That makes sense. Almost like audio amplifiers producing harmonics when clipped. Thanks for all the help guys. This is very interesting stuff but not for the faint of heart.
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ADTech did some interesting tests that show how weak signals are damaged when a preamp is overloaded by strong signals:
Just the antenna, no preamp: http://forum.tvfool.com/attachment.p...7&d=1441052886 This is what the same signals look like when the preamp is moderately overloaded. Notice that the weakest signals are damaged first. The noise floor rises from the spurious signals created by the IMD. This reduces the SNR of the weak signals to less than the required 15 dB minimum: http://forum.tvfool.com/attachment.p...0&d=1441054170 This is what the same signals look like with a badly overloaded preamp: http://forum.tvfool.com/attachment.p...8&d=1441052947 This is what the same signals look like with a high quality preamp that isn't easily overloaded: http://forum.tvfool.com/attachment.p...9&d=1441053000 |
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Ok, removing the db8e from the equation gives me identical results. Any other ideas? Too much FM?
edit: ok it seems to be worse. Signal quality is around 45 now |
Just ran a test by hooking up the antenna output to my stereo. I am still able to bring in local fm channels crystal clear even with the fm trap on in the preamp. Could this be causing the problem?
edit: also interestingly enough while trying to tune in to a detroit fm station I am getting spillover from one of the locals even though they are about 5 MHz apart (turning the trap back on stops this) |
Sorry to keep adding stuff on here but I am unsure if this is pertinent information or not. It seems as the temperature outside gets warmer throughout the day the signal gets worse.
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Well, at least your getting Fox even if it's not a high quality signal. Quote:
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All FM filters aren't alike; they have different attenuation curves and a HLSJ can also be used as an FM filter. It attenuates all signals below CH7, including the FM band. See attachments 2-4. I'm wondering if you could go back to your original setup where you were using the preamp for both antennas but insert several filters before the preamp input. That might also be inconclusive if the strong signals were getting into the plastic case of the preamp which would bypass the filters. Then you could try a preamp with a metal case that is resistant to overload in place of the preamp with the plastic case. You missed the boat on the Juice, but another one might do. You could also try a preamp in a metal case that is resistant to overload with an FM filter in front of it to amplify just VHF, but you would need a UVSJ that passes DC to the preamp. Is your coax grounded with a grounding block? That reduces interference and makes filters much more effective. Quote:
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Was this TL;DR?:) |
Not TL;DR at all. I will order up some fm traps and see if that helps. Buying another amp right now is out of the question as i am running out of money lol. Are the Antennas Direct FM traps good for the job? Oh and i have a coax grounding block with a wire that runs to my plumbing, is that good?
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CJFIFM 99.9 MHz -14.4 dBm CHKS-FM 106.3 MHz -22.1 dBm CBEGFM 90.3 MHz -27.2 dBm WSAQ 107.1 MHz -29.2 dBm http://www.mcmelectronics.com/produc...800829%2Cd.eXY |
Alright, I ordered 4 of the MCM ones. I guess i may as well work on some of the other stuff while i wait. Mainly grounding since I already have the guy wires installed.
Right now the wires come in the front of my house and are grounded to the water pipe there. Looking at the ground in my electrical panel it seems to hook up to my water line there ( I am sure this is not to code anymore but it may have been when the house was built) Another option is i could run my coax to the back of the house and ground at the same spot the panel is. I have bought one of these: http://www.amazon.com/TII-Broadband-...tning+arrestor Also for mast grounding can I run a wire to the same spot? |
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You have done the most important thing when you grounded the coax with a grounding block, to protect yourself from leakage current shock if any of the AC equipment that is connected to the coax becomes defective. The code also requires that the mast is grounded by a separate 10 gauge wire connected to the house electrical system ground.
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Right. But since my house ground system is connected to my water pipes I should theoretically be able to ground to any one of them? Or should it be close to my panel?
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I'm not an electrician and I can't see your setup. The local electrical inspector has the final say, but you might not want to get him involved; some are more friendly than others. A local electrician could advise you. Todd Humphrey doesn't speak for the NFPA that publishes the NEC code, but he has some ideas that are helpful.
Satellite System Grounding Part 2 - NEC Overview Presented by Todd Humphrey http://www.dbsinstall.com/diy/Grounding-2.asp Quote:
For the price of that device you could have bought an RCA TVPRAMP1R preamp. The RCA TVPRAMP1R preamp does have a history of quality control problems, but you can buy three of them for the price of one Channel Master 7778. One of the problems is with the separate/combined switch. If you have the switch in the separate position to use two antennas, one for VHF and one for UHF as in your case, sometimes the switch doesn't make good contact with the VHF antenna. The workaround is to use a UVSJ to combine the two antennas and connect the UVSJ to the combined input of the preamp. Quote:
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Haha yeah i know. Trust me you do not want to know what I paid for the amp i bought. Sometimes it sucks when you want to get things done right away.
edit: Would this work for all my connections to keep them weatherproof? http://www.homedepot.ca/product/liqu...des-bru/411161 |
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http://static.dxengineering.com/pdf/...ax-TechTip.pdf https://www.youtube.com/watch?v=6eHgyxo3e9A http://www.qsl.net/n9zia/con_seal.html http://forums.radioreference.com/ama...t-weather.html |
Try this with your preamp if you want to amplify VHF and UHF, using the combiner that came with the C5:
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DB8E > You can use a combination of an adjustable attenuator and fixed attenuators for the test, then replace with a fixed attenuator/attenuators. variable attenuator: https://www.antennasdirect.com/store...ttenuator.html fixed attenuators: http://www.3starinc.com/drop_in-line_attenuator.html http://home-automation.smarthome.com...=&w=attenuator http://mjsales.net/collections/atten...ant=1083705673 Attenuation values 1, 3, 6, 8, 10, 12, 16, 20dB (FAM) click on 1 dB for other values; the up and down arrows are faint |
Alright thanks. I will let you know how it goes when i get the FM traps. I got a few just in case one wouldnt cut it.
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So right after a thunderstorm i get 85% quality. Wtf
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Well it hasnt been very dry here lately. Over 90% humidity every day. If anything the humidity has dropped since it rained. If that is the culprit how would I go about fixing it?
edit: something like this perhaps? http://www.amazon.ca/CyberPower-CP85.../dp/B00429N18S |
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