This 3×5 Cross Yagi can be totally tear down for easy storage. After the procedure we are left with just a few pieces of the antenna elements are neatly tucked inside the boom. Gamma match, tuning stub, phasing harness, gamma match bracket, mounting bracket, and screws can be put inside a separate plastic bag for safe keeping.
This is the complete tear down video linked to my youtube channel. Take time to watch and enjoy.
Pencil Torch is a good tool for soldering materials requiring extra heat. However care must be taken to successfully use it on electronics soldering work. The downside of the stock pencil torch is that from time to time the flame becomes intermittent due to the soot forming from the torch burner mainly cause by butane impurities and largely because as you use it longer than necessary the air pressure on the canister becomes weak. The cartridge can be refilled at the bottom of the torch through its pin charging system much like that of a car wheel. You poke the butane canister and press it for about 10 secs for a complete charging using a pumping action. This pushes the charging pin on the torch cartridge to allow fuel charging. To turn on the pencil torch use a lighter and slowly open the valve knob until you can hear some air escaping and light is using a lighter. A complete charge will usually allows you for about 2 minutes of working without interruption however when butane charge is slowly consumed you may experience intermittent operation. The reason I decided to convert this to a single continuous flow soldering system using a broken flame torch to be use as feeder system.
Pencil torch conversion to continuous flow soldering system
1. Remove the charging pin on the pencil torch
2. Cut about 1.5 inch of copper tubing to be use as extension for both the feeder and the inlet on the pencil torch
3. Insert the copper tubing on the pencil torch charging port and secure it with moldable epoxy until it cures
4. Do the same on the butane feeder system
5. Once the epoxy has completely cured attach the silicon tubing to the torch fuel inlet and the feeder system by inserting about an inch of coax insulation to the silicon tube.
6. Secure this connection with the tube clamps
7. Finished the conversion process using shrinkable tubes on joint for a more professional look.
This is a short video demonstrating the performance of N1201SA RF Vector Impedance Analyzer in comparison with Diamond SX400 SWR meter on individual frequency check across the designed frequency 435-445 Mhz on a UHF 70cm Yagi. The advantage of course of the N1201SA over the Diamond SX400, is it can directly plot the frequency sweep analysis of the antenna very quickly on the LCD monitor. However when it comes to precision both of the devices gives out a similar readings with little variation from the analog display of SX400 as compared to N1201SA digital display.
The N1201SA is a Vector Impedance Analyzer or commonly known as antenna analyzer from AAI technologies in China. AAI stands for Accuracy Agility Instrument. The strong point of this antenna analyzer as compared to other brand is the range of frequencies which it can operate from 137Mhz to 2.7Ghz aside from the digital read out and quick performance of the device to display the parameter of interest it also features a frequency sweep analysis with graphing function which you cannot find on most known brands within the same price range. It currently sells at around $148 USD online.
The primary reason I purchased the device is base mainly on good performance review from other users aside from the range of frequencies it can operate which is very much suitable for much of my work. I currently have a Diamond SX400 which is a dual band VSWR meter suitable for VHF/UHF work the only downside is it only measures VSWR, forward and reflected power on analog dial display, with N1201SA VNA it measures most of the antenna parameters I need on digital screen read out, coupled it with antenna simulation analysis software 4NEC2 life is really much easier.
Diamond SX400 VSWR Meter features
So for quick specifications the Diamond SX400
The SX400 measures forward and reflected power and VSWR. Compact size makes meter useful for testing both base and mobile installations.
• Illuminated meter
• Switchable r.m.s. or peak power
• Measures forward, reflected & VSWR power
• 6″W x 2″H x 4″D, 2 lbs.
Frequency: 140-525 MHz
NS1201SA Vector Impedance Analyzer features
N1201SA series is the handheld radio frequency vector impedance measurement analysis instrument, easy to use, simple operation. Built-in high capacity lithium ion battery for mobile and outdoor use.
Working frequency: 140MHz~2700MHz
Actual frequency : 137.5~2700MHz
Stepped frequency: 1kHz
Display: 2.4″ TFT trdp
Resolution ratio: 320 x 240(QVGA)
Battery capacity: 2000mAH(7.4Wh)
Power consumption: <1.5W
Charge current: 400mA
Charge port: USB
Auto power off can be set 5-60minutes.
Measured parameters: Resistence, Reactance, Standing wave, S11
Resolution ratio: 4 number
Frequency accuracy: about 5ppm
Standing wave: 1.000~65
Working temperature: 0~40℃
Atmospheric pressure: 860hPa~1060hPa
This instrument has four interfaces: single point measurement, scanning, system information, correction and calibration
The default boot into single-point measurement interface.
Measurement comparison on VSWR Readings
With both of the device specifications presented we are ready to proceed and compare the actual measurement on VSWR readings and compare the accuracy of the read out against each other. Please see the video below of actual comparison of VSWR read out on both device.
This is a testing video for 3 Elements Yagi (Lightweight End Mount) using a portable HT Cignus UV85 (A Baofeng UV5R variant). I’m testing from my present location at Maligaya, Atimonan Quezon climbing a hilly location near my QTH. The terrain is a mountainous area with a bowl like topography with lush vegetation. I managed to contact the station from Sariaya, Quezon about 45kms from Atimonan point to point.
Testing nominal range using HT @ 5watts
This Yagi is designed for 146Mhz as center but easily covers 144-148Mhz with similar pattern across the operating frequency this Yagi is designed using 4Nec2 antenna simulation software. Antenna boom measurement is the same as the 3 Elements Yagi designed for 145Mhz except for the elements which are cut for 146Mhz as center frequency.
Like most of my antenna design this is lightweight collapsible for easy keeping, and end mount. The advantage of end mount design is obvious as there is no pattern distortion on the antenna unlike the mid mount configuration.
Google Map Highlighting Sariaya Quezon
Point to point distance of Sariaya Quezon to my location in Atimonan, Quezon
Let us try to answer the question above. How to program VHF channel on Baofeng BF888s UHF radio and will it be useful?. So on the first question, can we program VHF channel on BF888s UHF radio?. Fortunately yes it seems that the radio chip on Baofeng BF888s are capable of accepting VHF frequency channels although I have not open the radio to check the datasheet on what chip was actually used on this tiny radio with a good form factor.
Now that we are sure that the radio can accept both VHF and UHF frequency, let’s move to the second question, will it be useful?. Let’s answer that by watching the how to video and let’s give out the conclusion later on.
So let us now give the conclusion after watching the video playlist. Will it be useful after programming VHF channel on it?. My answer is a YES and NO, yes it will be useful for monitoring radio frequency on VHF channel and no it will not be useful for field work as the measured output power on VHF is less than 1 watt for it to be useful on normal field work. Although I must admit the radio has a good form factor and suitable for short distances communication office or home work.
Please leave your thoughts on the comment form below…
Tutorial video on building a high performance 3 Elements Yagi for 2 meters VHF radio transceiver. This design is centered on the Philippine amateur frequency band (144-146Mhz VHF) center frequency is 145Mhz with 1:1 SWR. The design and technique used on this video can be adopted on other antenna design for other specific frequency you intend to use. This is the same antenna we are selling on this website (for those who doesn’t have time) you may directly order the antenna on our shop. The antenna is tuned to the published frequency range as specified on the product page however you may still use the antenna on the edge of the band and it will be operational from 143Mhz to 148Mhz.
At the end of the video we made some SWR measurements and tuning including propagation testing. The antenna is mounted indoor with camera tripod 1 meter above the ground using Yaesu2900R 2meter rig. The result is a very much acceptable range with almost reciprocal transmit receive (S2 to S3 TX / S3 – S4 RX) with a very good quality audio . From my QTH at Las Piñas (DW1ZWS) to Fairview Quezon City (DU1RFU) is 36kms air distance.
If you like this video please follow us on our youtube channel for more videos of our antenna projects.
Cheers and thank you for watching everyone!.