How to make magnetic loop antenna

mrel

Member
Joined
Oct 14, 2005
Messages
10
#1
Hello
Want to make magnetic loop antenna for 20meter band ,how big circumference do need to receive the 20 meter band.
thank for the help.
mrel
 

pastian

Member
Premium Subscriber
Joined
Jan 1, 2004
Messages
20
Location
Sioux Falls
#3
I built one of these today: https://www.youtube.com/watch?v=Dw1rz0CVn90&t=705s

I won't transmit on it listening only

I have the cheapest SDR I could buy
I cheated and used one continuous 205" for the 80/40 loop
I used all quad RG6 and crimped on B&C
The hardest part was the pick up loop which I did in RG6 as well
I have no idea what the air capacitor is rated at came out of a vintage AM/FM radio

Works great...however she is very high maintenance and my tuning finger is stiff.
Pretty narrow bandwidth.
You are almost guaranteed to hear both sides of a conversation
A monkey could tune this thing with the VERY noticeable increase in "noise" when your on Freq.

I think I will try it outside next

This video will point you to a lot of calculators for 20 Meter band

Have fun!
 
Joined
Jun 30, 2006
Messages
7,195
Location
So Cal - Richardson, TX - Tewksbury, MA
#4
For listening only check out my quick reviews of the W6LVP active receive loop in the RR SW antenna area.

I built one of these today: https://www.youtube.com/watch?v=Dw1rz0CVn90&t=705s

I won't transmit on it listening only

I have the cheapest SDR I could buy
I cheated and used one continuous 205" for the 80/40 loop
I used all quad RG6 and crimped on B&C
The hardest part was the pick up loop which I did in RG6 as well
I have no idea what the air capacitor is rated at came out of a vintage AM/FM radio

Works great...however she is very high maintenance and my tuning finger is stiff.
Pretty narrow bandwidth.
You are almost guaranteed to hear both sides of a conversation
A monkey could tune this thing with the VERY noticeable increase in "noise" when your on Freq.

I think I will try it outside next

This video will point you to a lot of calculators for 20 Meter band

Have fun!
 

mrel

Member
Joined
Oct 14, 2005
Messages
10
#5
Hi
Anyone know what circumference would be using soft copper tube to make 20 meter magnetic loop antenna.
What other parts need to make a 20 meter magnetic loop antenna.
Thank for your help .
mrel
 
Joined
Dec 25, 2008
Messages
3,045
Location
New Zealand
#8
Why the expense and weight of copper tube? I use RG8 on a cross with the pickup loop at the top and the capacitor at the bottom - much easier to use - receiving only but it works well. If you wanted to make it really posh you could fit PL259's on each end, SO239 sockets on a box and the tuning cap inside the box - room for an amp if you felt like it. Just the braid outer of course but I'm contemplating the same principle to make a screened loop with the braid as the screen and the centre as the tuned section.
It's a diamond shape 40inches across from corner to corner.
 
Top