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
1942Grampz: 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,,,,
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 ...