Posted: 1/17/2010 4:51:28 PM EDT
| Can someone please explain why or why not putting either (2m/440) base antenna or a mobile antenna in the top of a tree would or would not: A)work B) be a good idea. I looked through the entire ham 101 thread and found nothing about UHF/VHF antennas in trees. Thanx, E |
| why? an antenna mounted to the roof line or chimney works just fine and requires less cable. hell, im running a little home brew antenna mounted to a telescope tripod inside and have no problems hitting the repeater 8 miles away with a 5w HT. if your looking to do long range VHF/UHF you would be better off with a tower and a directional anyways. |
|
Quoted:
Can someone please explain why or why not putting either (2m/440) base antenna or a mobile antenna in the top of a tree would or would not: A)work B) be a good idea. I looked through the entire ham 101 thread and found nothing about UHF/VHF antennas in trees. Thanx, E there is no reason that it won't work. put it up and go for it. some advice though, if you are planning on using a tree... a) be very careful climbing. b) the typical 2m/70cm antenna will work most effectively if there is nothing within about 1 to 2 wavelengths of the vertical. i don't know what kind of tree you are considering, but try to get a location with a little nearby as possible. the location doesn't have to be perfect, just be aware that if you mount the antenna directly adjacent to the trunk the resultant pattern may be poor. c) note that low loss coax must be used at VHF and especially at UHF frequencies. if you run 100 feet of cheap RG58 up a tall tree, don't be surprised that you don't hear a whole lot on UHF. attenuation-vs-length tables for various types of coax are available at the coax manufacturer websites (Belden, Times-Microwave, etc) and at the vendor websites (AES, Gigaparts, HRO, etc). ar-jedi |
| The pattern and gain of a vhf or uhf mobile antenna mounted on a car will be different from that when mounted in a tree. See this article for some discussion of the point... |
|
Quoted:
The pattern and gain of a vhf or uhf mobile antenna mounted on a car will be different from that when mounted in a tree. See this article for some discussion of the point... correct, the OP should avoid using a 1/4wave type –– which is dependent on a ground plane –– and instead use a 1/2wave type (the Comet SBB-5 comes to mind). ar-jedo |
|
Quoted:
Do you have an attic? If so, something like this might be easier (and require less cable): http://home.comcast.net/~cjan99999/antenna2.jpg +1 What he said. The attic antenna works well for me, too. 
|
|
Quoted:
Can someone point me to some 1/2 wave 2 meter antenna's, all I am able to find are 1/4 wave and 5/8 wave? if your looking to build your own try HERE. |