2×4 2m/70cm Compact Cross Yagi Sat Comm Antenna

2x4 Cross Yagi Antenna

Compact satellite communication antenna

This antenna built is similar to the 2×3 Compact Cross Yagi antenna with the addition of additional element on the UHF side. We have similar measurements for all the elements.




Antenna measurements and mounting guide

2x4 2m/70cm Cross Yagi measurements and mounting

Download the PDF document here

Materials list

1″ X 1″ Rectangular Aluminum tubing for the boom (cut to length)
3/8″ Aluminum tubing for antenna elements (cut to length)
2pc SO239 connector
#12 AWG Copper wire with insulation (12″for Gamma match)
Soldering iron
6pcs Stainless steel nuts and bolts 30mm length 3mm diameter
6pcs Stainless steel nuts and bolts 30mm length 3mm diameter
1, Butterfly nut and 1 bolt 18mm length 3mm diameter
Aluminum plate 0.5mm thickness
Collapsible tube (shrinkable tubes)

4Nec2 data analysis

Antenna gain, beam width and predicted pattern spit out by 4Nec2 antenna modelling software

Antenna pattern for the VHF side

Antenna Pattern for the VHF side
Antenna Pattern for the VHF side

Antenna pattern for the UHF side

Antenna pattern for the UHF side
Antenna pattern for the UHF side

Vector impedance analyzer frequency response data




This is the result of impedance analyzer testing for 2×3 elements cross yagi. Obtainable SWR is around 1.2:1 at the center frequency antenna reflection coefficient is at -24dB at VHF and -19dB at UHF. Pretty usable antenna, as you can see as well, the data spit out by 4Nec2 with regards to SWR on VHF side is close enough, I just directly cut the elements and assemble it with respect to the antenna measurement for the UHF side it was compensated with the use of gamma matching and correct length of the phasing harness.

Actual testing of the antenna

This is actual testing of the antenna see the video for SO-50 satellite

and this video is for AO-91 satellite contact.




2 Elements Yagi for FM Broadcast band center at 107.1Mhz

2 Elements Yagi for the FM Band

2 Elements Yagi Build for FM Broadcast Band 104-110Mhz

This antenna build is for FM broadcast band, the center frequency of this antenna is on 107Mhz as measured from 104 to 110Mhz with less than 1.5:1 SWR across those frequencies.

Materials

The materials required to successfully build the antenna are:

1″ x 1″ aluminum square tube
3/8″ anodized aluminum tubing
#12 AWG solid wire for the gamma match (Watch building the Gamma Match video here)
Suitable screws and nuts
Different sizes of shrinkable tubes

The antenna placement and mounting are cut through the 1″x1″ aluminum square boom. The elements are inserted through the boom and secured by a mounting screw at the center. A gamma match bracket is made from a piece of aluminum scrap to form L and cut at the center to hold the gamma match in place. See antenna measurements.

Antenna Measurements

2ElementsYagiFMBroadcastAssembly

Antenna Pattern and Gain from 4Nec2

Expected pattern and SWR
Expected pattern and SWR
Horizontal Pattern
Horizontal Pattern beamwidth / gain and front to back ratio
Vertical Pattern
Vertical Pattern beamwidth / gain and front to back ratio

Frequency response and VSWR testing video

4 Elements Yagi UHF 70cm antenna at 409Mhz

4 elements 70cm yagi @409Mhz

70cm 4 Elements Yagi @ 409Mhz usable frequency 406-412Mhz

Antenna specifications
Antenna Bandwidth: 406-412Mhz
Antenna gain @ center frequency: 7.16dBi
Beam width: 66° Horizontal / 108° Vertical
Front/Back ratio: 14.4dB

4 Elements Yagi 70cm UHF Antenna Materials List

1. 1″ X 0.5″ Rectangular Aluminum tubing for the boom
2. 3/8″ Aluminum tubing for antenna elements
3. 1cm Outside diameter antenna tubing for elements holder
4. 1pc SO239 connector
5. Pop rivets / Rivet tool
6. #12 AWG Copper wire with insulation (12″for Gamma match)
7. Soldering iron
8. 8pcs Stainless steel nuts and bolts 20mm length 3mm diameter
9. 1, Butterfly nut and 1 bolt 18mm length 3mm diameter
10. Aluminum plate 0.5mm thickness
11. Collapsible tube (shrinkable tubes)


Antenna Measurements

4 Elements Yagi 70cm 409Mhz dimensions
4 Elements Yagi 70cm 409Mhz dimensions

Download the PDF document here

Build the gamma match for this yagi here. Although the gamma match is originally for 3 elements yagi antenna UHF this will also work with this 4 elements UHF yagi antenna.

Expected antenna pattern generated using 4NEC2

Antenna combined pattern

Horizontal pattern

4 Elements Yagi 70cm 409Mhz
4 Elements Yagi 70cm 409Mhz horizontal pattern

Vertical Pattern

4 Elements Yagi 70cm 409Mhz
4 Elements Yagi 70cm 409Mhz vertical pattern

Antenna Pattern on the low band 406Mhz

No skewing detected on the antenna pattern as generated by 4NEC2

4 Elements Yagi pattern @ 406Mhz
4 Elements Yagi pattern @ 406Mhz

Antenna Pattern on the high band 412Mhz

Minimal skewing on the 412Mhz antenna pattern as generated by 4NEC2

4 Elements Yagi pattern at 412Mhz
4 Elements Yagi pattern @ 412Mhz minimal skewing on the pattern generated by 4NEC2

Complete Antenna Analysis using NanoVNA and N1201SA antenna analyzer



Build a 157.000 Mhz 4 Elements Yagi for VHF

4 Elements Yagi 157.000 Mhz measurement

4 Elements Yagi for 157.000 Mhz

This antenna is 4 elements yagi built for the frequency 157.000 Mhz, in the Philippines most of the users of this frequency bands are Government Organizations, LGU’s, Civic Groups, Fire volunteers and the like. Although most of the requested antenna designs fall on the Amateur Band (144.000 Mhz to 146.000 Mhz) frequency. I decided to published the details of this antenna although not frequently requested. The details of the build is similar to building the 4 Elements Yagi for Amateur Frequency. Elements measurements and spacing are of course adjusted to resonate properly on the 157.000 Mhz band.



Antenna Specifications

Antenna Center frequency 157.000 Mhz
Lowest usable band 152.000 Mhz
Highest usable band 160.000 Mhz
Antenna Gain: 9.52dBi
F/B ratio: 9.87dB
Beamwidth: 60° Vertical / 24° Horizontal

Expected Antenna Pattern Generated by 4NEC2

4 Elements Yagi Antenna pattern 157.000 Mhz
4 Elements Yagi expected antenna pattern at 157.000 Mhz. Generated by 4NEC2

Antenna Pattern Vertical

Vertical antenna Pattern 157 Mhz
4 Elements Yagi expected antenna pattern vertical at 157.000 Mhz. Generated by 4NEC2

Horizontal Antenna Pattern

Horizontal Antenna Pattern 157 Mhz
4 Elements Yagi expected antenna pattern horizontal at 157.000 Mhz. Generated by 4NEC2

Antenna Measurements

4 Elements Yagiat 157.000 Mhz measurements and spacing.

Download PDF Document antenna measurements here.

Material Listing

1. 1″ X 0.5″ Rectangular Aluminum tubing for the boom
2. 3/8″ Aluminum tubing for antenna elements
3. 1cm Outside diameter antenna tubing for elements holder
4. 1pc SO239 connector
5. Pop rivets / Rivet tool
6. #12 AWG Copper wire with insulation (12″for Gamma match)
7. Soldering iron
8. 8pcs Stainless steel nuts and bolts 20mm length 3mm diameter
9. 1, Butterfly nut and 1 bolt 18mm length 3mm diameter
10. Aluminum plate 0.5mm thickness
11. Collapsible tube (shrinkable tubes)

Antenna Matching / Gamma Match

For the antenna matching you may use the Gamma Match for the 4 elements yagi. The measurements of the gamma match and tuning procedure are the same.

Gamma Match 4 Elements Yagi

Finished Antenna Testing

4 Elements Yagi Antenna 157.000 Mhz
4 Elements yagi antenna for 157.000 Mhz

Antenna Calibration Video using NanoVNA

SWR response on the center frequency as confirmed by N1201SA

Antenna SWR at center frequency 157.000 Mhz
N1201SA analyzer readout for SWR/S11 response of the the 4 elements yagi antenna at 157.000Mhz center frequency.



NanoVNA vs. N1201SA low cost antenna analyzer compared

nanoVNA

N1201SA Specifications

Manufacturer: Accuracy Agility Instrument
Model: N1201SA
Working frequency: 137.5 MHz – 2700 MHz
Frequency stepping: 1 kHz
Display: 2.4″ TFT 320×240 (QVGA)
Build in battery: 2000 mAh
Power consumption: <1.5 W Charging current: 400 mA[embed]https://youtu.be/3PI5P_fXs5g[/embed] Charging port: USB Weight: 250g Automatic shutdown: set in range 5-60 min Measured parameters: resistance (R), reactance (X), standing weve ratio (VSWR), S11 Resolution: 4 significant digits Frequency accuracy: < +/- 3ppm Antenna connector: SMA-K Measurement range: Impedance: 0.1 - 1000 Ohm Standing wave: 1.000 - 65 S11 (dB): od 0dB do -60dB

nanoVNA Specifications

Basic performance:
PCB: 54mm x 85.5mm x 11mm (excluding connectors and switches)
Measurement frequency: 50KHz ~ 300MHz (50KHz – 900MHz, with extended firmware enabled)
RF output: – 13 DBM (max. – 9 dbm)
Frequency accuracy: <0.5 ppm Measurement range: 70dB (50kHz-300MHz), 50dB (300M-600MHz), 40dB (600M-900MHz) with extended firmware enabled; Port SWR: < 1.1 Display: 2.8 inch TFT (320 x 240) USB interface: USB type-C communication mode: CDC (serial) Power supply: USB 5V 120mA, built-in 400mAh battery, maximum charging current 0.8A Number of Scanning Points: 101 (Fixed) Display Tracking: 4, Mark: 4, Settings Save: 5 Measuring S parameters, VSWR, phase, delay, Smith circle chart and it supports touchtones files which can be exported for various radio design and simulation software.


The package also includes a set of calibration kit SOL for (short, open and load) calibration, the calibration kit is not included on N1201SA but it is pre-calibrated at the factory. Calibration for N1201SA takes time to complete but it is just a snap on nanoVNA. The included calibration kit for the nanoVNA can also be used to calibrate the N1201SA so that’s a bonus point for the nanoVNA.

For the actual testing I’ve used an antenna a 3 element yagi for 2m designed for the amateur band as device under test (DUT). I conducted the test sweeping the frequency from 140 to 150Mhz, taking note of SWR response, S11 and impedance measurement on the exact center frequency.

Side by side the read out against each other is on point, the discrepancy is just because of the decimal point resolution from the two antenna analyzers 2 decimal digit resolution on nanoVNA and 3 decimal digit for N1201SA.
Feature wise and overall usefulness nanoVNA is much complete against the N1201SA. Read out is on point on both devices.

Actual test and comparison of the antenna analyzers

Note:
Crap, I called the NanoVNA as N1201SA ha ha!, but anyway don’t be confused 🙂 enjoy!




2×3 2m/70cm Cross element yagi build instruction – compact that works

2x3 2m/70 cm Cross Yagi

Compact satellite communication antenna

If you’re a fan of satellite monitoring (hunting for birds) as they call it, you probably want a bigger antenna with lots of elements for good contacts. Long antennas are good for satellite contacts with low elevation angle now the downside of those antennas are the lengths and they are cumbersome to work with specially if you’re home brewing and the materials available are not light enough. Each element will add up to the weight and will easily become unwieldy for hand operations holding the antenna on one hand and on the other the radio unless you are muscular then that would be easy. For casual contacts and mobility a compact antenna will get you where you want to go and still hunt for satellite with high elevation passes if you’re a fan of long distance and low elevation then this may not be for you.




Antenna measurements and mounting guide

2x3 2m/70cm Cross Yagi measurements and mounting

Download the PDF document here

Materials list

1″ X 1″ Rectangular Aluminum tubing for the boom (cut to length)
3/8″ Aluminum tubing for antenna elements (cut to length)
2pc SO239 connector
#12 AWG Copper wire with insulation (12″for Gamma match)
Soldering iron
5pcs Stainless steel nuts and bolts 30mm length 3mm diameter
6pcs Stainless steel nuts and bolts 30mm length 3mm diameter
1, Butterfly nut and 1 bolt 18mm length 3mm diameter
Aluminum plate 0.5mm thickness
Collapsible tube (shrinkable tubes)

4Nec2 data analysis

Antenna gain, beamwith and predicted pattern spit out by 4Nec2 antenna modelling software

2x3 Cross Yagi VHF side
2×3 Cross Yagi VHF side – VHF side data was optimized using 4Nec2 antenna modelling optimization option SWR is spot on at 1.1:1
2x3 Elements cross yagi UHF side
2×3 Elements cross yagi UHF side – don’t worry with the SWR data being spit out by 4Nec as you still need to match the UHF antenna for optimum SWR. The gamma matching can bring it down as you will see on the vector impedance analyzer.

Vector impedance analyzer frequency response data




This is the result of impedance analyzer testing for 2×3 elements cross yagi. Obtainable SWR is around 1.2:1 at the center frequency antenna reflection coefficient is at -23dB at VHF and -19dB at UHF. Pretty usable antenna, as you can see as well, the data spit out by 4Nec2 with regards to SWR on VHF side is close enough, I just directly cut the elements and assemble it with respect to the antenna measurement for the UHF side it was compensated with the use of gamma matching and correct length of the phasing harness. The capacitance of the gamma match when un-attached to the antenna assembly is around 10nf (0.01uf) and 20nf (0.02uf) respectively for UHF and the VHF side as measured using capacitance meter.

Actual testing of the antenna

This is actual testing of the antenna see the video around 2:30-2:38 I called out DV2JHA unfortunately we didn’t manage to confirm a successful QSO until the satellite signal started to fade out. Over all it’s a successful build.




Dualband 3×5 Cross Yagi 145Mhz – 435Mhz mounting and measurements

Dualband Cross 3x5 Cross Yagi

Dualband 3×5 cross yagi 145Mhz – 435Mhz

This is the actual measurements of the cross yagi antenna I’ve used for satellite work, though the inline version of this yagi in which the VHF and UHF side are mounted inline but on the opposite side of the boom will also work for satellite communication. Inline version is here.

I have optimized this antenna for 145Mhz and 435Mhz painfully adjusting the exact length of the phasing harness to obtain lowest possible SWR/S11 curve on the antenna analyzer (measurements taken while actually holding the antenna). I just use 1/4λ length of the phasing harness, factoring the velocity factor of the coax for the actual length of the cable. VHF 145Mhz and UHF 435Mhz are complimentary harmonics frequency by design, actual length of the phasing harness are equal and using PL259 connector at both ends of the coaxial cable this connects to T-connector SO239. Patch cable is RG58 coax connector at the end is PL259 which will connect to the T-connector SO239, the opposite end of the RG58 coax is an SMA male connector which connect to my Vector Impedance Analyzer and also double as a patch cable for the radio which is about 65cm.



Materials preparation

The bill of materials are similar to the inline version of this build except for the boom which uses 1 X 1 inch square boom.

Cross Yagi 3x5 145Mhz - 435Mhz

Download the PDF document version here

4NEC2 Antenna Data

4Nec2 data shows beamwidth, expected pattern and predicted gain.

145Mhz 4NEC2 Data
145Mhz 4NEC2 Data
435Mhz 4NEC2 Data
435Mhz 4NEC2 Data

Antenna analyzer measurements and actual video footage

Measurements are taken while holding the antenna and the analyzer since we know that yagi interacts with the actual measurements if it’s too close to an object. This is to simulate the actual use case when using the antenna aiming it to the satellites.

Actual build, measure, cut and drill

These are some photos I took when building the antenna.



Preparing the materials 3x5 cross yagi
Preparing the materials 3×5 cross yagi and drilling holes.
Mounting the elements
Mounting the elements of the 3×5 cross yagi. Elements are fastened at the center with the screw, chosen so that it just touches the wall of the boom.
Preparing the feed point
Preparing the feed point. Dual feed point which will connect to the T-connector via phasing harness
Gamma match preparation
Gamma match preparation which will serve as our feed point for our yagi
Gamma Match final look
Gamma Match final look and feel. The tuning stub are now properly connected to the antenna.

Initial testing of this antenna

I initially test this antenna using a phasing harness of 75ohms at 1/4λ x 3 for the actual length of the harness considering the velocity factor of the coax. The final use case testing, uses 1/4λ x velocity factor for the actual length of the phasing harness.

The fun part programming the radio before the hunt

Programming the radio with the satellite frequencies before the actual bird hunting. Since I work on a budget a Baofeng radio will suffice. I used a CIGNUS radio a rebranded radio that uses Baofeng internally ;). I encoded the frequency on the radio using CHIRP taking note of the CTCSS tone for each satellite and marking the channel name as name of the satellite and U for uplink D for downlink and A for arm to trigger some satellite timers before use.

Programming the satellite frequencies
Programming the satellite frequencies before actual hunt. This setup will work on cheap radios for the budget concious ;).
Cignus UV85
Cignus UV85 a rebranded Baofeng radio which I uses for satellite work. Who say’s you need too expensive gear to work satellites?

Aside from programming the frequencies on your radio you also need a satellite tracker to predict the passes of the satellite you’re hunting. I uses Gpredict which works on both Windows and Linux machines, for Android you may use AmsatDroid Free version and tons of other satellites tracking apps on both Android and IOS.

Satellite tracking
I use Gpredict for satellite tracking which work on both Windows and Linux machines, because of a very useful interface for predicting satellite passes. You may also use apps on both Android and IOS smart phones

The fun part really start when you begin the hunt and successfully received a very readable reception on your radio coupled with your homebrew antenna. If you’re not familiar with the actual satellite operations listen first until you feel comfortable pressing the PTT on your radio. Satellite resource hog are always frown upon so be courteous every time. Have fun!, and if you feel this will help someone feel free to share, thanks again!



Actual use video

Tuning 3 Elements two stacked Yagi – effects of feed line to a tuned antenna

Two stacked 3 elements Yagi

Stacking two antennas – and effects of feed line to a properly tuned antenna

Stacking antenna is done to achieve additional gain ideally a 3dB additional gain is targeted but may not be achievable in real world due to losses introduced by additional cables, you need to make sure that the phasing harness is of the same length and construction. If your cable is not the same length then the signal from those won’t reach the antennas at the same time. The differences may be small but it is enough to create phasing problems, when your signal get to the antenna at two different times they don’t result in a much stronger signal in fact in extreme cases if the signal are exactly 180° degrees out of phase they would cancel each other and you’ll get nothing.

Basic Stacking Requirements

1. Two antenna’s with similar characteristics in terms of
Gain: 8.89 dBi
Center Frequency: 145Mhz
Matching: Gamma Match (Tuning stub)
Impedance: 50 ohms
Beamwidth: 84° vertical 58°horizontal
Front/Back ratio: 11dB
SWR: 1:1 @ center frequency



2. Phasing harness – must be of the same length Velocity Factor of coaxial cable accounted for, use two basically identical cables. If the cable types are different, or if the connectors are different, you can have the same phasing problems.

phasing-harness

3. Tune the antenna to the lowest possible VSWR match, identically the same response is ideal but a slight mismatch or mis-alignment is acceptable but not much. Your antenna analyzer can help you check this before stacking.

Tuning two stacked Yagi Antenna

Conclusion

A properly matched single antenna, combined with a similar antenna to achieve stacking gain will perform much better than a single antenna, however care must be taken to achieve a good stacking practice. The result of a combined antenna when tested with a good antenna analyzer will result in very little deviation in its Center Frequency , VSWR curve, S11 curve, and Impedance even if different lengths of feed lines are used to test the antenna system.

2.42 Ghz 15 Element High Gain Yagi Antenna for WiFi

Improving on the design of my 15 Element Yagi Antenna for 2.4Ghz Wifi band, now with a much cleaner pattern no side lobes and higher front to back ratio at 24.8 dB. This antenna is pretty much usable from to 2340 Mhz to 2460 Mhz with less than 2:1 SWR this is centered at 2420Mhz with 1:1 SWR and about -30dB S11 antenna reflection coefficient.

2420Ghz WiFi Antenna
Download the PDF Document Here



WiFi 2.420Ghz Pattern

Im still using the same materials to build the antenna

Materials Lists
1. 12mm x 8mm uPvc moulding (Boom)
2. #12AWg solid wire for elements
3. Measuring tool / precision cutter
4. 1 SMA female connector
5. Coaxial cable suitable for SMA connector
6. Sandpaper or file tool for removing rough edges of the elements

antenna materials

Building it is pretty straight forward just cut and paste (lol) bend the driven element and feed it with a 50 ohm coaxial cable rated for WiFi frequency, and check the SWR of the antenna.

Cut and paste the elements directly to the boom
Cut and paste the elements directly to the boom use the wire insulators as fittings to glue on the boom

Here’s the finished antenna side by side with my previous build.

Finished antenna
Finished antenna with center frequency at 2.42Ghz

SWR testing video of 15 Element 2.4Ghz yagi antenna

Actual receive analysis and link performance of the yagi antenna