Friday, May 29, 2020

It has begun: CQ-WPX-CW

I knew the contest would be especially popular this year but WOW:


I'll be operating from home (Flex/KPA-500) and from a park (mcHF) this weekend. Good luck to all who are participating.
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Sunday, May 24, 2020

Cheap DC-DC converter for QRP with batteries

My recent outtings with the mcHF on battery power have made me realize, once again, that there is always a compromise to be made when matching battery type to the rig's maximum safe input voltage level. Quite often, a 3S battery will be a couple of volts less than the radio's maximum level but a 4S pack will exceed the radio's rating.


The ramifications are minimal and may not seem to make a significant real-world difference but consider the 25% variation in maximum permissible input voltages of several QRP rigs:
  • mcHF - 16v
  • KX2, KX3 - 15v
  • Anan-10E - 14v
  • MTR-3B - 12v
A battery that is safe to use with an MTR-3B will underpower my mcHF, decreasing its 10-watt output to 6 watts.

Saturday, May 23, 2020

An RF-derived hieroglyphic

I'm getting my helium ready... an email exchange with Hans G0UPL has me excited for his next kit - the U4B.

This is a lightweight beacon transmitter designed to be carried aloft by balloons. Several prototypes have been launched and one is now on its third circumnavigation of the planet.

One of the things that make this transmitter unique is that, in addition to WSPR transmissions on 20m, a glyph (yeah, I had to look it up) is drawn when the received audio is sent to ARGO. An avatar written by RF - Rudolf Hell would be proud!

You can monitor the progress of U4B-6 here and, if using ARGO, you may see a depiction like the one below.
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Saturday, May 16, 2020

Lab 599's TX-500 transitioning from Vaporware to Reality?

Lab 599's TX-500 SDR transceiver may be about to become a reality. Like other radios some of us eagerly anticipate - Elecraft's K4, Icom's IC-705 and QRP Labs' QSX - the TX-500 was announced so long ago that many may have forgotten about it.


Sunday, May 10, 2020

WV0H/p KX2 to mcHF QSO

I had an enjoyable QSO this afternoon with Myron WV0H who was set up at a picnic table at a city park in Colorado.

As our QSO progressed, I had  a feeling of deja vu - just four days ago I rode my bike to a city park and made a few (too few) contacts with my mcHF. The weather was sunny and cool but, being a Wednesday, contacts were tough to come by, even with the quarantine so many are enduring.

When Myron told me that he'd arrived at his destination park by bike I immediately regretted having not done the same on a weekend day. Next time...

Myron's KX2 was sounding great - a bit of QSB here and there, but mostly strong and easy to copy. I was using the mcHF into the Hardrock-50 amp, for about 50 watts into the Yagi.

After our QSO I listened to Myron work one station after another, easy as you please. He told me that he'll be posting details and photos to his blog soon regarding the antenna he was using and a voltage booster (Anyvolt 3).

Myron, here's how you sounded in SE Texas. Thanks for the QSO and 72!
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