Home |
Search |
Today's Posts |
|
#1
![]() |
|||
|
|||
![]()
N3 wrote:
Because of restrictions i am unable to put up a two meter fm vertical antenna. What is the feasability of putting up a random or long wire antenna for the two meter fm band? Doing a Google search i could not find any information concerning the above. Any assistance would be appreciated. Thank You. You can try several thinks. One is a J-Pole antenna, if you have enough room. It can be made from clear twin lead, like the kind that come with FM stereo systems. Another choice would be a dipole. Two 19 inch pieces of wire will do fine. Using the right thickness of wire and small enough coax would make it almost impossible to see. Due to the polarization issue, a horizontal wire is not very usefull You can also find if you look around a base for a "rubber duckie" type antenna that has a suction cup. You use it to put mount your antenna on a window while you are using it. 73, Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM IL Voice: (07)-7424-1667 Fax ONLY: 972-2-648-1443 U.S. Voice: 1-215-821-1838 Visit my 'blog at http://geoffstechno.livejournal.com/ |
#2
![]() |
|||
|
|||
![]()
Geoff Mendleson offered some good advice.
The dipole he suggested can be made using one 19-inch whip as the upper half of a vertical dipole and a 19-inch metal tube as the lower half of the dipole. The tube is also used as a sleeve over the coax which feeds the dipole at its center. This antenna is often called a coaxial or sleeve antenna. It is also often disguised to appear as something else such as a flagpole, etc. This antenna has 0 dBd gain and is omnidirectional in the horizontal plane. It works well in almost any line of sight direction and so is useful with portable and mobile stations. It is as good as a ground plane antenna without projections to cause injuries. Best regards, Richard Harrison, KB5WZI |
#3
![]() |
|||
|
|||
![]()
Richard Harrison wrote:
Geoff Mendleson offered some good advice. Thanks Richard. I appreciate the mention. The dipole he suggested can be made using one 19-inch whip as the upper half of a vertical dipole and a 19-inch metal tube as the lower half of the dipole. The tube is also used as a sleeve over the coax which feeds the dipole at its center. The advantage of using a whip and tube are the much wider bandwith than with a wire antenna. However if you are really stuck for places to put it, two 19" pieces of wire will do. Since most people only use a few watts on 2m FM, then the thinnest wire you can find will probably do. This antenna is often called a coaxial or sleeve antenna. It is also often disguised to appear as something else such as a flagpole, etc. This antenna has 0 dBd gain and is omnidirectional in the horizontal plane. It works well in almost any line of sight direction and so is useful with portable and mobile stations. It is as good as a ground plane antenna without projections to cause injuries. I think someone sells one that is a plastic pipe you slip over a vent pipe. If you are allowed TV antennas, you can build a "CIA special" which is a 2m and 440 beam fed by 300 ohm twinlead. On HF, the twinlead becomes the antenna and the beam part a capacative hat. I hid a J-Pole made of 300 ohm twinlead in side a white plastic pipe. If you use thin enough coax to feed it, it can be used to support all sorts of things, a pin-wheel or wind speed gage for example. 73, Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM IL Voice: (07)-7424-1667 Fax ONLY: 972-2-648-1443 U.S. Voice: 1-215-821-1838 Visit my 'blog at http://geoffstechno.livejournal.com/ |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
Bose Wave Radio - What's Your Opinion ? | Shortwave | |||
The Long and Thin Vertical Loop Antenna. [ The Non-Resonance Vertical with a Difference ] | Shortwave | |||
Question is 'it' a Longwire {Random Wire} Antenna -or- Inverted "L" Antenna ? | Shortwave | |||
ABOUT - The "T" & Windom Antenna plus Twin Lead Folded Dipole Antenna | Shortwave | |||
Question for better antenna mavens than I | Shortwave |