AmateurRadio.com

In this episode Bob McCreadie reports from the recent AMSAT-UK Colloquium, and finds time to test out the SuperAntenna Superstick delux package. Nick Bennett travels north and discovers a rather remarkable radio club. And we reveal the winner of our first free-to-enter competition.

See the new episode at www.txfactor.co.uk

We hope you enjoy the show!

TX Factor Team

Nick Bennett 2EØFGQ co-hosts TX Factor with Bob McCreadie GØFGX and Mike Marsh G1IAR. Contact the team at [email protected]

My first PSK31 contact

For some time now I have been trying to get my feet wet with the digital modes and have had no luck. This morning I gave it another go with the setup, in the past I have tried Fldigi, Digipan, Digital Master 780 and WinPSK and the list goes on. These are all great programs as many use them and have great success but as for me I just was not able to make them tick with my set up. I became frustrated and it was do to me just not figuring out the setup. As I said this morning I tried it again but from another angle, there are two programs I use to control my rig from my PC the first being N4PY's program and the other program is DXlab. The DXlab program has many modules  from rig control, logbook, propagation, DX cluster and a digital program that's called Winwarbler! DXlab already controls my

Screen shot

radio and does a fine job of it so I added the Winwarbler module and with a few configuration tweaks I had radio control and was able to read signals from the waterfall. It was now time for the moment of truth to see if I am transmitting a PSK signal. On 20m I pressed the "call CQ" macro button and low and behold my power meter showed 5 watts making it's way to the antenna!!! Next was to find someone calling CQ and make my first contact with PSK31. I saw W1AW/5 calling CQ and I gave him a call and W1AW/5 came back to me with a 599 report. I now can say that I am PSK active but there was not much time left to make any other contacts as things around the house had to be done. I was thrilled to get things up and running and the waterfall was very busy. One of the drawbacks to Winwabler is it's limited to PSK and RTTY but for now I'm ok with that.

The K3 all ready to go

This is the setup that I am running….
Rig is the Elecraft K3 in DATA A mode set at 5 watts
The sound card interface is the Signalink USB
Software is DXlab's  Winwabler
Antenna is the MFJ 1788
Some of the items on the "to do list" are
1. Set the macro's up as they are generic ones right now.
2. Learn more about the Winwabler  program.


Mike Weir, VE9KK, is a regular contributor to AmateurRadio.com and writes from New Brunswick, Canada. Contact him at [email protected].

What exactly is “zero distance communication”?

Matt Thomas, W1MST, is the managing editor of AmateurRadio.com. Contact him at [email protected].

Today I took a step back 15 years and went for a hike with an old MFJ Cub and a plain dipole. I worked Wales and Wisconsin with only 2 watts.

I hiked up to the cabin at Knox Mountain and had a beautiful afternoon.

As I approached the pond I found a small patch of mountain gentians near the old dam. The pond was beautiful in the afternoon sunlight.

An old cabin overlooks the pond. I set up my gear just on the other side of the front porch under the wild cherry tree.

I tossed a line over a high branch and pulled up a half wave dipole fed with RG-174. I hung a water bottle from the low end. This way I could use the dipole as a vertical.

I plugged the dipole into the 20 meter MFJ Cub without a tuner. I searched around for a while and soon heard GW0FZY from Wales calling CQ. Justin had a strong signal and was kind enough to answer me. He gave me a 569. There was some QSB earlier on, but toward the end of the QSO he sent, “Solid Jim… FB on UR hike.” It was an absolute pleasure to work Justin all the way across the ocean!

The little Cub performed well… I think I built it nearly 15 years ago from a kit. I used to hike with it all the time.

Next I answered Ron W9UW in Wisconsin. Ron was very gracious and sent, “UR doing a great job there with 2W.” Ron also gave me a 569.

I packed up the gear for the downhill journey. I took one last photo of the pond.

As I left the blue jays sent 73 with their “Dee Dee Dee” calls. Along the trail, I treasured each moment. As I noticed the change in color, I realized our days are numbered before the woods turn gray.

Jim Cluett, W1PID, is a regular contributor to AmateurRadio.com and writes from New Hampshire, USA. Contact him at [email protected].

It's often easier to achieve high power on 630m or LF by combining lower powered amplifiers than it is to build a single high-power rig. A simple Class D push-pull switching FET amplifier can readily produce 400-500W when operated in the 35V range. Combining two such amplifiers, both sharing a common oscillator / driver stage, would yield 800-1000W output...probably much more than needed on 630m.

The low parts-count of the amplifier stage in the GW3UEP Class-E transmitter should easily produce 150-200W when run at a slightly higher drain voltage and proper heatsinking. Combining two such modules would yield 300-400W output at very low cost.

Combining can be done with a Two-Way (3-port) Wilkinson Splitter / Combiner. Splitters and Combiners are one and the same, depending on which ends are used for input(s) / output(s). When used in the 'combine' mode, insertion losses are virtually zero and mainly due to the miniscule resistive losses of the coils.



Combiner component values can be calculated the old fashioned way or by using one of the numerous online calculators. This excellent online video by Sebastian (KF5OBS) explains exactly how to calculate component values for the truly dedicated amongst us:

Courtesy: https://www.youtube.com
He also has a new video showing how to calculate values for combiners having more than two outputs, should you want to combine three or more individual amplifier modules.

The first combiner I built was for my 2200m kW and combined the output of two 500W Class-D modules:


The air core coils are high-Q, cheap and easy to produce. If space is important, the inductors could just as easily be made using frequency-suitable powdered iron toroids, but at more expense. In actual operation, I have never been able to detect any heat from any of the combiner components, even when running a full kW at lengthy keydown periods of several minutes during QRSS transmissions, affirming the almost 'zero' insertion loss when used in the combining mode.

When I decided to use the same amplifier on 630m, a suitable circuit was designed and built for that band as well:


The terminating / balancing resistor (R) is used only as a safety device in case one of the two amplifiers fails during operation. It allows the still-working amplifier to safely dump some of its power into the load without destroying itself. Under normal operation, no current flows through this resistor so no power is wasted, assuming both inputs are equal. I have read of some schemes that will sense any current flow through 'R' and immediately shutdown the entire transmitter, thus allowing a resistor of lower dissipation to be used for 'R'.

Another benefit of the Wilkinson L-C Combiner is its filtering capability, as it works extremely well as a LPF. Neither my 2200m kW or 630m kW use any low-pass filtering other than that provided by the combiner's L-C network. It also seems to work well as a buffer of sorts, as both myself and VE7TIL noticed with our 2200m systems. We immediately stopped blowing FETs mysteriously when operating at full power. The amplifiers did not seem to react any longer to reactive components suddenly appearing in the antenna system or somewhere in the output network....everything was 100% more stable and reliable it seemed.

I can envision an exciting project consisting of a pair of GW3UEP finals feeding a toroid-based combiner, all in a very small footprint.

Should you choose to combine a pair of amplifiers for 630m, here are the values that were used in my own combiner:



Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].

I spent some time on 20m in the CW portion of the band and as always I wanted to make contacts with the lowest power possible. I came across 9A2G who was calling CQ and at the time he was not to busy with takers. This is a great opportunity for me to drop my call to someone who is listening. I started out at 500mW's and moved all the way up to 5 watts and nothing no contact. He did have some stations answer his CQ  and some where very weak so  he had good ears but not for VE3WDM. I then came across EG7MAL and I worked my way up to 5 watts and he came back to me with VE3?. He decided to move on as I was just not making the trip. At this point I was wondering how my low power signal was doing so I decided to call CQ at the QRP watering hole on 20m. I was checking with the Reverse Beacon Network to see how I was doing.  My 500mW signal was heard by AA4VV in North Carolina which was just over 1,000 miles per watt. I then bumped my power up to 1 watt and was very happy to see F4DXW was hearing me which meant my 1 watt of power made it 3461 miles. I did not make any contacts but I did find a way to make the radio evening a bit exciting even without making a two way contact.
Mike Weir, VE9KK, is a regular contributor to AmateurRadio.com and writes from New Brunswick, Canada. Contact him at [email protected].

then I will take it!

I had two very nice DX QSOs during lunch today.  These were not "UR 599 TU 73" QSOs, nor were they exactly ragchews. But they were a nice change of pace from the typical "wham, bam, thank you Ma'am" kind of micro-QSOs that seem to be so prevalent these days.

The first was with Vic SM7ZDI who answered my CQ on 18.086 MHz.  Vic was using a Yaesu FT-1000D at 100 Watts to a Windom. He had a good 569 signal and gave me the same. Vic told me that it was about 8C (46F) in Sweden. I was very grateful for the 65F (18C) that we had today, when I had heard that.




Larry Makoski, W2LJ, is a regular contributor to AmateurRadio.com and writes from New Jersey, USA. Contact him at [email protected].