-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Base Antenna Coax length,Best Coax and best Antenna under $250.00
- Thread starter Lil'Yeshua
- Start date
The last few sites you posted are pretty good ones, especially the 'dipole' thingy from NJ2L. I guess I'm lucky because I don't particularly need a vertically polarized antenna and all the problems they can cause (where to hang the thing mostly). Lucky also because I've got a few trees that I can hang things from, no HOA, and I really don't care what an antenna 'looks' like as long as it works well.
In NJ2L's article about dipoles he said that they are 'infinitely' variable as far as shape, size, etc. That's a lot more true than you might think. The closer you can get to the 'idea', the better off you are, but sometimes that's not possible/practical, so you do what you can and then 'customize'/adjust/modify/"skootch" the @#$ thing into working well enough to working 'well enough', you know? That's basically what you do with any/all antennas no matter what they are or who makes them. Doing all that is what's included in that 'tuning' procedure.
The two biggies with any antenna is resonance (length) and matching impedances (SWR). Even those aren't something to get 'exact', close makes a large difference. How does the thing perform, that's what it's all about.
Supporting a dipole. How/where to put the thing so that it performs adequately. That's probably the hardest thing to accomplish, and sometimes there's just no place to put the thing that's practical/acceptable. Got no place where it would 'fit'? Then start thinking about some other type of antenna (keep in mind that "infinitely variable" shape thingy).
Good luck with all of it.
- 'Doc
In NJ2L's article about dipoles he said that they are 'infinitely' variable as far as shape, size, etc. That's a lot more true than you might think. The closer you can get to the 'idea', the better off you are, but sometimes that's not possible/practical, so you do what you can and then 'customize'/adjust/modify/"skootch" the @#$ thing into working well enough to working 'well enough', you know? That's basically what you do with any/all antennas no matter what they are or who makes them. Doing all that is what's included in that 'tuning' procedure.
The two biggies with any antenna is resonance (length) and matching impedances (SWR). Even those aren't something to get 'exact', close makes a large difference. How does the thing perform, that's what it's all about.
Supporting a dipole. How/where to put the thing so that it performs adequately. That's probably the hardest thing to accomplish, and sometimes there's just no place to put the thing that's practical/acceptable. Got no place where it would 'fit'? Then start thinking about some other type of antenna (keep in mind that "infinitely variable" shape thingy).
Good luck with all of it.
- 'Doc
Thought about not using the tv antenna tower but mounting a vertical dipole on a fiberglass pole against the house. Maybe to a height of twenty feet at the feed point above the house. My dwelling place is on a 1960's sand pit which the ground slopes down from the road to the backyard. 300ft. Behind the backyard,the ground slopes upward at a 45 degree angle to my neighbor's property. This upsweep of land is northwest of my home which is 45 miles southeast of Charlotte,nc. Standing on top of that slope,I can see three feet of my tv antenna which is above where I'm standing at. Talking about whacked?! Fortunately I only rent and am planning on moving to Mountian City,TN in the near future.
A couple of fiberglass fishing poles would make a descent dipole.
Here's a video to all who have that inventive spirit in them.
The Red Green Show - Handyman Corner Zamboni - YouTube
Here's a video to all who have that inventive spirit in them.
The Red Green Show - Handyman Corner Zamboni - YouTube
Rf isolator
Got my coax and rf isolator(1:1 balun)in today. Gotta contact the manufacturer and ask if I could place this at the antenna end.
Instruction sheet:the MFG-915 RF Isolator is a 1:1 current balun designed to be placed in line with 50-ohm coaxial cable and can be used in fixed station and mobile applications. It is rated at full legal SSB power. The RF Isolator can reduce or eliminate stray RF often found on coax. The MFJ-915 is made up of 50 ferrite core beads placed on a 13-inch length of RG-303 coaxial cable. The coax and the SO-239 connectors have Teflon insulation for maximum insulation. The TF Isolator is enclosed in a Schedule 40 PVC pipe for strength and protection.
Installation:The RF Isolator should be placed close to the transmitter,in line with the coax feeding an antenna. This can be done using patch cable such as the MFJ-5803 or MFJ-5806. Check the SWR of the antenna using a very small amount of power (less than 10 watts)and a SWR meter. A SWR analyzer such as the MGJ-269 may also be used.
Got my coax and rf isolator(1:1 balun)in today. Gotta contact the manufacturer and ask if I could place this at the antenna end.
Instruction sheet:the MFG-915 RF Isolator is a 1:1 current balun designed to be placed in line with 50-ohm coaxial cable and can be used in fixed station and mobile applications. It is rated at full legal SSB power. The RF Isolator can reduce or eliminate stray RF often found on coax. The MFJ-915 is made up of 50 ferrite core beads placed on a 13-inch length of RG-303 coaxial cable. The coax and the SO-239 connectors have Teflon insulation for maximum insulation. The TF Isolator is enclosed in a Schedule 40 PVC pipe for strength and protection.
Installation:The RF Isolator should be placed close to the transmitter,in line with the coax feeding an antenna. This can be done using patch cable such as the MFJ-5803 or MFJ-5806. Check the SWR of the antenna using a very small amount of power (less than 10 watts)and a SWR meter. A SWR analyzer such as the MGJ-269 may also be used.
Attachments
MFJ-915
Update:I've got a email reply from MFJ Enterprises about how to use the MFJ-915. They said that I can use it at the antenna end as well as the transmitter end of the feed line and that some of their customers bought two to use at both ends.
Update:I've got a email reply from MFJ Enterprises about how to use the MFJ-915. They said that I can use it at the antenna end as well as the transmitter end of the feed line and that some of their customers bought two to use at both ends.
The antennas on that website that have the highest gain figure are of the co-linear design.
The following from his website:
Latest News: 11 meter Collinear part production (50' antenna shown)
I am the only antenna designer and builder out there that I know of, that has ever made (or even attempted) to make a "collinear" antenna!
Its a 50' (thats right 50 foot) 11 meter ground plane antenna, that is actually
"two" highly efficient 5/8 wave (.64 wavelength to be more precise) antennas in one that are actually vertically stacked and phased together to "double" the gain of my 5/8 wave antennas.
Keep in mind, my regular sized 5/8 wave antennas are already more efficient and already offer more performance/gain than other 5/8 wave antennas out in the market today, so doubling that gain is quite an impressive feat!
Often, this omni-directional ground plane has been known to outperform 3 element beams (but unlike the beam it receives and transmits and puts them on "hold" in "all" directions at the same time)!
I may start offering these 50' antennas next summer, after more long-term structural testing is done.
If you look at the picture you can see the phasing stub sticking out about half way up the antenna.
But I don't understand why the website is still active.
I told a friend of mine about the antennas and he sent an email or talked on the phone (don't remember which) with the owner and was told that he quit trying to sell the antennas. ( don't remember the reason given )
The owner works at the Indianapolis Airport and is a technician/engineer for the communications/navigation euqipment at the airport.
A few years ago he talked with the people that were on the air on channel 16am here in Fort Wayne, In.
Where he claims he is at is Anderson, In. ( about 85 miles from Fort Wayne )
Some people up here said "Boy, he must have a huge amplifier."
But they failed to understand the situation.
If they had payed attention they would have realized that not only did he talk to the base stations here in Fort Wayne (even base stations that were not very capable) he also talked to people in Fort Wayne in mobiles.
If I can remember I think he talked to everyone in Fort Wayne that wanted to try to talk to him.
(Impressive to say the least)
After he talked to everyone in Fort Wayne and the channel got quiet you could hear him talking to the whole state of Indiana and then some.
He would answer someone west cental and into Illinois then you would hear him go back to someone in the south end of the state and then he would talk to somone over into Ohio.
I remember that he talked all over the state of Indiana.
At the time I had an A99 with the top of it over 100 feet and I could talk pretty good but he was talking to people that I had not a chance to hear.
He talked to people in the north west part of Indiana and I still could not hear the people he was talking to.
Some might say "Big Amp", but they would be wrong, because you can't talk to them if you can't hear them.
That's about all I know about it that I can remember at this moment.
Big ears
You think he may know something about antennas?! Might can learn something off of him.
You think he may know something about antennas?! Might can learn something off of him.
I did it my way
Sounds like he did things his way. I was thinking about folded dipoles today. Here's a clip.
Cb Antenna homebrew (The gumtree dipole) - YouTube
Sounds like he did things his way. I was thinking about folded dipoles today. Here's a clip.
Cb Antenna homebrew (The gumtree dipole) - YouTube