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Archive for the ‘qrp’ Category

Portable Ops 13/45: Sing it with me….YyyyyMCAaaaa

April 1st, 2016 |

On Tuesday and Thursday nights my daughter takes Tae kwon do at the local YMCA. I typically run a few miles while she in class, but last night I decided to setup portable and play a little radio. The SKCC sprints run from 7-9pm once a month local time, and her class starts at 7:00 pm.

Since I would like to participate in these sprints, I have been looking for a location in the parking lot I could do this while she was in class.

The parking lot at the YMCA is large and at one end there are zero cars parked. There are small trees that I can attach my portable antenna to.

So last night I decided to test it out. The antenna strapped easily to a small tree and the coax easily reached in my car where I operate.

I made one contact…

AC4FZ (4987T) – Wally was working another station on 10.120 and once the QSO was over, I gave him a call. He was nice and loud here in Kansas. Wally was in North Carolina and had a nice signal and fist – with just a slight bit of QSB. He was a 559 here and he gave me a 549 – I am constantly amazed and just what 5 watts can accomplish!

That was it for the night, but I am glad I tested the setup for the SKCC sprint at the end of April – I will be active!

Portable Ops 9/45: Just 1 1/2 contacts today….dead battery

March 25th, 2016 |

Author: Burke NØHYD

Friday was a bit frustrating – the bands seemed really weird, and not much if any activity was heard here in Kansas.

I did manage one and a half contacts!

N5NAA – On 30 meters I worked Steve down in TX for a 2xQRP contact. Steve was running 3 watts and even mentioned that he reads my blog! Hi Steve!

VE4CWF (10492T) – I replied to Chris calling CQ. He came back to me and gave me all his specifics, and then just as I completed sending our call signs back, my battery died in the KX3! I admit it, I had operated probably 3 portable sessions without charging the internal pack – my fault. So….sorry Chris for dropping you like a hot potato! Hopefully we can connect down the line.

Thats all for today, I hope to have some time this weekend for a bit of SKCC CW!

Portable Ops 9/45: Just 1 1/2 contacts today….dead battery

March 25th, 2016 |

Author: Burke NØHYD

Friday was a bit frustrating – the bands seemed really weird, and not much if any activity was heard here in Kansas.

I did manage one and a half contacts!

N5NAA – On 30 meters I worked Steve down in TX for a 2xQRP contact. Steve was running 3 watts and even mentioned that he reads my blog! Hi Steve!

Thats all for today, I hope to have some time this weekend for a bit of SKCC CW!

Portable Ops 8/45: One NPOTA + Two More!

March 22nd, 2016 |

Author: Burke NØHYD

It was another windy, windy day here in Kansas! Once again the Jackite dropped a couple sections right during a QSO. When I took it down at the end of the session the tip section is stuck and won’t release to slide down inside the next section – will have to work on that.

Today was pretty slow, 20 meters was a weird band for me today. I was spotted all over the far east coast, but really nothing in between.

Tuning around I heard a strong station on 14.064, but for the life of me I could not copy the call sign. I asked him to QRS (slow down) and he did and I finally got his call!

KA4RRU – Mike was activating NPOTA HP06 – this is my first NPOTA station other than when I was an activator.

AH6AX (11165S) – Larry answered my CQ, we had worked each other before. He had a great signal from Maryland today, and it was nice to know I was getting out. I had been calling CQ for some time with no takers!

KG4LLQ (5883T) – Ken answered my CQ from North Carolina. Looking at his QRZ page he has some interesting rigs – I hope he was using one of the cool ones for our QSO today!

So in my quest for SKCC Centurion, I am now sitting at 18 unique contacts on my way to 100!

Portable Ops 8/45: One NPOTA + Two More!

March 22nd, 2016 |

Author: Burke NØHYD

Today was pretty slow, 20 meters was a weird band for me today. I was spotted all over the far east coast, but really nothing in between.

Tuning around I heard a strong station on 14.064, but for the life of me I could not copy the call sign. I asked him to QRS (slow down) and he did and I finally got his call!

KA4RRU – Mike was activating NPOTA HP06 – this is my first NPOTA station other than when I was an activator.

KG4LLQ (5883T) – Ken answered my CQ from North Carolina. Looking at his QRZ page he has some interesting rigs – I hope he was using one of the cool ones for our QSO today!

So in my quest for SKCC Centurion, I am now sitting at 18 unique contacts on my way to 100!

A visit with a QRP contest station

March 13th, 2016 |

Author: Richard AA4OO

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

March 12th, 2016 |

Author: Richard AA4OO

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.

The SWR bridge instructions are separate from the kit instructions and simply googling them will give you instructions for an older version. Use the version here.

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