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- เผยแพร่เมื่อ 12 มิ.ย. 2024
- This video will describe how to build a 915 MHz monopole antenna that can be used on your LoRa radio. ( USA/Canada ) Other types of antennas will also be covered.
www.parallax.com/ Propeller Flip
www.cdebyte.com/en/ LoRa E32-DTU
us.banggood.com/ FTDI, Nano, Bluepill
www.dipmicro.com/store/ USB to serial cable
www.gpscity.ca/ Garmin GPS - วิทยาศาสตร์และเทคโนโลยี
performance of those 1/4 wave groundplane antennas is ridiculously good for the cost and effort involved. i made one for 2m and it's a monster performer.
Thanks for the feedback!
I can’t wait for your test results for these! Really interesting, good work!
Thanks for this great video , and for the other LoRa videos.
Thank you for this video. A very big help!
Glad it was helpful!
Nice video thanks
Would love to see a tuning video.
Wonderful
HI Forgive the question as am a newbie to Antenna design but I have two questions..
1) you mention your want a VSWR of 2v, why 2v and how could you measure that (is it easy) - I assume this could help you tune the antenna for the best resonance?
2) on your example of a PCB board antenna, unlike the quadrupole, it looks like the TX line is connected to the ground - is that right? I was expecting it to be more like the quarapole where the tx is only connected to ground via air?
Finally - Great video - thank you so much for sharing this, really simple and straight forward - I will be making some quadrapoles for my Lora Systems. Thanks. Dave
VSWR is a ratio ( Voltage Standing Wave Ratio ) which indicates how good the antenna is matched to the transmitter. 1:1 would be a perfect match and 2:1 would indicate about 11% of the power is reflected back to the transmitter. A VSWR greater than 2:1 indicates a problem and should be looked into. A VNA is used to measure VSWR. Check out this video: th-cam.com/video/wR-2c8VgunI/w-d-xo.html
2. The TX line is not connected to ground for the PCB antenna. The drawing shows a RF connector soldered on the PCB. Thanks for your feedback.
Hi. Great video! Could you add a parts list for the first one? Thank you
www.amazon.ca/uxcell-Female-Chassis-Connector-Adapter/dp/B00MFRUGIW
N connector and 14 AWG solid copper wire.
Can you elaborate on the antenna pcb connection for your sample pcb diagram please? I’m not sure if the mount terminals are connected to signal lead in center.
I am confused by the "ground plane" connected to ground yet its also connected to the signal pin. I made a post asking about an implementation of your video here. electronics.stackexchange.com/questions/561441/pcb-antenna-connector-and-copper-signal-names
Can you make a Antenna on youtube for SMA connector 70cm only ? Thanks exact freq 442.XXXX to replace the rubber duck insufficient antenna :)
could you make a video for making an omnidirectional antenna that could get say about 10Miles range?
Range depends on more than just the type of antenna. Power output, Fresnel zones, height above ground, feed line loss, spreading factor all come into play.
th-cam.com/video/jZB5SH8gmAg/w-d-xo.html
Hello. If a reply the same project for a 1 wavelength scale (915mhz) would I get good results for a wider range? In may case, I have no size or power limitations)
Maximum scale would be 5/8 wavelength where you would need a matching network. Greater scale than this will result in a unusable radiation pattern and increase in input impedance.
Is a 6” aluminum disk an optimal ground plane for 915 MHz? Is the shape or type of metal important?
Yes, that would work. The antenna was originally designed for mobile applications to be mounted on the roof of a car which was the ground plane.
HEy could you tell us the VSWR of these antennas? Will the quater wave groud plane antenna has =1 VSWR? i mean, can we go close to it? Thanks.
The 1/4 wave ground plane antenna will give you a good match. VSWR will be close to 1:1. Check out this video on VSWR and range. th-cam.com/video/jZB5SH8gmAg/w-d-xo.html
Any idea how much gain these antennas can give?
0dBd.
Does the MLPV800 cantenna have the same omni shaped broadcast pattern as effective as the taller whip type LoRa antennas?
Yes, it has the common omni do-nut pattern when placed on a good ground plane.
d3dqzy9ky05fbv.cloudfront.net/wp-content/uploads/2020/06/MLPV-Series-Patterns.pdf
@@0033mer Thanks for providing that link. Just what I was looking for.
Do you have part numbers for the two connectors?
Check out Digi-key, they carry the whole range of RF connectors.
www.digikey.ca/product-detail/en/amphenol-rf/82-97-RFX/ARFX1023-ND/21820
1:40... Where does the 2832 number come from ??
A wavelength is the speed of light divided by the frequency. 186000 mi/sec/freq Hz
That would be 982.08 feet/sec/freq Mhz
A quarter wavelength would be 245.52/Freq Mhz (feet)
Multiply by 12 to get inches
2946/Freq Mhz (inches)
The speed of light is slower in a wire because of its dielectric constant.
To compensate we multiply by the velocity of propagation factor.
Vp can vary but I use .961
2946 X .961 = 2832
For a metric calculation use the speed of light in meters/sec
Great explanation... Got it. ;-)
So it wasn't just me wondering where the 2832 came from.
Wow, thanks so much for the enlightenment. Seen a lot of videos that throw numbers around arbitrarily, but rarely (first time here) have I seen the reasoning behind them. Keep up the good work!
Woooow... So cool :) writing this down hehehe
Hmmm, could this be used for GMRS, with the radial coming up longer like 6 inches or so?
Yes .. just use the calculation formula shown in the video for the radial lengths.
@@0033mer Thanks!
sweet. maybe just show the measuring device or what the
" Equal or less than 2" refers to the VSWR ( Voltage Standing Wave Ratio ) You can Google or check out this video.
th-cam.com/video/oiBi9RbNBUY/w-d-xo.html
To measure the VSWR of an antenna we use a VNA. Check out the end of this video for a demo.
th-cam.com/video/wR-2c8VgunI/w-d-xo.html
Where does the 2832 number come from?
A wavelength is the speed of light divided by the frequency. 186000 mi/sec/freq Hz
That would be 982.08 feet/sec/freq Mhz
A quarter wavelength would be 245.52/Freq Mhz (feet)
Multiply by 12 to get inches
2946/Freq Mhz (inches)
The speed of light is slower in a wire because of its dielectric constant.
To compensate we multiply by the velocity of propagation factor.
Vp can vary but I use .961
2946 X .961 = 2832
For a metric calculation use the speed of light in meters/sec
Nickel plated, not silver.
You can use nickel plated connectors, but I find you have to apply an acid based flux for good results. I use AMP 1-1337418-0 connectors which are silver plated.
www.onlinecomponents.com/en/te-connectivity-amp-brand/113374180-10146065.html
@@0033mer How you tested that cantenna? I wonder if it works better than copper wire quarter wave antena alone? I like it because its simplicity and it protects cable connector from weather conditions.
For tuning and testing my antennas I use the N1201SA antenna analyzer. Check out this video for more info. th-cam.com/video/wR-2c8VgunI/w-d-xo.html
antenna "build" without vna and tuning equals to a 6th grander's afternoon workshop. you just solder/screw random components to another without any proof.
The mono-pole antenna described in the video is fairly wide-band so building it with measurements only will result in a VSWR of less than 2:1. This antenna was used in a high school electronics project where all the antennas made in the class passed when checked with an Anritsu S412E. If you want proof you can do the same as covered in this video at the 6 min mark. th-cam.com/video/wR-2c8VgunI/w-d-xo.html