building a 170 mhz yagi

[Jason Porter]

Hi all,

I'm a sound recordist in TV and film, and I use wireless mics for a
lot of my work. I want to improve the reception of my wireless
receivers (in the 170 mhz area) by using a yagi antenna. Does anyone
know where I can get plans to build one? I have good knowledge of
contruction, but not the math.

Thanks,

-Jason

[Mark Keith]

jason...@sympatico.ca (Jason Porter) wrote in message news:<a592a30a.02071...@posting.google.com>...

You could download a modeling program such as the eznec demo and
convert the existing NBS yagi to 170 mhz. I doubt there will be many
plans for a yagi that frequency. Myself, I once built a 4 el yagi for
exactly 170 mhz to listen to a local NASA feed from JSC. I ran the 3
el NBS converted to 170 mhz.
The reflector would be 33.89 inches.
The driven element would be 32.34 inches.
The director would be 32.01 inches.
From the reflector to driven element, the spacing would be 13.9
inches.
From the reflector to the director, the spacing would be 27.8 inches.
Feed with whatever matching device you desire. I usually use gamma
matches as they are simple, and I haven't had any problems with them.
1/4 inch rod would be a good match to those dimensions. You could make
the whole thing welded as one piece out of copper tubing if you have a
torch. I built a 50 mhz 3 el yagi that way.

MK

[Tom Bruhns]

If you do a web search for something like "2 meter yagi design" you
should get lots of hits. Just scale all the dimensions by the ratio
of design-frequency/your-frequency. For ratios near unity, you
shouldn't have to worry about the element diameters, just scale the
lengths and spacings.

Here's one of the hits I got:
http://home.att.net/~dale.keller/ham/antenna/yagi3.htm

Cheers,
Tom

jason...@sympatico.ca (Jason Porter) wrote in message news:<a592a30a.02071...@posting.google.com>...

[JASON A DUGAS]

The easiest way to do this is to use one of the "Yagi calculators" on the
web. They are pretty basic but very simple. Just enter the frequency and
it will spit out the element lengths and spaces.
http://www.nemr.net/~aschmitz/antennas/calcantenna.html

Try the link above. I'm not sure if its the best one, but its just the
first one that popped up using Google.com.

Jason
KB5URQ
"Jason Porter" <jason...@sympatico.ca> wrote in message
news:a592a30a.02071...@posting.google.com...

[Lord Velveeta]

On Mon, 15 Jul 2002 21:42:22 GMT, "JASON A DUGAS" <kb5...@prodigy.net>
wrote:

>The easiest way to do this is to use one of the "Yagi calculators" on the
>web. They are pretty basic but very simple. Just enter the frequency and
>it will spit out the element lengths and spaces.
>http://www.nemr.net/~aschmitz/antennas/calcantenna.html

Besides if I read his request correctly, this will be a receive only
antenna. The "fine tuning" is a lot less critical with no SWR
ajustments to deal with and a basic yagi can work wonders. (he says
after having built a rough yagi out of a stick and 4 coat hangers to
DRAMATICALLY improve my reception for 88-108mhz broadcast band FM at
my backcountry house where reception was zilch)

Pat