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This is sorta like 20 questions. You posted a question looking for some free advice, and you have a bunch of talented engineers offering suggestions but without knowing the whole picture it is getting even more difficult to follow this thread. Unless it is a state secret why not share the name of the station and perhaps some of this brain trust can offer a more informed opinion. We can probably give you a go-no go opinion (the majority currently leaning toward no go) but in the end if you "go" you will need the services of a consulting engineer to make the maps, clear the interference contours, ect plus the actual cost of construction and perhaps new equipment. Again, as most posters have pointed out- cost vs benefit.
That's because there is no one single right answer and there is a ton of stuff to consider before doing something like this. Unfortunatly, you have people that think putting a radio station on the air is like putting up an icee stand. It's just not that simple.
Anyone serious about these questions needs to study the applicable sections of section 73 of the fcc rules.....really not that complicated, and will enlighten anyone as to what meets and fails FCC expectations...perhaps those questioning do not have the time or dedication to go to the source? Not being critical......factual! Thanks JBI
Another thing to think about is trees and buildings soaking up signal. At such low height you will probly see a greater increase than what is being calculated do to over shaowing the trees and buildings better, if you have them. If this is not going to present a problem with surrounding stations or translators 3 frequencies up or down the dail near you which I dought it would and your not going to have to pay an arm and a leg to get it done ie: tower climbing charge, more hardline, what have you and the FCC approves it then the decission is yours but make sure you check everything out good first before you jump in and make the move.
That is exactly right, and for this reason it is probably well worth the money for the additional height. Whether it's fresnel zone clearance or something else, an antenna that is too close to the ground won't radiate properly. I personally have had a station at around 120'above ground that I raised to 200'above ground, and took the power decrease so that, according to everyone's calculations, should have given me the same coverage. It was VASTLY improved, a night and day difference.
You want to raise your antenna without lowering your power! That's sure to be a plus, as long as the costs to do so isn't crazy, by all means do it.
Another example- an LPFM in the town where I lived increased his antenna from 60' to 100'. He was thrilled with the results.
Taking a station (Licensed C2) from 44KW/469ft HAAT to 50KW/492ft HAAT.
average terrain pretty flat all around it, no valleys, large hills or anything.
Would this accomplish anything if it were approved? This move would be done regardless (even at old height), as a new 1,000 foot stick would be built for it's sister 100KW to move from the same 469 to 981.
The RMS value of the 60 dBu contour will move from 31.1 miles to 32.4 miles, per the FCC F(50,50) curves.
Moving the antenna to a new mounting location on that tower could change its azimuth and elevation patterns compared to what it now has, so there could be areas with less signal as well as areas with more.
A pattern study on the antenna manufacturer's test range will be helpful in an attempt to avoid "surprises," before this change is made.
Have I got this right? You've currently got two stations on the old (shorter) tower. One is 100 kW @469'; the other us 44 kW @ 469'. If that's the case, why isn't station that is currently running 44 kW @ 469' already running 50 kW @ 469'? Presumably, there is a reason. And the answer could reveal a lot about the problems you may encounter in trying to move the lower-powered signal to the new tall tower.
If no one has mentioned this, use the Longley-Rice online calculator at http://lrcov.crc.ca/main/ . You will have to register, but it's free. I recently built a new Class A site. Before deciding on a final HAAT, I moved the antenna up & down and adjusted the power each time. At a certain point, you'll see the improvements diminish (fortunately I had a enough tower to achieve full performance). Where it says Antenna Gain (dbi), enter a figure of 2.1 and for power, enter 250 assuming your power at each height can be 250 watts. Run one calculation at the lower height & print it. Run the other calculation at the higher height. Then ask yourself, Am I willing to pay $XXX for this degree of change? In my case, the results of what I built vs what this calculator predicted are nothing shy of remarkable.
If no one has mentioned this, use the Longley-Rice online calculator at http://lrcov.crc.ca/main/... In my case, the results of what I built vs what this calculator predicted are nothing shy of remarkable.
That online calculator is a good resource, but for best accuracy the az/el radiation patterns of the FM antenna should be considered. Not specifying pattern data on that web form will give the results for a perfectly omni radiation pattern in the horizontal plane (and vertical plane data is not even accommodated).
The radiation patterns of side-mounted, non-panel FM antennas can have significant lobes and nulls, which won't be accounted for in the L-R calculations and display unless they are known, and used. And of course, there is no provision in the web app to consider other than the terrain database it uses (no buildings, etc).
If no one has mentioned this, use the Longley-Rice online calculator at http://lrcov.crc.ca/main/... In my case, the results of what I built vs what this calculator predicted are nothing shy of remarkable.
That online calculator is a good resource, but for best accuracy the az/el radiation patterns of the FM antenna should be considered. Not specifying pattern data on that web form will give the results for a perfectly omni radiation pattern in the horizontal plane (and vertical plane data is not even accommodated).
The radiation patterns of side-mounted, non-panel FM antennas can have significant lobes and nulls, which won't be accounted for in the L-R calculations and display unless they are known, and used. And of course, there is no provision in the web app to consider other than the terrain database it uses (no buildings, etc).
Those are good points I failed to mention. The A that I built (after much study of the ERI predicted patterns) does indeed sound far better at 50 miles in the desired direction than at 35 miles in the predicted shadow direction. The advantages and/or disadvantages of side mounting on even a 24" face tower should not be underestimated.
I have never understood not having an antenna range tested. You're spending a lot of money for that final link to the listener without knowing what it's going to do when you hang it if you've gone cheap and bypassed the range. Jampro and ERI are the only ones that can do full scale range testing, and I would never hang an antenna without going through that process.
Anyone - even the CFO - ought to be able to look at a 'before' and 'after' pattern run and realize the expenditure of 10% or less of the basic antenna cost - 3 - 5% of the total job cost - is a bargain. And, given that ERI and the other major builders never throw anything away, they can often tell yuo roughly what you're going to get if they've patterened your frequency on that tower before. It will vary according to the stuff in the tower, and that's why patterning each individual install is worthwhile.
CEO's and others are far enough away from any common sense to not understand why this is important.
Can't tell you the number of times I have seen this. Same with height and power. it just doesn't make sense to them because this is not black or white. They can't easily look at it through their culture. Like trying to get the Mek to wear pants and not gourds as a good example.
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