Different antennas for wireless video?
antennas wireless video
By Clemens Hönig
on 6/12/19, 10:43 AM • 1,757 views
What`s your experience using different antennas on your wireless video system?
Are you using circular polarized antennas (f.e. mushrooms) or linear antennas.
What is your take? What are your favorites?
On 6/12/19, 4:40 PM
I was going to do a whole post, but with circular polarized (mushroom, clover, stubby, etc) antennas catching on, it’s important for everyone to understand the role they play in the RF toolkit and when/where/how to use them.
The main takeaway (as I understand them - I’m no expert) is that in order to minimize signal loss, you need to match the polarization of your RX and TX. This means if you’re running stubby right-hand circularly polarized (RHCP) antennas on your camera TX, you should run them on your RX as well otherwise you’ll experience around 3dbi of signal loss, which is significant in most wireless systems we’re using these days. I see a lot of people running standard linear antennas on their receivers and stubbies on the camera and this is pretty detrimental to the strength of the signal...
The main benefit of circularly polarized antennas over linear antennas (besides the small size and ruggedness that Martin mentioned) is that they work on all 3 planes and are much less affected my orientation or direction than linear antennas. I’ll attach some charts and links when I’m back at a computer, but for Steadicam and MōVI shots where the camera is spinning and it’s almost impossible to make sure the linear antennas are always oriented correctly, CP antennas do the job for you. If you take two linear antennas and hold them at a 90 degree angle from each other, they theoretically provide no power to each other - imagine this in a camera system where the camera is tilting straight up to straight down... If the receiver is in the same place an all antennas are oriented vertically, your Teradek Bolt3000 becomes a Bolt300.
I’d be curious to hear everyone’s thoughts on why most systems are linear based by default... I’ve never gotten a straight answer.
On 6/12/19, 11:11 AM
Personally I use mushroom antennas for the teradek transmitter(TX) and receiver(RX). Main reason why I use them on the TX is so the build get as small and compact as possible so the operator don’t break or damage antennas while using the camera. Trust me that happens all the time. I also use mushroom antennas on the smallHD 703 bolt monitor that has a built in teradek receiver. Been using them for almost a year now and haven’t had any problem signal wise so far. For the cPro motor I use the ARRI outdoor antenna for the UMC-4.
I got my mushroom antennas from amazon.