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Here is a TV fool link:

TV Fool

It is only showing some of the Myrtle Beach SC area stations and none of the Wilmington stations that I receive.

Also, while it does show WILM on the report, the real channel for this station has moved from 40 to 15. This is the only channel that I am having problems with occasionally.

Thanks!
 

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Thank you for the TVFool report link. If my estimate based on that report is correct, you are down by the water near the Beach Club.



This is an image of your TVFool report:



and this is a report from rabbitears.info which should have a more accurate list of channels, because Trip in VA who runs the site, now works for the FCC:



Well, this is odd. In the fcc.gov link, the station I am having the occasional problem with is WILM-LD broadcasting on real channel 15 and is not included in the stations available where I am.
The FCC doesn't list the low power stations on their map site.

I am splitting an OTA signal as follows:

Antenna AntennaCraft U-4000
|
2ft coax
|
Pre-amp - Winegard AP-8700
|
about 40 ft of coax
|
pre-amp power injector
|______________________
| |
2 way splitter 16V wall wart
|____________________________
| |
about 4 ft coax about 2 ft coax
| ________|_______
TV input | |
HDHR tuner 1 HDHR tuner 2

Problem I am having is I have one channel that is a low power station
of the 5 I can receive loses about 10% of its signal strength with the addition of the splitter That I put in recently to give the TV its o(w)n coax input.

There are occasional times when the signal will drop below a reasonable level for the HDHR tuners, and cause drop out in recording.

The remaining channels are all 90 - 100 % signal strength after the additional split.

I have a PCT distribution amp with 4 ports (+8db) That I am interested in using instead of the 2 splitters above, and would like to power the distribution amp with the same wall wart as used for the pre amp using a splitter on the power. They are both using the same voltage input.

Or, should I consider switching to an pre-amp such as the CM-7777 and forget about the distribution amp.
Not a good idea to power both amps with one power supply. Even if the voltage is correct, one power supply can not provide enough current for both amps.

I suggest you use the power supplies provided for each amp. If that is a location problem, I can show you how the 4-port distribution amp can be powered through one of its output ports at the HDHR or TV.

Keep the preamp, and replace the splitter with the distribution amp.
 

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I don't see a grounding block in your connection list.

If the antenna is outside, the coax shield should be grounded with a grounding block that is connected to the house electrical system ground with 10 gauge copper wire for electrical safety and to reject interference. For further compliance with the electrical code (NEC), the mast should also be grounded in a similar manner to drain any buildup of static charge which will tend to discourage a strike, but the system will not survive a direct strike.

 

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since you are using an hdhomerun, before making any changes, I would suggest doing a sanity check of all your reported signal strengths and snr. Based on that we can see exactly what you are seeing there with ur current setup.

run the hdhomerun_config_gui program and record the strength and quality numbers for each channel you are interested in.

There is no need to use two stages of amplification. Only use one or the other..
Winegard + splitters, or PCT + no splitters.

Your existing AP-8700 preamp has more than enough gain to overcome any losses in your system with 40 feet of downlead and the splitters...

example of readings from an hdhomerun at my house. taken using 905shmick's bash script. If you don't know what bash is, just record the readings manually and make a table and post it. we can sort it out later. That is after being split 8 ways, plus the hdhomerun is a dual tuner, so is like effectively adding another 2 way split internally.

 

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since you are using an hdhomerun, before making any changes, I would suggest doing a sanity check of all your reported signal strengths and snr. Based on that we can see exactly what you are seeing there with ur current setup.
Good idea to make a comparison.

There is no need to use two stages of amplification. Only use one or the other..

Your existing AP-8700 preamp has more than enough gain to overcome any losses in your system with 40 feet of downlead and the splitters...

Winegard + splitters, or PCT + no splitters.
It is a good general rule that both are not usually needed, but it is poor troubleshooting technique to make assumptions about what is not needed or what should not be done without actually making a test.
Problem I am having is I have one channel that is a low power station of the 5 I can receive loses about 10% of its signal strength with the addition of the splitter that I put in recently to give the TV its o(w)n coax input.
The quote by jr3us indicates to me that more signal strength might help. I see no harm in trying it both ways.
 

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Using 2 HDHomerun tuners with a splitter will introduce about 7dB loss to each tuner. Add line loss and balun loss to get total distribution losses. A 14dB preamp should be sufficient to compensate for that. The AntennaCraft U-4000 has a nominal 10dB gain so the system should be close to optimum.

The real issues here are that WILM is lower in power and 2-edge. Local conditions may be attenuating the signal further. The are several ways to effectively overcome those issues.
  • Using a lower noise, higher gain preamp may help.
  • Using a better antenna. An antenna that has higher gain and is more selective, such as an 8 bay bow tie antenna or high gain yagi, can improve the problem signal. However, it may cause the loss of other signals unless a rotor is also used.
  • Increasing antenna height. Enter increased antenna heights into TV fool or another calculator to see where the station becomes 1-edge or LOS. Sometimes just 5 feet can make a significant improvement.
  • Looking for local obstacles such as trees or buildings that may be interfering with the signal and repositioning the antenna to avoid them.
I realize that it's not always possible to raise or reposition the antenna but they often provide the best solution.
 

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Losing 10% "strength" from an hdhomerun going through splitters sounds about right to me and is not a cause for alarm on it's own. As long as the SNR or "Quality" didn't change much. Remember, as I said my hdhomerun is connected to an eight way splitter. So mine is like at least 10 dB down from signal available at the downlead coming in, and it does just fine on weak signals.

Agree with the height story/suggestions as well, since nothing will help a signal that just isn't there at the antenna terminals, and anything you improve there will most often help the most. His trouble channel moved just moved to rf 15, was gonna point that out, but he already mentioned it. when I saw this https://enterpriseefiling.fcc.gov/d...&id=25076f9163d5a32a0163d632491d035b&goBack=N.

Not familiar with his antenna, but since most antennas have lower gain at the low end of UHF, that may explain why he is having more trouble than what he is used to.

However I wouldn't wanna go through the trouble changing things without first seeing the measurements
from HIS system as it is. From there he will see what needs to be improved, and have a baseline to compare to after any modifications.
 

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Antenna height does seem to be critical at his location, because his elevation is listed as 20ft below mean sea level. The signal skims the surface just before reaching his antenna, so extra height makes a big difference.

 

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Thank you all very much for the information! I am thinking I am going to just stay with what I currently have as it is only messed up occasionally. It is much better than before when it was broadcasting on real channel 40.

The antenna is an Antennacraft U4000, which is on the antenna chart.

If it decides to get worse, I may try swapping out the AP8700 pre-amp with a CM7777.

Right now, signal strength is showing 70% and signal quality 85 to 90% according to the hdhr4 tuner.

thanks again!
 

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hdhomerun strength 70% -> 70 * 60 / 100 - 60 - 48.75 = -66.8 dBm

hdhomerun quality 85% -> .85 * 33 = 28 dB SNR

plenty of margin at the moment, given to lose signal lock your SNR would need to degrade to around 15.2 dB (~46% quality on ur hdhomerun)
 

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Considering the distance and terrain, those are actually pretty good values. I have closer stations with similar values. The main concern is with it being 2-edge. That can result in loss of signal due to multipath or more distant stations interfering during tropo events.
 

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When it was on real channel 40, it was more sensitive to tropo events due to a strong channel 40 that was located in the Virginia beach area that is in nearly the same direction as 40/15 is to me. Since it has moved to 15, it doesn't drop out nearly as often.

Thanks all!
 

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Thanks majortom,

I didn't realize that those percentage numbers could be directly related to the dBm and dB SNR values!

learn something new every day!
 

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Hello, new poster from Central Connecticut USA. I'm primarily looking for a recommendation on an antenna to replace my current flat one.

TVFool link is here: TV Fool
My house faces North-West, so that makes angle determination relatively easy. You can see the majority of channels are front-facing, with a few off to the left.

The flat antenna I have now is a Wineguard FL5500 flat antenna, just hanging over a curtain rod, facing forwards. Due to the relatively strong signals I get (and we are up on a hill) I'm getting pretty decent signal overall to my two Tivo units (via basic splitter). Picture and signal is good, but we get minor dropouts here and there on some channels (mostly ABC real channel 10) which is all I'm looking to solve. Of course, this is high VHF so I need an antenna for that.

I'm only interested in improving my signal on the existing, pretty strong channels. Not looking to pick up much in the fringes. A few channels are missing from the TVFool report, but if we can improve signal on the major networks then I expect it would be a little better on those anyway, so I'm not concerned.

So the questions:
1) What antenna would be recommended? I'm happy to build, but I don't want to waste my time with a complicated design and end up with no benefit.
2) I ran across a few angled SH (superhawk) antennas by holl_ands, and liked the bi-directional nature on the back side, which matches the 70-degree angle of my desired stations. SH is also what was recommended by the antenna guide. I think, the V would be open "backwards" in my application.
3) Again, just to keep it simple (I don't expect to need much complexity) I was trying to avoid a reflector plane...
4) I saw a few people build one using metal tape on a flat board... this would be easiest since I can simply tape-out the pattern and then bend the board (and tape) to get an angle... hence I was looking at the SH again. Is this workable, particularly due to my already pretty-strong signals? Or do I have to use wire/piping?
5) I also wonder, what is the typical gain of a flat antenna like the FL5500? This will help me decide how much gain I "need" for this application. I figure if I can get a little better, then I know I'm on the right track.

Thank you in advance!
 

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Hello, new poster from Central Connecticut USA. I'm primarily looking for a recommendation on an antenna to replace my current flat one.
Hello, apurohit8; welcome to the forum.

Here is an image of your report:



For comparison, here is a report from rabbitears.info which should have a more accurate list of channels:



The Winegard FL5500 doesn't have much more gain on UHF than a dipole, and even less on VHF-High. IIRC, it comes with an amp, but if the signal coming from the antenna isn't good, the amp can make it stronger but not better quality; GIGO.

You will need an antenna with more gain for ABC because it is one of your weaker channels. It is also in a different direction. I suggest the VHF antenna be aimed at ABC and combined with your UHF antenna with a UVSJ.

I will let others suggest a DIY VHF antenna for ABC. A 5-element DIY Yagi for VHF-High might work. If it were my problem, I would buy a Stellar Labs 30-2475 from Newark.

You have two nearby FM transmitters that might interfere with the reception of ABC, but a filter should solve that problem.
http://www.fmfool.com/modeling/tmp/c193f2ad57/Radar-FM.png

Also, electrical interference (LED and CFL lamps, etc) is more likely to affect the reception of VHF channels than UHF channels.
 

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You might wanna try the biquad antenna, which is easy as it gets build wise, and small enough to fit in just about any size window. As demonstrated in the below .ppt.


https://drive.google.com/open?id=1HheUKltcnzVAafYX1fWhe-IDtbCTriiQ


Regardless what you decide for an antenna, ur probably better off to use a 2nd story window for more height if possible. Hopefully you have standard glass windows, and not UV resistant Glass in your windows.
 

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Took me long enough, but I finally built the biquad suggested, and I'm not impressed. I'm getting about the same signal as I did with the Wineguard, and I was hoping for more. What's weirder is that the antenna is rotated about 90-degrees right (clockwise) relative to the Wineguard, and that's where it seems to work best (the biquad is facing almost east-west, while the WG is facing almost north-south). I would have thought it would be best at the same direction as the WG, but it's not? ABC (8.1) is what I'm using as a primary reference for quality, as it's a weaker signal, but I checked all of the channels and they all come in... 8.1 has flickered a bit on the WG, so I'm hoping this one won't do that, at least... but I've seen it do a few blips in the short time I've watched it just now.

Maybe I built it wrong or something... maybe I just need one pre-built... very weird.

Makes me think I might have to consider the big one that rabbit73 suggested. I don't want to have to put one outside if I can avoid it.

Any ideas, comments, or thoughts?
 

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Your assumption of basing your build's performance on it's VHF performance is wrong.
You built a UHF antenna, not a VHF antenna.

For VHF reception you need a VHF antenna. Something like the stellar labs yagi that Rabbit mentioned. Personally I use the larger Stellar Labs 30-2476 myself. But also have a 30-2475 in the toolkit...
My opinion is your always better off using separate antennas for UHF and VHF so that both bands can be optimized independently.
Than using dual band antennas, as quite often the direction of best reception is completely different for the two bands or different enough where you have to sacrifice one for the other.
 

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Duh, good point. I really wish the TVFool list would show this more clearly, but I get what you're saying.

I'll have to recheck/compare to the old one on other channels. I did do some initial testing on WFSB (channel 36, virtual 3.1) and found that this antenna was similar to the old one there (based on the antenna signal meter provided by my Tivo)... but I could stand to do more careful testing. I guess I should be happy that the antenna works at all for these channels. Still seems weird that it's rotated 90-degrees from the other one, but it probably has to do with the design.

I'll see what I can find. I think I prefer the unamplified antenna here anyway (the WG is amplified)... since it should provide cleaner signal anyway.

Thanks for the clarification... again, duh on me!
 
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