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Discussion Starter #1
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=f1f0aa219673f3

I have both a Channel Master 4228 aimed at the Sutro Tower and a Channel Master 4221 aimed at in the opposite direction with a switch to select between them. The mast is on a tripod/railroad tie stand on my balcony that a friend installed for me.

I am not sure why but it seems that my reception is worse than it used to be.

I did add the 4221 to the back of the mast and a switch on the balcony to select between the two (the mast is on a tripod on 3rd floor balcony) a couple of years back and am wondering if I accidentally got the baluns swapped in the process.

Would the balun for an 8 bay have different impedance than 4 bay?

I am going to try swapping them to see if it improves the signal.:confused:
 

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Discussion Starter #2
The baluns appear to be identical (Made in China is the only marking) and swapping them did not improve anything.

I do not remember where the baluns came from but probably at least one of them came with the 4-bay since I bought that new, but with my box of junk parts here they could have come from anywhere.

After swapping them I tried replacing the one on the 8 bay with one of those white indoor baluns (marked UHF - VHF - Made in Taiwan) and it seems I gained a couple of bars of signal off the Sutro Tower and the fringe stations came back to life but are still marginal.

If a bowtie is 300 ohms and four of them are series-parallel then the 8-bay that is two 4-bays in parallel should be 150 ohms? So why does the 8-bay seem to work better with a 300 ohm (presumably) indoor balun?

If all the baluns are the same then why do the outdoor baluns seem to work worse than the indoor balun?

Not getting this. Anybody?

I have the 4-bay disconnected for now. It seems it was not helping much if at all. There is another building in the way to the east and my building is in the way to the south. I never seem to get much signal from anything but the Sutro Tower from here.

Oh yes, I live in the flight path to San Francisco Airport so there are intermittent multipath issues affecting my reception also. I do not think that is why the situation changed though. It seems the signal is consistently better with the indoor balun now.
 

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I'm getting it but was posting when you were.
I am not sure why but it seems that my reception is worse than it used to be.
Worse in what way? Pixelation, picture freeze, dropout, all channels, just the weak channels, both directions or only one direction?
am wondering if I accidentally got the baluns swapped in the process.
That would only matter if one was working better than the other. I have measured differences of over 5 dB between baluns on certain channels, but with signals as strong as yours, you might not notice it except on the weak channels. It seems more likely that there has been some deterioration of a balun, coax, switch, or antenna connections.

Some substitution tests seem appropriate.
Would the balun for an 8 bay have different impedance than 4 bay?
The 4221 & 4228 were both designed for 300 ohms, so the 4:1 balun is proper. There is such a thing as a 1:1 75 ohm balun for other antennas.
If a bowtie is 300 ohms and four of them are series-parallel then the 8-bay that is two 4-bays in parallel should be 150 ohms? So why does the 8-bay seem to work better with a 300 ohm (presumably) indoor balun?
It's not quite that simple. The 4221 has 4 bays that are connected together with a phasing line giving a feed impedance of about 300 ohms. As you move away from the design frequency, the feed impedance and SWR change.

The original 4228 uses two 4-bay antennas connected together with a wiring harness, resulting in wide variations in feed impedance. Some of the newer 8-bay antennas connect the two 4-bay antennas together with a splitter in reverse as a combiner.
If all the baluns are the same then why do the outdoor baluns seem to work worse than the indoor balun?
I have also noticed that one of my best baluns was an indoor balun, but it doesn't hold up as well in the weather as an outdoor balun.
I have the 4-bay disconnected for now. It seems it was not helping much if at all.
What will use for that direction?
There is another building in the way to the east and my building is in the way to the south. I never seem to get much signal from anything but the Sutro Tower from here.
That makes the problem a little more complicated.
 

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Discussion Starter #4
I'm getting it but was posting when you were.
Worse in what way? Pixelation, picture freeze, dropout, all channels, just the weak channels, both directions or only one direction?
That would only matter if one was working better than the other. I have measured differences of over 5 dB between baluns on certain channels, but with signals as strong as yours, you might not notice it except on the weak channels. It seems more likely that there has been some deterioration of a balun, coax, switch, or antenna connections.

Some substitution tests seem appropriate.
The 4221 & 4228 were both designed for 300 ohms, so the 4:1 balun is proper. There is such a thing as a 1:1 75 ohm balun for other antennas.
It's not quite that simple. The 4221 has 4 bays that are connected together with a phasing line giving a feed impedance of about 300 ohms. As you move away from the design frequency, the feed impedance and SWR change.

The original 4228 uses two 4-bay antennas connected together with a wiring harness, resulting in wide variations in feed impedance. Some of the newer 8-bay antennas connect the two 4-bay antennas together with a splitter in reverse as a combiner.
Thanks for the info.

I have not used the 4 bay for a while because it seemed it was not really helping what with the stronger signals coming in on the backside of the 8-bay and the weaker signals blocked by the building next door. I removed the switch too for this test.

The signal is worse in that the weaker stations just do not come in any more. My receivers do not seem to pixelate. They just seem to drop out when the signal is too weak.

I already replaced one feed line (it is indoor cable and part of it was hanging off the balcony so it was deteriorated from sun and rain) and noticed improvement, but that was last year. It might not have changed at all since the improvement seemed to vanish the next day when the weather changed.

The two baluns that were out there for several years look like this:

http://www.amazon.com/dp/B00EIB6AR4

The balun that seemed to improve the performance today looks like this:

http://www.amazon.com/dp/B00R344ZES

I also tried one of these, probably from a very old junk box but still in its sealed plastic bag, and got no signal whatsoever:

http://www.amazon.com/dp/B00QXUPXSK

I guess the thing to do is maybe replace everything in the path that runs outside. The runs are short so it should not be an issue. At least the balun seems to be questionable.

What about the 4228 antenna itself? It has been on that balcony for nearly a decade and is covered with city grime plus it was used already when I bought it. Would cleaning it help? Clean with what?

What about a different model? Can I replace the interconnect between the halves with a combiner and get better performance?

How can I receive the channels to the south that are on the opposite side of the building? I have to mount my antenna on a tripod on the balcony -- no masts over/outside the canopy.

It seems from where I am I should be getting 30 channels but I only get a dozen or so (RF wise).
 

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Thanks for the info.

I have not used the 4 bay for a while because it seemed it was not really helping what with the stronger signals coming in on the backside of the 8-bay and the weaker signals blocked by the building next door. I removed the switch too for this test.

The signal is worse in that the weaker stations just do not come in any more. My receivers do not seem to pixelate. They just seem to drop out when the signal is too weak.

I already replaced one feed line (it is indoor cable and part of it was hanging off the balcony so it was deteriorated from sun and rain) and noticed improvement, but that was last year. It might not have changed at all since the improvement seemed to vanish the next day when the weather changed.

The two baluns that were out there for several years look like this:

http://www.amazon.com/dp/B00EIB6AR4

The balun that seemed to improve the performance today looks like this:

http://www.amazon.com/dp/B00R344ZES

I also tried one of these, probably from a very old junk box but still in its sealed plastic bag, and got no signal whatsoever:

http://www.amazon.com/dp/B00QXUPXSK

I guess the thing to do is maybe replace everything in the path that runs outside. The runs are short so it should not be an issue. At least the balun seems to be questionable.

What about the 4228 antenna itself? It has been on that balcony for nearly a decade and is covered with city grime plus it was used already when I bought it. Would cleaning it help? Clean with what?

What about a different model? Can I replace the interconnect between the halves with a combiner and get better performance?

How can I receive the channels to the south that are on the opposite side of the building? I have to mount my antenna on a tripod on the balcony -- no masts over/outside the canopy.

It seems from where I am I should be getting 30 channels but I only get a dozen or so (RF wise).

I see you live not too far away from Lake Elizabeth in Fremont. I used to live in the Ardenwood district of Fremont. All the SF stations are rock crushingly strong in Fremont. Calling some the "weaker stations" is like saying 100 MPH winds are lighter than 110 MPH winds, technically true but still extremely strong. This was back in the analog days, but I had perfect reception on every SF station with an antenna 20' off the ground, not a hint of a ghost or a spec of noise even on channel 2. OTOH, the stations on Monument Peak and Mt. Allison in Fremont had terrible ghosts unless I turned the antenna around.

The difference between where I was and where you are is that I could see Sutro Tower on a clear day and you are blocked by buildings. Once you no longer have line-of-sight to the transmitters, especially in the Bay Area, you get terrible multipath problems. The only real solution is to have the antenna high enough to clear the buildings. I know that may be impossible for you but that doesn't change the antenna requirement.

I don't know why your reception has degraded over time. It's possible that there have been changes in the local environment, trees have grown up or something like that and your antenna location is no longer adequate.

There are only two kinds of baluns; transforming baluns and non-transforming baluns. All those multi-bay antennas use the same 300:75 ohm transforming balun. All that is inside of those baluns is a ferrite bead and a couple pieces of wire. Although not impossible, it's unlikely for them to go bad.

I do wonder why you don't have an antenna to receive high VHF? You have real channels 7 and 12. Those UHF antennas you are using are rather poor on high VHF.

Please let us know if changing the balun and coax makes any difference.
 

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I agree with Calaveras. Your reception results don't match your expectations based on your tvfool report because the buildings are in the signal path.

If you are not able to find a better location for your 4228 (with a VHF antenna added with a UVSJ), as suggested by Chuck, the only suggestion I can make is to find a way to monitor signal quality, in addition to signal strength, to aim your antenna at the most useful reflection in your multipath laden location.

I have used the signal quality bar of the Apex DT502, and the SNR and Errors readings of my Sony TVs to monitor signal quality to optimize antenna aim. If the signal is brought to the edge of the digital cliff with an attenuator, the aim can be adjusted more precisely.
http://www.digitalhome.ca/forum/showpost.php?p=2476561&postcount=302

The 4228 has a narrower horizontal beamwidth (because of the horizontal stacking), which helps in picking out the best quality signal in a location with many multipath reflections.
 

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Did you try swapping the leads on one of the baluns? There may be addition or subtraction of signals between the two antennas, due to leakage or reflections of signals.
 

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Discussion Starter #9
I see you live not too far away from Lake Elizabeth in Fremont. I used to live in the Ardenwood district of Fremont.
So did I. On a ground-floor south-facing apartment with a 4' rise just outside my sliding glass door and buildings immediately across the drive followed by the trees of Ardenwood Park, I still got very good analog reception with built-in TV antennas on my old Sansui CRT. I moved here just before the transistion to digital and my reception even with analog was much less than it was in Ardenwood.

All the SF stations are rock crushingly strong in Fremont. Calling some the "weaker stations" is like saying 100 MPH winds are lighter than 110 MPH winds, technically true but still extremely strong. This was back in the analog days, but I had perfect reception on every SF station with an antenna 20' off the ground, not a hint of a ghost or a spec of noise even on channel 2. OTOH, the stations on Monument Peak and Mt. Allison in Fremont had terrible ghosts unless I turned the antenna around.

The difference between where I was and where you are is that I could see Sutro Tower on a clear day and you are blocked by buildings. Once you no longer have line-of-sight to the transmitters, especially in the Bay Area, you get terrible multipath problems. The only real solution is to have the antenna high enough to clear the buildings. I know that may be impossible for you but that doesn't change the antenna requirement.
This is a north-facing apartment and there is another building in the complex directly to the south. To the east is another building from a different complex and to the north is both a building and Mission Peak. To the west is a row of trees at the edge of the parking lot but not much else at my height.

Planes are frequently flying overhead and the signal wavers on a few of the channels when they do.

I really like PBS. Channel 60 (real channel 43) is usually strong but lately has some rare issues. Channel 9 (real channel 30) used to be mostly OK but is very flaky now where it used to be usually quite reliable if not super strong.

Seeing as real channel 43 and real channel 30 probably both come off the Sutro tower but have radically different behavior, I would guess they are at least at different heights if not different power levels or something too.

Channel 54 (real channel 50) reception used to be fairly reliable but is problematic. The other channels to the south are mostly strong here so even receiving them off-axis and through the aparment complex is not enough to block them. 50 (pbs) must be running low on power or height too. Is PBS limited in broadcasting budget?

I don't know why your reception has degraded over time. It's possible that there have been changes in the local environment, trees have grown up or something like that and your antenna location is no longer adequate.

There are only two kinds of baluns; transforming baluns and non-transforming baluns. All those multi-bay antennas use the same 300:75 ohm transforming balun. All that is inside of those baluns is a ferrite bead and a couple pieces of wire. Although not impossible, it's unlikely for them to go bad.
I suspect the equipment of being degraded based on the change of a couple bars in strength with a simple change of balun, especially since the two identical channel master baluns are both behaving the same and have both been in use approximately the same amount of time. Maybe the antenna is also degraded. Soot may be causing leakage or something. There is substantial traffic and fast food frying near here. If I put plastic over the antenna it will become a sail and fly right off the balcony.:eek:

I do wonder why you don't have an antenna to receive high VHF? You have real channels 7 and 12. Those UHF antennas you are using are rather poor on high VHF.


I never really got much performance out of the 4-bay but the 8-bay seems to do very well with the Sutro Tower as long as I aim the antenna directly parallel to the building and facing west. I suspect that the corner of the building is actually maybe very close to, or partially obscuring, the Sutro Tower LOS.

Channel 7 has two issues. The first one is that I detect two of each 7.1 7.1 7.2 7.2 7.3 7.3 and the ones with identical channel number have identical programming. My Samsung TV does the same thing, as does my Haupphauge 2250 tuner card and my Panasonic plasma and my
Samsung DTB-H260F tuner.

The second issue is that 7 never comes in any more except for very brief flashes. It used to work fine even with a very old Hughes DirecTV first- or second-generation tuner.

I never see channel 6 here, not even detected. Channel 11 (real channel 12) comes in fine, so apparently this 8-bay might be the reason the VHF is not working so well.

What do you think of me adding this antenna? Will combining through it cause any signal loss or conflict on the existing channel master? How about if I replace my channel master with a DB8, will that help with the degradation and the matching to this one::confused:

https://www.antennasdirect.com/store/C5-Clearstream-5-vhf-uhf-long-range-outdoor-DTV-antenna.html

Please let us know if changing the balun and coax makes any difference.
Apparently so. Reception is up but not quite as good as it used to be when I first installed the antenna.

I agree with Calaveras. Your reception results don't match your expectations based on your tvfool report because the buildings are in the signal path.

If you are not able to find a better location for your 4228 (with a VHF antenna added with a UVSJ), as suggested by Chuck, the only suggestion I can make is to find a way to monitor signal quality, in addition to signal strength, to aim your antenna at the most useful reflection in your multipath laden location.

I have used the signal quality bar of the Apex DT502, and the SNR and Errors readings of my Sony TVs to monitor signal quality to optimize antenna aim. If the signal is brought to the edge of the digital cliff with an attenuator, the aim can be adjusted more precisely.
http://www.digitalhome.ca/forum/showpost.php?p=2476561&postcount=302
Can you recommend a TV or other item I am likely to purchase some day, or a stand-alone instrument that is affordable, to do this function? Actually forget the TV, I already have an LCD and a projector in here and a plasma in the bedroom. Not likely to upgrade soon. Stand-alone? How about a tuner card with a meter that actually works under Linux with MythTV, Kodi or some command-line utility at least? One with a good tuner, modern chipset, multiple tuners etc. would be good too.

The 4228 has a narrower horizontal beamwidth (because of the horizontal stacking), which helps in picking out the best quality signal in a location with many multipath reflections.
The man who installed the antenna is a really nice guy who drove all the way from Concord and only charged me $175 to mount a tripod on railroad ties and install my antenna on a mast and run brand new wires he crimped himself into my living room and bedroom (4 total). I had the splitters and amplifiers already plus a bunch of short cables but he did all the longer runs off a spool.

That is $175 total for parts and labor. The tripod and mast and antenna were used, the railroad ties he found in a pile in the woods, and the rest of the parts were new.

He had a camcorder of some sort with built-in tuner and signal meter. He tried a Yagi first and then tried the 4228 and decided it was a better fit. The only improvement I have managed to make since he finished is to rotate the rear railroad tie so that the tripod leg 'comes off' the side instead of the top, in order to lower that leg add some upward tilt to the angle of the antenna.

I like to tinker so if I have to invest some thought and effort I am willing to do it but I have to keep the cost down so I go with the absolute best deal I can find, almost always used equipment plus an element of DIY.

Did you try swapping the leads on one of the baluns? There may be addition or subtraction of signals between the two antennas, due to leakage or reflections of signals.
I am using a switch so that is not an issue. Actually the switch is out of circuit because the 4221 was only a first attempt that failed and got repurposed into experimentation, not an antenna that I added for more reception. I replaced the 4221 with the 4228 since the signal was so poor.

Thanks for that, it was informative.
 

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Discussion Starter #10
What about combining these two?

Clearstream 5
https://www.antennasdirect.com/store/C5-Clearstream-5-vhf-uhf-long-range-outdoor-DTV-antenna.html

and DB8e
https://www.antennasdirect.com/store/DB8e-Ultra-Long-Range-Outdoor-DTV-Antenna.html

or DB8
https://www.antennasdirect.com/store/DB8_ultra-long-range-dtv-Antenna.html

I know the application is multipath but I am wondering if my location is such that the real problem is just no line of sight and not enough signal to Sutro. The meter on the Samsung tuner and TV is always low for the more problematic stations even with the original performance when the antenna was first installed. Would concentrating on gain be most effective?

Here is the current multipath:

The way the 4228 antenna is oriented now, when viewed from overhead with main lobe pointing up, the Sutro tower is directly up and half the PBS from there is unusable now, my building is to the left with strong stations behind it easily received (but PBS from that direction has intermittent break-up), another building is to the right and nulled out from being 90 degrees off-axis plus only a couple weak stations that way that I do not care much about, a third building with very strong San Jose stations behind it is blocked by the screen and essentially all of those stations are being received just fine off the backside of my antenna with no conceivable building reflection providing any signal from them.

It almost seems that any similarly constructed antenna will have similar directionality characteristics because the screen and off-axis null are the features I am taking advantage of to control the multipath anyway. The biggest issue seems to be seeing the Sutro tower through the trees and all the way across Fremont. Exta gain should help that, right? Add the VHF and presto, I get all channels just like I should:confused:
 

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It almost seems that any similarly constructed antenna will have similar directionality characteristics because the screen and off-axis null are the features I am taking advantage of to control the multipath anyway. The biggest issue seems to be seeing the Sutro tower through the trees and all the way across Fremont. Exta gain should help that, right? Add the VHF and presto, I get all channels just like I should:confused:

You could add the Clearstream 5. It'll be better for VHF, especially channel 7. The dual virtual channels for 7 is because KGO has a translator on RF 35 on Mt. Allison that uses the same virtual channel numbers. You're receiving RF 7 and RF 35.

More gain is not going to help you because the problem is not signal strength. Your TV reads low numbers because that is a Signal Quality meter, not a Signal Strength meter. You don't know exactly what your signal strength is.

If Sutro Tower is through a lot of trees then then likely to be the problem. Trees cause multipath and since they grow the problem can become worse over time. There's no antenna based solution to this since the multipath is in the same direction as the stations. You can try moving the antenna around to see if there's a better compromise spot. Of course higher is better. The farther away the trees are the less the problem.

KQEH is not running low power and is one of your strongest stations. I've attached a little chart I made to help people see where their stations fall on a signal strength scale. Read the NM(dB) column from your TV Fool report and see where they fall on my chart.

I assume you're not using any amplifiers. If your are, get rid of them.
 

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Discussion Starter #12
You could add the Clearstream 5. It'll be better for VHF, especially channel 7.
Insertion loss combining UHF with it? I would not want to make it any harder to get PBS in order to get channel 7.

More gain is not going to help you because the problem is not signal strength. Your TV reads low numbers because that is a Signal Quality meter, not a Signal Strength meter. You don't know exactly what your signal strength is.
If changing out the original balun(s) with a new one improves things, is that not de facto proof that signal strength is marginal?

So what device can I use to figure out signal strength? Anything affordable? I am not running Windows but if the WinTV 2250 has a working signal strength meter it might be worth it to install an OS that can use it. Not working in the Linux driver:( but maybe in Ubuntu 14.04 things are better. Have not tried it yet.

If Sutro Tower is through a lot of trees then then likely to be the problem.
There is a tree on the corner of the building that gets pruned back every winter. It is currently bare but the signal is still down.

There is only a single line of trees at the edge of the parking lot. They are large but not extremely thick or densely packed close together.

I see no visible change in the density of their foliage year-to-year but there is moderate seasonal variation with maybe some minor effect on reception or maybe it is just the weather.

There is basically nothing else blocking Sutro as far as I know except that the wall of my building forms a parallel line only a few feet from the antenna and extending maybe 7 feet above it. The floorplans vary and the exterior wall has about 4' deep shelf for two apartments past mine but comes back out flush for the last two apartments at the far corner of the building.

I do not have a compass so I am not sure what the orientation of the building is and I am not sure whether Google maps uses magnetic or true north. What I can say though is that the north wall of the building (where I live) apparently lines up almost exactly with Fremont Boulevard where it crosses Mowry, and on the map that section of Fremont Boulevard points directly toward San Francisco.

I am wondering if highest available gain UHF (DB8e claimed to be) would help because the line-of-sight to Sutro seems to only have one line of trees in the way, although it also is skimming the side of the building for four apartments' worth. It seems to me a worthy line of investigation since the ads for the antenna say it will help pick up signals weakened by trees and it is unlikely they are completely blocking it with only a single tree's worth of foliage thickness in the way.

KQEH is not running low power and is one of your strongest stations. I've attached a little chart I made to help people see where their stations fall on a signal strength scale. Read the NM(dB) column from your TV Fool report and see where they fall on my chart.
Cannot see any attachment:confused: but the comparable signal strengths of all the PBS stations on the TVFool chart to other stations in their vicinity that I receive fine indicates something is not right with their chart for this particular location.

I assume you're not using any amplifiers. If your are, get rid of them.
I have tried running a single cable straight to the receiver and the performance seems identical to using the amp and splitter to route the signal to four or five devices. I have also tried several different arrangements of splitters and have two amps to play with. So far I have not found any reasonable combination of amps and splitters that seems to function any better or worse than any other.

I suppose if I try the five-way splitter with no amp I can count that as an attenuator, provided I put termination on all its outputs? That does not seem to work quite as well as putting an amp in front of the splitter.

If I put fine mesh screen around/behind the antenna will that help stop multipath from adjacent buildings, or just make things worse if my signal source is actually a reflection? Worthwhile debug experiment?

So besides removing amplifiers from the path (that do not seem to be causing any problem anyway), what would YOU do if you were debugging and attempting to improve reception here? Your votes?

Ignoring VHF and KQEH for the moment, what about trying a DB8e to see if I can pull in KQED again?

How about a pair of widely separated DB4 to try and reject the multipath from adjacent buildings that are not in the path to Sutro?

A pair of widely separated DB8 to do the same with very sharp lobe pointing straight at Sutro (not that I have room for it)?

I could certainly stack them one over the other if I add another mast that attaches at an angle to the one already in the tripod. The lower one would be about 2' from the floor of the concrete balcony. More gain but only same top-view directionality as a single DB8...

I am detecting an assumption that the 4228 could not have degraded. I am not that optimistic. Any idea of something I could try cleaning the grime off with that I can safely use down in the parking lot where the water hose is?

I saw lifespan of antenna is about 10 years and I bought mine used about 10 years ago. Could mine be leaking signal from all the soot that landed on it over the past 10 years, as evidenced by the improvement from replacing the balun? I do often smell restaurant barbecue and burger grilling from the Fremont Hub and surroundings plus there is lots of traffic here. everything gets dusty/grimy outside. Could the (apparently plastic) insulators absorb minerals and become leaky?

I would be happy if I could just restore the performance where it used to be. Any extra improvement over that would be pure gravy (umm, wonderful easter dinner last night...):)
 

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Discussion Starter #13
I decided to post some pictures of my skyline and antenna here. I cannot do it until tomorrow at the earliest. From what I can see I should have a nearly perfect straight shot at Sutro. The trees barely poke up above the roofs of the buildings at this elevation.

Until you actually see what it looks like here I doubt you can evaluate it properly. The reception was really quite pleasing when it was first done. Puzzling why it got worse seeing as there is absolutely nothing visible to me that could have changed it except maybe the grime and age of the components.
 

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I decided to post some pictures of my skyline and antenna here. I cannot do it until tomorrow at the earliest. From what I can see I should have a nearly perfect straight shot at Sutro. The trees barely poke up above the roofs of the buildings at this elevation.

Until you actually see what it looks like here I doubt you can evaluate it properly. The reception was really quite pleasing when it was first done. Puzzling why it got worse seeing as there is absolutely nothing visible to me that could have changed it except maybe the grime and age of the components.

Okay. I'll look forward to the pictures but in the meantime......


Insertion loss combining UHF with it? I would not want to make it any harder to get PBS in order to get channel 7.
I'm still having a hard time getting my point across that you have giant signals and a little insertion loss won't make any difference. :) You will need a VHF/UHF diplexer (also known as a VHF/UHF Signal Joiner) which has perhaps 1dB loss.


If changing out the original balun(s) with a new one improves things, is that not de facto proof that signal strength is marginal?
You certainly can try that but but I'd surprised if it makes any difference.


So what device can I use to figure out signal strength? Anything affordable? I am not running Windows but if the WinTV 2250 has a working signal strength meter it might be worth it to install an OS that can use it. Not working in the Linux driver:( but maybe in Ubuntu 14.04 things are better. Have not tried it yet.
Some of the PC based receivers have detailed diagnostic information including real signal strength. You should ask others about this since I don't watch TV on my computer.



I am wondering if highest available gain UHF (DB8e claimed to be) would help because the line-of-sight to Sutro seems to only have one line of trees in the way, although it also is skimming the side of the building for four apartments' worth. It seems to me a worthy line of investigation since the ads for the antenna say it will help pick up signals weakened by trees and it is unlikely they are completely blocking it with only a single tree's worth of foliage thickness in the way.
Check out this page to see what buildings and trees do to signals:

http://www.hdtvprimer.com/ANTENNAS/siting.html

It's unlikely the DB8e will do anything in your situation.


Cannot see any attachment:confused: but the comparable signal strengths of all the PBS stations on the TVFool chart to other stations in their vicinity that I receive fine indicates something is not right with their chart for this particular location.
It's in my Post #11 . If you can't see that then you must not see anyone's attachments. Try a different browser.



I have tried running a single cable straight to the receiver and the performance seems identical to using the amp and splitter to route the signal to four or five devices. I have also tried several different arrangements of splitters and have two amps to play with. So far I have not found any reasonable combination of amps and splitters that seems to function any better or worse than any other.

I suppose if I try the five-way splitter with no amp I can count that as an attenuator, provided I put termination on all its outputs? That does not seem to work quite as well as putting an amp in front of the splitter.
If you have tried a passive splitter and a distribution amp and there wasn't any difference then that is telling you the signals are plenty strong. For example, take one of the +50 dB noise margin signals. 50' of RG-6 has 2.5 dB loss and an 8-way splitter has 10.5 dB loss for a total of 13 dB. That lowers your noise margin to +37 dB which is still more than 4000 times more signal than the minimum required.


If I put fine mesh screen around/behind the antenna will that help stop multipath from adjacent buildings, or just make things worse if my signal source is actually a reflection? Worthwhile debug experiment?

So besides removing amplifiers from the path (that do not seem to be causing any problem anyway), what would YOU do if you were debugging and attempting to improve reception here? Your votes?

Ignoring VHF and KQEH for the moment, what about trying a DB8e to see if I can pull in KQED again?

How about a pair of widely separated DB4 to try and reject the multipath from adjacent buildings that are not in the path to Sutro?

A pair of widely separated DB8 to do the same with very sharp lobe pointing straight at Sutro (not that I have room for it)?

I could certainly stack them one over the other if I add another mast that attaches at an angle to the one already in the tripod. The lower one would be about 2' from the floor of the concrete balcony. More gain but only same top-view directionality as a single DB8...

I am detecting an assumption that the 4228 could not have degraded. I am not that optimistic. Any idea of something I could try cleaning the grime off with that I can safely use down in the parking lot where the water hose is?

I saw lifespan of antenna is about 10 years and I bought mine used about 10 years ago. Could mine be leaking signal from all the soot that landed on it over the past 10 years, as evidenced by the improvement from replacing the balun? I do often smell restaurant barbecue and burger grilling from the Fremont Hub and surroundings plus there is lots of traffic here. everything gets dusty/grimy outside. Could the (apparently plastic) insulators absorb minerals and become leaky?

I would be happy if I could just restore the performance where it used to be. Any extra improvement over that would be pure gravy (umm, wonderful easter dinner last night...):)
The idea of having a directional antenna is to reject signals from other directions. Normally this takes care of reflected multipath signals. If you have LOS to the transmitters then the LOS signal will be much stronger than any reflected signal. Reflections become a problem when the LOS path is blocked and the path to the things the signal is reflecting off of is not blocked. In that situation you can end up with strong reflections and a weaker direct path signal. This is a very common problem in SF for people who don't have LOS to Sutro Tower but are surrounded by buildings that are efficient reflectors. I have that problem here with a 2 edge path to the transmitters in the west but higher mountains east of me that are LOS to the transmitters. The reflections are nearly as strong as my direct path signals. I depend on the directionality of my antennas to reject the reflections enough to receive my stations.

You can inspect your antenna for degradation. It's not going to short out or something if there's a little dirt on it. You can always clean it up if you like.

Most likely you had marginal signal quality all along but were unaware of it until it degraded just a little and you lost reception. That's the problem with DTV, all or nothing.
 

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How about a tuner card with a meter that actually works under Linux with MythTV, Kodi or some command-line utility at least? One with a good tuner, modern chipset, multiple tuners etc. would be good too.
So what device can I use to figure out signal strength? Anything affordable? I am not running Windows but if the WinTV 2250 has a working signal strength meter it might be worth it to install an OS that can use it. Not working in the Linux driver but maybe in Ubuntu 14.04 things are better. Have not tried it yet.
This is what Pete Higgins uses:
My Samsung TV only displays signal strength so when I'm rotating my antenna array I use my computer and the Hauppauge HVR-1800/SNR meter to optimize the final antenna parking. Works better for me.
Pete and majortom can help you on this thread at DHC:
OTA Signal Analyzers, Meters, Aimers, Bench Gear, Diagnostic Software
http://www.digitalhome.ca/forum/showthread.php?t=96705

The Hauppauge tuners have a signal monitor available that gives you SNR and errors:
http://www.hauppauge.com/site/support/support_digital_signal_monitor.html

home page
http://www.hauppauge.com/index.htm

I have used their 850 and 950 USB tuners, but the software is not user friendly. Pete and majortom have better luck with Linux.
 

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Cannot see any attachment but the comparable signal strengths of all the PBS stations on the TVFool chart to other stations in their vicinity that I receive fine indicates something is not right with their chart for this particular location.
It is necessary to be logged in to see attachments. Even then, it is sometimes necessary to refresh. The new software for this forum is not user friendly. This is what Chuck's attachment looks like:


 

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Insertion loss combining UHF with it? I would not want to make it any harder to get PBS in order to get channel 7.
It would make it easier because the added gain of the VHF antenna would more than make up for the 0.5 dB loss of the UVSJ.
I do not have a compass so I am not sure what the orientation of the building is and I am not sure whether Google maps uses magnetic or true north.
A small pocket compass isn't very expensive. The Google maps use true north; your tvfool report lists both.
 

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I decided to post some pictures of my skyline and antenna here. I cannot do it until tomorrow at the earliest. From what I can see I should have a nearly perfect straight shot at Sutro. The trees barely poke up above the roofs of the buildings at this elevation.
What would also be helpful, if you are willing, would be an aerial view of your location with the green signal lines like this example:



If by some weird chance I have guessed your location, it wasn't intentional.:)

You can make your own aerial photo by going here and moving the cursor to the location of your antenna:
http://www.tvfool.com/index.php?option=com_wrapper&Itemid=90

To get the 90 degree vertical, remove the check by 45 in the dropdown menu below satellite; likewise to remove street names.
 
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Discussion Starter #19
Apologies for the file sizes. I am not familiar with how to do these graphics edits on open source system.

The first picture shows virtually unobstructed line of sight to Sutro, except that the signal hugs the wall of the building. The balcony is higher than almost all the trees and those couple that approach the signal path are mostly far away and isolated. There are no buildings of any consequential height along that path for about a mile.

It is necessary to tilt the antenna upward and sort of aim through the indent in the roofline for best performance. Currently it is aimed parallel to the wall and angled upward about 10-15 degrees or so.

There seems to be no reason for this signal path to have changed so much that channel 9 is not being received, whereas channel 60 comes in fine. They both originate on the same tower as far as I know. The only explanation I can think of is that KQED is on the lower antenna that is positioned inside the tripod tower rather than mounted on top of a leg.

The second picture shows the signals hitting the backside of the antenna and those toward the south that hit the backside at an angle after passing through my building (or maybe reflecting off another building across from my balcony).

It just seems a little fishy that the performance would change so drastically without any substantial foliage in the way of the weaker signals and all the obstructions being so close to me. If it works well for years and then gradually gets worse, what has changed? Did the buildings move? They keep the trees trimmed in the city.

Anyway I guess I will keep looking into this to see what potential changes will help. It appears that I might be able to improve the bead on Sutro by moving the antenna as far toward the corner of the balcony as possible and maybe angling it a little bit.

I still am leaning toward a DB8(/e?) and a CS5. Not trusting an old antenna covered with city grime, especially one that is not necessarily impedance matched.

Let me know what you think...
 

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Thanks for the images.
Apologies for the file sizes. I am not familiar with how to do these graphics edits on open source system.
No apology necessary. The large file size (244 KB) gives us more detail, and the large pixel size (1542 x 866) can be adjusted as needed.
The first picture shows virtually unobstructed line of sight to Sutro, except that the signal hugs the wall of the building.
299 degrees true looks clear, but 291 is obstructed.
It just seems a little fishy that the performance would change so drastically without any substantial foliage in the way of the weaker signals and all the obstructions being so close to me......Anyway I guess I will keep looking into this to see what potential changes will help......Not trusting an old antenna covered with city grime, especially one that is not necessarily impedance matched.
I don't think you will be happy until you substitute some new antennas to see if they make a difference in reception.
 
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