Will I need a Pre-Amp???

[kalmana1]

Hello - First time poster here and hopefully soon to be first time cord cutter.

My question basically centers around the idea of whether I will need a pre-amp in my setup or not. I read conflicting ideas and was hoping to get some feedback on my specific scenario. Please see the details below:

• Analysis - http://www.tvfool.com/?option=com_wr...46ae7fba59ad01
• Antenna Purchased - ClearStream 2V Long Range UHF/VHF
• Antenna will be installed outdoors approx. 25ft high
• There will be 2 TVs - Both cable runs are less than 40ft
• I am most concerned about the digital channels only

Your feedback is appreciated and thanks for running a great site!

-Andy

[jeff92k7]

Short answer, probably not. At least not for the UHF channels. Your report looks like you will have pretty good signal strength at your location. With a short cable runs, you likely won't need a preamp, but that antenna's VHF performance looks pretty weak and you do have some channels in the High band VHF range.

You probably will need one for the VHF channels though. just to keep the splitter and cable loss from reducing the VHF signal. Even then, your VHF channels may break up regularly.

Is there any way you could return that antenna and get something with better VHF performance? I'm sure someone here will chime in with a specific antenna model.

For comparison, I have a bit better reception (based on my tvfool report), but I still run a preamp and separate UHF and VHF antennas. My preamp is to overcome splitter loss and longer cable runs even though I'm starting with a stronger signal to begin with. But I also have crappy tuners (TiVo Premieres) that need a good, strong signal.

[kalmana1]

Thanks for the reply.

I never took into account that the antenna might not be good enough. When I look back at my analysis, the channels listed in VHF-HI have a similar noise margin to the UHF ones. Were you referring to the max gain that I can receive for VHF for my antenna or was it my antenna and something coupled with my analysis report that makes it worse?

I guess the next logical question that I need to find the answer to is: Will my antenna receive a sufficient digital signal for UHF and VHF channels? If yes, will I incur enough loss that I might need a pre-amp based on the signal strength I will be getting?

Andy

[ADTech]

If actual conditions match your TVFool plot, the C2V is plenty of antenna for your location. You do not need a pre-amplifier. Your weakest high-VHF station has a noise margin of 46 dB. With a bit better than unity gain on that channel, the C2V will have enough signal power at the antenna to supply several homes with enough signal if raw signal power is the only factor.

You probably will need an FM filter (or two) along with patience in selecting a mounting location. Do NOT drill any holes in your home until you've proven reception of all your desired channels.

Channel 11 is the most likely station to get 2nd harmonic interference from FM. The rest of the VHF stations will be susceptible to some degree, hence my recommendation that you might need an FM filter.

[kalmana1]

Thank you very much for your feedback ADTech.

Do I place the filter inline before my splitter or will I need a filter on each line after the splitter?

Thanks again!

[GroundUrMast]

The FM trap(s) can go in-line between the antenna and splitter input.

You probably will need one for the VHF channels though. just to keep the splitter and cable loss from reducing the VHF signal. Even then, your VHF channels may break up regularly.

I come to a different conclusion. I agree with ADTech, the signal levels are very good for all the major network options. No amplification should be needed. On top of that, cable and splitter loss is lower at VHF frequencies. If there is a problem with reception, it's quite unlikely that it would be a signal level issue.

[jeff92k7]

While others have said that you won't need a preamp and that your antenna is fine, let me explain why I said otherwise. First of all, every situation is different.

I commented from my own experiences. Based on your TVfool report and comparing it to mine, I am closer to our local stations, I get a bit higher noise margin at my location, I have a bigger antenna, my antenna has higher rated gain (on VHF), but my signal still broke up pretty regularly before getting a preamp.

While the other comments are right, and you SHOULD be able to get sufficient signal, reality rarely matches theory.

The UHF performance of that antenna looks very good, but the VHF performance doesn't come close to matching it. If you put it in without a preamp, you will likely find that the UHF stations work fine, but the VHF stations will likely break up regularly. My suggestion to look into a different antenna was with the intent of getting an antenna with similar UHF and VHF performance, since both UHF and VHF channels in your area will arrive at about the same strength. It's certainly up to you how you want to take in all the suggestions.

(Side note: never base purchasing decisions solely on what someone on the internet says. It's always easy to spend someone else's money. You have to decide what will work best for you).

If I were you, I'd hook it up and test it. If it works, great. But if you can't get a reliable signal on VHF channels, then look into another antenna. If you can't get reliable signal for any channels (less likely), then add a preamp.

[ADTech]

Since I'm the individual who did all the pre-release field testing on the VHF element for the C2V, I'm in a very unique position to comment on it's performance. Personally, I've received VHF signals from beyond 70 miles with the VHF element, so mere distance is a poor indicator of performance and requirements. Now, I do have some playtoys that make such experiments easier, such as a portable spectrum analyzer, that very few users will ever have access to.

As a tuned dipole, the VHF element on the C2V is roughly a unity gain element for channels 7-13. It is bi-directional and has the typical gain and radiation pattern of a simple dipole. If there are no concerns with multi-path or other interference facgtors, then it will work fine. There's plenty of signal power coming off Mt Wilson, primarily due to the impressive height of the transmitting towers above the Greater Los Angeles basin. Even with 50+ miles of signal path, the signal powers are forecasted to be very strong and, in this location, free from terrain obstructions.

Gain and directivity are interlinked with directional antennas. Higher gain antennas are very useful in focusing on a signals from a certain direction while diminish signals from other, undesirable directions, a common situation with terrain-blocked locations. No such factors are observed to be present in this location. Calculated signal powers are in excess of 30 dB (1,000x for linear-thinking folks) including cabling losses and fade margin.

The best advice is indeed to simply install the antenna (temporary mounting facility) and test it as that will answer a multitude of 'What if.." questions. It takes all of 5 minutes to assemble a C2V. Place it on a plastic chair, a wooden ladder or a broomstick (or whatever) or simply have someone hold it over their head and face it toward Mt Wilson. Hook it up to the HDTV and run through the TV set's setup procedure for antenna usage.

Cheers!