AmateurRadio.com

I made another trip to American Sa’moa (KH8 for the radio amateurs in the audience) to deploy instrumentation.  It was a tight timeframe but the instruments seem to work and I managed to make a few ham radio contacts as well.

Ethan Miller, K8GU, is a regular contributor to AmateurRadio.com and writes from Maryland, USA. Contact him at [email protected].

At 1000z this morning I exchanged RST 579 reports with G6ALB who is 3km from me on my 40m Pixie on 7.023MHz CW. This was my first on-air QSO. Netting was perfect and I used the rig directly into my low Par triband antenna. An ATU might have helped. Andrew G6ALB said the channel was pretty busy but that I was a good RST579 with no hint of chirp. This afternoon we’ll put the rig on his spectrum analyser. I gave Andrew 579 probably reflecting the poorer MDS of the Pixie. I have no idea of his power or antenna.

My initial goals have been met: I built the kit and have managed a QSO on the air with it. With the fatigue associated with my brain bleed still very apparent (I am well and truly shattered currently), I was well pleased. A few more QSOs with the 40m Pixie would be good, HI.

$10 well spent. Excellent little kit. FB little transceiver. Works surprisingly well.

Roger Lapthorn, G3XBM, is a regular contributor to AmateurRadio.com and writes from Cambridge, England.

                                                   Visit to G-QRP Rishworth 2012.

So far it is the only Amateur Radio video I have made. I find I can write about this stuff, quicker and better than I can make video's. However I have not ruled out future output if I find something decent to record and I have the time to edit the footage.
 



For now I will leave it to the likes of VK3YE and  K7AGE etc, both who output some great "updated" interesting Video's over a wide area of various Ham Radio subjects.






Steve, G1KQH, is a regular contributor to AmateurRadio.com and writes from England. Contact him at [email protected].

Hello, dear listeners. Linux in the Ham Shack is pleased to bring you Episode #141 of our program. In this episode, we talk about topics like satellite communications software for Linux, the new Raspberry Pi, The Walking Dead and making a quick, hot breakfast--among may, many other things. We hope you enjoy this program. And if you can help send us to Hamvention by giving us a donation, our campaign is almost over. Please check it out. And thank you for listening!

73 de The LHS Guys

Russ Woodman, K5TUX, co-hosts the Linux in the Ham Shack podcast which is available for download in both MP3 and OGG audio format. Contact him at [email protected].

Well, it took a super-human effort on my part as a result of my extreme fatigue (brain bleed issue) but today I bench tested the little 40m Pixie kit I managed to build earlier this week. It is hard to explain just how exhausting this simple task was for me currently. I now need to recover my energy!

On receive a 1uV signal was perfectly readable and I could detect carrier on/off down to at least below 0.5uV. On TX it was putting out about 250mW into a 50 ohm load. On my antenna it was suffering some AM breakthrough, but less than I was expecting. I was using standard Walkman stereo headphones and a rechargeable 12V sealed lead acid battery. On a small 9V battery I’d expect about 100mW RF out, although this was not tried.

Overall, these results exceeded my expectations: it is more sensitive than I was expecting and the breakthrough of AM broadcasters is certainly OK in the day time. This is of course with no casing at all and no ATU. Using the fitted pot and fitted 1N4001 as a varicap it is easy to get the TX frequency and RX frequency to correspond, often an issue with very simple QRP rigs.

Next stage will be some on-air tests, but it most definitely works. Working the locals should certainly be possible. Sked with G6ALB (3km) arranged for 1000z Sunday on 7.023MHz CW.

UPDATE 2120z:  There is a contest in full swing and several Russians and Asiatic Russians copied on the little 40m Pixie. I did not stay on long but there was no apparent BC interference noticeable. So, on a quiet night I should able to use the rig in the evenings. The main issue on RX seems to be the lack of AF filtering, so one has to use “the filter that is between the ears” i.e.the brain.

Roger Lapthorn, G3XBM, is a regular contributor to AmateurRadio.com and writes from Cambridge, England.

From the World Radiosport Team Championship (WRTC) website:

The World Radiosport Team Championship (WRTC) is a competition between two-person teams of amateur radio operators testing their skills to make contacts with other Amateur Radio operators around the world over a 24 hour period. All teams use identical antennas from the same geographic region, eliminating all variables except operating ability.

WRTC2014 included 59 competing teams from 29 qualifying regions around the world. Competitors represented 38 different countries.

This is a unique contest in that the stations used are roughly identical so that operator skill is the main variable. I love watching these guys work the radios, especially the CW ops. Even if you are not a contester, take a look at this excellent video and enjoy radio hams having fun messing around with radios.

WRTC 2014 Documentary from James Brooks on Vimeo.

The post 2014 World Radiosport Team Championship appeared first on The KØNR Radio Site.

Bob Witte, KØNR, is a regular contributor to AmateurRadio.com and writes from Colorado, USA. Contact him at [email protected].

This article follows up on this one. The title could also be: doing measurements on hand held radios is hard. Actually, some measurements I did in the past might not be so accurate after all.

Measuring in dBm
If you measure in dBm, what I always did, you assume that the device at the other end is 50 Ohms, just like the manufacturer promises you in the specs. Slowly but surely we are finding out that this is not always the case. As a result I might have to switch to microvolt (µV), a method which doesn’t require a perfect 50 Ohms at the other end.

Can’t we just convert it? 0.5 µV @ 50 ohms = -113 dBm, a piece of cake, right? No. You must know the actual impedance of the receiver if you want to convert from dBm to µV. Erik PE1RQF did some measurements on a few hand held radios to find out the true impedance. The outcome was, well, a bit scary.

What this means for us
What this outcome basically means is that generating cold numbers on sensitivity and antenna performance are nice, but don’t tell the whole story, or could be misleading.

• Antennas which prove to be the best performers (RX/TX, VSWR), tested under optimal conditions, are not necessarily the best performers on a specific brand/model of hand held radio.
• There are antennas which aren’t 50 Ohms at all, but could very well outperform everything else on the market because your radio isn’t 50 Ohms either.

Do the test yourself
The best example I can give you is this one: take a Baofeng BF-666S, 777S or 888S, use the stock antenna, and make notes of the performance in the field. Try to hit repeaters which are barely in range. If you have a field strength meter, measure field strength when transmitting.

Remove the stock antenna and replace it by a Nagoya NA-701, NA-771, the $3.79 antenna, or the Baofeng UV-B5 antenna. I tried all of these; just pick whatever 3rd party antenna you have. Repeat the tests.

What happened here is that the short stock antenna was the best of the bunch, all 3rd party antennas had a negative influence on the performance of this specific Baofeng model. The same 3rd party antennas mentioned above did improve the performance of the Baofeng UV-5R, often by a wide margin.

Exception to the rules
The funny thing is that reception suffered greatly too. This is quite uncommon and a sign that hand held radios don’t follow the rules. For example, if you just want to receive on 20 meters and your dipole is 2×6 meters instead of 2×5 meters, you would never notice the difference. With your hand held radio however you will.

Hans, PD0AC, is a regular contributor to AmateurRadio.com and writes from Almere, The Netherlands. Contact him at [email protected].