Dual antenna setup help

Playground Antenna Help
#1

Hello antenna knowledgeable folks!

I am trying to help a family member in her 70's with her antenna setup. She is running the latest version of Channels DVR on a Synology DS220+ as the server and using ethernet connected Firestick 4K's at each TV as a playback device. Her tuner device is an HDHR 4K Flex. She happens to reside right in between 2 different major TV markets in Wisconsin - Green Bay and Milwaukee. She is roughly halfway between both of them. She has a roof mounted dual antenna setup on top of a tall 2 story house that has been working well for over 20+ years.

The issue she is currently facing is signal degradation problems that I believe are probably related to the way the signal from 2 antennas are being combined into one coax cable. I am including some pictures of the current setup. The roof mounted antennas are on one pole, with a coax cable for each of them coming down inside the conduit running through the roof. One antenna is facing north, the other south. Following the coax cables I can see that the signal from both antennas is being combined into one coax cable by using a dual splitter in reverse.

I don't think this is the best way to handle this. One market (Green Bay) recently went live with ATSC 3.0 and since that time she is having issues with the Green Bay market channels. I did some troubleshooting by disconnecting each antenna feed coax one at a time. When I did that, I could reliably get solid reception on either the Milwaukee or Green Bay channels, as long as only one antenna was connected at a time. When I connected them both back together again, I would lose one of them. When I say "lose" I don't mean completely, but basically the signal breakup is bad enough to make the channels unwatchable.

I'm guessing the mix of ATSC 3.0 from only one market, combined with the use of the coax splitter in reverse is causing most of the problems. What is the proper way to combine antenna signals from 2 different physical antennas into one HDHR device? Is that even possible? If it is not possible, I'm assuming the correct way is to purchase a second HDHR tuner and divide up the channel responsibilities between the 2 devices by feeding one antenna coax direct to each HDHR?

Any feedback/suggestions are appreciated. Thanks!

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#2

Using a coax splitter to combine signals from two different antennas will likely result in multi-path, meaning that both antennas will receive the same frequencies slightly out of phase, which will cause significant problems for ATSC digital channels. The NTSC analog equivalent is ghosting, but ATSC digital signals are more susceptible to multi-path interference.

What you likely need an amplified programmable combiner, which can combine signals from up to three different antennas. I installed one of these. It will automatically filter frequencies based on the best signal level from each antenna, or you can manually force which frequencies are from each antenna. It has a mobile app that connects via bluetooth. It's a "set it and forget it" Ron Popeil device.

https://www.amazon.com/gp/product/B0BSG23PHL

AntennaMan has the best explanation videos and also provides an antenna recommendation based on your location for a small fee.

P.S. Just looking at the existing installation, the SmartKom would replace the two separate pre-amps and the combiner. Each connection induces approximately 3dB of signal attenuation. It might have been OK with NTSC analog broadcasts, but not acceptable for ATSC. I would start with ripping all that [redacted] out. You couldn't do any worse.

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#3

I was just going to post about the SmartKom You can tell it which channels should come from which antenna and it will filter out the ones you don't want to come from that antenna. Or at least that is my understanding of it. Not the cheapest solution but seems most likely the correct solution.

#4

Considering you could purchase a new FLEX 4K (HDFX-4K) or Refurbished FLEX 4K REFURBISHED (HDFX-4K-R) for less, I would do that.

#5

That will not solve the problem of being located between two different markets and trying to receive signals from two different directions.

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#6

Yes it will. Each antenna goes to its own FLEX tuner

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#7

Yeah, for ease and simplicity, I'm leaning toward the addition of another HDHR 4K tuner. My only hesitation would be the temperature swings in that attic space. In winter, it gets really cold and likewise in the summer, it gets pretty hot. I can run network cable into the attic space with minimal effort and have the 2 tuners connect directly to the coax feeds coming in from the roof antennas. I'm just wondering how much the seasonal temperature extremes would affect the HDHR's?

#8

Don't install the HDHR in the attic. The SmartKom is the correct answer.

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#9

I would recommend the 2 hdhr route but not located in the attic. Run an additional coax for the second one. If you cant do this then i would say go with the proper signal combiner route

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#10

Considering the weather proof box the SmartKom comes in, I assume it would be fine to place that device directly in the attic space?

Though it would also be nice to have expanded tuner capacity for when the Milwaukee stations eventually go live with ATSC 3.0. Directly below the point where the current pre-amps are mounted is an old chimney which goes straight down to the basement, which conveniently is exactly where the network switch for the house is - at the bottom of that cavity. I could just use a coax coupler to connect extended coax cables from the current terminations in the attic space and run a length of coax to the basement, so that each HDHR tuner is still directly connected to one antenna feed each?

My only question for that would be if the coax cable length would be too long and introduce some loss? Though the Winegard amps (if that's what those are) are still there and as far as I know function just fine as well.

#11

@jziggity Based on the labeling on the Winegard PS-9370 boxes, those are just the power supplies/injectors and there is a pre-amp on the antenna masts or the amp is built into the antenna. In order to use the SmartKom, you would need to remove the existing pre-amp on the antenna masts. I would simply run new RG6 coax down from each antenna (make sure the antennas masts and coax shields are properly grounded), then install the two parts of the SmartKom in the attic in the current location next to the incandescent light.

There are two parts to the SmartKom. The programmable amplifier/combiner/filter and the power injector/controller. Both are rated for -5 to +45 C (23 to 113 F). The heat generated from the power input should keep it above -5 C or you can leave the incandescent light on during the winter. Keep the distance between the two short and close to the antennas. If you place the amplifier/combiner/filter far from the antennas you will be amplifying more noise vs the signal level, resulting in poor SNR. Of course, make sure you are using quad shielded RG6 coax cable with a copper center conductor.

I tried to put the combiner in the attic and power injector >75 ft away where all my coax runs originate, but the voltage drop was too high to power the combiner/amplifier. I have both in my attic. You can just let it auto program and forget it, or you can use the mobile app to tweak the settings.

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#12

Awesome. That is a gift right there. Tie a weight to the end of some coax and drop it down there. Thats exactly how i would set it up, one hdhr per antenna feed.

Well all cable introduces loss... there is no way around that. Its just how much loss can you afford. Its all math really. If i just bought that house the first thing i would do is disconnect the amplifiers and see what i am working with as far as signal. I would use the ios app signalGH and do a scan. If my levels are good then i would not use an amp. Using an amp when you dont need one can cause problems. If the signal is low then introduce the amplifier. Remember amplifiers dont improve the signal, they make up for the loss encountered from cable and splitter loss.

Example, lets say i have a 2 way splitter and a 4 way splitter hung off of each leg. Thats -3.5dB + -7dB for a total loss of -10.5dB on each of the 8 connections that i have available. Factor in -4dB for my long cable run and thats a total loss of almost -15dB. I put a 15db amplifier at the antenna and each of my 8 outputs are now at 0dB loss.

Now where an amp can also be beneficial is when you have a marginal signal that is just above the threshold of "good signal". But when you go through 75ft of RG6 coax it goes below the threshold and is unwatchable.

I learned all of this the hard way. I am 7 miles from my towers. I had a signal amplifier because i thought anything amplified is better. Pretty much every channel was unwatchable. Turns out i needed to get rid of the amp and add -17dB of attenuation to get my signal just below 100% on all channels.

Here is a cable loss calculator that will tell you what you are losing...

#13

I'm using a SmartKom to pick up 3 markets. Down by the power inserter, I run that into a 4-way balanced passive splitter. Then it goes to a Tivo Roamio, a HDHR 4k Flex, (for my Channels DVR server) and two tv sets. They all work perfectly. IMO, the SmartKom is the BEST device they've ever come out with, in 40 years!

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#14

Man thats awesome. What is your furthest reach?

#15

Detroit, at 106 miles. My regular DMA towers average 32 to 47 miles away. The 3rd DMA is 56 miles.

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#16

@ 20+ years age, I would replace the coax with new RG6 quad shield. The loss is gradual and you will be surprised at the difference it can make.

And I also recommend the second HRHR tuner method.

#17

I have the same issue in Florida. I tried two antennas and combining them before and after amplifying and it didn’t work. So I bought two HDhomeruns and the two antennas are now completely independent and it works great.

It’s something you can do with Channels!

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#18

Sure you can use separate HDHRs for each antenna. I’m sure SiliconDust would prefer that option. But then any TV with an ATSC tuner would not get the benefit of receiving signals from both antennas. Not to mention the added complexity of two HDHR tuners, duplicate channels, DVR config, etc.

I prefer solutions that make life less complicated. The SmartKom is an off the shelf solution which accomplishes that. Takes minutes to install and works automagically!

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#19

I am in awe.

#20

Going back to why your problems started with ATSC 3.0 going live, did those channels replace all the corresponding ATSC 1.0 channels in your guide without your knowledge?

In OKC, the ATSC 3.0 broadcast actually has the big 4 sharing one transmitter all at 1080P and using PSIP info to make them appear separate on your tuner. So it would make sense that all the major networks have issues at the same time. Perhaps only your ATSC 3.0 channel is getting cochannel interference from the other market. And/or perhaps it is only low power for now. A lot of speculation here…

Do a signal search for your location at https://www.rabbitears.info to see all stations and potentials for cochannel interference. Also you can learn more from locals in your area in your local market thread for hdtv reception at https://www.avsforum.com/

Activate the onscreen stats. I don’t have 4K HDHR, but I would think the stats would show that ATSC 3.0 channels are HEVC?? Instead of MPEG2.

You can also use the HDHR app to see more info.

While that SmartKom thing sounds awesome, the advantage of a second HDHR is that you may get a few more channels that happen to share the same frequencies. Edit - But probably just duplicates. Normally major networks in adjacent markets are on different frequencies. Again, check your rabbit ears report. Also, as more ATSC 3.0 stations go live, you could get more cochannel interference until the ATSC 1.0 signals get turned off in 10+ years if ever.