Quadrifilar Heliciodal Antenna question.
Posted: Fri Jul 18, 2008 9:31 am
Hi all,
I'm pretty new to this game; I've had a few projects over the years - mainly based on computers controlling servos etc...(made an automatic cat-flap once with motion detection - sad, I know).
However, I am in the process of making a quadrifilar helicoidal antenna and have found a few designs on the good old Interweb, but out of the designs I have found where they make the antenna from coax cable, they use four lengths of cable and solder them together at the top and bottom.
My question is, does this matter? Can I just use one long length of coax to save the soldering?
Here is what I am making:
http://www.cidb.co.uk/pics/helicoid.jpg
...as you can see, it would be possible to feed one long length of coax through from the bottom, up around etc... and back down to the bottom to the connector and still keep the helicoidal shape.
One other thing is, I believe that the coax in the UK is 70 ohms - I'm not sure what the receiver that this is going to be plugged into is. Would I need to convert it (by maybe soldering to a heavier ohm coax cable) to the same before attaching to the unit?
The unit that this is going into is an Icom PCR1000 (in case that means anything to anyone!).
All help gratefully recevied - I really am a complete electronics beginner.
I'm pretty new to this game; I've had a few projects over the years - mainly based on computers controlling servos etc...(made an automatic cat-flap once with motion detection - sad, I know).
However, I am in the process of making a quadrifilar helicoidal antenna and have found a few designs on the good old Interweb, but out of the designs I have found where they make the antenna from coax cable, they use four lengths of cable and solder them together at the top and bottom.
My question is, does this matter? Can I just use one long length of coax to save the soldering?
Here is what I am making:
http://www.cidb.co.uk/pics/helicoid.jpg
...as you can see, it would be possible to feed one long length of coax through from the bottom, up around etc... and back down to the bottom to the connector and still keep the helicoidal shape.
One other thing is, I believe that the coax in the UK is 70 ohms - I'm not sure what the receiver that this is going to be plugged into is. Would I need to convert it (by maybe soldering to a heavier ohm coax cable) to the same before attaching to the unit?
The unit that this is going into is an Icom PCR1000 (in case that means anything to anyone!).
All help gratefully recevied - I really am a complete electronics beginner.