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




What do you think about this video?

Gene B: I have watched these 2 videos multiple times. I am still confused, even with your last comment. Can the boom of this antenna be attached to ground? I am not talking about the negative connection on the SO-239. Could the boom be electrically attached to a metal post pounded into the ground? No one does antenna videos as well as you do on the entirety of Youtube. 73's KA7QJU, Gene.

Dave Tadlock: Normally all the elements are grounded to the boom when using a gamma match. An antenna with a dipole driven element uses an insulator to separate the two halves of the driven element and can be used to insulate it from a metal boom. Dipole fed antenna elements can be mounted on either a non-conductive boom or a metal boom using insulators. Hope this helps and thank you for watching! :)

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!

Owen Baldwin: Dave, excellent videos on all your projects, very instructive and educational. Well done young man you are an inspiration to young amateur enthusiasts. All the best 73 ...Owen G0RCL

haassman: what is in the middle of your gamma (the white insulator....with copper). Can you not just use the element, or double aluminum elements up together? When do you have to use a type capacitor in line with the coax?

Jackupnow: Thanks mate very useful info

joe s: how would i build a 900mhz RF yagi antenna i love this stuff

matthewz07: purely awesome work sir !!!!!

Dave Tadlock: @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.

VO1SMC: I'm pretty new when it comes to antenna design, so perhaps my question is something that every ham SHOULD know, but "there are no stupid questions", so I'm told! I notice that the elements are attached to the aluminum boom using metal mounts. Is there any difference in attaching all elements to the boom using metal vs an insulator, or is there any advantage in separating the boom from the elements, electrically speaking.

Dave Tadlock: @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! :)

ipromisenot: If you didn't reach the desired frequency range, what can and cannot be adjusted? Can you slide the Gamma rod up/down the coax? Can you move the shorting stub? (is that like a j-pole)? On the quads video, did you say you move the director or longer/shorter it? Does the shorting stub need to be so "beefy", and wide? What needs to be different if I wanted a wider bandwidth, would I need a folded dipole as the driven element? Have you/could you do a folded dipole driven element with matching yagi?

JuggledaJungle: what bout the frequency? it will transmit in 144 mhz?? how can you fix that to for example 105 mhz?

Djordje Marjanovic: Can I use this type of antenna for WiFi signal

JuggledaJungle: this can be used as an fm antenna??

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

joee2047: when you wrapped the copper part of the gamma match on the pin of the coax connector and than soldered it,,,, it was only to the center pin and not touching the side at all,,, is that correct,,, just so I know,,,, thanks!!!!

Dave Tadlock: @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.

808514: Excellent vid! 73, WH7WX

honeybees1: Is the driven element isolated from the rest of the antenna?

Dave Tadlock: @808514 Thanks! I'm glad you enjoyed it. :)

umajunkcollector: Looks as good as a Cushcrap. I like it, and think i'll try to emulate it for 2m ssb. Now all I need is an old TV antenner.

VO1SMC: Thanks for the help, and a big thanks for the helpful videos!

Dave Tadlock: @M0csi Glad you can use the info. Good luck with your antenna projects and have fun! :)

Dave Tadlock: @JuggledaJungle The original antenna worked great receiving the FM broadcast band (105 MHz) when the TV antenna was new and fresh out of the box from Radio Shack. But the antenna, old and broken now, has found a new useful purpose by being converted to transmit and receive on Amateur Radio (ham radio) frequencies. ;)

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

Dave Tadlock: It was fortunate that the holes that I reused were spaced 12-3/8" which is an optimal length on two meters. The TV elements have also been trimmed to the correct lengths and were calculated using yagi antenna modeling software. This old TV antenna has been completely turned into a terrific little 2 meter amateur radio antenna. ;)

Dave Tadlock: No. The driven element is attached directly to the boom. More information about building this antenna is on my web site. The link to my web site is on my YouTube channel. Click my username, then click the Feed tab. The link is in the upper right corner of the page. 73 and thanks for watching! :)

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

M0csi: Thanks for the information with regards to the Gamma Match ... pictures or in this case now video ... tell a thousand words ... I will use this feed system for 440mhz on the beams I make ... Thanks Mike ...

EMT: Thanks! They sometimes skip corners and take the easy way. If they ever did that, I suggest you consult with a paralegal or lawyer. This way they won't be able to cheat you.
Rating:
2 Meter Yagi Antenna w/ Gamma Match (Part 2/2) 4.9 out of 5

Shared by Others

2 Meter Yagi Antenna w/ Gamma Match (Part 2/2)
2 Meter Yagi Antenna w/ Gamma Match (Part 2/2)
2 Meter Yagi Antenna w/ Gamma Match (Part 1/2)
2 Meter Yagi Antenna w/ Gamma Match (Part 1/2)
Coat Hanger 2 Meter Yagi Antenna
Coat Hanger 2 Meter Yagi Antenna
2 element beam for 20 metres from gw0jxm
2 element beam for 20 metres from gw0jxm
2 Meter Quad PVC Pipe Antenna (Part 1/6)
2 Meter Quad PVC Pipe Antenna (Part 1/6)
6m/2m/70cm Yagi Antenna (Part 7/9) Built from Old TV Antenna
6m/2m/70cm Yagi Antenna (Part 7/9) Built from Old TV Antenna
VHF 2 Meter Yagi Antenna Making
VHF 2 Meter Yagi Antenna Making
6m/2m/70cm Yagi Antenna (Part 2/9) Built from Old TV Antenna
6m/2m/70cm Yagi Antenna (Part 2/9) Built from Old TV Antenna
2 Meter Quad PVC Pipe Antenna (Part 4/6)
2 Meter Quad PVC Pipe Antenna (Part 4/6)
2 Meter Quad PVC Pipe Antenna (Part 2/6)
2 Meter Quad PVC Pipe Antenna (Part 2/6)
2 Meter Quad PVC Pipe Antenna (Part 5/6)
2 Meter Quad PVC Pipe Antenna (Part 5/6)
6m/2m/70cm Yagi Antenna (Part 4/9) Built from Old TV Antenna
6m/2m/70cm Yagi Antenna (Part 4/9) Built from Old TV Antenna

Featured Video