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Base Antenna Coax length,Best Coax and best Antenna under $250.00
- Thread starter Lil'Yeshua
- Start date
Push it to 36 ft or higher...
Best to get a Full Wave length in height
11 meters = 36.1 ft (about )
for best results (or as close as you can)
Of course Higher always works well Too..
Best to get a Full Wave length in height
11 meters = 36.1 ft (about )
for best results (or as close as you can)
Of course Higher always works well Too..
1:1 balun
Ok. I ordered a mfj 1:1 balun. How does the balun connect to the antenna feed point? Jumper,how long jumper?Double pl-259?
MFJ Enterprises Inc.
Ok. I ordered a mfj 1:1 balun. How does the balun connect to the antenna feed point? Jumper,how long jumper?Double pl-259?
MFJ Enterprises Inc.
Just a few things in no particular order.
If it's not needed, why use the feed line (length) to 'adjust' SWR or the impedance match with an antenna? There's no benefit other than it's a fairly easy 'work around' to actually tuning an antenna, and it definitely does have disadvantages. A feed line's purpose is to provide a path to get current from the transmitter to the antenna without any undue losses. Feed line length, using the feed line's velocity factor only comes into play when phasing/timing comes into play.
'Tuning' antennas is always a 'two-part' thingy involving resonant (efficient radiation) and impedance matching (SWR) which involves efficient energy transfer. If you don't do both then you have not tuned the antenna, make it compatible with the rest of the system. The 'bad' part of that is that SWR tells you absolutely nothing about resonance, and the most common way of adjusting that SWR is at the expense of resonance (adjusting antenna's length). There are several 'meters' that can tell you if an antenna is resonant but an SWR meter just isn't one of them.
'Best' antenna height. For all practical purposes there is no such thing, it always varies because of propagation (conditions). Unless you have the option of multiple antennas at multiple heights, the 'best' that you can do is to put the antenna at the highest -practical- height you can get/afford. What may work well for one particular location and propagation state may not do well at all at another location during different propagation conditions. There's no absolute, never varies, 'perfect' height for all cases. How do you tell what would be a 'best' height for your particular installation? The only sure way is by trying them all. Have fun with that! Or just take what you can get.
Chokes, baluns, line-isolators.
They all serve a purpose and are nice to have -IF- they in fact are serving a purpose. If one isn't required then it's only another 'point of loss' or possible point of failure, it just ain't doing you no good. Of those three thingys a choke is probably the least 'obtrusive/invasive/just-in-case' thingy you can use. It only adds a few feet of feed line. A choke only affects the outside of a feed line, not the inside.
A balun only makes the change from a 'balanced' state to an 'unbalanced' state. (It may do some impedance transforming, just like any transformer except it's transforming impedance.) They can certainly 'help' things, but in most cases those 'things' are specific, not just a general improvement.
Line-isolators do the same thing a choke does, 'cleans off' the outside of the feed line from the point where it's placed to the transmitter. That's what most of the 'short' radials you see on some antennas are, line-isolators.
Here's the 'disclaimer' (or the CYA thingy)!
There are gobs of things that affect how well your radio 'system' works. The above only touches on a few of them, is NOT very comprehensive or a detailed explanation, it's a 'generalized' thingy. If you want to know exactly how/why something works I would suggest hitting the library to find legitimate texts about those things, there are tons of it available.
Have fun.
- 'Doc
If it's not needed, why use the feed line (length) to 'adjust' SWR or the impedance match with an antenna? There's no benefit other than it's a fairly easy 'work around' to actually tuning an antenna, and it definitely does have disadvantages. A feed line's purpose is to provide a path to get current from the transmitter to the antenna without any undue losses. Feed line length, using the feed line's velocity factor only comes into play when phasing/timing comes into play.
'Tuning' antennas is always a 'two-part' thingy involving resonant (efficient radiation) and impedance matching (SWR) which involves efficient energy transfer. If you don't do both then you have not tuned the antenna, make it compatible with the rest of the system. The 'bad' part of that is that SWR tells you absolutely nothing about resonance, and the most common way of adjusting that SWR is at the expense of resonance (adjusting antenna's length). There are several 'meters' that can tell you if an antenna is resonant but an SWR meter just isn't one of them.
'Best' antenna height. For all practical purposes there is no such thing, it always varies because of propagation (conditions). Unless you have the option of multiple antennas at multiple heights, the 'best' that you can do is to put the antenna at the highest -practical- height you can get/afford. What may work well for one particular location and propagation state may not do well at all at another location during different propagation conditions. There's no absolute, never varies, 'perfect' height for all cases. How do you tell what would be a 'best' height for your particular installation? The only sure way is by trying them all. Have fun with that! Or just take what you can get.
Chokes, baluns, line-isolators.
They all serve a purpose and are nice to have -IF- they in fact are serving a purpose. If one isn't required then it's only another 'point of loss' or possible point of failure, it just ain't doing you no good. Of those three thingys a choke is probably the least 'obtrusive/invasive/just-in-case' thingy you can use. It only adds a few feet of feed line. A choke only affects the outside of a feed line, not the inside.
A balun only makes the change from a 'balanced' state to an 'unbalanced' state. (It may do some impedance transforming, just like any transformer except it's transforming impedance.) They can certainly 'help' things, but in most cases those 'things' are specific, not just a general improvement.
Line-isolators do the same thing a choke does, 'cleans off' the outside of the feed line from the point where it's placed to the transmitter. That's what most of the 'short' radials you see on some antennas are, line-isolators.
Here's the 'disclaimer' (or the CYA thingy)!
There are gobs of things that affect how well your radio 'system' works. The above only touches on a few of them, is NOT very comprehensive or a detailed explanation, it's a 'generalized' thingy. If you want to know exactly how/why something works I would suggest hitting the library to find legitimate texts about those things, there are tons of it available.
Have fun.
- 'Doc
B
BOOTY MONSTER
Guest
Ok. I ordered a mfj 1:1 balun. How does the balun connect to the antenna feed point? Jumper,how long jumper?Double pl-259?
MFJ Enterprises Inc.
so what antenna did you decide on and why do you think you need a balun for it ?
Choices
I'm thinking about getting the Solarcon A99 but I like the fact that the Solarcon IMAX 2000 does a better job overall. Plus a couple of locals are using A99's and Maco v58's. I want mine talk local(30 miles) and the capability to do DX. I think that these two antennas need a coax choke and according to what I've read,ground plane kits for these aren't needed. The best performance at a good price using legal power.
I'm thinking about getting the Solarcon A99 but I like the fact that the Solarcon IMAX 2000 does a better job overall. Plus a couple of locals are using A99's and Maco v58's. I want mine talk local(30 miles) and the capability to do DX. I think that these two antennas need a coax choke and according to what I've read,ground plane kits for these aren't needed. The best performance at a good price using legal power.
P.S. the ground that my tower sits on is 40 to 100ft. Or more of sand. Most of the regions sand for concrete comes from a sand pit five miles away. Sugar sand.
B
BOOTY MONSTER
Guest
well , that MFJ balun is not optimal for a choke on 27 MHz and may even increase CMC's that may cause/increase the issues you're trying to avoid . considering that hurricanes do hit SC on a regular basis i'd think a gainmaster or penetrator 500 would be at the top of your list . but , it's your money and your headache so enjoy yourself .
Balun
I made my decision to get a 1:1 balun after reading forums on the subject concerning A99's and the IMAX 2000. A couple of guys use coax chokes on their A99's so I figured I would need one as well. They don't have ground planes on their A99's either and they get out very well. Help!
I made my decision to get a 1:1 balun after reading forums on the subject concerning A99's and the IMAX 2000. A couple of guys use coax chokes on their A99's so I figured I would need one as well. They don't have ground planes on their A99's either and they get out very well. Help!
Ok
I agree. I was concerned that the GainMaster would need to be up higher than the 32-36ft. I have planned for on account of it's low angle of radiation.
a better way is to buy the gainmaster which does not need a balun radials the coax outer shield or the mast for return currents, plus you have better performance than any other no radial end-fed i have tested
I agree. I was concerned that the GainMaster would need to be up higher than the 32-36ft. I have planned for on account of it's low angle of radiation.
in our multiple tests at different locations this seems not to be the case, even as low as 14ft of mast where the gm is supposed to not work very well the only antennas that have outperformed the gainmaster are the i-10k by a small margin and the vector/sigma4 style antennas by a larger margin,
the imax and a99 are behind for noise and performance in our tests, 1 wavelength is high enough,
my only reservation with the gainmaster is we have not yet had 100mph+ winds since the gainmaster became available to see how durable they are in real wind,
we have had 70+mph but that don't count as high wind in my book, its not until we get 100+ that the men are sorted from the boys,
good luck with whatever you decide to buy
the imax and a99 are behind for noise and performance in our tests, 1 wavelength is high enough,
my only reservation with the gainmaster is we have not yet had 100mph+ winds since the gainmaster became available to see how durable they are in real wind,
we have had 70+mph but that don't count as high wind in my book, its not until we get 100+ that the men are sorted from the boys,
good luck with whatever you decide to buy
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