Home |
Search |
Today's Posts |
|
#1
|
|||
|
|||
Newbie antenna help
New to ham radio. Interested in building an antenna for a base station.
I dont have anything yet, just in the planning stage. Thought about buying a handheld and using that as part of my "base station" one maybe capable of 2 440 and 6. These seem cheaper used than the home units. My question is, is there information out there on how to build one? I have a radio shack book at home that has a plan for a 440. It uses aluminum ground wire. What I find when working with this stuff is it is impossible to make it perfectlyu straight. Doesn't that effect the performance? I mean it comes coiled and when I cut it to length I cant get it perfectly straight. Also, it is posisble to have good performance with one antenna for all the bands? Or is it absolutely necessary to have one antenna for each band? I have limited room. I appreciate your help! |
#2
|
|||
|
|||
wrote in message ups.com... New to ham radio. Interested in building an antenna for a base station. I dont have anything yet, just in the planning stage. Thought about buying a handheld and using that as part of my "base station" one maybe capable of 2 440 and 6. These seem cheaper used than the home units. Yes the handhelds are cheaper but they have a lot less power. However if your antenna is high enough, you can do amazing things with it. My question is, is there information out there on how to build one? I have a radio shack book at home that has a plan for a 440. It uses aluminum ground wire. What I find when working with this stuff is it is impossible to make it perfectlyu straight. Doesn't that effect the performance? I mean it comes coiled and when I cut it to length I cant get it perfectly straight. It doesn't have to be perfectly straight. You won't notice any difference unless you have loops coiled in it. Also, it is posisble to have good performance with one antenna for all the bands? Or is it absolutely necessary to have one antenna for each band? I have limited room. Yes there are multiband antennas. Basically, they use some type of coil or trap to subdivide the antenna. The full length of the antenna is used for the lowest frequency, etc. Dee D. Flint, N8UZE |
#3
|
|||
|
|||
Dee Flint wrote: wrote in message ups.com... New to ham radio. Interested in building an antenna for a base station. I dont have anything yet, just in the planning stage. Thought about buying a handheld and using that as part of my "base station" one maybe capable of 2 440 and 6. These seem cheaper used than the home units. Yes the handhelds are cheaper but they have a lot less power. However if your antenna is high enough, you can do amazing things with it. My question is, is there information out there on how to build one? I have a radio shack book at home that has a plan for a 440. It uses aluminum ground wire. What I find when working with this stuff is it is impossible to make it perfectlyu straight. Doesn't that effect the performance? I mean it comes coiled and when I cut it to length I cant get it perfectly straight. It doesn't have to be perfectly straight. You won't notice any difference unless you have loops coiled in it. Also, it is posisble to have good performance with one antenna for all the bands? Or is it absolutely necessary to have one antenna for each band? I have limited room. Yes there are multiband antennas. Basically, they use some type of coil or trap to subdivide the antenna. The full length of the antenna is used for the lowest frequency, etc. Dee D. Flint, N8UZE What would you recommend? Building a beam for two meter? If I did that would it work ok on 440 too? Also, I have seen beams mounted bothe on it's side and upright like an outside tv antenna. Which way is better? |
#4
|
|||
|
|||
|
#5
|
|||
|
|||
Here is some antenna theory to read to answer your questions
URL: http://k9erg.tripod.com/theory.htm -- Caveat Lecter |
#6
|
|||
|
|||
"Caveat Lector" wrote Here is some antenna theory to read to answer your questions URL: http://k9erg.tripod.com/theory.htm Nice site. Except for the inaccurate advice warning of disastrous effects from operating a J-Pole w/o a BalUn. I use neither a BalUn nor any coiled-feedline as a choke. If my feedline is radiating, it's the most efficient feedline radiator ever made, getting loud and clear 100 mile coverage on VHF Marine between other high sites, and surface contacts between 20-30 nautical miles depending on height of vessels antenna. Another misconception about J-Poles is from at least one web-site offering plans, in which the offerer warned against grounding the antenna. Dangerous and wrong of course, as the antenna and its mast should be grounded and performs very well as such. The stub-capped tops of a copper-pipe J-Pole antenna at the highest point of a structure will indeed be an air terminal for lightning that was going to strike that immediate area anyway. Maybe my lightning down conductors heading 180 degrees from the J-Pole to series of ground rods are the SECRET G. -- Users considering a static and lightning-grounded (and un-choked) J-Pole should make sure the British did not already invent/patent this form of improvement to the J-Pole radiation pattern. ;-) -- 73, Jack |
#7
|
|||
|
|||
wrote in message oups.com... Dee Flint wrote: wrote in message ups.com... New to ham radio. Interested in building an antenna for a base station. I dont have anything yet, just in the planning stage. Thought about buying a handheld and using that as part of my "base station" one maybe capable of 2 440 and 6. These seem cheaper used than the home units. Yes the handhelds are cheaper but they have a lot less power. However if your antenna is high enough, you can do amazing things with it. My question is, is there information out there on how to build one? I have a radio shack book at home that has a plan for a 440. It uses aluminum ground wire. What I find when working with this stuff is it is impossible to make it perfectlyu straight. Doesn't that effect the performance? I mean it comes coiled and when I cut it to length I cant get it perfectly straight. It doesn't have to be perfectly straight. You won't notice any difference unless you have loops coiled in it. Also, it is posisble to have good performance with one antenna for all the bands? Or is it absolutely necessary to have one antenna for each band? I have limited room. Yes there are multiband antennas. Basically, they use some type of coil or trap to subdivide the antenna. The full length of the antenna is used for the lowest frequency, etc. Dee D. Flint, N8UZE What would you recommend? Building a beam for two meter? If I did that would it work ok on 440 too? I'm not into a lot of VHF/UHF work personally however my OM likes loop antennas. However loops don't have any significant gain unless you stack them. Many people do like beams and some build their own. There are MANY good antenna books available from the ARRL. Start with The ARRL Antenna Book. As for working on more than one band, only those designed with that in mind will work adequately on two bands. If it is designed for only one band, it will be very bad on the other. Also, I have seen beams mounted bothe on it's side and upright like an outside tv antenna. Which way is better? Vertical elements on beams will yield vertical polarization and are thus suitable for repeater work and a lot of FM simplex. Horizontal elements will yield horizontal polarization and are thus suitable for weak signal work such as working distant SSB stations (horizontal is the custom on SSB). You really need to get and read a good antenna book. A newsgroup cannot give you enough detail. Dee D. Flint, N8UZE |
#8
|
|||
|
|||
For two meters and 440 I would suggest a J-pole. If you look on the arrow
antenna site http://www.arrowantennas.com/j-pole.html He gives you the information to build your own. FM by mutual agreement is vertical where sideband is horizontal. This relationship is used on VHF and UHF. On 6 meters a simple dipole will get you started. Use the formula 468/desired frequency in MHz equals the total wire length in feet. Make it a little longer for adjustment purposes then cut it in half. Add a center insulator and end insulators. At low power (=100 watts) use pieces of PVC pipe. Tie the shield of the coax to one side of center and the center conductor to the other. Welcome to amateur radio and if I can help you in any way just e-mail me. 73 Fred wrote in message ups.com... New to ham radio. Interested in building an antenna for a base station. I dont have anything yet, just in the planning stage. Thought about buying a handheld and using that as part of my "base station" one maybe capable of 2 440 and 6. These seem cheaper used than the home units. My question is, is there information out there on how to build one? I have a radio shack book at home that has a plan for a 440. It uses aluminum ground wire. What I find when working with this stuff is it is impossible to make it perfectlyu straight. Doesn't that effect the performance? I mean it comes coiled and when I cut it to length I cant get it perfectly straight. Also, it is posisble to have good performance with one antenna for all the bands? Or is it absolutely necessary to have one antenna for each band? I have limited room. I appreciate your help! |
#9
|
|||
|
|||
W4JLE wrote: For two meters and 440 I would suggest a J-pole. If you look on the arrow antenna site http://www.arrowantennas.com/j-pole.html He gives you the information to build your own. FM by mutual agreement is vertical where sideband is horizontal. This relationship is used on VHF and UHF. On 6 meters a simple dipole will get you started. Use the formula 468/desired frequency in MHz equals the total wire length in feet. Make it a little longer for adjustment purposes then cut it in half. Add a center insulator and end insulators. At low power (=100 watts) use pieces of PVC pipe. Tie the shield of the coax to one side of center and the center conductor to the other. Welcome to amateur radio and if I can help you in any way just e-mail me. 73 Fred wrote in message ups.com... New to ham radio. Interested in building an antenna for a base station. I dont have anything yet, just in the planning stage. Thought about buying a handheld and using that as part of my "base station" one maybe capable of 2 440 and 6. These seem cheaper used than the home units. My question is, is there information out there on how to build one? I have a radio shack book at home that has a plan for a 440. It uses aluminum ground wire. What I find when working with this stuff is it is impossible to make it perfectlyu straight. Doesn't that effect the performance? I mean it comes coiled and when I cut it to length I cant get it perfectly straight. Also, it is posisble to have good performance with one antenna for all the bands? Or is it absolutely necessary to have one antenna for each band? I have limited room. I appreciate your help! I like the looks of that. I wonder if I could use stainless? Is it necessary to use a balun on that? At the same height, what would the difference be between this one and a 6 element yagi? What are those red things on the top? They look like wire twisters. |
#10
|
|||
|
|||
Let me suggest that you order a copy of the ARRL Amateur Radio Handbook.
Just like any other hobby, this one has a bible that answers most of the questions that come to mind. You can save yourself the delay of having to ask and wait for a reply. To answer your questions. A J-pole requires a balun to eliminate feed line radiation. The difference between it and a yagi at the same height can be likened to a yard sprinkler vs. a hose nozzle. Same amount of water comes out the hose, the j-pole sprays the signal all around, the yagi is the hose nozzle. Are you trying to get a crowd wet, or a single person? On VHF your more often limited by line of sight distance than signal strength. If your beyond line of sight, a gazillion watts or a 100 element beam won't help. The red things keep you from poking your eyes out. wrote in message oups.com... W4JLE wrote: For two meters and 440 I would suggest a J-pole. If you look on the arrow antenna site http://www.arrowantennas.com/j-pole.html He gives you the information to build your own. FM by mutual agreement is vertical where sideband is horizontal. This relationship is used on VHF and UHF. On 6 meters a simple dipole will get you started. Use the formula 468/desired frequency in MHz equals the total wire length in feet. Make it a little longer for adjustment purposes then cut it in half. Add a center insulator and end insulators. At low power (=100 watts) use pieces of PVC pipe. Tie the shield of the coax to one side of center and the center conductor to the other. Welcome to amateur radio and if I can help you in any way just e-mail me. 73 Fred wrote in message ups.com... New to ham radio. Interested in building an antenna for a base station. I dont have anything yet, just in the planning stage. Thought about buying a handheld and using that as part of my "base station" one maybe capable of 2 440 and 6. These seem cheaper used than the home units. My question is, is there information out there on how to build one? I have a radio shack book at home that has a plan for a 440. It uses aluminum ground wire. What I find when working with this stuff is it is impossible to make it perfectlyu straight. Doesn't that effect the performance? I mean it comes coiled and when I cut it to length I cant get it perfectly straight. Also, it is posisble to have good performance with one antenna for all the bands? Or is it absolutely necessary to have one antenna for each band? I have limited room. I appreciate your help! I like the looks of that. I wonder if I could use stainless? Is it necessary to use a balun on that? At the same height, what would the difference be between this one and a 6 element yagi? What are those red things on the top? They look like wire twisters. |
Reply |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Inverted ground plane antenna: compared with normal GP and low dipole. | Antenna | |||
Newbie, UHF antenna for TV questions | Antenna | |||
Mobile Ant L match ? | Antenna | |||
Poor quality low + High TV channels? How much dB in Preamp? | Antenna | |||
QST Article: An Easy to Build, Dual-Band Collinear Antenna | Antenna |