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Amateur Radio Antenna Plans

2 Elements Yagi VHF antenna for 144Mhz


If you liked the 3 elements yagi, this antenna build is very close to the performance of that antenna. This VHF antenna is for 144Mhz with 10Mhz bandwith from 140Mhz to 150Mhz. The antenna measurements are computed and then simulated on 4Nec2 antenna modelling software.

Materials

1×1/2″ rectangular aluminum tubing for the boom
1/2″ aluminum tubing for the elements holder cut in half
3/8″ aluminum tubing for the antenna elements
1pc SO239 connector
Pop rivets / Rivet tool
#10 or #12 AWG copper wire with insulation for the gamma insert
3.5cm 3/8″ aluminum tube for the gamma tube
1 Butteryfly nut and 1bolt 18mm length 3mm diameter
4pcs Stainless steel nuts and bolts 20mm length 3mm diameter
Aluminum plate 0.5mm thickness for the tuning stun
Collapsible tubes different sizes.
U bolt with mounting for the antenna mount

Construction

The antenna measurements is provided here for reference. Building it is straightforward you just need to follow the diagram and assemble your contraption. If in doubt you may watch the DIY video of me building a 3 elements yagi without power tools except for the drill.

Antenna measurements in PDF format is downloadable here.

Matching System

I usually used a gamma match for my build, there is nothing special about this impedance matching system but since I’m using a grounded design, (grounded elements to boom) this is I think, the most logical impedance matching system to use, but that is just on me. The reason behind is that the boom is on the zero potential during transition period between the sinusoidal signal therefore elements can be grounded on the boom. In practice there isn’t a noticeable difference between the performance of a grounded elements and an isolated one (debatable). The caveats yagi’s driven element, should be isolated from the boom when using a different matching system. When using a gamma match the center conductor is just capacitively coupled to the driven element via the tuning stub, so it is not electrically grounded.

4Nec2 Data

2 Elements Yagi – free space antenna pattern, front to back ratio, beam width and approximate gain
2 Elements Yagi – antenna pattern considering ground effec, approximate antenna gain, front to back ratio and beam width
3D pattern and approximate gain considering ground effect and antenna currents
Approximate VSWR/S11 (Antenna reflection coefficient) from 4Nec2

Antenna frequency response/tuning

Antenna frequency response from antenna analyzer is very much similar to the modelling results from 4Nec2.

Categories
Antenna Plans

2 Elements Yagi UHF antenna for 410Mhz


This 2 elements yagi antenna is intended for the 70cm UHF band center frequency is 410Mhz with 10Mhz bandwidth. The antenna measurements are computed and then simulated on 4Nec2 antenna modelling software.

Materials

  • 1×1/2″ rectangular aluminum tubing for the boom
  • 1/2″ aluminum tubing for the elements holder cut in half
  • 3/8″ aluminum tubing for the antenna elements
  • 1pc SO239 connector
  • Pop rivets / Rivet tool
  • #10 or #12 AWG copper wire with insulation for the gamma insert
  • 3.5cm 3/8″ aluminum tube for the gamma tube
  • 1 Butteryfly nut and 1bolt 18mm length 3mm diameter
  • 4pcs Stainless steel nuts and bolts 20mm length 3mm diameter
  • Aluminum plate 0.5mm thickness for the tuning stun
  • Collapsible tubes different sizes.
  • U bolt with mounting for the antenna mount

Construction

Measure and cut the boom according to the diagram and assemble the antenna following the antenna construction technique here. Of course you may improvised and follow your own construction technique the goal of the video is to help you visualize the technique I’ve used to build this antenna successfully – but everything is not set in stone.

Note: You may have downloaded a wrong copy of the diagram that sets the spacing to 30.2cm – that is incorrect sorry my mistake I uploaded a wrong version of the diagram when I initially uploaded the article. It has now been corrected with the diagram below.

2 Elements Yagi – dimensions for 410Mhz with 10Mhz bandwidth. You may download the PDF Document here of the measurements. For the gamma match dimensions, you may use the measurements here this will work on this build.

Antenna Pattern from 4Nec2

Free space pattern analysis on 4Nec2
Antenna pattern and gain with respect to ground.
3D diagram gain, antenna current and antenna pattern with respect to ground

Antenna Tuning

Here’s the antenna frequency response and tuning video on my Youtube Channel

Categories
Amateur Radio Antenna Plans

7 Elements Yagi for 146Mhz band build

For yagi’s the longer the yagi’s the better the gain until you reached the point of diminishing returns – the point in which adding additional directors no longer produced a substantial gain or improving the front-to-back ratio. So worry not this 7 elements yagi is not there yet. The yagi design here is simulated using 4Nec2 antenna modeler, the measurements may not be your typical yagi, but I want it that way ;).

Thank you for the people that keeps the site afloat by asking me to design antenna for them, thereby buying the end product and testing the end result. Shout out to Mr. Jonathan Mendoza thanks to your generosity.

Here’s a quick look to the antenna that I built for him, he sent me the picture and I asked him if I can post it on my antenna facebook page he obliged, not knowing that I will also post it here. Bro, thanks a lot for the support!

Owner: Mr. Jonathan Mendoza – DY3BSW (Blackshadow), QTH: Marilao, Bulacan

To those people following my facebook page, this website and sending me a private message asking for the measurements, as promised – though it took a while, the diagram is finally out. Similar build instructions and materials are used same as my previous antenna builds.

Material list for building a 7 Elements 2m VHF Yagi

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. 14pcs Stainless steel nuts and bolts 20mm length 3mm diameter
9. 1pc, Butterfly nut and 1 bolt 18mm length 3mm diameter
10. Aluminum plate 0.5mm thickness
11. Collapsible tube (shrinkable tubes)

Cut the materials according the the measurements here:

7 Elements Yagi 146Mhz band

Download the PDF Document here

Antenna pattern simulation using 4 Nec 2

Combined antenna pattern 146Mhz gain as color

Horizontal pattern

146 Mhz Horizontal Pattern

Vertical pattern

146Mhz Vertical Pattern

Combined pattern / approximate gain / beam width

146Mhz combined Pattern

7 Elements yagi configured in vertical 2 stacked antenna tuning video (frequency response) using N1201SA antenna analyzer

The same antenna configuration frequency response and calibration is confirmed using NanoVNA antenna analyzer

So what gamma match to use on this build?

You can use the gamma match measurements that I used on 4 Elements Yagi build. You can follow this link to see the gamma match diagram: https://dw1zws.com/building-the-gamma-match-for-4-elements-yagi/

So that’s it, I hoping that it will help you somehow in building your own 7 elements yagi antenna. If you found this post interesting please consider subscribing on my youtube channel https://www.youtube.com/c/EphraimGariguez or follow me on my facebook page https://www.facebook.com/panda.antenna. Cheers and 73!

Categories
Antenna Plans Schematics

G7 Antenna Cutting Chart

This is the cutting chart for G7 antenna for those looking. I just uploaded it here for reference for those people that want to adjust their G7 antenna to other frequencies as stated in the manual.

Categories
Antenna Plans

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

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 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.

Categories
Antenna Plans

2 Elements Yagi for FM Broadcast band center at 107.1Mhz

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

Antenna Pattern and Gain from 4Nec2

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

Frequency response and VSWR testing video

Categories
Antenna Plans

4 Elements Yagi UHF 70cm antenna at 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

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

Categories
Antenna Plans

Build a 157.000 Mhz 4 Elements Yagi for VHF

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 expected antenna pattern at 157.000 Mhz. Generated by 4NEC2

Antenna Pattern Vertical

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

Horizontal Antenna Pattern

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

Antenna Measurements

4 Elements Yagi at 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

Finished Antenna Testing

4 Elements yagi antenna for 157.000 Mhz

Antenna Calibration Video using NanoVNA

SWR response on the center frequency as confirmed by N1201SA

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

NanoVNA vs. N1201SA low cost antenna analyzer compared

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 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.

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

Categories
Antenna Plans

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

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

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

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
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.

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