Antenna: before make receiver
@2014/6/19
every time, while i build a regen receiver, I MADE SAME MISTAKE.
i made mistake because i had built super regenerative receiver, MW , air band receiver, make me get an illusion about them. it seems there even don't need a decent antenna for Short Wave receiver, i would think 1 meter wire supposed to do the work, because regen receiver had very high gain or something bla bla.
I built very simple antenna for super regenerative receiver , like Air plane band, only a half meter wire. For middle wave station , I use ferrite rod antenna. When i came to regenerative receiver for short wave, I thought 1 meter wire should do the work, but random wire antenna beat me EVERY TIME.
I try to throw a wire outside window, hope it would be much better than indoor wire, but still receive nothing.
Listen shortwave station or ham radio
i try to find out how people listen Shortwave station. It turns out they all have Antenna for SW, DX.
Why failed while use short wire antenna?
A short wire is work well for FM band/Air Craft band, for 100 Mhz, 50 cm is really not very short.
But for shortwave 1.6 Mhz to 30 Mhz, half meter antenna is nothing. Plus there is no ground connect to the receiver ! Short wire or telescope whip antenna is Monopoles antenna, to make it better, you need connect it to ground as another pole. For FM band receiver, it quite long and efficiency, body capacitance couple also enough to be a ground plan.
Whip some times works well and some time don't, especially for SW band. Some whip antenna does work, like PA2OOH‘s receiver， one reason might because the receiver is sensitive, and PA2OOH use metal box seems had good capacitance couple to ground.
So if you trying make your first regen for SW, please use long wire antenna(5 Meter to 30 Meter ) and a good ground connection if possible.
What Antenna other Ham use for their Regen
I'm curious of what antenna they use for their regen receiver. I have been misleading for long time thinking Regen might work well to listening SW only by an un-ground whip. One reason for this is that most of published article , Even ARRL/QST , does not mention what kind of antenna they used for the Regen Receiver. Another reason is, i mis-understanding some online article, they do have ferrite rod antenna or they said they use short antenna, but for SW, a shot antenna at least 5 meters long.
hern at icehouse.net said his tube regenerative receiver is performed well with good antenna. Tom Dufresne said his receiver is very very sensitive, good result with 400 foot giant loop antenna with excellent results. I have also used a 20 foot antenna with good results. you know 20 foot is about 6 meter long, this is what sensitive mean to Shortwave band. Zarucki M0DGQ also suggest 10 meter to 15 meter long wire as antenna. m0dgq himself use a 30 meter long wire as antenna.
SV3ORA experience his regen receiver with connecting to a coaxial wire coming out of his window, with no antenna attached to it on the other end, and he said, this is really amazing sensitive. even-though he did not mention this wire length, it's actually a whip antenna.
ON6MU make state his receiver for LF, MW does not need external antenna the ferrite rod antenna is good. but for SW, external antenna is necessary. TenTec Model 1054 4-band regen receiver KIT , in comments section, KU4UV said he use a long wire out of window as antenna and use power cord ground.
What Antenna i Use
I have no antenna by now, I throw a 3-5 meter wire out of window to testing my SW receiver. For outdoor testing, a whip antenna is used, some time connecting a long wire as ground.