DIY BiQuad 11dbi antenna tutorial! - Page 45 - RC Groups
Thread Tools
Dec 31, 2012, 05:46 PM
Registered User
1fullbird's Avatar
Is there a recommended post mortem fix? e.g. use a shielded wire for the active. I used Romex 14-3 and stripped the insulation for the wires. (At least I got to try out my new soldering station)
Sign up now
to remove ads between posts
Dec 31, 2012, 09:27 PM
Registered User
1fullbird's Avatar
I grabbed some coax stripped the outside sheath, removed the shield/foil, exposed the pin then hollowed around the pin so it would fit over the N chassis active feed. Then, I de-soldered the feed from the active, soldered the coax on the feed, trimmed to length and soldered the feed to the element. Is this sufficient to thwart a radiating feed?

Picard, thank you on the weather proofing.
Dec 31, 2012, 09:29 PM
WannaBeLikeJoshTheSlowJet
bakchos's Avatar
Quote:
Originally Posted by 1fullbird
I grabbed some coax stripped the outside sheath, removed the shield/foil, exposed the pin then hollowed around the pin so it would fit over the N chassis active feed. Then, I de-soldered the feed from the active, soldered the coax on the feed, trimmed to length and soldered the feed to the element. Is this sufficient to thwart a radiating feed?

Picard, thank you on the weather proofing.
what you have to keep is the shield (foil) the plastic will let the wave pass like butter.
Dec 31, 2012, 09:41 PM
Registered User
1fullbird's Avatar
Got it. Thank you.

Updated picture of active feed with shielded cable. Is this sufficent to prevent the radiating feed? (unsure of the exposed center element of the N chassis at the point of origin?)
Last edited by 1fullbird; Dec 31, 2012 at 10:29 PM.
Jan 13, 2013, 05:55 AM
Registered User
Can I use a 1.2mm galvanized steel for reflector?
Jan 13, 2013, 10:59 AM
Engineer for Christ
IBCrazy's Avatar
^Yes. That's what I use.
Jan 13, 2013, 11:00 AM
Engineer for Christ
IBCrazy's Avatar
Quote:
Originally Posted by 1fullbird
Got it. Thank you.

Updated picture of active feed with shielded cable. Is this sufficent to prevent the radiating feed? (unsure of the exposed center element of the N chassis at the point of origin?)
You need to connect the wire to the shield at the feedpoint, not at the base or you end up with a unbalanced transmission line.

-Alex
Jan 13, 2013, 03:05 PM
Registered User
1fullbird's Avatar
Alex, Thank you. I have since built another one with the 1/4" copper pipe instead of the N chassis. It seemed to go easier. Had nothing to do with practice (right).
Feb 07, 2013, 03:03 AM
Registered User
Alex, Thank you for making science as easy as anyone with shallow knowledge about electronics can deal with such important issue for FPV guys
Feb 26, 2013, 01:30 PM
throw new IOPilotException();
IceWind's Avatar
A gust of wind decided to damage my biquad.
So I was facing the problem of where to get a copper tube to make a new one.

Destiny (or me as a bad pilot) put in my hands a broken skid pipe from a 450 heli. That thing is aluminium and scrapping the coating it seems to conduct energy quite well.
So I'm just wondering if that is ok to use? I suppose copper would be better but in lack of it.
Feb 26, 2013, 02:52 PM
Foam Snow
I tested my biquad today and was 5km out when my RTH kicked in, except there was a mountain below my plane, higher than the RTH altitude... I watched helplessly as my plane crashed into it.. and kept on watching it! 4.6km away, crashed into some bushes my inverted V touching the ground, I was still reading the OSD no problem!!

I'm so impressed with this design... thanks Alex.

If only my radio link was as robust... :/
Feb 26, 2013, 11:30 PM
Registered User
picard10th's Avatar
Sorry about your SW I also have a SW w RL and IBC DIY bi-quad (1280) and have been out over 13km with both still solid. I fly in a very noisy RF environment. You look like that area is pretty desolate unless there is a tower on that hill. I wonder why the failure at such a short distance. I have some Q's if you don't mind.
Did you do micro tests to make sure there was no onboard interference?
Were you able to monitior your RSSI? If so was there a gradual or sudden drop?
If you have a video of the flight I would like to view it.
It looks like your electronice are ok so I hope your back in the air soon!
My setup is in my blog. I appreciate your input.
Feb 27, 2013, 12:36 AM
Foam Snow
Quote:
Originally Posted by picard10th
.. I have some Q's if you don't mind...
Thanks Picard, sent PM.
Feb 27, 2013, 09:09 AM
Engineer for Christ
IBCrazy's Avatar
Quote:
Originally Posted by IceWind
A gust of wind decided to damage my biquad.
So I was facing the problem of where to get a copper tube to make a new one.

Destiny (or me as a bad pilot) put in my hands a broken skid pipe from a 450 heli. That thing is aluminium and scrapping the coating it seems to conduct energy quite well.
So I'm just wondering if that is ok to use? I suppose copper would be better but in lack of it.
If you can solder it, it will work. In my tutorial, you will see I use no tube. I just folded over the coaxial cable shield. The tube is added in many people's builds for simplicity.

-Alex
Mar 08, 2013, 08:09 PM
Registered User
zooman's Avatar
Could one use stainless steel as the back ?


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log How To Build a BiQuad RX antenna Talajouy FPV Talk 21 Dec 23, 2010 12:52 AM
Question DIY Biquad antenna for a 900mHz Moosthegoose FPV Talk 5 Jan 14, 2010 04:37 AM
Discussion Antenna tutorial JIMOOO FPV Talk 1 Feb 25, 2007 01:04 AM
Discussion looking for a DIY tutorial. TonyBAMF Beginner Training Area (Aircraft-Electric) 8 Jan 10, 2006 05:56 PM
I need help to DIY flywire antenna for 36 MHZ RX GoodHeli Radios 5 Aug 24, 2003 09:05 PM