7 September 2012, 07:36
Following yesternay's note about the little Lidl multi-band receiver, this thread describes how to make a wire antenna and simple, low cost, tuning coil to greatly improve reception of simple receivers of this type.
The attached word file duplicates the descrption below and illustrates the Tuning coil with two diagrams.
What you’ll need
• Needle nosed pliers
• 50 -60 ft (20m ) of insulated wire ( any thickness will do)
o Stranded loudspeaker wire is a good low cost choice.
• 8†to 10†(approx) of 1â€Âdiameter white PVC waste pipe.
• 2 x screw on small crocodile clips
• Screw driver
• Strong nylon fishing line ( for rigging far end of antenna wire.)
• OPTIONAL: If the tuning coil is effective it can be permanently housed in a plastic container ( PVC ice cream tub or similar)
o 10 position rotary switch ( Maplins) This makes a slightly easier to operate tuning unit, and avoids having to open the box to change the patch lead tap point connections. Fixed wires from tap points to the various connection tabs on the switch have to be soldered in position.
o Connections into and out of the box can be made using small bright metal bolts with double nuts on the outside of the box that will allow connection to the antenna and to the Fly lead.
Long Wire Antenna
Long wire should extend 20 to 30 feet outside of buildings and should be rigged with nylon line to nearby tree, buildings etc so as to be as high in the air as possible greater than 15ft above the ground is a good target. Wire does not have to be in straight lines. ( the longer and higher the better).
• Length is not too critical. Minimum that will get improved reception will be in the order of 10 feet long
• Insulated wires can be run in or under PVC gutters
• If possible select thin black PVC coated wire, because the insulation helps radio wise and also assists with OPSEC
Tuning Coil
1. Wind (close together) the same insulated wire as used to make the long wire antenna onto a length of 1†white PVC waste pipe .
2. Make a small hole in the pipe fir the start of the first winding.
3. Wind 50 to 100 turns of wire, twisting a small loop every 5 ot 10 turns ( stating on turn 1 and last one on final turn)
a. Use needle nosed pliers to make the loops
b. Loops should be small, say 5mm diameter
4. Tie off the final turn through a hole drilled in the pipe
5. Strip insulation of the small loops made in (3) above with Stanley knife
6. Cut a length of insulated wire to use as a Fly lead between the tuning coil and the radio
a. Strip 1cm ( approx) insulation off each end
b. Screw attach the bare wires to crocodile clips, one at each end
How to use:
Rig antenna wire
Clip one end of patch lead to receiver’s telescopic antenna ( best with antenna in its collapsed, stowed position)
Clip Other end of Fly lead to tap point near middle of coil
Turn on radio, select a shortwave band and tune into a quiet signal.
Move the coil end clip between tap points to find loudest signal.
It will be found that each Shortwave band will correspond with a specific tap point on the coil. This will pretty much stay constant unless you change the length of the long wire antenna.
The attached word file duplicates the descrption below and illustrates the Tuning coil with two diagrams.
What you’ll need
• Needle nosed pliers
• 50 -60 ft (20m ) of insulated wire ( any thickness will do)
o Stranded loudspeaker wire is a good low cost choice.
• 8†to 10†(approx) of 1â€Âdiameter white PVC waste pipe.
• 2 x screw on small crocodile clips
• Screw driver
• Strong nylon fishing line ( for rigging far end of antenna wire.)
• OPTIONAL: If the tuning coil is effective it can be permanently housed in a plastic container ( PVC ice cream tub or similar)
o 10 position rotary switch ( Maplins) This makes a slightly easier to operate tuning unit, and avoids having to open the box to change the patch lead tap point connections. Fixed wires from tap points to the various connection tabs on the switch have to be soldered in position.
o Connections into and out of the box can be made using small bright metal bolts with double nuts on the outside of the box that will allow connection to the antenna and to the Fly lead.
Long Wire Antenna
Long wire should extend 20 to 30 feet outside of buildings and should be rigged with nylon line to nearby tree, buildings etc so as to be as high in the air as possible greater than 15ft above the ground is a good target. Wire does not have to be in straight lines. ( the longer and higher the better).
• Length is not too critical. Minimum that will get improved reception will be in the order of 10 feet long
• Insulated wires can be run in or under PVC gutters
• If possible select thin black PVC coated wire, because the insulation helps radio wise and also assists with OPSEC
Tuning Coil
1. Wind (close together) the same insulated wire as used to make the long wire antenna onto a length of 1†white PVC waste pipe .
2. Make a small hole in the pipe fir the start of the first winding.
3. Wind 50 to 100 turns of wire, twisting a small loop every 5 ot 10 turns ( stating on turn 1 and last one on final turn)
a. Use needle nosed pliers to make the loops
b. Loops should be small, say 5mm diameter
4. Tie off the final turn through a hole drilled in the pipe
5. Strip insulation of the small loops made in (3) above with Stanley knife
6. Cut a length of insulated wire to use as a Fly lead between the tuning coil and the radio
a. Strip 1cm ( approx) insulation off each end
b. Screw attach the bare wires to crocodile clips, one at each end
How to use:
Rig antenna wire
Clip one end of patch lead to receiver’s telescopic antenna ( best with antenna in its collapsed, stowed position)
Clip Other end of Fly lead to tap point near middle of coil
Turn on radio, select a shortwave band and tune into a quiet signal.
Move the coil end clip between tap points to find loudest signal.
It will be found that each Shortwave band will correspond with a specific tap point on the coil. This will pretty much stay constant unless you change the length of the long wire antenna.