2 Meter Yagi Antenna w/ Gamma Match (Part 2/2)

Part 2 of 2. How to build a ham radio 2 meter 4 element yagi beam antenna with a gamma match using parts from an old T.V. antenna.

Category:

Education

Tags:

• yagi antenna
• ham radio
• amateur radio
• ham radio antenna
• 2 meter
• yagi
• beam
• antenna

[bognapalm]

Is there a formula to calculate a gamma match for different frequencies?

[zerozedzed]

@bognapalm If I remember right it has something to do with the formula for calculating a series LC circuit. The formula is in my old advance class study guide but I'll have to search for the book. Some yagi antenna modeling software, many available for free download on the internet, will calculate the length of the gamma rod for you. As for this style of gamma match you could scale it down for the 70 cm band but it might be a bit long and unsightly if used on a lower band such as 10 meters.

[zx636racer]

how but the space between the elements ????

[zerozedzed]

@zx636racer Element spacing is mentioned in part one. I simply removed the plastic TV antenna insulators and used the same holes to mount the elements. The spacing is 12-3/8" between all elements.

[virtualbush]

Perhaps some demonstration/information (A short Part 3?) regarding how to tune using the gamma in case the SWR is a bit higher than we might like. Enjoy! I will indicate that we would slide the tubing either in or out over the dielectric. Hopefully not inward in this case because your assembly is tight!

[zerozedzed]

@virtualbush Yes, the adjustment may be a bit tight. To increase frequency I could have made the gamma tube a few millimeters longer. Sliding only the grounding strap inwards seems to lower the frequency. SWR will of course also change with height and vary depending on the coax cable length. Thanks and 73! :)

[Jackupnow]

Hi would please do a video on a 6 or 10 element beam for 2 m

[Jackupnow]

Thanks mate very useful info

[zerozedzed]

@matthewz07 Have fun with your new antenna and good DX! :)

[matthewz07]

purely awesome work sir !!!!!