Posts Tagged ‘receiver’

I Need You in My Log! SKCC K3Y/0 Special Event (January 2016)

I need your help!

Come meet me on the shortwave (HF) ham bands for the Morse code (CW mode) special event, the Straight Key Century Club (SKCC) celebration, with special callsign, K3Y. During the shifts (time slots) listed below, I am the control operator as K3Y/0.

Tomas, NW7US - operating Morse code as special event station, K3Y/0I need you to make a contact with me.

This special event takes place every year during January. We celebrate the legacy of Morse code, and promote Morse code and manual creation of the code by any non-electronic (digital) device and method. Which means that we love mechanical bugs, straight keys, two ends of a wire, or any other manual device, if Morse code is generated. The Straight Key Century Club is a free membership group. The link to their website is below.

I need you to make a contact with me, during my scheduled times, listed below.

NOTE: YOU DO NOT NEED TO BE A MEMBER OF THE (free) SKCC GROUP. To get into my logbook, you meet me on my frequency, and use Morse code to communicate with me. It is painless. If you must, you can use computer-generated Morse code. Or, you can tap it out on any Morse code signalling device, like a bug, a set of paddles, or a straight key; whatever you choose to make Morse code emanate from your HF transmitter.

HOWEVER: For those of you who want to get fully immersed in the spirit of this event, you are invited to use a straight key. And, as a bonus, you may and can join the SKCC group for FREE. Then, you would have your own SKCC number. That’d be cool; we SKCC members use that number in our exchange during our QSO information exchange. But, you don’t need that. Since it is free, why not?

What is needed is simply you, getting on the shortwave band, finding me, hearing me, and responding to me with Morse code. In other words, we need to have a QSO using Morse code. I am not a fast operator, so no problem if you are not very fast. I’ll meet your speed.

In any case, here are some of the times I will be on the air as K3Y/0… please dust off your straight key, bug, paddles, whatever, and make a QSO with me. Thanks!

My current schedule:

UTC Start/End (remember, these are NOT your local times, but are the UTC (GMT) times!)

(revised times, as of edit date)

00:00 - 02:59 19-Jan-16
00:00 - 02:59 20-Jan-16
00:00 - 02:59 21-Jan-16
00:00 - 02:59 22-Jan-16
00:00 - 05:59 23-Jan-16
14:00 - 18:59 23-Jan-16
20:00 - 21:59 23-Jan-16
00:00 - 02:59 24-Jan-16
14:00 - 18:59 24-Jan-16
21:00 - 21:59 24-Jan-16
00:00 - 02:59 25-Jan-16
00:00 - 02:59 26-Jan-16
00:00 - 02:59 27-Jan-16
00:00 - 02:59 28-Jan-16
00:00 - 02:59 29-Jan-16
00:00 - 05:59 30-Jan-16
13:00 - 18:59 30-Jan-16
20:00 - 21:59 30-Jan-16
00:00 - 03:59 31-Jan-16
13:00 - 23:59 31-Jan-16

Now, what frequency will I be on?

To find out what frequency I am on:

Visit and look on the right side for my callsign, NW7US. I usually post my frequency of operation right after my call sign.

Typically, evening operation is 30m, then 40m, and then possibly 80m.

If you are trying to alert me to your presence, you may message me on my personal Facebook profile, under my “Tomas David Hood” profile messages, but I may not see that right away.

Here is the detail covering the K3Y operation and the SKCC group:

73 de NW7US
dit dit

This was last year:

Tomas, NW7US - operating Morse code as special event station, K3Y/0


DST 100 receiver

My very first communications receiver weighed a ton (it took 2 people to move it!) and was a DST100. I believe it was made by Murphy during WW2. This receiver, I have since learnt, was designed for intercept listening. It was built like a tank with a huge rotary turret tuning unit. The radio cost £7 from a local garage and it was overhauled (new valves?) by (the now late) G3CHN. It covered from around 50kHz to over 30MHz and heard some impressive DX. I was always puzzled why signals were so broad on the lowest range, not realising at the time that it covered 50 to about 150 kilohertz!  This was in 1962.

At that time there was little amateur band gear available (none from Japan) and lots of us used WW2 surplus gear which was available at low cost from many suppliers. Popular receivers were the AR88 and CR100. Transmitter-receivers included the WS19, WS38 and 52 sets.

Amateur radio in the 1950s and 1960s was quite different with lots of HF AM still and most people building their own transmitters. SSB was in its infancy. In many ways it was the high point of the hobby, although today we are blessed with low cost gear, free software,  more modes and more bands. The hobby means different things to different people. Long may it continue.

See .

SAQ – historic 17.2kHz CW transmission this Sunday.

A reminder that the historic alternator TX on 17.2kHz VLF will be sending a message this Sunday twice. They usually QSL via the amateur QSL bureaus. See for more details of this and other transmissions.

Some years ago I copied the transmission, QSLed and am the proud owner of one of their QSL cards. It is not hard to copy in Europe unless you have local noise problems. A small tuned loop is all the antenna needed. There are even a software receiver available free on the net capable of receiving the transmissions with a suitable antenna connected to the PC. The SM6LKM software receiver is excellent and covers 0-22kHz. It makes a very useful VLF receiver. I describe it on my YouTube Channel G3XBM.  See

1 Volt/2 Volt Transceivers

Transceivers with a power supply of 1 and 2 Volts, how much can one achieve with that? Well, actually quite a lot according to DL2AVH, Helmut, who together with DL4ALJ, Gero, wrote two articles about that in the German QRP-Report in 2011. I am impressed by the output power, up to 200 mW with one battery cell (1.5 Volts) and 0.5 Watts with two cells.

I wrote about this in April last year where I also mentioned that the 1 Volt design from 2000 later had been corrected. Those corrections can be found in the article in QRP-Report 3/2011: “Niederspannungs-Schaltungtechnik – der 1-V- und der 2-V-transceiver” (Low voltage circuit technology – the 1 Volt and the 2 Volt transceivers). The improvements are concerned with better input filtering at 14 MHz with a quartz crystal in the front-end filter and better efficiency in the mixer and removal of an audio stage in the direct conversion receiver. This design only uses bipolar transistors and no ICs.

This is different in the newer 2 or 3 Volt transceiver for 7 MHz. Here an impressive figure of only 5 mA power consumption for the receiver is achieved. The transmitter consumes about 250 mA. Several MC1496P balanced modulator/demodulator ICs are used for the mixers in the transmitter and the superhet receiver, and for the product detector of the receiver. They seem to run quite comfortably on only 1.8 Volts as supplied by a low-droput regulator from the battery supply. The TDA7050 is used for the audio output stage. This is a low voltage audio amplifier for headphones which can operate with  a supply voltage down to 1.6 V.

The design is said to benefit from low voltage technology of mobile phones. This is the case for circuitry like that of the output stage of the transmitter which consists of a pair of BFG21W transistors. However, both of the ICs have been around for many years.

I think this was a very inspiring read, and the final comment about power consumption from the second article is interesting. They say that with two AA-batteries, the receiver will last for 285 hours, which is the same as 70 days of listening of 4 hours per day. With transmission for 10% of the time, the set of batteries will last for 4 weeks!

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