TC3EC 433MHz Moxon Antenna by TA3NT
For detailed information, you can read our related blog post(TR).
This antenna was designed by TA3NT under the name "TC3EC Moxon Antenna" to meet the antenna needs of 433MHz LoRa Meshtastic Nodes in Turkey and was made available to amateurs without any financial interest.
As you can see from the images, the antenna became very popular in a short time and attracted great interest from Turkish amateurs. It continues to be used in many LoRa nodes today. In the following time, it evolved into a completely different position with the modifications of many amateur friends and turned into an ecole. You will also see our friends mentioned in the Remixes section of the project I uploaded here in line with his request. Of course, we would like to see you in both remixes and makes. Please feel free to post remixes, makes and comments.
TC3EC is a community of amateur radio operators from İzmir/Turkey, the flag bearer of AREDN, Meshtastic and many new communication technologies and a favorite of amateur radio competitions in our country. You can find more detailed information about them on their QRZ page and social media accounts.
Printer Brand:
Creality
Printer:
K1
Rafts:
Doesn't Matter
Supports:
No
Resolution:
.20
Infill:
%30
Filament: Porima PetG Kırmızı RAL3020 Notes:
Since you will be using these plastic parts mostly outdoors, it is essential that you prefer filaments that are more resistant to heat and UV radiation such as ABS, ASA, PetG.
Inserting Antenna Elements
After printing the"TC3EC_Moxon_Body.stl" file, insert the previously stripped 1.5mm NYA single-core copper cable into the channels inside the Moxon Antenna using tweezers or some poking tool.* You will need approximately 342mm wire for the reflector and two 140mm wires for the dipole elements. After inserting the copper wire into the channels, cut off the excess parts.
*At this stage, you can apply a thin layer of glue inside the channel to hold the antenna in position, tape the antenna, or use a soldering iron to melt the frame onto the copper wire at certain points.
Soldering Coaxial Cable To Antenna Elements
At this stage, strip the outer insulation of your coaxial cable around 1 cm. Now the braid part of the cable will be exposed. Roll the braid between your fingers to form a wire and also strip the inner insulation protecting the live end around 3 mm. If you want, you can cover the live tip and braid with solder before trying to solder to the elements. This will make it easier for you afterward. Now you have a cable to connect to the dipole elements.
Then solder the live end of your 50Ω coaxial cable (RG174, RG316, etc.) to the top dipole element as shown in the image and diagram, and solder the braid to the bottom dipole element.*
*Please do not short-circuit the live end and ground when soldering the dipole elements. At this stage, it is important to keep the inner insulation in the coaxial cable long and not to accidentally melt it with a soldering iron. However, you should remember that stray braid wires can also cause a short circuit. †No connection will be made to the reflector element.
Making Ugly Balun
After soldering the elements to your coaxial cable, create an ugly balun by wrapping* your coaxial cable 5 turns to the area just behind the dipole junction box as shown in the picture. After making your ugly balun, secure it by clamping it with plastic clamps at the notched places you will see in the photo and design.
*During this wrapping process, secure the cable in the dipole junction box to avoid pulling the cable and breaking connections with the dipole elements or removing the elements from their channels. †Ugly Balun is,
Securing The Antenna Elements
Coat the exposed copper parts of the antenna and the inside of the dipole junction box with epoxy resin or similar adhesive. Then place the printed"TC3EC_Moxon_Lid.stl" file on the dipole junction box and make sure that it sticks as well. This will provide extra protection for your antenna.
Assembly of RF Connectors To Coaxial Cable
Now your antenna is ready! Cut your coaxial cable to the distance you need and solder in your RF connector. If you don't have the ability or resources to do so, you can also cut one end of a coaxial cable that is already sold with a connector, solder it to the elements of your antenna, and make your ugly balun.However, you should keep in mind that with this method you need to decide in advance the length of cable you need.
Measuring The Antenna
Then you can test your antenna with a SWR Meter or NanoVNA and start using it. Again, if you do not have such a possibility, your vSWR will be less than 1.5 in the band if you follow the measurements exactly.
Placing The Antenna
Once you have completed the antenna and measured it, you can place it in any position you wish. You will now need to print one“TC3EC_Moxon_Mount.stl” file and at least one“TC3EC_Moxon_Arm.stl” file with at least two pairs of M5x15 screws and M5 nuts. However, it is important to note that once you have installed the antenna in the location where you will use it, you will need to measure again to see how it behaves where it will be mounted.
What is NanoVNA?
NanoVNA is a low-cost handheld Vector Network Analyzer that can measure SWR, cable loss, cable length, RF filters, and more. This device is characterized by its simplicity of construction and the fact that it does not require advanced knowledge to perform the mentioned measurements. Generally, there is a version that goes up to 900MHz, a version that goes up to 1.5GHz, and a version that goes up to 3GHz in the market. Since you will be measuring at 433Mhz in this project, you can use any of them.
How do you operate your NanoVNA in SWR measurement mode?
¹If your screen is upside down, first open the main menu by clicking on the screen once and select the"Display" tab and select"Flip Display" then click the"Back" button to go back to the main menu.
How do you set the frequency range of your NanoVNA?
Now click on the"Stimulus" tab.##### Method 1-)
Click on"Start". Here you will select the beginning of the frequency range you will scan. Enter the value"430" on the screen that appears and select the"M" button.
Click on the screen again, now select"Stop", enter the value"440" and select the"M" button. Here you will select the end of the frequency range you will scan. With this method, you will scan a bandwidth of 10MHz from 430Mhz to 440MHz, that is, the entire 70Cm Amateur Band.##### Method 2)
Or click on"Center" and enter the value"433" and click on the"M" button. You have now selected the center frequency you want to scan to.
Now click on"Span" and enter a value between 1 and 10 for example and click on"M".
This value will determine the width of the area you want to scan above and below the center frequency.
Click the"Back" button. How to Calibrate your NanoVNA?
Click on the“Calibrate” tab.
Press“Reset” to erase the previous calibration data and recalibrate to the specific frequency range you have just selected.
Then click on“Calibrate”. Then the calibration steps of the NanoVNA will appear.
Connect theopen circuit connector to“CH0”. Calibrate for open circuit by pressing“Open”. After the relevant option is no longer selected, proceed to the next step.
Connect theshort circuit connector to“CH0”. Calibrate for short circuit by pressing“Short”. Proceed to the next step after the respective option is no longer selected.
Connect the50Ω dummy load to“CH0”. Calibrate for 50Ω by pressing“Load”.
Proceed to the next step after the relevant option is no longer selected.
Connect the50Ω dummy load to“CH0” and“CH1”. Calibrate for isolation by pressing“Isoln”. After the relevant option is no longer selected, proceed to the next step.
Connect theSS405 50Ω coaxial cables supplied with your NanoVNA to the“CH0” and“CH1” ports and connect them with the SMA-F To SMA-F connector also supplied with your NanoVNA and calibrate for through by pressing"Thru". After the relevant option is no longer selected, proceed to the next step.
Click“Done” and select“Save 1” from the list and save your calibration settings in the relevant section.
You are now ready to measure your antenna. How do you measure the SWR of your antenna with NanoVNA?
Since that you are ready to measure your antenna, now you can connect your antenna to NanoVNA.
You can move your marker around the screen by tapping with the stylus or using the directional keys and scan a predetermined frequency range, and measure that SWR by leaving your marker at the point frequency you want to measure.
If you want to automatically find out where the lowest SWR is at all times:
What is MoxGen?
MoxGen is a simple and functional Moxon Rectangle Antenna generation program created by AC6LA based on W4RNL's algorithm. By only entering the frequency and wire diameter values you prefer into the MoxGen.exe, you can get measurements of a Moxon Antenna operating at 50Ω impedance with a single click.
How To Make Moxon Antenna With MoxGen?
You can easily generate your antenna by simply entering the frequency at which you want your Moxon antenna to operate in the "Frequency" section, then entering the wire thickness you want to use in the "Wire size" section, selecting your measurement unit (in/mm/AWG) from the box next to it, and pressing the "Calculate" button.
You can now see the Moxon antenna measurements that MoxGen has calculated for you under the "Calculate" button as A, B, C, D, and E.* You can change these values to "Feets", "Inches", "Meters", and "Millimeters" in the "Results Units" section, which is the box just below the measurements.
*The meaning of these mentioned values is explained in the Moxon Rectangle diagram located to the left of the values. †If you are going to enter a fractional frequency or wire diameter in the "Frequency" or "Wire size" sections, use a comma(,) instead of a period(.).
How do you get output from MoxGen?
After having the values of your antenna calculated, you can get a printout of your antenna's measurements by using the "Print" button at the bottom right of the program.
If you want to export your antenna model, you need to use the "Generate Model" button in the upper left corner of the program. If you select "EZNEC" in the Format tab downwards, you will export your antenna model as a ".ez" file, if you select "NEC", you will export your antenna model as a ".nec" file. In the "Polarization" tab, you can select the antenna polarization as "Horizontal" and "Vertical", and in the "Main lobe" tab, you can select the main lobe direction as "On X axis" and "On Y axis" and you can get the output that way.
Video containing combination of 2D images and 3D animations showing the TC3EC 433MHz Moxon Antenna's pattern in many different styles.
Legal and Ethical Disclaimer
Producing and selling this design and its remixes, which were designed without any financial interest and presented to Amateurs all over the World, for the purpose of gaining financial benefit is not only against Amateur Ethics and Morals but also against the law as of license.
In this context, we would like to state that we have the right to file a lawsuit against those who adopt this behavior as if the shameful position they have fallen in the Amateur Radio Community is not enough.
Considering the ethical and moral values of our society, the most appropriate behavior to be done at this point is for fellow Amateurs who have a 3D printer to gift this antenna to their friends who do not have this opportunity free of charge. Acting in this way will undoubtedly prevent divisions in our community, contribute to its development, and ensure the continuation of such projects.
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Category: Engineering
The author marked this model as their own original creation. Imported from Thingiverse.