AmateurRadio.com

Daniel DO7FOX and Gregor DO5SSB have released a premium version of their QRZCQ callsign database. Attached below is the press release they sent.

If you’ve tried it out, I’d like to hear your thoughts. Will you be switching to it or are you happy with what you have now?

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

I have had this radio for about three months now. I have not found out how to program any of the memory channels.  If anyone learned the secret please post a comment here.

Julian Moss, G4ILO, is a regular contributor to AmateurRadio.com and writes from Cumbria, England. Contact him at [email protected].

Roger's adaptation, shown below, appeared to be getting excellent results when used in his over-the-horizon clear air scattering tests.



Although Markus, John and myself all built the same design, it is interesting to see the end results, as each used a different construction method.

John chose to use perfboard and point to point-to-point wiring:

VE7BDQ's Perfboard RX

I built mine on a PCB....

VE7SL's PCB RX

...and Markus used 'dead-bug', also known as 'ugly construction' style, the preferred method of most scratch-build homebrewers:

VE7CA's Dead-Bug Style RX

I made a couple of small changes and used a 2n5457 JFET in place of the MPF102 as well as some 2n5089's in place of the 2n3904's. I think Markus swapped JFETs as well and used 2n4401's for the bipolars, while John built a stock version of the receiver.


All of us used the Osram BPW34 PIN diode for the detector after having it recommended by Clint in e-mail 'detector discussions' as being a good performer . It is still readily available from the usual places, at around eighty-cents.

BPW34 Spectral Range

The BPW34 turns out to be sensitive over a fairly wide range of frequencies. At our frequency of interest (deep red) at the edge of the IR range, the detector is operating at about 65% of its peak performance which is lower and well into the IR range.


Many silicon PIN photodiode detectors are available with filters that let them achieve maximum sensitivity at the lower IR range while blocking the unwanted higher frequency visible light sources. Such is the case with this one, available as the BPW34FA. If you wanted to run an all IR system, reducing visible light QRM, this detector might be a better bet.

BPW34FA Spectral Range

When it comes to diode detectors, there are always  new challengers appearing in the marketplace. There are still many opportunities for experimenting when it comes to optimizing the front-end of your receiver.









When coupled with its focusing lens in the final stage of construction, the receivers are amazingly sensitive. Even the slightest hint of a light source, often invisible by eye, would produce a response from the system....even starlight!

One of the first sounds detected was a low-pitched and repetitive 'thump-thump' which turned out to be the wingtip strobe lighting of jet aircraft activity approaching and departing Vancouver International Airport. After several nights of listening it was apparent that the strobe lighting could be detected from at least 70 miles out and from aircraft still above 10,000'. Panning over to the runway (about 25 miles away), I could often detect the strobes from departing aircraft even though they had not appeared above my sea-level horizon. Eventually I would see them rise above the horizon, about a minute after hearing them on the runway while on their takeoff roll. I suspect the propagation mode would be a form of clear-air scatter since there was no direct line-of-sight to the signal source when initially heard.

Panning the receiver slowly along the many miles of coastal mainland, on the other side of Georgia Strait, revealed many signals, most of them with different audio signatures. Some sounded rough and buzzy, like an unfiltered CW note, while others were T9 and very clean. Most had different repetition rates resembling radar sweep speeds but, once again, most sources were not visible to my eye...nor were they located when scanning the signal source with binoculars. I suspect that most signals were from various fixed lighting installations either strobe lighting or area flood lighting. Some targets appeared to be slowly moving and were found to be coming from tankers and container ships travelling along the far coast line. Hearing so many of these modulated lightwave signals was certainly an interesting experience and something I had not really expected. Even individual stars would produce a detectable 'hum' as the receiver/lens combination was aimed directly at them.

My one and only daylight test revealed extremely high levels of hum from the bright sky and, no doubt, front end overload desensitising....but the sudden sound of a buzzing bee in the headphones turned out to be just that, as the reflected light from its wings was being modulated by the rapid flap-rate....all very eye-opening to me and totally unexpected.

Here are some recent audio recordings made during a period of heavy cloud cover over Georgia Strait. All are on the far mainland coast or further inland and most sources were not visible to my eye.

• Landing aircraft strobes at Vancouver International ~ 30 miles.
• Aircraft over Georgia Strait, ~ 40 miles.
• Unidentified with odd repetition rate.
• Washington coast unidentified ~ 30+ miles.
• Washington coast unidentified 2.
• Washington coast unidentified 3.

I think such a system would make a wonderful 'science-fair' project for a budding student, complete with recordings....but perhaps it has all been done before!

For a very in-depth study of various current RX designs, see the Optical Receivers page of KA7OEI.

With all three receivers working well, the transmitters would be next....
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].

A happy looking KX3

I decided to take the KX3 out and about on my day off Friday, it was an overcast day so I thought it wise to do my operating from the mobile rather than taking the bike. I set up the mobile whip antenna on my car and situated myself in the passenger seat and was ready to go.(note….this time before the trip out I made a list of things to bring so I was not without important items as happened in the past)  Brought the KX3 up to the 20m QRP watering hole (14.060) and just wanted to check the SWR on the radio before sending out my 5 watts of raw power. The KX3 gave me an error message but it seemed I was still able to transmit and I did for a short time. Then I noticed as I moved up and down the band my

Not so happy KX3

SWR stayed the same at 1.4:1 no matter where I was on the band….even up into the SSB portion. It was then determined something was wrong and I had a fast look at the antenna and coax but all seemed ok. I then switched to my 15m whip antenna and the error message was gone but I still had this strange low SWR across the 15m band as well. So it was time to pack things up and head home. Once at home I put the KX3 on a dummy load and tried it out and all was just the way it should be. I then put the rig on the MFJ 1788 loop and again no problems. So I suspect it's the mobile setup and I did post the problem on the Elecraft reflector and was given advice to check the mobile setup. When at home I did want to give the KX3 the full workout and to do so I started to call CQ on 20m. Terry WA0ITP came back to me from Iowa and our signals were in around 339 and conditions wee not that great but we were able to carry on a decent QSO. So the KX3 is working good but it's just another "project" I have on the burner that has to be worked out.  No time today as I am on call  this week and the phone has not stopped ringing with calls for me to go in!
Mike Weir, VE9KK, is a regular contributor to AmateurRadio.com and writes from New Brunswick, Canada. Contact him at [email protected].

Shortwave Broadcasting is Dead

Who among us didn’t get baptized in ham radio via shortwave listening? A special committee on the future of shortwave broadcasting paints a grim picture. “While there is still a critical need for shortwave in key countries, it is a medium of marginal and continuously declining impact in most markets.” The report said that even in countries where shortwave radio enjoys significant usage levels, “audiences will migrate to other platforms as they become more accessible.”

QRP Blog Ends Syndication

W2LJ decided to end the syndication of his ham radio blog on AmateurRadio.com, a popular blog aggregator. I don’t know how long his posts had been picked up and re-broadcast there, but it’s been available for quite some time. His explanation was guarded, though he did write that it was a decision he’s been mulling “since this past Easter”. He also mentioned that not all his musings are about ham radio, some of them detail his religious beliefs and that may have played a factor.

Larry says his blog will remain open for business.

Leaving TenTec

In other passages, Jim Wharton, NO4A has resigned from TenTec. He assumed day-to-day operation of the company as President in January of this year when Jack Burchfield, K4JU retired.

This is likely related to the new association with RF Concepts and the assessment of the need for multiple leaders as a result of the merger. Or Wharton found a better gig. Or maybe TenTec really is going belly-up. Hard to say as the situation there seems anything but predictable…

Filed under: Ham Radio Tagged: blog, tentec, w2lj

Jeff Davis, KE9V, is a regular contributor to AmateurRadio.com and writes from Indiana, USA.

If you are like me, you appreciate electronic gadgets with dials and displays. So when I discovered this “USB detector”,  I thought to myself that I really always wanted to know the voltage as well as the current consumption of my USB devices. And since it is more or less impossible to connect a multimeter, this is exactly what I need.

The device fully satisfied my curiosity. Actually one surprising result was that the charger for my Samsung Galaxy Note 8 has a negative output resistance.

With a load it outputs 5.27 Volts as shown in the top image. Usually one expects the voltage to increase when the load is removed. But for this charger the voltage dropped instead to 5.13 Volts (second image). That should mean that there is the equivalent of a series resistance of (5.13-5.27)/0.98 which is about -0.14 Ohm.

I measured other chargers also, without finding a negative output resistance, so it seems as if it applies to this particular charger only. Out of curiosity, I also measured the current consumption of my Arduino Mega to 0.08 A without any shields connects.

The unit has two outputs which are different from each other. Output 1 is a fully functional USB port, while output 2 only connects DC power. What is that good for? Well, the epanoroma blog opened my eyes to the utility of this. If you charge your phone at some public place, then this feature isolates the data port of your phone. That may protect you from being hacked.

So there you see. The €5.13 were well spent and I even learnt something new by giving in to the temptation to click “Buy It Now” on Ebay.

But why does the Samsung charger have what amounts to a negative output resistance, is it by design or by accident?

Sverre Holm, LA3ZA, is a regular contributor to AmateurRadio.com and writes from Norway. Contact him at [email protected].

North America SOTA Activity Weekend 2014, September 13ths and 14th, is a casual event involving tiny battery-powered radios on mountain summits.  It i s not a contest but is intended to introduce "Summits on the Air" to newcomers with home stations who try to work summit operators during one or two days. There are no rules regarding power levels, modes or number of bands worked, but please be courteous when more than one station is trying to talk to a SOTA operator on a summit.  The SOTA operators have just climbed mountains as high as 14,000 feet; they use low power; and they don't receive on split frequencies.

Mike Crownover, AD5A, is a regular contributor to AmateurRadio.com and writes from Texas, USA. Contact him at [email protected].