Is a pre-amp necessary?

Probably not. A preamp is needed for locations that are far from the transmitters or behind a hill.

As Tower Guy says, it is a function of your specific conditions. In Florida, I am 42 miles from the antennas, and driving 75 feet of RG-6. I use a preamp. In SC, I am about 20 miles from the antennas, driving about 20 feet of RG-6. No preamp, everything works fine.

How far are you from the transmitters?
Enter your complete address at:
http://www.antennaweb.org/

Well, a zip code would be more helpful. We could look up your stations and make specific antenna recommendations. The CM 3016 is a directional medium range antenna and if there is a wide spread in azimuth for your locals, it may not get all of them without a rotator. But if you have the CM 3016, try it without a pre-amp first. A 25 ft cable run is not a long one.

My non-expert advice is that 3016 is fine and no pre-amp needed. This assumes your digital stations aren't at pitiably low power such as 1 or 2 kW and even then you might be OK. Any analog stations you could probably easily get. But then why would you want an analog station if digital available! And if it was me, I'd first try the attic, but YMMV!

You should not need a preamp at that distance, unless, like Bill Johnson said, your stations are not yet full power, or you have a very long coax run. To find out if your stations are all full power, ask in the thread for your particular town. Find it HERE. The cities are listed by market size.

At 16 miles line of site and all station in the same directionthat antenna should be fine without a preamp or rotor.

The FCC database shows ERP's ranging from around 1kW up to a 1,000 for WGNM-DT all from the same direction. I'd say avoid a pre-amp at all costs and with LOS the 3016 should be fine, hopefully even for WGXA-DT at the pitifully low end.

He faces a common reception problem viewers in many smaller markets still face - stations broadcasting anywhere from a kilowatt to a megawatt of power.

The 1 kilowatt stations such as WGXA may be too weak to be received without a high gain antenna system and the megawatt stations like WGNM on the same antenna setup may overload the tuner.

Trying the without a preamp is a good start.

Wow, you are certainly bashing the 3016. I wouldn't put it down that much. I live fairly close to the original poster, and have a CM 3016, and get my highest signal on the lower VHF Channel 4.

* yellow - uhf WPGA-DT 32.1 ABC PERRY GA 60° 10.3 32
* yellow - vhf WMAZ-DT 13.1 CBS MACON GA 60° 10.4 4
* yellow - uhf WGNM-DT 45.1 CTN MACON GA 57° 10.8 45
* yellow - uhf WGXA-DT 24.1 FOX MACON GA 61° 10.2 16
* green - uhf WMGT-DT 41.1 NBC MACON GA 59° 10.2 40

If anything, he might just need to get the next size up of the CM something like the 3018. My lowest channel is Fox 24, and that is only because they are not at full power yet. But, I still get a strong steady signal on it. I have only had one problem with it so far.

One other thing I will note. the CBS channel (Digital 4) will be changing to UHF 13 as soon as they shut down analog (2009 sometime). So, that is something to keep in mind. If you can get a decent signal on a 3016, I would say keep it...because in little over a year they are moving to 13 anyways.

Well then my question to you is this, how accurate and reliable is the antennaweb website. Does it take into account possible elevation changes and other factors I am unaware of that could cause potential problems. Because if that is the case I can understand, but if not we are only talking about an additional 5 miles of distance from my location to the towers and his location to the towers. Now, I am not trying to be stuborn or anything here..I am just trying to figure out why 5 miles of distance you go from a yellow -2.5 dbd to a red -25 dbd. Especially since ch 4 is my strongest signal. To me that just doesn't make since how that little bit of distance, can have that large of an impact.

Another thought here is that the FCC shows WMAZ going to ch. 13 at shutdown. And a 12 ft. long antenna would become obsolescent at that point IMO.

A 4221 or even a 4228 stuck near the ceiling or in the attic should then be sufficient for the 4 hi-vhf/uhf digital stations, based on my experience.

Jerrold 5 or 10 element single channel antennas (about halfway down this page) usually work well.
Not familiar with the V4.

Good luck.

Lowband VHF digitals often suffer from impulse noise interference from motors, light switches, lightning, etc. :-(
The FCC should've abandonded chs 2 thru 6 for digital TV. It would have made antenna selection a lot simpler for OTA viewers.

Even a few hundred yards can make a difference. Make sure your location on antennaweb's street-level map is accurate. When I enter my address, it puts me a few hundred yards away from my actual location, and down a hill a ways. When I zoom and re-center the map properly, my listing gains a few stations.

Sing1gniS, you can go check at lowes. I just went to the one in Warner Robins last night and they had a few different Channel Masters in stock. Or the newer one in Kathleen I believe had a few more, that is always an option.

Where did these -2.5 and -25dBd figures come from?

An antenna has to develop a suitable signal to noise ratio from the ambient signal, and then your transmission medium has to sustain an adequate signal to noise ratio from there to our tuner input. We think that digital, off-air tuners need to see an input signal to noise ratio of around 16dB in order to reliably lock onto a signal, that cable boxes need to see about a 32dB S/N ratio (which is easier for them to meet, because it is a different kind of signal and transmitted under more controlled conditions), analog tuners need about a 45dB S/N ratio to develop pictures generally considered to be excellent by most viewers, and DBS satellite receives need an S/N of 8dB to reliably lock.

The amount of gain needed by an antenna to develop such a level depends on the ambient signal level at the reception point, which is a functionally related to signal transmitter's output, the distance to the reception pint, and is irregularly adversely affected by signal path obstructions.

If a person understands what any of that means, he surely wouldn't be coming to this thread looking for antenna advice, and unfortunately, unless he even has some idea, conceptually, what that might mean, he probably will not be able to utilize any advice given here by those who do understand it to develop remedies to their own antenna problems. They may find it intellectually stimulating, but they will not be able to make any definitive decisions regarding product sufficiency based upon it, other than, perhaps, to be able to rule out the absolutely unsuitable antenna selections.

When I was young, I used to primitively calculate signal levels and S/N ratios (which we more commonly called C/N ratios when working with analog signals), based on the assumption that I had line-of-site to the tower, but I haven't done so for broadcast TV reception analysis in thirty years because I can always do a good enough job estimating it. (I still do it for satellite signal sufficiency, however)

I am a commercial installer and I only use "Antenna Web" for analyzing azimuth relationships and estimating likely relative signal levels over generally line-of-sight transmission paths, usually under 40 miles. I have never bothered to learn what their arbitrary cut-off points are for calling an antenna low, medium or high gain, or directional versus non-directional, as I have much more detailed and specific information available to me when I develop multi-antenna headends for tall buildings, and I have a spectrum analyzer to furnish me with the actual signals levels, I am working with, rather than having to rely on the calculated or estimated ones.

That all having been said, I can't imagine any product claiming to have an output at a given frequency of -25dBd, as I think a paper clip antenna would outgain that, at least for channels 7-69. If consumer antenna dealers are now furnishing VHF lowband "gain" figures for antennas designed for UHF only use, they are furnishing numbers that are as useless for that application as itheir product is.

There is a lot of confusion in discussions in which lay people exchange published information regarding antenna signal levels, as sometimes they believe that numbers they are seeing describing different products are expressed in like terms and are describing the same signals or needs when they are not.

Those seeking advice on hardware additions to their home antenna system are always better going to their local sub-forum and opening a thread there, as there will be other participants who know the local considerations, like relative signal strengths, azimuth angles and sources of interference or signal degradation, and can offer solutions more specific to the unique circumstances of installations in their own back yard.

By dBd, do they mean "gain over dipole"? What am I not getting here? Can you furnish a link to the CEA page where they publish their own, comprehensive definition of terms and standards?

Every Yagi and Log Periodic antenna made meets or exceeds all of those minimum performance specs except for (violet/pink), where the bottom of the line Winegard, Channelmaster and other combo antennas come up a little short on VHF lowband, and the only gizmo antennas that might not meet those VHF highband and UHF gain figures are the ones that look like flying saucers.

At 16 miles, anything that is tuned for lowband will work provided there are no transmisstion path problems. You can buy any bottom of the line U/V combo for $20 to $30, and use a hi-lo combiner that passes 2-6 on one leg and 7-69 on the other.