Cape Cod Credit Card Crystal Radio DIY KIT Schools, scouts science fairs

£9.75

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Description

buy from eBay

This is a kit if you want it ready built – see my other listings. UK postage included.

To celebrate international Marconi Day!!

The Cape Cod 2 band Crystal Radio in kit form Frequency Range ( approx.) 555KHZ to 3.5 MHZ – You need to solder the components. This kit  comes with everything in the photo, leads crystal earpiece aerial and earth leads and adjusting screwdriver for tuning. Plus card holder in blue and clip. Comes with full build instructions.

Quality board with solder mask coating  so ideal for camping, dxing on holiday or  standby emergency use on expeditions when all your batteries are flat.

No coils to wind, tuning is by on board tuning capacitor, with tuning screwdriver provided.

If you are fascinated by power free radios then this may interest you. Ideal for portable use, hiking, camping, etc. Just clip the aerial or earth wire on to a metal structure to provide the aerial.

Each germanium diode and earpiece is selected for optimum performance.

A fun little radio, just clip aerial and earth crocodile clips to the large pads on the board. Pads could be soldered for a more permanent connection.

 

Cape Cod Instructions

Instruction DIY Cape Cod Crystal Radio Kit

1. Solder D1 the germanium diode. RED band to the right.
2. Solder L1 220uH inductor (Red Red Brown Silver )
3. Solder L2 470uH Inductor (Red Violet Brown Silver )
3. Solder R1 82K ohm resistor (Grey Red Black Red ) Above Switch
4. Solder band change switch, make sure it is parallel with the board
5. Solder the 3.5mm earphone socket, ensure it is parallel to the board before you solder and the locating pins align with board holes.
6. Solder the variable capacitor 120pF. Any way it is not polarity sensitive.
7. Two silver pins are provided for aerial and earth connections,just clip the crocodile clips to these pins or, leave these pins off and connect to the pads on the board. For portable use and younger children best to leave these pins off the board.
Connect the crocodile clips for the earth and aerial wires. Strip approximately 25mm of the insulation, thread through hole and crimp both the insulated part and the bare wire with pliers.
L1 is an inductor, a 220uH coil in series series with L2 a 470uH inductor. The switch shorts out the L2 in ther band 1 position. D1 is a specially selected germanium diode to give optimum performance in this particular circuit. R1 is a 82K resistor across the high impedance output. The variable capacitor is a 9 – 120pF capacitor
Getting Started .Plug the headphones into the socket. Holding your thumb behind the socket when plugging in will avoid any stress on the solder joints.To get the strongest signals in your area you will need to experiment if you need both an earth and an aerial. In some cases just an earth will pull in strong signals. Check the earth on both the earth and aerial pads. When hiking camping etc. You can clip the earth or aerial clip to a fence or metal structure. An aerial is also provided; this can be coiled or fixed in a straight line. (Always disconnect a long outdoor aerial when not in use, to prevent damage from a possible lightening strike). If many stations are breaking through on the same setting this is an indication that the aerial is not required.
Adjusting the tuning. Use the small screwdriver provided to adjust the variable capacitor on the board. The capacitor rotate continuously from maximum to minimum, then increase again. Technical description. Approximate frequency range band 1 – 553KH – 2 MHZ , band 2- 1KHZ – 3.5KHZ.
You will need to experiment, in some cases just a good earth is all that is required. Metal water pipe is ideal. Signals will usually be stronger in the evening. If selectivitly is poor and a few stations breaking through together, try shortening the aerial. Experiment with different aerial lengths to obtain the optimum performance in your aerea.
Detector – Germanium diode.Earpiece supplied– High impedance crystal earpiece.
Fault finding. If no sound is heard then check the earpiece on a powered appliance, sometimes in transits the earphones “lock up”.
Feedback on your area and stations received would be invaluable – enjoy your power free radio!!
On multiple orders these instructions can be emailed in colour for you to print.
If you require further help please contact me trevorsmith50@hotmail.com

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