How to make magnetic loop antenna

[mrel]

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

 

[majoco]

Depends on the value of the tuning capacitor.

 

[pastian]

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!

 

[prcguy]

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]

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

 

[iMONITOR]

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

DIY 20m loop antenna

https://www.google.com/search?q=bui...+antenna&ie=utf-8&oe=utf-8&client=firefox-b-1

 

[WRCM]

Try this (pdf): http://www.cvarc.org/resources/Tech_Articles/magnetic_loop_antenna.pdf

 

[majoco]

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.