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kenj66 24-Jun-2014 8:27 PM

Difficult location 15 miles west of Seattle
I appreciate the resources provided here and the volunteers so willing to help. Retired IT guy here. No stranger to technical issues but I am new to OTA TV.

First question: I am not familiar with Real vs Virtual TV channels. Why can't channel numbers increment sequentially as they did in the analog days? It seems really odd that my old channel 5 is now on UHF 48.

Second question: is there any economical (cheap!) way to measure channel strength in real time? That would solve so many problems right away! Pro gear is out of my price range. (A cheap tuner might work)

Third question: How do you accurately indicate signal problems in a digital system? The signal strength indicators on my two TVs seem rather useless since anything less than 85 percent is simply not watchable. The three channels I do get read a solid 100 percent yet the picture and audio are somewhat impacted by sporadic loss of audio and macro-blocking.

I am located only about 15 miles due east of Seattle but there is a significant ridge in between. The ridge is less than two miles away so I am in rather deep shadow. I am using the Monoprice HDA-5700 amplified antenna which is pointed due east to the Seattle cluster of major network transmitters. It is mounted 23 feet above street level on my roof. I have 50 feet of brand new quad shield RG-6 running to the entry point for the house cabling. The power for the antenna is inserted there before being connected to the two way splitter and the existing ~50 foot built in house cables. I lease the house and I doubt the HOA would allow a full sized array.

I do receive KOMO-TV 38 (4.1) and the position of the antenna with 100 percent signal strength correlates correctly with the coverage map. I do get occasional "stuttering" though, which is disconcerting and not fun to watch.

I am not picking up any other channels out of Seattle except for 33.1 on one TV which is surprising since the signal is coming in from 18 degrees south of where the antenna is pointed and - I really don't care about ION TV.

I suspect the real issue here is channels 13.1 and 20.1 which are 150 degrees off axis from my antenna, are line of sight, but come in 100 percent anyway. Can my amplified antenna be overloaded by those two?

I would like to pick up the NBC, CBS and PBS affiliates but wonder why I do get ABC (KOMO) and not any of them.

The TV Signal Analysis Results are here.

Monoprice HDA05700 amplified antenna.

Photo of my installation:

GroundUrMast 25-Jun-2014 5:46 PM

Real and virtual channels are confusing to a lot of people. One of the reasons that stations changed was that they wanted to continue their analog operations on their established frequency while building and testing the new and completely separate digital transmitter facility. Once built, shifting the new transmitter to the old channel was cost prohibitive in most cases. There is also the value of 'brand'... a broadcaster has a great deal of investment in their name. (The broadcaster wanted to avoid the confusion to their viewers that would occur if they suddenly changed from “KING 5 News” to “KING 48 News”) Another reason for the change is that the UHF frequencies have less problems with interference than the lower frequency VHF channels. Finally, the concept of virtual channels was made necessary by the desire to multiplex several programs on each real channel.

When choosing an antenna, use the real channel number listed in your TV Fool report to guide the decision regarding the type. Antennas have no awareness of virtual channels. Only when the signal arrives at the tuner does the signal get broken down to a point where virtual channels become relevant.

Because you are in a bit of a hole so to speak, you need an antenna that is directional and has a significant amount of passive gain. I'd suggest a full size solution such as the combination of an Antennas Direct 91XG + Antennacraft Y10713 + RCA TVPRAMP1R. For best results, avoid a mounting location that forces you to aim through trees or buildings if possible.

tomfoolery 25-Jun-2014 7:06 PM


Originally Posted by kenj66 (Post 44607)
I lease the house and I doubt the HOA would allow a full sized array.

I think the FCC may beg to differ. Except under some narrow circumstances, the HOA has no authority to restrict your installation, including on rental properties.

Telecommunications Act Of 1996 Guide in plain english

kenj66 25-Jun-2014 8:49 PM

Wow! So this is nothing that a ten foot Yagi wouldn't solve. Thanks for the education and antenna suggestions. They seem like fine equipment.

I will re-ask what would make reception on one channel "stutter" (periodic dropouts - I don't know what the appropriate terminology is) even though it has 100 percent signal strength on both TVs? Reason for asking is it seems I could spend hundreds of dollars to get the very best equipment and still have stuttering.

Also, I can see dropping out distinctly poor channels from displaying on the TV but if I have a channel with 25 percent signal strength it ought to show on the TV signal strength meter anyway. A marginal channel indication would help determine if spending the time and money to improve the antenna system worthwhile. That's why I asked if inexpensive signal strength tuners are available.

ADTech 25-Jun-2014 10:42 PM


what would make reception on one channel "stutter" (periodic dropouts - I don't know what the appropriate terminology is) even though it has 100 percent signal strength on both TVs?
Amplifier overloading or multi-path. Either will cause it.

Your Monoprice antenna contains a built-in amplifier of unknown performance characteristics. You have two full power stations very close by with unimpeded signal paths that have substantial potential to put most amps into intermodulation distortion or compression. You're on the back side of a 20-50 dB attenuator called a "hill" using an antenna with no ability to focus on receiving signals from one direction.

Okay, now you know the complications of your location. You will need a very directional antenna with strong rejection off the back (or expensive suppression filtering for the two strong stations) along with a properly selected pre-amp. The antenna(s) must be mounted to give the clearest possible line of sight back towards downtown and should likely be tiled up and aimed at your visible horizon.

Reliable meters or analyzers aren't cheap unless you get lucky on eBay. A good one will cost several hundred dollars.

kenj66 26-Jun-2014 12:37 AM

Thank you, ADTech. You have "spelled out" the situation nicely. The truth has finally dawned about the complications of my location.

The Monoprice antenna is quite directional as I found when orienting it and without a giant attenuator in the way it looks to be a good performer. The FOX station nearby is 133 degrees from the "beam" heading but puts out a big signal and is only 9 miles away LOS so the suspicions about overloading are likely.

Dang! Removing the stuttering and getting more stations may cost more than it's worth - or at least more than "momma" thinks it's worth.

:cool: Someone needs to design a spectrum analyzer smartphone app that connects via the USB charging cord to a TV tuner dongle. Hook it up at the base of the antenna mast and "dial in" the antenna direction, favoring the preferred channels. Perhaps someone could make a few bucks on this! You're welcome. :)

ADTech 26-Jun-2014 1:08 AM


Someone needs to design a spectrum analyzer smartphone app that connects via the USB charging cord to a TV tuner dongle.
Well, you can do that in Linux on computer. Skipped my mind earlier. Costs only a few dozen dollars plus time and a computer. It's called an SDR (Software Defined Radio) analyzer. They're not very fast, but they're inexpensive. I don't know off hand if any of the regulars here have talked about it, though.

kenj66 26-Jun-2014 2:11 AM

Interesting! I did a search and found the idea is not new and solutions are getting cheaper all the time. Try this link:

ADTech 26-Jun-2014 11:32 AM

Yep, that's the one.

kenj66 26-Jun-2014 7:16 PM

I just noticed the forum moderator is in Seattle. Hello, from your neighbor Ken!

Looking at the analysis map and the desired stations it looks like I could use just the suggested UHF, Antennas Direct 91XG, and forget the VHF antenna. I plan to replace the fence rail mast with some genuine 18 gauge mast and guy wires - a 93 inch long array will need beefy support. (Why is mast steel so expensive? Does anyone know where to get it local and cheap?)

I plan to try it without a preamp first. I have a PCT MA-B1015-1A-VG pre-amp on hand (long story) and if it appears I need it I will also get a channel 13 inline trap to prevent swamping the TV tuners.

Thanks again for your help. :)


GroundUrMast 27-Jun-2014 4:25 PM

Yes, hi neighbor :)

If you omit the VHF antenna, you will very possibly eliminate the need for the CH-13 filter. The built-in balun of the 91XG will pass some VHF, but at lower levels.

I've used chain-link fence 'top rail' from Home Depot. It's 1 3/8" in diameter, and has a swedged end. I believe the price is about $12 / piece.

kenj66 27-Jun-2014 6:15 PM

(I couldn't get the quote check-mark to work so I did it manually)

If you omit the VHF antenna, you will very possibly eliminate the need for the CH-13 filter. The built-in balun of the 91XG will pass some VHF, but at lower levels.
Thanks! Good to know.


I've used chain-link fence 'top rail' from Home Depot. It's 1 3/8" in diameter, and has a swedged end. I believe the price is about $12 / piece.
The fence rail shown in my photo allows wobbles with a breeze. That doesn't seem good to me. It is 8 feet long and, due to the roof pitch, only about a foot of it is fastened by the mounting clamps. So, the antenna is about 7 feet above the roof. An expensive yagi deserves better so I ordered two 4 1/2 foot masts from Walmart at 8 bucks a piece. I'll get the guy hardware from the local Rad Shack.

GroundUrMast 28-Jun-2014 3:53 PM

Any time I stack mast, I presume that each section will need to be guyed. Here's a somewhat hard to find piece of hardware that is useful in such situations,

kenj66 28-Jun-2014 5:08 PM

Thanks for pointing that out. I just looked on the Rad Shack website and noticed they don't carry that item.

I'm using two 4 1/2 foot sections. Seems a little overkill to have two sets of guy wires for that. The mast will be 9 1/2 feet tall. The first foot will be in the eave mount, leaving 8 1/2 feet. I will put that ring 1 foot below the array at about the 7 1/2 foot mark. Seems adequate, no?

GroundUrMast 30-Jun-2014 10:03 PM

I was thinking of 10' sections in my previous post. I would not expect to guy the lowest section.

kenj66 2-Jul-2014 3:25 AM

I just got the XG91 put together. It is awesome. But who wrote the instructions? There was a lot of trial and error.

Too late to get on the roof tonight.

kenj66 3-Jul-2014 5:54 AM

Since I still don't have my new mast I installed the XG91 on the existing fence rail just above the roof. It has been fun dialing in the new stations. Unamplified I now get 5 additional stations including KZJO, KONG and KING (NBC). Thanks for suggesting such a great antenna!

Plugging in the PCT line amp KIRO (CBS) shows up but unreliably. Perhaps an extra 8 feet elevation and tweaking the azimuth slightly will cure that.

The elevation according to my iPhone compass is 9 degrees, pointed just above some distant trees. I wonder if a slightly higher elevation would collect more signal?

Flint Ridge 3-Jul-2014 11:11 AM

Given the strength of everything else above it, I would work my aim based on the KIRO and yes the elevation may very well help your situation.

Have to say KING KONG - what a marketing plan there.

GroundUrMast 3-Jul-2014 3:41 PM

As long as you have the PCT amp in hand, experiment with it located close to the antenna. Amplifiers are only able to overcome the effects of loss in cable and splitters that are connected to the output of the amplifier. (No amplifier 'pulls' signal from the antenna or air. An amplifier can only 'push' signal down the line.)

kenj66 3-Jul-2014 5:05 PM

KING KONG call letters here have always been amusing.
KIRO (39) is THE final prize in this installation.
I suppose the PCT amp could be hung off the antenna tilt bracket since it is designed for outdoor use although it requires another piece of coax for supplying power - 50 feet in this case. I am hoping with the extra elevation I won't need it at all.

The XG91 is supplied with a dandy elevation-tilt clamp. I have it set now at 9 degrees, pointing just above some trees in the distance. I recall studying RF propagation called "scatter" and I think that is exactly what this antenna is trying to collect. Has anyone experimented with varying amounts of tilt? Would pointing it higher in the sky be better?

My late-model Vizio TV in the living room displays without stuttering video/audio but my 2007 Emerson (Funai Electric) in the bedroom stutters even with strong signals. That leads me to believe the OTA tuner is poor.

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