Projects

A Simple ShortWave Receiver

I constructed this simple receiver having seen the circuit at WB4LFH's web site which he calls it the 'audion'. This circuit is almost identical to the last circuit on that page, except I changed the inductor connection to the variable capacitor from being a tapped connection to being a transformer coupling.

The inductor was a T50-2 toroid with secondary being 28 turns of enameled copper wire and the primary (connected to the antenna) being two turns. (Remember a 'turn' on a toroid is the passing of the wire through the hole). The transistors were 2N3904 types, but you can try any general npn transistor. The tuning capacitor was a air plate type taken from an old radio receiver, likely about 300pF. The circuit was constructed 'ugly style' on a small piece of unetched circuit board. Use what you have in your junk box and experiment.

The performance is very good considering the simplicity of this receiver. Below are a set of sound recordings from this receiver. Recordings are in .ogg (Ogg Vorbis) and .wav formats. The recordings show how the volume can change (no AGC here!) and that the selectivity is not too good.

If you consider building this receiver please note that these recordings were done with the receiver connected to my external antenna (my G5RV which has 102 ft of wire in the air). I tried using a long whip antenna, which I had in the junk box, and there was no discernable reception of a signal with it. So you will likely need to use a good length of wire to act as an antenna. Let me know if you have any success with this circuit.

• Guitar music Ogg Vorbis format.  
• Guitar music Wav format.  
• Station identifier Ogg format.  
• Station identifier Wav format.  
• Radio Habana Cuba Ogg format.  
• Radio Habana Cuba Wav format.  

QRP performance

This section is for anyone wondering how effective is QRP on HF, something that I wondered when I first started out. I should stress with this list I am a very casual operator. I do not have a lot of spare time (due to family and work) and I am not a serious contestor nor DXer. These are the results of casual radio operation.

I will break the information into section. Not all have been QSLed but all contacts were made.

• Worked all states (WAS)
• Countries worked
• 1W SSB during the RAC Canada Contest (40m only)

Worked All States

This is my work towards the award to contact an amateur station in all the States of the USA. I am increasing the challenge by restricting to contacts made only by the mode PSK31 and having my power level to QRP levels (5W or less). The callsign given with the State is the station that has QSLed the contact. Thanks goes to all the stations listed here for the QSO and the QSL card.

Table 1: WAS contacts.

State	Callsign
Alabama	WA4KBD
Alaska
Arizona
Arkansas	WA5EOG
California	W6VZV
Colorado	N0GRA
Connecticut	AA6E
Delaware
Florida	KG4MWO
Georgia	K4ODI
Hawaii
Idaho	N7UVH
Illinois	AA9UF
Indiana	KB9WWM
Iowa	KN0R
Kansas
Kentucky	KC4WQ
Louisiana	KC5BYE
Maine	KC1DI
Maryland	N3WT
Massachusetts	W1JCJ
Michigan	N8KBG
Minnesota	K0TCP
Mississippi	K8FA/5
Missouri	W0LPR
Montana	KK7OA
Nebraska	NE0DX
Nevada	KB7NO
New Hampshire	K1WO
New Jersey	N2DP
New Mexico	K5PAX
New York	WB2NSC
North Carolina	WA2FLN/4
North Dakota
Ohio	N8MWK
Oklahoma	N5UMH
Oregon	N7QU
Pennsylvania	N3KNZ
Rhode Island	N1ZW
South Carolina	KI4RO
South Dakota	W6YQ
Tennessee	N4LI
Texas	AD5JZ
Utah	KJ7NO
Vermont
Virginia	KG4VQU
Washington	W7QQ
West Virginia	KB8QLG
Wisconsin	KC9AA
Wyoming

The total sits currently at 42 and I am now getting down to some of the more challenging States to contact, due to their location or population.

This work is licensed under a
Creative Commons Attribution-NonCommercial-ShareAlike 2.5 License.

Last modified 19/07/2006