Backcountry Forum
Backpacking & Hiking Gear

Backcountry Forum
Our long-time Sponsor - the leading source for ultralite/lightweight outdoor gear
 
 
 

Amazon.com
Backpacking Forums
---- Our Gear Store ----
The Lightweight Gear Store
 
 WINTER CAMPING 

Shelters
Bivy Bags
Sleeping Bags
Sleeping Pads
Snow Sports
Winter Kitchen

 SNOWSPORTS 

Snowshoes
Avalanche Gear
Skins
Hats, Gloves, & Gaiters
Accessories

 ULTRA-LIGHT 

Ultralight Backpacks
Ultralight Bivy Sacks
Ultralight Shelters
Ultralight Tarps
Ultralight Tents
Ultralight Raingear
Ultralight Stoves & Cookware
Ultralight Down Sleeping Bags
Ultralight Synthetic Sleep Bags
Ultralight Apparel


the Titanium Page
WM Extremelite Sleeping Bags

 CAMPING & HIKING 

Backpacks
Tents
Sleeping Bags
Hydration
Kitchen
Accessories

 CLIMBING 

Ropes & Cordage
Protection & Hardware
Carabiners & Quickdraws
Climbing Packs & Bags
Big Wall
Rescue & Industrial

 MEN'S APPAREL 

Jackets
Shirts
Baselayer
Headwear
Gloves
Accessories

 WOMEN'S APPAREL 

Jackets
Shirts
Baselayer
Headwear
Gloves
Accessories

 FOOTWEAR 

Men's Footwear
Women's Footwear

 CLEARANCE 

Backpacks
Mens Apparel
Womens Apparel
Climbing
Footwear
Accessories

 BRANDS 

Black Diamond
Granite Gear
La Sportiva
Osprey
Smartwool

 WAYS TO SHOP 

Sale
Clearance
Top Brands
All Brands

 Backpacking Equipment 

Shelters
BackPacks
Sleeping Bags
Water Treatment
Kitchen
Hydration
Climbing


 Backcountry Gear Clearance

Topic Options
Rate This Topic
#88512 - 01/30/08 07:08 PM Paul's Yagi Q.
huskyrunnr Offline
member

Registered: 05/29/05
Posts: 54
Loc: E. WA
Paul, my call sign just showed up tonight on the FCC database. Yahoo!

I'm considering a vx-7r and looking at improvements to the stock antenna. Your Yagi is intriguing and a brilliant design, and just has to be better than a tiger tail. I think this will be my first homebrew project in Ham radio. My question is, do you figure out the tuning at home and then call it good, marking the feed points, or do you tune it in the field? If you tune it in the field, how?

TIA

David Lowry
KE7RGP
_________________________
David KE7RGP

Top
#88513 - 01/30/08 07:22 PM Re: Paul's Yagi Q. [Re: huskyrunnr]
Dryer Offline

Moderator

Registered: 12/05/02
Posts: 3591
Loc: Texas
Hey, congratulations and welcome to the hobby! Post your callsign in your signature.

If you build my yagi exactly as described, it should be tuned and ready to go. Won't make that much difference at 5 watts. It doesn't use a matching network, so a VSWR swing of 2:1 is no big deal. I modeled it to be hi-gain but very forgiving. I think mine bottoms at 1.3 and tops at 2.4 across the band. The gain more than makes up for any impedance mismatch. Make sure you use 174U as feedline and order some SMA connectors from Mouser or Digikey for 174U. The copper sub-mini alligator clips are what works best at the feed point.

Note: You can use a wooden arrow shaft as the boom if you want, but the carbon shaft allows for element storage when you pack it. Have fun!


Hint: Once built, IF you can talk your park rangers out of the radio collar frequencies of bears/cats, you'll be able to pin point their locations. <img src="/forums/images/graemlins/cool.gif" alt="" />
_________________________
paul, texas KD5IVP

Top
#88514 - 02/02/08 11:11 AM Re: Paul's Yagi Q. [Re: Dryer]
ajherman Offline
member

Registered: 05/02/06
Posts: 208
Loc: Rock Springs, WY
i built one using an old fishing pole for the shaft. it worked ok, but something with a constant diameter would be better. welcome to the hobby, i hope you have fun with it.
_________________________
KD8DYO
www.hikeforacause.wordpress.com

Top
#88515 - 02/04/08 06:57 PM Re: Paul's Yagi Q. [Re: ajherman]
huskyrunnr Offline
member

Registered: 05/29/05
Posts: 54
Loc: E. WA
Thank you both! My HT arrives on Wed. I just found an open repeater at a pass in the Cascades that links to a repeater in my hometown. It is a location that I frequent often for backcountry rambles. Now, if I could just get my wife and son licensed.... Otherwise, I'll have to cajole the local club members to monitor while I'm out.
_________________________
David KE7RGP

Top
#88516 - 03/16/08 06:03 PM Re: Paul's Yagi Q. [Re: Dryer]
huskyrunnr Offline
member

Registered: 05/29/05
Posts: 54
Loc: E. WA
Thanks again Paul. I just finished it today. I am astounded at how well this antenna goes together and how light it is. I used .047" music wire so less droop or wind effect and moved the driven element about 1" closer to the director. This gave (theoretically) close to 50 ohm input impedance and almost null reactance with a loss of 0.3 dBi gain compared to your parameters. Six of one, half dozen the other. I'm bottoming out at 1.10 VSWR at 146 MHz with 1.21 and 1.41 VSWR at the ends of the band. This was measured with a Bird 43 with a 250 mW element on the reflected power, so it is accurate.

Your design is ingenious. I'm going to have good times with this.


Edited by huskyrunnr (03/16/08 06:09 PM)
_________________________
David KE7RGP

Top
#88517 - 03/16/08 06:17 PM Re: Paul's Yagi Q. [Re: huskyrunnr]
Dryer Offline

Moderator

Registered: 12/05/02
Posts: 3591
Loc: Texas
Hey great! Glad you like it. Moving that element probably doesn't change the pattern much. I can model it to see but really, as you say, it won't matter.
Now, go enter a few local 'transmitter hunts'! You'll find the antenna is very effective running through the trees and not breaking.
You'll find you can hit repeaters impossibly far away as well as satellites, with ease.
Enjoy!
_________________________
paul, texas KD5IVP

Top
#88518 - 03/17/08 04:06 PM Re: Paul's Yagi Q. [Re: huskyrunnr]
midnightsun03 Offline
member

Registered: 08/06/03
Posts: 2936
Loc: Alaska
Parlez vous "english"?

Just kidding... just felt like I was reading another language (then again, I suppose I am, LOL).

MNS
_________________________
YMMV. Viewer discretion is advised.

Top
#88519 - 03/17/08 05:31 PM Re: Paul's Yagi Q. (the knack...oh nooooo! ) [Re: midnightsun03]
Dryer Offline

Moderator

Registered: 12/05/02
Posts: 3591
Loc: Texas
MNS, you must understand (and take pity... <img src="/forums/images/graemlins/grin.gif" alt="" />)...huskyrunner and I are geeks and have "the knack". <img src="/forums/images/graemlins/cool.gif" alt="" /> It's a disease acquired at birth.

This will explain everything:
http://www.youtube.com/watch?v=CmYDgncMhXw
_________________________
paul, texas KD5IVP

Top

Shout Box

Highest Quality Lightweight Down Sleeping Bags
 
Western Mountaineering Sleeping Bags
 
Lite Gear Talk - Featured Topics
Backcountry Discussion - Featured Topics
Make Your Own Gear - Featured Topics
Featured Photos
Spiderco Chaparral Pocketknife
David & Goliath
Also Testing
Trip Report with Photos
Seven Devils, Idaho
Oat Hill Mine Trail 2012
Dark Canyon - Utah
Who's Online
0 registered (), 170 Guests and 0 Spiders online.
Key: Admin, Global Mod, Mod
Newest Members
Noodles, McCrary, DanyBacky, Rashy Willia, WanderBison
13240 Registered Users
Forum Links
Disclaimer
Policies
Site Links
Backpacking.net
Lightweight Gear Store
Backpacking Book Store
Lightweight Zone
Hiking Essentials

Our long-time Sponsor, BackcountryGear.com - The leading source for ultralite/lightweight outdoor gear:

Backcountry Forum
 

Affiliate Disclaimer: This forum is an affiliate of BackcountryGear.com, Amazon.com, R.E.I. and others. The product links herein are linked to their sites. If you follow these links to make a purchase, we may get a small commission. This is our only source of support for these forums. Thanks.!
 
 

Since 1996 - the Original Backcountry Forum
Copyright © The Lightweight Backpacker & BackcountryForum