| Author |
Message |
    
Slim1
| | Posted on Thursday, January 23, 2003 - 12:47 am: | 
|
i'm looking for input/ideas on building a homebrew base antenna for the MURS band freq.s...
i've seen manufacturers antennas and WOW are
they expensive! there has got to be someone here
who has an idea of a simple homebrew base ant. for
this application. thanks,SLIM-CDX285 |
Znut
| | Posted on Thursday, January 23, 2003 - 10:18 am: |
|
http://www.packetradio.com/jpol.htm
This is my favorite. Don't forget to put a coil of 8 or 9 turns of coax, about 5 inches in diameter right at the base of the antenna and tape it together real tight.
Znut |
Mr_Rf
| | Posted on Thursday, January 23, 2003 - 10:44 pm: |
|
The J-Pole inthe previous post is a good choice for a cheap all-directional antenna. Also, a directional antenna could be used. The cheaper Cushcraft beams for 2 meter ham radio would modify well to the business band by cutting about 3/4" off the tip of each element. (leave the gamma match length alone...shorten just the elements)
FYI...Info below from: http://www.provide.net/~prsg/murs_faq.htm#Q6
11. May I connect an external antenna or power amplifier to my MURS radio?
The FCC Rules permit connecting an external antenna to your MURS radio. However, the Rules limit the height of your antenna to a maximum of 20 feet over the mounting structure (exclusive of the tower, mast or pole on which it is mounted), or to 60 feet above ground, whichever is greater. (These are the same limits that apply to the original Citizens Band Radio Service at 27 MHz.) [95.1315]
The FCC Rules [95.1311] prohibit connecting your MURS radio to a "booster" or to a power amplifier. The Rules limit you to a maximum of 2 watts transmitter power output (TPO). [95.639(h)]
Good luck and have fun! |
Nobody077
New member
Username: Nobody077
Post Number: 4
Registered: 4-2004
| | Posted on Monday, April 26, 2004 - 1:07 am: |
|
Go with a J-Pole, Easy and Cheap only takes about $10 and 15min to build one, or build a Super J-Pole they are a little harder to build and a few dolarrs more but add about 2.5db gain. If you build the antenna with 3/4 or even 1inch copper pipe it wil cover 140-160mhz with >1.5 swr
check http://www.geocities.com/n2uhc/jpole.html
for some Super J plans |
Bullet
Intermediate Member
Username: Bullet
Post Number: 330
Registered: 7-2003
| | Posted on Tuesday, April 27, 2004 - 8:31 pm: |
|
i was gona mention the super j pole but 77 beat me to it. its a great choise for that freq.
id hook it up using the so-239 method so you can screw on your coax like normal. |
Davemcc
Junior Member
Username: Davemcc
Post Number: 17
Registered: 4-2004
| | Posted on Wednesday, April 28, 2004 - 6:49 am: |
|
ZNUT,
Do the turns of coax act as some kind of a choke? I was told it helped to prevent the (coax) outer sheilding from transmitting RF. I found, in my case, it seemed to help prevent telephone interference. That's what I was led to believe anyway.
Anyone else ever heard this?
Dave
376RI |
Barracuda
Intermediate Member
Username: Barracuda
Post Number: 234
Registered: 3-2003
| | Posted on Thursday, April 29, 2004 - 5:48 pm: |
|
Davemcc,
Yes, they form a choke as you were told. |
Barracuda
Intermediate Member
Username: Barracuda
Post Number: 235
Registered: 3-2003
| | Posted on Thursday, April 29, 2004 - 5:54 pm: |
|
Slim1,
Any 2m ground Plane or dipole can be cut down. I use a 5/8 wave 2m mag mount trimmed down for the mobile MURS xcvr I have. If you want a really simple JPole, you can make one out of 300 OHM twinlead. Do a search on the net for plans. This is very portable, takes about 5 minutes to build and goes anywhere. If you run the 2watts max, there is no problem with power on this antenna either.
Good luck and have fun |
Barracuda
Intermediate Member
Username: Barracuda
Post Number: 237
Registered: 3-2003
| | Posted on Friday, April 30, 2004 - 11:14 am: |
|
Slim1,
Here's a link to a twinlead MURS J-Pole plan.
MURS Twinlead J-POLE Plan
73,
Barracuda |
