Ynot713:
Your equipment is acting in a way that is normal and to be expected.
Your problem is overload. If you look at
your tvfool report you will see that the signal power for WFXV is -10.4 dBm. It is highlighted in red to indicate the possibility of overload in a preamp or tuner. I quote from tvfool Signal Analysis FAQ:
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NOTE 2: If you live very close to some transmitters, you might see a few of the values in the "Pwr(dBm)" column highlighted in red if power levels get a bit high. This is a warning that such high power levels might be enough to cause overload problems on some amps and receivers if you're not careful.
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THREE TYPES OF OVERLOAD
There are three types of preamp or tuner overload, in order of increasing signal strength:
1. The strong signals almost cause enough IM distortion to interfere with the reception of weak desired signals, but the spurious signals are at or below the noise floor. This is the point that holl_ands uses in his preamp charts to obtain max SFDR (Spurious Free Dynamic Range). No damage will happen. A preamp chart by him is here:
http://imageevent.com/holl_ands/files/ota
Click on Modified solidsignal Chart Comparing Preamps - RevA
His chart shows the max input for various preamps that will give best SFDR. Most tuners will tolerate a -10.4 dBm signal, but if you look at the chart you will see that it is too strong for ANY of the preamps listed.
As the strongest signals continue to increase in strength, more of the weaker signals are damaged until you reach:
2. The strong signals cause overload to the preamp or tuner that makes it impossible to receive any signals. No damage will happen.
3. The signals are so strong that the input transistor is toast. You are not likely to encounter OTA signals that strong.
TUNER SPECIFICATIONS
If you look at the tuner specifications you will see that there are limits to what they can handle in the way of signal stength:
ATSC Recommended Practice:
Receiver Performance Guidelines
Document A/74:2010, 7 April 2010
http://www.atsc.org/cms/standards/a_74-2010.pdf
scroll down to page 12:
RECEIVER PERFORMANCE GUIDELINES
5.1 Sensitivity
A DTV receiver should achieve a bit error rate in the transport stream of no worse than 3x10-6 for input RF signal levels directly to the tuner from
–83 dBm to –5 dBm for both the VHF and UHF bands.
5.2 Multi-Signal Overload
The DTV receiver should accommodate more than one undesired, high-level, NSTC or DTV signal at its input, received from transmission facilities that are in close proximity to one another. For purposes of this guideline, it should be assumed that multiple signals, each approaching
–8 dBm, will exist at the input of the receiver.
As you can see, WFXV is about right at the overload point without preamp gain, taking into consideration the antenna gain is added and the coax loss is subtracted from that -10.4 dBm figure.
WHY YOU GOT THE RESULTS YOU DID
So, your question is why did the antenna and preamp inside the attic give you the channels that you wanted, but the antenna and preamp outside didn't?
The answer is that when the antenna and preamp were in the attic, there was sufficient attenuation of the signal by the attic construction to prevent overload of the preamp or tuner. But when the antenna and preamp were outside, you didn't receive any signals at all because of the type 2 overload mentioned above.
TVPRAMP1R SPECIFICATIONS
These are the specs for the TVPRAMP1R. As you can see, when you add the preamp gain to the -10.4 dBm figure, overload is certain.
Designed specifically to improve the performance of outdoor antennas in low signal strength areas
Gain: VHF: 16 dB; UHF: 22 dB
Separate or combined inputs for UHF/VHF
Switchable FM trap reduces interference from FM frequencies
Separate amplification for UHF & VHF bands to improve performance
You can use the 1296F as a variable attenuator to control the dB Gain
WHAT HAPPENED IN THE BASEMENT AND ATTIC
When you ran the coax directly from the outside antenna down to the basement TV there was sufficient signal strength to receive the local signals, but you were missing amplification to receive the weaker signals.
The attic setup (and in your living room with Monoprice antenna and its 20 dB amp) were able to achieve that happy compromise of not enough signal to cause overload, but enough preamp gain to receive the weaker signals. This is what holl_ands is talking about in type 1. overload mentioned above for maximum SFDR. The dynamic range that you need to accomodate is -10.4 dBm for WFXV to -50.9 dBm for WCBT, which is 40.5 dB. If you want even weaker signals, the dynamic range will be even greater.
WHAT YOU CAN DO
In order to duplicate the results of the previous attic antenna you can try the 751 and preamp up there. If the 751 is outside, then you will need to run your coax directly down to the basement and put a preamp there wth an attenuator just before it to simulate the attic loss. The attenuator should be adjusted to make the strongest signals just weak enough to prevent overload. If your TV has a signal strength meter, it would help with the adjustments.
attenuator
Because you are in a strong signal location the coax for the outside antenna should be grounded with a grounding block to prevent direct pickup by the TV and so the quad shield isn't wasted. The grounding block and the mast should be connected to the house electrical system ground with no. 10 copper wires to comply with NEC requirements.
Once you have achieved that, then your distribution system should be designed to maintain that balance by making the signal stronger for the longer coax runs and weaker for the short coax runs. You can do that with a cascade arrangement of 2-way splitters.
A MORE ACCURATE TVFOOL REPORT WOULD BE HELPFUL
Because you are so close to the local transmitters, it would be useful if we could see a more exact tvfool report for your location.
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WARNING: Address was only resolved to block level and might not be that close to your actual location. For more accurate results, try entering a specific address or coordinates.
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If you use the interactive map feature you can move the marker to your exact location (left click on marker and hold down, move x to spot and release) and then produce a report by clicking at the upper right of the map. It's fun to watch the coordinates change as you move the marker. Don't forget to enter the antenna height below the map.
http://www.tvfool.com/?option=com_wrapper&Itemid=90