General thoughts/advice on my antenna setup...

[Slack]

TL;DR Is LTE/5G interference a real thing for NTSC Digital broadcast reception?

Details.

(2) HD Homerun Duos and (2) DB8 Antennas in my attic, one each pointed at geographically removed antenna clusters in my metro area...Charlotte, NC.

Despite every-time visual glitches get me thinking I need to adjust something. While adjusting, everything I care to tune is at 100% green bars or very near that for all three bars the HD Homerun app lists.

Still, this weekend while watching the little league world series and other things, I get occasional green pixel blocks and audio drops - very occasionally. Yet my morning live TV channel really has no issues.

This used to not happen, and at one point I had a single DB8 antenna that split the difference between the two tower clusters. So the 'used to not happen' had me thinking of a new build for the Sagetv server. But otherwise it's just fine. Wintel 7 box. Been pretty damn reliable.

Back to the antenna arrangement. I only recently added the second DB8 antenna, both going into a channelmaster JOINtenna, then that into a Lindsay broadband LSA84-E08 amp. From there into the (2) HD Homeruns and the other two outputs of the amp have terminators on them. It all seems legit.

I was on amazon looking to throw new tuners into the mix (one of the HD Homeruns is quite old and cannot have firmware updates). It is there, that I see LTE/5G filters (by Silicon Dust no less) and mentions of quad shielded RG6 coax.

I suppose it's possible that new cell towers and frequencies are interfering. What is more, the current setup is using coax I found in my stash from the garage - collected over decades, & decades of TV/Cable and other technology requiring coax.

I could replace all of that with quad shielded RG6, and add some LTE/5G filters to mix.

Questions.
1) Are the channel master and Lindsay devices known to be crap by other Sage users?
2) How many filters and where?
At antenna(s)? (2)
Output of JOINtenna/input of amp? (1)
Input of tuners?(2)

Option??: Get rid of the joiner and amp, and create (2) separate lineups in Sage each being unique to the tuner that can tune it's antenna's aimed tower(s). Not ideal if there are 3 simultaneous recordings set for the same tower cluster - hence my attempt at getting all 4 of my tuners to see all 2 of my metro tower clusters.

[JustFred]

Originally Posted by Slack

TL;DR Is LTE/5G interference a real thing for NTSC Digital broadcast reception?

Without knowing your exact coordinates and exact channels involved, I can only make some general observations.

1. LTE *interference* is less likely than LTE *overloading* that Lindsay LSA84 amp (which is intended for cable TV, NOT for OTA). Unless there's a *proven* need for the amplifier, temporarily remove it completely.

2. Before replacing the existing coax, consider that poorly crimped coax connectors are often the greatest point of ingress. Push-on (instead of screw-on) connectors are almost certain to be a problem.

3. Attempting to use a "simple" JOINTenna with a pair of (relatively) non-directional DB8 antennas in an urban environment has the potential to result in a LOT of multipath, which could easily cause the symptoms reported. Again, unless there's a *proven* need to use multiple antennas, temporarily use a single DB8. Or a single DB8 and an amp that's intended for OTA (with a max freq of 650 MHz). There might be other things to try, but I'd need your exact coordinates to go beyond this.

4. The JOINTenna specs claim that it already has a built-in LTE filter. Unfortunately I didn't see any real specifications that might hint as to the quality of that filter, so I'm left to suspect that it's marginal at best.

Have you looked at tvfool.com? It might seem a bit geeky, but provides alot of insight for dealing with these kind of issues.

[wayner]

How was the weather when you were having this reception issues? I have found that heavy rainstorms and thunderstorms can cause reception issues, particularly when channels are farther away - I am in Toronto and I am pulling in OTA channels from Buffalo which is about 60 miles / 100km away.

If you are very close to a cell tower then it is possible that you are getting interference, but if you aren't that close to them then this is less likely to be an issue.

Have you tried using a 4 bay antenna as they are less directional? I assume that you antenna is something like a CM4228. The 4 bay is the CM4221.

Presumably you mean ATSC rather than NTSC as NTSC is the analog broadcast standard that was shut down several years ago. And we are now going to ATSC 3.0 which brings 4K OTA, amongst other things.

[Slack]

Thanks for the reply.

Originally Posted by JustFred

1. Unless there's a *proven* need for the amplifier, temporarily remove it completely.

Replace with what a simple splitter / Y ?
I saw it as possibly better than a simple splitter.

Originally Posted by JustFred

2. Before replacing the existing coax, consider that poorly crimped coax connectors are often the greatest point of ingress. Push-on (instead of screw-on) connectors are almost certain to be a problem.

While all are screw on, some of them look iffy with the crimps. I ordered new ones last night.

Originally Posted by JustFred

3. Attempting to use a "simple" JOINTenna with a pair of (relatively) non-directional DB8 antennas in an urban environment has the potential to result in a LOT of multipath, which could easily cause the symptoms reported. Again, unless there's a *proven* need to use multiple antennas, temporarily use a single DB8. Or a single DB8 and an amp that's intended for OTA (with a max freq of 650 MHz). There might be other things to try, but I'd need your exact coordinates to go beyond this.

4. The JOINTenna specs claim that it already has a built-in LTE filter. Unfortunately I didn't see any real specifications that might hint as to the quality of that filter, so I'm left to suspect that it's marginal at best.

Some things to ponder, thanks.

Originally Posted by JustFred

Have you looked at tvfool.com? It might seem a bit geeky, but provides alot of insight for dealing with these kind of issues.

Not aware of this url until now. Will check it out.

All of this has me pondering a test of my plan B.

[Slack]

Originally Posted by wayner

How was the weather when you were having this reception issues? I have found that heavy rainstorms and thunderstorms can cause reception issues, particularly when channels are farther away - I am in Toronto and I am pulling in OTA channels from Buffalo which is about 60 miles / 100km away.

If you are very close to a cell tower then it is possible that you are getting interference, but if you aren't that close to them then this is less likely to be an issue.

Have you tried using a 4 bay antenna as they are less directional? I assume that you antenna is something like a CM4228. The 4 bay is the CM4221.

Presumably you mean ATSC rather than NTSC as NTSC is the analog broadcast standard that was shut down several years ago. And we are now going to ATSC 3.0 which brings 4K OTA, amongst other things.

Weather was fine if a bit hot. I typically notice issues with heavy wind. But in this case I would not expect weather induced glitching.

And yes, I meant ATSC, OTA digital.

[KeithAbbott]

If you are an iPhone user, you might want to check out the "Signal GH" app in the appstore, I think it's $3. It specifically works with HDHR tuners, and shows signal strength, quality, etc. for each tuner. But, it also shows a map with the location of the television station antenna towers, and tells you when your antenna is adjusted so that it is directly pointing to that tower. Invaluable tool for when you are working on your roof antenna, or attic antenna (like I have).

[JustFred]

Originally Posted by Slack

Replace with what a simple splitter / Y ?
I saw it as possibly better than a simple splitter.

Yes, try replacing that amp with a simple 2-way splitter.

What was the reason for adding the amp in the first place? A common misconception is that an amp will magically "improve things". But especially in urban areas, unless the actual signal strength numbers are known, an amp often amplifies your problems. This is especially true if using an amp that's intended for cable TV (like the Lindsay LSA84)... it's intended to be used in an environment that has a relatively even signal strength across the entire range of channels, but can easily be overloaded with OTA signals which may widely vary in relative signal strength (such as often exists in urban areas). And it will amplify signals way above the broadcast TV range (i.e, cell signals), which can also be problematic.

Knowing your approx coordinates and the problematic channels might allow us to reduce the number of unknowns.

[Slack]

Originally Posted by KeithAbbott

If you are an iPhone user, you might want to check out the "Signal GH" app in the appstore, I think it's $3.

I will check that out, I typically take a laptop up there and remote into my Sage server.

The map stuff may be worth 3 bucks.

[Slack]

Originally Posted by JustFred

What was the reason for adding the amp in the first place?

1) I'm German
2) I'm an engineer
3) Too lazy to do this particular job right.

We love to over complicate things. You should see my electric smoker.

Originally Posted by JustFred

Knowing your approx coordinates and the problematic channels might allow us to reduce the number of unknowns.

South East Charlotte.
Little league world series was on ABC, WSOC.

A crude map. Can't recall exactly when in the process I sketched this. Farther cluster on left is ~30miles, closer cluster on right is ~14miles.



Looks like this on antenna web....

[KeithAbbott]

Originally Posted by Slack

I will check that out, I typically take a laptop up there and remote into my Sage server.

The map stuff may be worth 3 bucks.

There are a couple of videos on this site that explain the app pretty well: https://genhelp.com/apps/signalgh.html

[JustFred]

Originally Posted by Slack

1) I'm German
2) I'm an engineer

Ditto here.

South East Charlotte.
Little league world series was on ABC, WSOC.

Looking at your whiteboard pix, it appears the stations of interest are spread across approx. a 60 deg. angle. So based upon the DB8 datasheet (pg 4), I'd try a single DB8 with the left & right sides set 30 degrees off broadside to give good coverage over 90 deg. with 5-10 dB gain.

I'm not clear about the RF frequency for WSOC. Antennaweb says RF channel 19; TVFool says RF chan 30 or 46; AntennasDirect says RF chan 12. If WSOC is really on RF 12 (VHF band), then the DB8 (a UHF antenna) isn't going to pick that up very well regardless how it's aimed.

[Slack]

Originally Posted by JustFred

Ditto here.
Looking at your whiteboard pix, it appears the stations of interest are spread across approx. a 60 deg. angle. So based upon the DB8 datasheet (pg 4), I'd try a single DB8 with the left & right sides set 30 degrees off broadside to give good coverage over 90 deg. with 5-10 dB gain.

So...this is exactly what I did in the before times....
I split the difference.

In any case, I will try out your suggestions...first being the deletion of the amp.

My freshly minted COAX was deliver today, and as luck would have it, it's a false fall in the Carolinas this week. So temps in the attic will be tolerable.

Many Thanks and Kind Regards,

[Slack]

Re-reading your post.

The before-time DB8 did not have independent left and right panels.

[Slack]

Originally Posted by JustFred

Yes, try replacing that amp with a simple 2-way splitter.

Old coax is out.
New coax is in.
Amp is out.
Aim 11-4120 splitter (found in garage) is in.

So far Sage can tune everything, and looks fine. Lots of college football today will exercise the existing setup.

A casual observation, the red numbers in my first image were the 3 bars the HD Home Run app produces.

Signal Strength
Signal Quality
Symbol Quality

Strength is down a bit, but quality remains high.

Thanks JustFred & others for the suggestions.

[davidk21770]

It sounds like you may have it under control, but I tried 2 antennas for a while and ran into the following problems...

1 Using a combiner without individual preamps doubles your noise power.
2 Get the best combiner that you can find. If you're using a splitter, make sure that it is truly usable as a combiner.
3 Strong stations in one antenna suppress or overload weak stations in the other. (Overall dynamic range). This varies over the day depending on local conditions (air moisture, rain, etc).
4 Cables and connectors can't be emphasized enough.
5 Multipath in a city coming into the other antenna can cause intermittant dropouts or fades.

David

[wayner]

Another alternative to a combiner is to use separate antenna with separate tuners. This does have the shortcoming in that it limits you to only two recordings from Antenna A, assuming that it is connected to a dual tuning device like most HDHRs, but that may not be a big issue if you get all networks from both antennas.

[Slack]

Originally Posted by davidk21770

It sounds like you may have it under control, but I tried 2 antennas for a while and ran into the following problems...
David

Yeah I thought I did.

Lots of college football recorded without issue.
Then the Notre Dame Florida State Game. It was gawd aweful, never been that bad on such a strong station. WSOC in this case. Earlier in the weekend one or two other games were recorded on that station without issue.

So, I manually tuned WSOC on all 4 tuners, and one of the 3 the signal quality was bouncing between 100% and 68%.

So took it out and went with plan B.
Each antenna to it's own tuner pair.

Then I futzed around with the channel line ups and created mutually exclusive lineups, one for each antenna.

Did not bother with overlap - although I may re-visit that.
Tested it briefly with all 4 tuners going, and had to resolve some conflicts that this produced.

Time will tell but I think I now have it. No amps, no splitters, no joiners. And a bit of reduced flexibility.

[Slack]

Originally Posted by wayner

Another alternative to a combiner is to use separate antenna with separate tuners. This does have the shortcoming in that it limits you to only two recordings from Antenna A, assuming that it is connected to a dual tuning device like most HDHRs, but that may not be a big issue if you get all networks from both antennas.

This is what I ended up with.

I will re-visit any overlap in the days to come, may be able to get some channels with all 4 tuners getting good quality.

[JustFred]

Originally Posted by Slack

So, I manually tuned WSOC on all 4 tuners, and one of the 3 the signal quality was bouncing between 100% and 68%.

I once had a similar problem, where just one of my 4 HDHR tuners had occasional problems tuning to one particular station. Turned out that the wall-wart (power supply) was going bad. No idea why that one power supply affected only one of the two tuners in that particular HDHR box. Dumb luck led me to swap out the power supply. I'm sorta in the flight path for landing aircraft, so multipath caused by nearby planes is a known (unavoidable) problem, too.

[Slack]

So the conflict resolution engine is now getting a workout. I did not think it would be that way. I think I will be pointing both antennas to split the difference between the towers, and attempt to revert to a single line-up.