The roll top radio desk

The ARRL DX CW has come and gone and I took a part time approach to the contest. I was operating single op, non assisted and QRP. The setup is an Elecraft k3 and P3 along with Win4K3suite, N1MM+, MFJ 1788 loop and MRP 40 cw decoding software. I have MRP running in the background as when the CW speeds hit 33-40 it's just easier to use the software. A contest policy that I have is to NOT update any contest software before a contest. There was a new Win4k3suite and N1MM+ update and I resisted the temptation to update. I have had some very frustrating contest's when I have updated software just before the event.  I was able to get on Saturday morning and Sunday morning/afternoon. On Sunday I thought I would get at it early, so I was on the rig at 7am local time on 15m ...BUT... the band was really not all that active out this way. That's a good sign for me as during the next contest I can sleep in a bit and not really miss anything. Around 8:00 A.M local time 15m started to come alive and things were hoping right up until I had to shut things down at 9:30am due to chores. I was back on again around 1pm local and 15 was good and 20 meters had lots of Eastern Europe booming in. I soon exhausted my contacts on 15m as N1MM+ was telling  me "DUPE" for a majority signals on 15m. I was then off to 20m and it was interesting there as the signals were booming in but it seemed I was barely making it, I had to do many repeats. I was off and on until about 3:45 local time and I then decided it was time to shut down. I had a great time making 40 contacts with 33 multipliers for a score of 3960.While writing this post to clear my head head of the dit's and dah's I have Motown booming on the  Studio Beat wireless headphones! 

The contest desktop

Mike Weir, VE9KK, is a regular contributor to AmateurRadio.com and writes from New Brunswick, Canada. Contact him at ve9kk@hotmail.com.

With over 120 cosponsors in the House and Senate, the Amateur Radio Parity Act (ARPA) is gaining momentum. The House version, HR 1301, has been favorably reported out by the House Energy Subcommittee on Communications and Technology and is on its way to the full House Energy and Commerce committee for consideration. This is great news, but there is still a lot of work to do.

Colorado ham Kurt Fehlhauer, KUØO, has created an easy-to-use website to help hams tweet their support for ARPA to their representative and senators. SupportParity.com lists the cosponsors of the bill and makes it easy to tweet your member of Congress to thank them for their support — or encourage them to sign on.

Visit SupportParity.com to see where your members of Congress stand and let them know that your support the bill.

Matt Thomas, W1MST, is the managing editor of AmateurRadio.com. Contact him at editor@amateurradio.com.

Amateur Radio Weekly is curated by Cale Mooth K4HCK. Sign up free to receive ham radio's most relevant news, projects, technology and events by e-mail each week at http://www.hamweekly.com.

In this episode, Martin M1MRB / W9ICQ is joined by Chris M0TCH, Martin M0SGL, Dan KB6NU, and Colin M6BOY to discuss the latest Amateur / Ham Radio news. Colin M6BOY rounds up the news in brief, and this episodes feature is Resistors

• Google use 71-76 and 81-86 GHz Amateur Bands
• ARRL Partnership Added to RFinder
• Alex Discovers Amateur Radio
• Amateur Ham Radio on BBC Radio Norfolk
• Trinidad and Tobago Lighthouse Joins Ham Radio Event
• ZS1MM Beacon Now Operational
• Emergency Ham Radio Equipment for Indiana Hospital

Colin Butler, M6BOY, is the host of the ICQ Podcast, a weekly radio show about Amateur Radio. Contact him at info@icqpodcast.com.

In this episode, Martin M1MRB / W9ICQ is joined by Chris M0TCH, Martin M0SGL, Dan KB6NU, and Colin M6BOY to discuss the latest Amateur / Ham Radio news. Colin M6BOY rounds up the news in brief, and this episodes feature is Resistors

• Google use 71-76 and 81-86 GHz Amateur Bands
• ARRL Partnership Added to RFinder
• Alex Discovers Amateur Radio
• Amateur Ham Radio on BBC Radio Norfolk
• Trinidad and Tobago Lighthouse Joins Ham Radio Event
• ZS1MM Beacon Now Operational
• Emergency Ham Radio Equipment for Indiana Hospital

Colin Butler, M6BOY, is the host of the ICQ Podcast, a weekly radio show about Amateur Radio. Contact him at info@icqpodcast.com.

0.33 uF X2 capacitors which measured only 0.097, 0.1, and 0.118 uF.

Many devices now use a capacitor power supply thus saving the space that a mains transformer occupies. The principle is that a series capacitor from the mains supply is used to drop the voltage and reduce the current. Provided that the circuit is completely isolated from human touch, this is an economical way to provide DC power.

The image shows three such capacitors as I were measuring them. They came from three malfunctioning devices in my home: two wall-mounted thermostats for floor heating and a remote controlled mains switch.

Their power supplies were designed with a capacitor of 330 nF in series with a bridge rectifier which supplies the low voltage DC. This value is typical, it seems, for 230 Vac, 50 Hz circuits that are designed for about 20 mA. The value will be higher for an equivalent 115 Vac, 60 Hz circuit.

The malfunctioning happened because the value of the capacitor in my cases was reduced to 1/3 and less of the nominal value. These capacitors are all marked X2 and a voltage of 275 Vac.

The X2 means that they are safety capacitors which will not fail by short-circuiting as this would be a fire hazard in this circuit. They have self-healing properties and that means that they fail by “burning away” on their own foil, leading to a reduction in capacitance and eventually failure of the circuit as the power supply cannot supply the required current any more. They should never be replaced by anything but X2 capacitors with the same or higher voltage rating.

Go to the Wikipedia page Capacitive power supply for more description of this circuit.

By the way, the devices which these capacitor came from were 15 year old Microtemp MTN-1991 thermostats and a 20 years old Nobø System 500 RCE 512 remote receiver. They now all work again thanks to the fitting of new 0.33 uF capacitors. And all of them are safety capacitors of type X2 of course – no gambling with safety here.

Sverre Holm, LA3ZA, is a regular contributor to AmateurRadio.com and writes from Norway. Contact him at svholm54@gmail.com.

0.33 uF X2 capacitors which measured only 0.097, 0.1, and 0.118 uF.

Many devices now use a capacitor power supply saving the space that a mains transformer occupies. The principle is that a series capacitor from the mains supply is used to drop the voltage and reduce the current. Provided that the circuit is completely isolated from human touch, this is an economical way to provide DC power.

The image shows three such capacitors as I were measuring them. They came from three malfunctioning devices in my home: two wall-mounted thermostats for floor heating and a remote controlled mains switch.

Their power supplies were designed with a capacitor of 330 nF in series with a bridge rectifier which supplies the low voltage DC. This value is typical, it seems for 230 Vac, 50 Hz circuits that are designed for about 20 mA. The value will be higher for an equivalent 115 Vac, 60 Hz circuit.

The malfunctioning happened because the value of the capacitor in my cases was reduced to 1/3 and less of the nominal value. These capacitors are all marked X2 and a voltage of 275 Vac.

The X2 means that they are safety capacitors which will not fail by short-circuiting as this would be a fire hazard in this circuit. They have self-healing properties and that means that they fail by “burning away” on their own foil, leading to a reduction in capacitance and eventually failure of the circuit as the power supply cannot supply the required current any more. They should never be replaced by anything but X2 capacitors with the same or higher voltage rating.

Go to the Wikipedia page Capacitive power supply for more description of this circuit.

By the way, the devices which these capacitor came from were 15 year old Microtemp MTN-1991 thermostats and a 20 years old Nobø System 500 RCE512 remote receiver.

Sverre Holm, LA3ZA, is a regular contributor to AmateurRadio.com and writes from Norway. Contact him at svholm54@gmail.com.