With summer coming on 160m will turn noisy from atmospheric static and the opportunities for top band contacts fewer. Attention will turn to other bands and challenges for a while. Maybe Paul will decide it's time to get that 40m Moxon back up on the tower as the sunspot cycle decreases this summer.
I enjoyed the opportunity to watch real CW contesting first hand. It is technically challenging and requires skills I do not yet possess and I look forward to progressing in my CW/QRP journey to the point where I can assist Paul in a contest.
That's all for now
So lower your power and raise your expectations
73/72
Richard, AA400
I will have a BLT please
The BLT-Plus Balanced line QRP tuner
I was looking for a QRP tuner for the 1Watter 40m transceiver I am building that would work with both balanced feedline antennas as well as coax feedline. The traditional Z-Match tuner is quite efficient at tuning balanced line antennas and the built-in SWR bridge gives you an all-in-one tuner and SWR indicator without having to take a separate SWR meter along with its inherent mess of cabling a separate SWR meter. The BLT in the name stands for "Balanced Line Tuner".This tuner kit is available from the fine folks at Pacific Antenna.
 |
| The Kit as it comes out of the bag |
The kit comes with everything you need except for hookup wire and your soldering equipment. Instructions are downloaded from the qrpkits website.
Why use a z-match ?
Here are some advantages that the Z-match design offers:
- Matches balanced loads without the use of lossy baluns.
- Being a parallel resonant circuit, the Z-match can provide some band-pass filtering for your receiver and harmonic attenuation for your transmitter.
- A well-designed Z-match tuner has a high Q and is more efficient (less lossy) than other types of tuners.
- The fixed inductor simplifies construction (no taps or rollers needed).
The secret sauce
Matching balanced line fed antennas is sometimes problematic for a traditional balun and tuner as the antenna can present impedances that are far outside of the balun's design. The Z-Match uses a center tapped coil to keep the complex impedance balanced across the inductor (at least that's how I understand it). I have measured my Elecraft BL2 balun getting appreciably warm at QRP levels when connected to my doublet indicating loss I'd prefer to avoid. The Z-Match design supposedly results in less loss.
Built in SWR indicator
The BLT plus includes a Dan Tayloe N7VE LED SWR indicator which eliminates the need to carry a separate SWR meter. The concept is beautiful. The SWR bridge is switched into "Tune" mode and presents a 50 Ohm impedance to your transmitter while you are tuning so that you don't risk damaging sensitive home-brew finals. The LED lights when the SWR is too high and dims and then goes out as the match is made. It is simple and fast to use. The instructions for the bridge are not with the BLT instructions. Download them from this link.
 |
| SWR bridge with LED indicator |
 |
| Switch to Tune to present a low SWR to the transmitter while matching, switch to Operate when finished |
Building
The kit is relatively easy to build with one tapped toroid to wind for the SWR bridge and one 3 winding toroid for the tuner. I faced a few issues that you might avoid:
- The kit is provided with really nice water slide decals that give it a commercial look (if you don't ruin them like I did). The instructions recommend applying a clear coat to the decals after they are applied. I used a Krylon matte finish clear coat which indicated it was fine for metals and plastics but it partially melted the decals and caused them to bubble. I'd suggest testing whatever you are going to clear coat them with first.
- Don't over tighten the plastic tuner shafts or you won't be able to slide the knobs on (yes I did).
- The binding posts have little plastic spacers that separate and it isn't obvious. If you install them and wonder how they don't ground themselves (like I did) you've done it wrong and will have to go back after it's together and try to remove them with all the wiring in place.
- The bolts for the binding posts are very soft metal and the nuts can strip them if you apply too much force (yep I did that too).
- The main toroid has three sets of windings and they overlap. Pay attention to the instructions about winding them all in the same manner (clockwise or counter clockwise) or you will have to rewind them (yep, I did that too).
- The 3 windings on the main toroid overlap so you won't be able to go back and verify your turns when doing the 2nd and 3rd winding so count carefully (ask me how I know).
- Temporarily attach the SWR bridge to the front panel to get the spacing correct to solder the LED leads.
My tuner toroid ended up being a bit messier than I'd like because I had to rewind it and my resulting leads aren't as short as they could be. I may go back and trim the leads to make it tidier but my least favorite part of winding toroids is heat stripping the insulated magnet wire so I'll probably leave it as is. Initial tests indicate it's working great.
 |
| My messy toroid winding... but it's working fine |
Operation
- Connect your transmitter and antenna.
- Choose the appropriate switch in the back for coax or balanced line antenna (Up for coax, Down for balanced line).
- Start with the inductance switch on the back set to low-impedance (Low-Z) because it is the most efficient. It uses the 6 turn secondary rather than the 12.
- Switch the front switch to "Tune"
- Key the transmitter and be sure you are using 5 watts or less
- Turn the "Load" knob first until you see a dimming of the LED then the "Tune" knob to make it go out completely
- The knobs interact so you'll need to go back and forth between them to achieve best match
- If you can't get a good match switch the inductance switch on the back to "High Z" and try again
- Don't apply power too long at a time during tune because the 50 Ohm resistors are heating up in there during the Tune process
- When the LED goes out or gets very dim you have a very good match. Switch to "Operate" and enjoy a well matched antenna
Photos
 |
| Result of having to rewind the secondaries made it messier than I'd like |
Dimensions
Remarks
Qrpkits offers a great little kit that results in a commercial looking product. You end up with a small portable tuner plus SWR indicator that reduces the complexity of your portable operation. Pacific Antenna is very responsive to questions. I sent a question concerning the incorrect instructions I'd downloaded for the antenna bridge and James answered me the same day with a different link (included above).
So if you have a QRP radio that needs an antenna tuner I recommend this kit. It's well thought out and works well.
That's all for now
So lower your power and raise your expectations
72/73
Richard, AA4OO
The N3ZN Iambic CW Paddle
Behold… mechanical beauty
 |
| N3ZN ZN-QRP Iambic Paddle (sporting my new call sign) |
I re-entered the amateur radio hobby in the summer of 2015 after a bit of a hiatus. To get my General license in 1996 a Morse code proficiency test was required. At that time I had purchased a cheap MFJ practice key and a used version of the ubiquitous Bencher BY-1 paddle. My Bencher was in reasonable shape but I just never became comfortable with it. It always felt a bit imprecise to me and I wasn’t happy with the width and size of its paddles.
The Grand Illusion
Five by Nine... QRP... How can it be?
What does an S-Unit really mean and how can a QRP station sound like a 500w station?
 |
| The real gain doesn't come from transmitter watts |
I rarely go up to the phone portion of the bands. Since I started doing QRP and CW last summer I think I've only made two SSB contacts just because my focus has been CW. But last night I was working on a bench project and tuned the Elecraft KX3 up to the phone portion of 40m for some entertainment.
A station in Rhode Island was testing his amp with a new antenna and was getting reports from various stateside operators. There was a lull where no one was answering his CQ so I thought I'd give him a call. He was peaking at S9 on my KX3's meter and he also sent me a signal report of S9 with some 10 over peaks. I then told him I was a QRP station running 10 watts and heard the usual surprised reaction from a QRO station.
I gave him reports as he switched back and forth from running barefoot ~75w to his amp ~500w. With his amp on he was an S9, running barefoot he was S8. So the amp gave him one additional S unit. In terms of hearing him I would have been hard pressed to tell much difference simply by volume. He was perfectly copyable without noise with the amp off.
We also did some tests with my station at reduced power (as if...) At 10w-12w output I received a S9 to S9+10. Reducing output to 5 watts netted me a S8 report and when I reduced to 1 watt (one watt) he was still able to comfortably copy me and I received an S5. So with my station at 1 watt and his running 500 watts we could still converse via SSB. Ladies and Gentlemen you don't need as much output wattage as you think you do.
He was running through a newly constructed homebrewed vertical while I was using my 80m OCF Dipole. We didn't discuss what sort of radial system he had installed, but the difference in antennas was likely the deciding difference in our stations. We were about 500 miles apart and his vertical probably had more low-takeoff gain than my dipole, or possibly more ground loss so I probably had better high angle gain on him for the short 500 mile skip. I think the take-away from this exercise is that the antenna is generally the key rather than transmitter power. If I can get 6 dB of gain from my antenna I have in essence quadrupled my effective radiated power. Quadrupled? Yes, Quadrupled effective output power.
Power and S-Units
You've probably heard it before but it's worth a refresher... Our radio's meter display a measurement in "S-Unit". To move the meter up one S-Unit the receiver must hear 6 more dB (decibels). So one S-Unit is 6 dB.
A decibel is:
- A Power Ratio: dB = 10 Log P2/P1
- A Voltage Ratio: dB = 20 Log V2/V1
You increase 3dB each time you DOUBLE your power
That's worth repeating...
You increase 3dB each time you DOUBLE your power. So to gain one S-Unit you must quadruple your power.
So if you are running 100 watts, to gain one S-Unit using the same antenna system you must increase your power to 400 watts. If you are running QRP SSB (10 watts) that is only 1.5 S-Units down from 100 watts. 100w / 2 (-3dB) = 50w / 2 (another -3dB or 1 S-Unit) = 25w... etc.
We have a great hobby, but there are so many aspects of it that sound like common sense when they really are not... like increase your power.
Increasing power gains you very little compared to a better antenna systems. Put that in your 811A amplifier tube and smoke it !
That's all for now.
So lower your power and raise your expectations (or your antennas)
72/73 (Note: 72 is a common substitute for 73 among QRPers... as in "not enough power for 73")
Richard, N4PBQ
Antennas offer the cheapest increase in dB
Note the statement above "using the same antenna system". That's the key then isn't it? It's easier to get 6 dB of gain from an antenna than from wattage. A 40m doublet can offer significant directional gain especially when operated on higher bands. Now unless it's rotatable you will be at the mercy of the directionality of its lobes but if you have trees or tall structures you can very cheaply string up a few dipoles oriented in different directions and for far less money that a 500 watt amp (6 dB). If you can only have one wire antenna you may miss out on some DX in the antenna's nulls but you will have some stellar gain in the direction of the lobes. Of course rotatable yagis and beams are the best but now we are talking about real money again. I'm talking bang for the penny. You don't have to buy a wire antenna. Some Dacron rope or weed-eater line and some surplus insulated wire is all you need. You can even make your own feedline cheaply from electric fence wire and insulators.We have a great hobby, but there are so many aspects of it that sound like common sense when they really are not... like increase your power.
Increasing power gains you very little compared to a better antenna systems. Put that in your 811A amplifier tube and smoke it !
That's all for now.
So lower your power and raise your expectations (or your antennas)
72/73 (Note: 72 is a common substitute for 73 among QRPers... as in "not enough power for 73")
Richard, N4PBQ
1 Watt and a Wire… in the Attic
You can't always get what you want, but you try sometimes...
Recently I've dialed my normal 5 watts down to 1watt (one watt, singular) for all my contacts. To throw some water on the fire I've decided to use my attic antenna which weaves all around my metal ductwork and electrical wiring. Mostly this was to prove a point to myself but it may be enlightening to deed restricted hams that they can use a qrp radio and an attic antenna successfully.
 |
| Key lineup... Palm Single (paddle), Vibroplex Bug (circa 1970s), Kent Hand key |
It only seems pointless until you try
Calling CQ with 1w QRPp into a poor attic antenna isn't as pointless as it would seem. I didn't have to wait long when calling CQ before I got an answer most of the time.
Now am I going to bust a pileup with 1 watt ? Possibly not but I think that my assumptions about both how much power I need and how big an antenna I need are usually out of proportion with reality.
 |
| 1 mighty watt |
My assumptions are often incorrect
I made QSOs on 30m, 20m, 17m and 10m this morning all at 1 watt. The solar conditions report was not really fantastic, especially for 10m. Yet 1 watt through the attic antenna bagged the only DX I heard on 10m. I had a couple of other multiple exchange contacts on 20m, 17m and one good old fashioned 25 minute long ragchew on 30m where I received a 599 report for my one watt from Bob (NR8M) in Ohio. Admittedly, Bob was booming in and we had good propagation to each other.
 |
| http://www.hamqsl.com/solar.html |
Video
The recording below was number 4 or 5 this morning. I wanted to post this one because I was working another QRP station in Arkansas (K5EDM) and we did NOT have great propagation to each other. He was running 5w while I was running 1w so it was QRP to QRPp. In the video you can see that I'm using some of the KX3's tricks to pull the signal up because there was a lot of QSB and noise (note the GEOMAGNETIC FIELD UNSETTLED in the solar report).
I had the volume maxed and was using the RF gain control mostly. I eventually had to turn on the preamp which really washed me in noise but I dropped the RF gain more and eventually switched in the APF (audio peaking filter) which performed magic on this contact. Often I find that APF doesn't help but this time it made a big difference.
That's all for now
So lower your power and raise your expectations
72/73
Richard N4PBQ
The need for speed in CW
CW QSO speed statistics...
As I continue on my Morse Code Journey I have been using a desktop application called Morse News to work on my code comprehension of natural language sentences for ragchew training. I set the program to send at speeds higher than I can copy to stretch me. Presently I have it set at 26wpm character speed and 23wpm Code speed. I can usually figure out what the news story is talking about but I miss a lot of the specifics.
 |
| I was a kid in the 1970s when Speed Racer was a popular cartoon |
The need for speed
Currently I'm OK working up to 20wpm qsos as long as the other station has good spacing. Sometimes I lose the thread or the specifics in a ragchew at 20wpm and I just ask them PSE AGN?
In sprints I can copy a callsign sent at 25wpm to 30wpm if I hear it a few times but that's no good for real contests where you need to catch that call sent at 30-40wpm sent the first time. My friend AA4XX has asked me to help him in multi-op contests but I know he is sending around 30wpm and I just can't hang there at this stage in my Morse Code journey.
Statistics show 25wpm is the magic number
So it got me to wondering what was the actual "average" qso speed. I downloaded days of raw data from Reverse Beacon Network. RBN collects the call sign, the SNR and the SPEED. The raw files contained between 40 to 50 thousand CW CQ calls logged each day after I filtered out other modes.
The average speed from RBN CW logs worked out to exactly 25wpm. The standard deviation was 5.34wpm which would mean most of the time you would expect to work stations between 20wpm and 30wpm. That seems reasonable and matches what I seem to hear on air. These numbers are from the CQ calls themselves and are only measuring character spacing speed so the code spacing is likely a bit lower in most cases and for ragchews is likely averaging 2 to 5 wpm lower than the actual sent character speed. Since I am not much interested in serious contesting at this stage in my hobby going over 30wpm isn't on my radar.
So based on those calculated CW speed statistics from RBN data if I can reach the point where I am comfortable in a 25wpm ragchew I should be content (for a while)
That's all for now.
So lower your power and raise your speed.... err expectations
72/73
Richard, N4PBQ
Making use of Elecraft Mini-module Kits
Connecting the bits and bobs
I have enjoyed building Elecraft Mini-Module kits. Now to put them to use...
 |
| Elecraft Mini-Module Kits |
What to do?
I built the kits as part of my learning adventure and to improve my soldering skills. It's also helped me learn to follow instructions better (my wife says I need to work on learning to follow instructions). But ultimately these modules are intended to be useful, and in my case they work nicely to when operating my old Ten-Tec Century/21.
My Ten Tec Century/21 is a 1970s CW-only, low(ish) power rig originally intended for Novice license holders of the time. It has no RF output meter or SWR meter. It has poor filtering/selectivity compared to modern radios and its analog tuning dial is a bit vague so you generally only know your frequency within 5 kHz.
The mini-module kits prove useful. I employ the W1 Wattmeter to determine my power output and SWR; the CP1 directional coupler is used to send a 20db attenuated signal to a frequency counter to determine operating frequency, and the AF1 Audio Filter makes operating near adjacent CW signals more pleasant by providing a narrow audio-band-pass filter. The result signal can be transmitted through a LDG tuner into the BL2 switchable balun connected to my attic Doublet.
Bring out your cables
All these independent modules need to be connected, so tying the bits and bobs together requires a few coax jumpers to route the RF around:
- UHF to BNC from the radio to the W1 Power meter
- BNC to BNC From the W1 Power meter to the CP1 coupler
- BNC to UHF From the CP1 coupler J1 input to switched T1 output to frequency counter
- BNC to UHF From the CP1 coupler J2 output to the tuner
And other cables:
- Serial cable from the W1 Power meter to the computer
- 12v power cables for the W1 and AF1 (unless I want to use 9V batteries)
- Audio cable from the TenTec C21 to the AF1
 |
| AF1 Audio Filter making crowded band operations pleasurable |
 |
| CP1 Directional Coupler sending off 20dB attenuated signal to the frequency counter |
 |
| Frequency Counter fed by the CP1 directional coupler. |
 |
| W1 Power Meter sending its measurement off to the computer |
W1 Power Meter Output to Computer
The W1 has a serial output to a PC for use with the Elecraft W1 software. The software can both configure the meter and display more detail than can be determined from the LEDs. Source code is supplied and the command set is documented so it would be easy to write your own software for this.
The W1 power meter LEDs give you relatively discrete output information for the lower two ranges (0.1w to 1.4w) and (1.5w to 14w). But in the high range (over 14w) the LEDs are only displaying 10 watt intervals. For instance in the high range, when the second LED is lit you don't know if your operating just 20 watts or 29 watts. It won't trip the next LED until it crosses the 10 watt boundary in the high range so it can be useful to look at the measurement on the computer if you are operating QRO. I'm not complaining. I understand that the meter is primarily intended as a QRP meter and for QRP power (less than 15 watts) it offers plenty of information.
Here I brought the TenTec Century/21 up to nearly full input drive (55-60 watts) to see what it could output. The rig probably had a few more watts left in there but I didn't want to push it because I haven't gotten around to replacing some of the out of spec components in the internal power supply. I normally use this radio under 10 watts (I look for about 30 watts input on the drive meter) but I was curious to see what the old girl could do since I had the meter hooked up to the computer display.
 |
| Measuring maximum RF output from the Ten Tec Century/21 |
Nits and Quibbles
My antenna's native SWR at 15m (~21.08MHz) is around 2.5 so it requires tuning (impedance matching). After my LDG auto tuner spends a ridiculous amount of time trying to find a match it settles at 1.7 SWR according to the W1 Wattmeter, while the indication on the Autotuner is that it believes the SWR is 1.5 or better, while the radio on the other side of the W1 meter sees a SWR over 2.5. I only see this behavior on 15m so I think there is some strange impedance reaction occurring in the W1 wattmeter that is changing the reactance on the jumper to the radio. I've tried a few different jumpers, swapping jumpers, etc. But it always presents an abnormally high SWR to the radio at 15m. Now when I transmit into a dummy load I don't see this behavior, so it is some combination of SWR / reactance present at W1 that causes a impedance mismatch downstream toward the radio. I have more investigating to do but for now I am choosing to not use the W1 Wattmeter in-line when operating on 15m.
The CP1 directional coupler is not entirely transparent and raises the SWR by a bit as signal passes through it. You would expect there to be losses according to the -20 db taps (one forward and one reverse). This should work out to about 0.08% loss but I wouldn't expect it to raise the SWR. It adds about 0.1 to your SWR and occurs even if the forward and reverse couplers are switched "off" and shunt their respective loads to the on-board 50 ohm resistors. I'm unsure what accounts for that slight SWR bump but be aware that CP1 contributes some very small losses.
Summary
So the Elecraft Mini-modules are fun to build; and with enough jumper cables, can be combined for experiments and general augmentation of other equipment in your shack. So go out there, build some kits and experiment. It's a rewarding experience.
I'm trying to decide what I'm going to build next.
That's all for now...
So lower your power and raise your expectations
73/72
Richard, N4PBQ
