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Which way is the antenna aimed in the photo?
Is it aimed at the solar panels? Quote:
Is the left side on the NW or SE? Maybe you could send me a satellite image of the antenna location in a PM, or I could send you an image with my guess marked. Does the corner point to the east? |
Thank you for the clarification by PM. I have a better understanding of your antenna location; not as close to the solar panels as I thought.
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If you are wondering about my concern with the 7777, here is the math:
your report for reference: http://www.tvfool.com/?option=com_wr...e2cb74ea324603 KVCR Noise Margin is 61.2 dB + antenna gain of 13 dB = NM 74.2 dB, which is overload when the antenna is aimed at KVCR. When it is not aimed at KVCR, the strength of the signal depends upon the antenna pattern. http://forum.tvfool.com/attachment.p...6&d=1471824123 Interpreting Noise Margin in the TV Fool Report http://www.aa6g.org/DTV/Reception/tvfool_nm.html KVCR has a signal power of -29.6 dBm = 19.4 dBmV Max input of the 7777 = 15 dBmV http://www.channelmaster.com/TV_Ante..._p/cm-7777.htm Quote:
KVCR signal power = -29.6 dBm -29.6 dBm + ant gain 13 dB + preamp gain 30 dB = +13.4 dBm; tuner overload even without adding antenna gain -29.6 dBm + 30 dB preamp gain = +0.4 dBm; tuner overload This calculation assumes that the tvfool report is accurate for your location, which isn't always true. But, it is necessary to be aware that a small amount of overload will affect the reception of weak signals even if the strong signals are not affected. ATSC Recommended Practice: Receiver Performance Guidelines Document A/74:2010, 7 April 2010 RECEIVER PERFORMANCE GUIDELINES 5.1 Sensitivity Quote:
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When the antenna is aimed at KCIO: -57.7 dBm + ant gain 13 dB + 30 dB preamp + 15 dB 3410 = +0.3 dBm; tuner overload Looking at your FM signals, KDEY-FM has a signal power of -23.6 dBm: http://www.fmfool.com/modeling/tmp/b...7/Radar-FM.png The 7777 says FM trap >15 dB -23.6 dBm - 15 dB trap +30 dB preamp + 15 dB 3410 = +6.4 dBm at the tuner input KDEY-FM is on 93.5 MHz; its 2nd harmonic is 187 MHz which falls on channel 9 (186 TO 192 MHz), which makes interference possible. Testing for DTV Interference http://www.tvtechnology.com/expertis...ference/202503 |
Hi Rabbit:
A couple years ago I had the RCA ANT751 antenna with the RCA TVPRAMP1R pre-amp. I had decent signals from Mt. Wilson, albeit many upper UHF stations barely came in. I decided to get the larger antenna and better/stronger pre-amp and I do get many more stations from Los Angeles. KVCR is not a station we watch. If that's the issue with all the other stations, can I block KVCR's signals? (91.9Mhz) AND The FM signals in that range? (I cannot tell you how many times I climbed that steep roof just to tweak the antenna!) I just received my LTE filters from the UK but I do not think this is the correct range here in the US. (Frequency range : VHF 5 - 300MHz (400Mhz trap) Frequency range : UHF 470 - 790MHz) LTE TV Filter Many Youtube videos I see regarding LTE and OTA TV interference are from Australia and Europe. I read that US LTE will soon be utilizing the 600Mhz range which seems to cut into many stations here in the So. CA area. :( I am going to remove the 3410 dist. amp and try out the LTE filter this weekend. I already grounded the coax, but still need to purchase and ground a new shorter 18 galvanized pole. Does the 7777 pre-amp have a sufficient FM trap? I will study the reports you sent this evening and once again, thank you very much for your help! :D |
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Thank you for your reply with further background information.
It is not necessary for you to quote my whole post.:) Your present antenna has much more gain than the RCA ANT751, and it is larger because it has more gain and it also covers real channels 2-6 VHF-Low, which may or may not be important to you. Quote:
http://www.tinlee.com/index.php http://www.tinlee.com/NotchTraps.php...ategory=offAir http://forum.tvfool.com/attachment.p...1&d=1473471644 If you want to experiment, you can try a notch filter that removes 24-29. ChannelPlus ModelNF-471 Notch Filter https://www.amazon.com/Linear-NF-471.../dp/B000J3AEYA The Jan Jenca ch26 filter would probably be about the same price, but is a custom order from Slovakia. http://www.antenne-komponenty.eu/eng...zlucovace.html they also sell combiners http://www.avsforum.com/forum/25-hdt...l#post37732809 Quote:
It is balancing act, between the strongest and weakest desired channels, which is called the dynamic range. You went from a low gain antenna with a medium gain preamp to a high gain antenna with a high gain preamp. The best compromise might be a high gain antenna with a medium gain preamp, but it might require further experimentation by you. I suggested the HLSJ because it is an inexpensive and fairly easy first step. Quote:
http://www.channelmaster.com/TV_Ante..._p/cm-3201.htm https://www.google.com/?gws_rd=ssl#q...ter+lte+filter Quote:
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http://www.channelmaster.com/TV_Ante..._p/cm-7777.htm The Antennas Direct Juice preamp has a 4G LTE filter built in, but no FM filter. |
Hi again:
Is there a site that displays all stations' frequencies, in short of Googling every single station? I've searched TVFool and other antenna sites, but not one shows the actual frequency channels these are using... UPDATE: Nevermind; I found this spreadsheet on RabbitEar.Info http://www.rabbitears.info/ss/DTV-Channels.xls |
A frequency list of real broadcast channels is quite easy to find.
http://www.csgnetwork.com/tvfreqtable.html Most of the current confusion is caused by the use of virtual channel numbers. |
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Thanks, but I was looking for something that had more of a channel list for an entire region with all frequencies in order from lowest to highest...
IE: KCBS 2 = UHF 43, Virt. 2.1, Freq. ? KNBC 4 = UHF 36, Virt. 4.1, Freq. ? KABC 7 = H-VHF 7, Virt. 7.1, Freq. ? I suppose I could tune each and every station just to see what their analog broadcast signal really is...? :confused: |
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I don't think there is a list that gives real channel, virtual channel and frequency of real channel. If you know the real channel number, then you can look up the frequency of that channel in the link that I gave in post #28.
by zip code http://www.rabbitears.info/search.ph...pe=dBm&height= http://forum.tvfool.com/attachment.p...1&d=1473618890 click on callsign to see subchannels http://forum.tvfool.com/attachment.p...1&d=1473619272 The display channel is the same as the virtual channel; the physical channel is the same as the real channel. You can do it here: http://www.rabbitears.info/search.php If you enter just the zip code, the distance and direction will be off. If you add your street address, it will be more accurate. If you also check Strength Search (optional), it will generate a report similar to a tvfool report. I will not give a link to that result because it will show your street address. http://forum.tvfool.com/attachment.p...5&d=1473620632 Why do you need to know the actual frequency of the channel? The only time I need it is to design an antenna for a certain channel, to calculate the specs for an interference filter, or to know if the second harmonic of an FM transmitter falls on a VHF-High channel. |
Thanks. I'm not sure how I missed post 28.
I'll add to my spreadsheet the real frequencies of local stations. The reason I wanted the real frequencies is because my TV tuner has a "Partial channel scan" where it asks for the frequency to find more stations. It's much quicker than doing a Full Scan and, more importantly, it doesn't delete the current channel list! 😁 |
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My Sony can also add a channel after scan, but I don't have to enter the freq. the Diagnostics Screen shows the center-channel freq: http://forum.tvfool.com/attachment.p...1&d=1473623660 |
Solar Panels?
Hi again:
Well, I haven't been able to swap everything out yet because I'm waiting for WM and HD orders to arrive... (18 ga pole, dielectric jelly, more coax connectors, etc...) On another reply you spoke of Solar Panels possibly interfering with the OTA signals. It just so happens that my other neighbor, 2 doors down behind us, has panels and this is directly where I am pointing my antenna towards Mt. Wilson ( ~280 degrees west) (see attached pic) https://drive.google.com/open?id=0B6...VF0UXNROHlodUU I notice that signals drop on many stations late afternoon, no matter how many times I tweak my antenna, and then great signal after about a couple hours.... How likely, in your opinion, would solar panels be the culprit? |
Ahh, yes. I see the green signal lines pass just to the right of his panels in the photo I sent to you by PM, but I didn't want to post it on the forum without your permission.
It is possible that you might be picking up EMI from his inverters. Some inverters produce more interference than others. case history: Would solar panels interfere with attic antenna? http://www.avsforum.com/forum/25-hdt...c-antenna.html |
I remember using Tripp Lite 12V inverters back in the 70s, before the car audio industry was producing anything larger than 24WPC.
The Crowns I was using, had ample filtering, but even being in the trunk, that noisy square wave, was still leaking into the system through the line level components. The only point I'm even close to making, is that regardless of proper grounding, EMI may be entering through an unshielded wall wart, or other plastic component case. Most filters may be capable of blocking 60HZ hum and ripple, but can't deal w/ the sharp transients of the higher frequency square waves. Or maybe at best, even not the newer modified sine waves. |
I was afraid that those panels being in the line of sight for Mt. Wilson would cause some sort of interference.
On another note, I was reading some Australian TV antenna forums and discovered that the loooong elements on VHF antennas are for stations 0-5 and could possibly cause more FM and other low-band interference. Many stations here are now H-VHF and UHF, and this HD-8200XL is more of a broad spectrum design. (FM, L-VHF, H-VHF, UHF) I was thinking of folding in the longest elements to test that theory out. Any input on this? |
Maybe a good start, but there's also the possibility of signal induction, when running them parallel to your phasing lines.
Not to mention, shorting out against the boom, or other elements. |
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When you mean "shorting out" are you saying the frequencies would go bonkers and no signal would be possible? Or would it pick up more interference than before? |
By "shorting out", I mean that any signal present on the longest elements that seeped over from the elements that are being used , could be shorted directly to ground when you fold them, resulting in almost zero signal.
Similar to a garden hose that's kinked. |
Hey guys:
I did some experimenting this weekend: I ran one coax directly from the large antenna (No splitters, pre-amps, or dist. amps) and all stations came in pretty well during the day. I relocated the cable run from the opposite corner of eve to the closer corner of the roof eve. (Left side) https://drive.google.com/file/d/0B6w...ew?usp=sharing I tried bypassing the dist. amp, (Pre-amp only) but the picture was pixelating pretty bad. Without the pre-amp, the 5 TVs in the house got only a couple stations. I re-installed the CM dist.amp and also closed/folded in the 3 longest elements and increased my KABC (177Mhz, the lowest frequency station) by about 6%. (see pic) We also experimented by raising the antenna to the top of the pole, but it decreased the signal, so I lowered it as far as I could so it would clear the tile roof if I rotated it via the rotor motor. I also replaced the pole with a Winegard 18 gauge steel one. I need to remove the 2 splitters and try to combine them somehow, but the difficulty in this is that the 2 wired-in cables (Downstairs living room and master bed) are inside a TV box on the side of the house. (3 other TVs are connected to a splitter in the attic.) Here's how it's all connected: 1. Antenna to CM pre-amp (exterior) 2. Pre-amp to CM dist. amp (attic) 3. Dist. amp to 4 port splitter (One goes to each of 3 other bedrooms. The 4th goes to the TV box on side of house. 4. TV box connection has one 2-way splitter for both master bed and downstairs living room. 5. Coax is house grounded; pole is not grounded yet. I'm pretty sure the coax is all dual-shielded RG6 only. Would replacing the short coax between the antenna and pre-amp with quad shield have any significance in gain? And do you think that a 5 port splitter would be best for our situation? Thanks again for your expertise. :D |
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