An Alternative to Rotators and Antenna Combiners
 

If you like your antenna rotor, I am not going to try to talk you out of it. I've used rotors in the past and find them a source of frustration for a variety of reasons. Until recently I suffered without a few stations, using an antenna system made of a VHF and UHF combined through an Antennas Direct® EU385CF.

I recently came across the SiliconDust HomeRun®. This device is equipped with two independent HDTV tuners that are accessible via Ethernet. This product provides a means to convert the RF signal to a data steam that is easily distributed over CAT5 or better wiring. I have reliable performance over 802.11g wifi also. This eliminates all of the problems with RF distribution (particularly the problem of mixing or combining RF signals from multiple antennae). I am able to use a variety of Home Theater PC software, including WIN-7 Media Center, XP Media Center, and a variety of Linux based options.

I now own three units, fed by signals from five independently aimed antennas. This provides additional channels, and the ability to record in HD to the hard drive.

The total cost is higher than one antenna and rotor, but that investment pays off in 'no fights over which way to aim the antenna' and support for HD recording with no hardware added to any PC.

I like the signal quality metering that is provided with the utility software, it reports relative signal strength, signal quality and symbol quality. Not as good as a pro-grade ATSC signal analyzer but a step or two above any other consumer equipment signal indication. The same utility reports the real time data rate of a given channel and some MPEG details. (See the attached screen shots. Notice that signal strength alone does not determine signal quality. Something to think about before you run out and buy an amplifier hoping it will do the antennas job for you.)


I have noticed that the sensitivity of the Silicondust tuner is not quite as good as the tuners in both of my LCD flat panel receivers. That simply means that I will need to use the right antennas when going after the more distant stations. Also worth mentioning, each tuner is able to stream data to one IP address at a time. That is not a problem unless the tuner in use is the only source for a channel that someone else wants to watch or record. With three HDHR units, I have not had any conflicts.

I think of this configuration as a poor mans CATV head-end.

So far I'm a happy tinkerer.

Block Diagram
 

A simple block diagram...

This is based on the HDHR-US model which as of March 2011 is superseded by the HDHR3-US. A primary difference is that the newer design has only one antenna input, despite having two tuners. I would have preferred that SiliconDust would have retained the separate inputs but they did not ask my opinion. :(

Simple raw MPEG-2 recording and play-back
 

On my XP based computer, I do not have a robust media center software package installed. Still, I am able to capture off-the-air to my hard drive. I did not need to write a scheduling script, just a batch file for each virtual channel.

Here is an example of a batch file that tunes the HD HomeRun tuner and then starts recording the data to a file. The file is MPEG-2 format.

The first line sets the current directory to the folder containing the HD Homerun utilties.
The second line sets the tuner to UHF CH 38 (the real channel KOMO-TV is broadcast on).
Line three sets the MPEG-2 transport stream number associated with virtual channel 4.1 (broadcaster dependent)
The forth line starts the save to file 'recording'.

The result is that I can start watching the recording file immediately, using Video LAN's VLC and if I want, I can pause and rewind. (Even though the file is being written too as VLC is reading from it.)

If I start the batch file manually, recording will continue until I terminate the batch process using CNTL+C.

I can also use the Task Scheduling utility in MS-XP (Start>Programs>Accessories>System Tools>Scheduled Tasks) to run the batch file for unattended recording. Task scheduler has an option that allows you to end a process if it runs for a length of time.

GUM,

I think this is a really great idea. I'm a bit surprised you haven't gotten more feedback on it. Perhaps others are more focused on watching in real-time vs. recording. Rotors work fairly well if you only need access to a single market at a time. Not so well when you're trying to catch an evening's programming on 4 different channels from 3 different markets. :eek:

I've been doing something similar to you, though my 3 Homeruns are each dedicated to one antenna/market a piece, each with a splitter driving the 2 inputs. So I can record 6 channels at once, with 2 from each market.

Depending on how many subchannels your sources are cramming in, the primary HD feeds can potentially be enough that 6 channels would saturate a 100 MBit network link. Besides my host PC has only a single gigabit port. So I use a gigabit router to run the 3 Homeruns into the system.

It took me a while to figure out how to use batch files to do what you've done so elegantly above. I was fighting with the TotalMedia craptastic app that SiliconDust includes with their product, which barely handles 2 channels at a time. That gave me a negative impression of the product for over a year.

I'd also point out that if you've got some enclosed space in proximity to your antenna farm (e.g., a shed or an attic), you can also save the cost of one or more low-noise pre-amps and long runs of quality RG6-coax. Just locate the Homeruns inside, close to the antennas (short coax feeds), patch them into a local router, and run a single Cat5 cable to the PC. (I'm not doing that at the moment, because I happened to already have installed a bundle of coax lines out to my shed when I first set things up out there. But it will come in handy if I ever need to steal some lines back for FTA satellite stuff.)

Anyway, I agree that this is a very nice alternative when it comes to combining a variety of antennas into a merged system. Thanks for sharing.

- Mark

Improved Batch file for recording
 

Here is an 'upgraded' version of the batch file I use to record OTA to hard-disk on my XP machine. It adds the year+month+day+hour+minute+AM/PM date/time stamp to the file name. now I don't have to manually rename the file after recording a show. I create a batch file for each show title which I expect to record more than one time.

Love my HDHR! My brother took the plunge when I showed him the device. Then I bought mine. Now my other brother is ready to get one and ditch his dish.

Are you using Tuner Salad with four of those? I would like another one but I am doing just fine with one dual tuner. If push comes to shove I can at least watch live TV on the SHARP while the HTPC is recording the other 2 shows.

I am surprised that the DTVPal DVR or The Channel Master 7000 is not talked about on these forums.

I actually own the DTVPal and my wife and I loved it, but I am slowly weening her off it and on to the HTPC :D

The wife's laptop runs WIN-7 so that does OK with the native Media Center app. WIN-7 Media center is artificially limited to 4 tuners... MS knows best... at least they think they do.:rolleyes: I've not seen a need to use Tuner salad to bump that up to 8.

I'm still running my DVR function on my XP box. Using the native scheduler utility + my custom batch files and VLC. There is no limit to how many tuners can be managed this way.:)

Presently, I'm working on a HTPC based on Mythbuntu. While I have it working, there are several hardware issues due to a lack of open source support for the video adapter currently installed.

Sorry I am bringing this up, but it got me to thinking about the whole amplifier thing. I have had some suggestions on possibly getting and amplifier in my situation from some people I know around here. I never gave it much thought and was just going to go with the suggestion I received from GroundUrMast. Now that I have a little more insight to what the software is showing, I might be able to understand it a little more. Is there a way to manually add the channel that is not being picked up by the HDHR? I am curious to what it is doing. My TV shows the channel pop to about 30 (out of 100) for second, and I have been able to see something on that channel randomly.

The configuration utility, "C:\Program Files\Silicondust\HDHomeRun\hdhomerun_config_gui.exe" certainly gives you access to manual channel entry.

Each media app is different. Which media app are you trying to manually add a channel in?

Media Center Edition (built in Win 7) I know how to add the channel. I was just wanting to see what the HDHR was showing. I didnt know you could just punch in the channel I was just using the seek and I guess it would just skip over it. Thanks for the help.

I have been an OTA person for the last 7 years but during the analog era I lived close to the towers. When I moved I put my antenna up and still had no problem. This is the first time I have had to actually research out stuff because it doesn't "just work" I am learning a lot :D

My 2 problem channels

Channel 15 shows
Signal strength shows %50
Signal Quality shows %0

Channel 51 shows
Signal strength shows %30
Signal quality shows %0

I guess this was the question I was refering to on your post about the amplifier. Will it help? Can you explain the difference between strength and quality?

@ sdubb

My experience with the HDHR has been that any signal strength or quality below 50% is an indication of imminent errors which will be visible as pixelation or signal loss.

Signal strength is an issue for you in the case of both channels. An amplifier might help... if the signal at the input of the amplifier is not already 'buried' in noise, distorted by multipath or other impairments which amplifiers are incapable of fixing. In other words, the antenna must be receiving a usable signal with enough quality to tolerate the damage that the amplifier will cause. http://forum.tvfool.com/showthread.php?t=1514

The HDHR documentation does not provide an in-depth explanation of how they determine the numbers displayed. I presume the indicated signal strength is derived from the automatic gain circuit in the tuner. The reported signal quality is an inverse indication of data errors ahead of error correction. The symbol quality is also inversely related to error rate, but after error correction has been attempted. (The ATSC standards for OTA DTV provides substantial forward error correction.)

More Generally, Signal Strength is simply a measure of the power of a signal. If the measurement is expressed in watts or some variant thereof, the measurement implies the the amount of heat that would be dissipated if all of the energy was terminated in a purely resistive load. Signal Strength does not measure the integrity of information that may or may not have been encoded or modulated into a radio wave. In the case of OTA DTV, power in units of dBm is common. Not as common, but still used are units of milli-volts and dBmV, and because the system impedance is nearly universally 75 ohms, a direct conversion to units of power can be made using Ohm's and Watt's laws. http://en.wikipedia.org/wiki/Decibel

Signal Quality generally refers to some sort of measurement that describes how well the measured signal resembles the original signal transmitted, or, how likely the original information may be decoded or demodulated without error. A signal can be altered, distorted or interfered with in many ways, therefor, the quality of a signal can be measured in many ways. Signal to noise ratio is a measure of how much noise and/or interfering signal has been added to the desired signal. In the case of digital signals, error rate is often used as a measure of quality.

An analogy exists in the audio world. As you are sitting at a stop light, listening to the stereo system in the car behind you, you are likely quite aware of how loud the sound is. Just because it's loud enough for you to hear, does not mean you can understand lyrics or even identify the song being played (perhaps the rattling fender sound is a source of interference). You could measure the power of the audio signal with a sound level meter, which may be helpful to understand whether you are at risk of damage to your hearing, but that simple 'sound strength' measurement will not quantify the quality of the audio. Measuring the ratio of desired signal verses noise plus interfering signals is a more complex measurement that would be an example of how to quantify quality.

This link http://www.guitarkitbuilder.com/cont...d-oscilloscope offers a visual of audio distortion. In the case of the guitar, distortion is desirable at times, if it can be controlled and used artistically. When trying to send information error free, distortion would not be desired or helpful.

Wow, this is great stuff! So you have a tuner that hooks up to your computer via ethernet? Where does one buy the unit that the antenna cable goes into, and the ethernet hooks up to?

You can purchase direct from Silicondust.com. I purchased through Amazon. A Google, Yahoo or Bing etc. search will show other retailers.

As I mentioned earlier, I own the older HDHR-US Dual. Silicondust has replaced this with the HDHR3-US which is generally reviewed well. I don't own one yet so I can only offer the one complaint that I do not prefer the internal splitter, I would have preferred the inputs to each tuner had remained independent.

UPDATE: see post #17 this thread

I went and looked at that, I am going to get that for sure. Thanks for posting the info about it.

HDHR3-US vs. HDHR-US
 

As of December 2011 I own an HDHR3-US. The unit is about half the size of the preceding model (HDHR-US). The GUI utility used to manage the older hardware recognizes the new model and gives the impression that there is no difference in between the functionality of the old vs. new models. When driving an older HDHR-US and the new HDHR3_US from the same 8-port DA, signal strength and quality reported by both the new and old design tracks in real time to within one or two percentage points. Thus far, I see no evidence that the new tuner design is any better or worse than the previous. I presume that the core tuner chip(s) are the same. Again, I wish SiliconDust had retained separate RF inputs to the individual tuners.

Your using XP?
 

Groundmast, thanks for this post. I've been posting in Reception sub-f and your replies have been helpful.
While I am awaiting better weather to install my new antenna and rotor that I received last night, I'm killing some time and reading this thread.
You mentioned that you are running an XP machine with the HDHR3-US and you have piqued my interest since I run a XP media center.

The Silicondust site mentions Windows 7/Vista but not XP.
I
must confess that I have never used Media Center for anything other than listening to my audio library. I've always been curious about the coax jack on the back of the computer.
Placing the HDHR3-US aside for the moment, am I correct when I assume that I could run my OTA antenna cable into that and, using my Media Center software, go ahead and run a channel scan and use my computer for watching OTA TV? ....perhaps even record a OTA broadcast, providing I have hardware space?

This may be a rambling post... but there are a bunch issues involved when picking a tuner, related hardware and Media Center software package. Here goes...

Yes, for PVR/DVR functions, XP is what I currently use. My wife's laptop has Win-7 Home Premium and can also provide PVR/DVR functionality. The recordings produced by Win-7 are in a proprietary format and may fail due to MS security features.

Without knowing the make and model of F-connector equipped card in your computer, I don't know what functionality it has. Many older tuner cards supported NTSC analog only. If your card has ATSC (US OTA DTV signal format) support, you may have all the hardware you need to record to disk. On the other hand, an analog only tuner card is of little use to most US viewers.

As I recall, XP included many audio codecs but did not ship with an MPEG2 video codec. This is needed if you are going to use the XP Media Player as your video player for OTA DTV. I have installed a third party codec. I'm sorry, I don't remember were I found it, just that I did a few Google searches and read through several on-line forums...

After installing a compatible codec and tweaking registry entries, I have been able to run the XP Media Center successfully but found nothing special about it and have since switched to VLC as my preferred video player.

I have not found any PVR/DVR functionality in the XP Media Center software which is why I wrote batch files and learned to use the MS Scheduler Utility to automate recording. The recording is in the native MPEG2 format and is not playable using XP or Win-7 Media Center Software. This is probably the single biggest reason I have for using VLC... I find the proprietary MS software to be a pain, Yeah Open-Source!

As I mentioned earlier in this thread, my ultimate goal is to build a Linux based system running MythTV, mythbuntu being the easy prepackaged distribution of choice. For now, I have reliable PVR functionality using the old XP box.

On another tangent, Silicondust is one of the few open source vendors offering tuners. This has been critical in my use of their products. I am able to obtain the needed documentation of their software commands which made it possible for me to write usable batch commands. I have no idea if you could accomplish a similar goal using a tuner card from another manufacturer.

Thanks for the info. I won't bother to investigate any more.

Is it bad to light up an old thread?! Hope not, as I think this one that GUM has started is pretty darn good. I thought that maybe I could add a little to it, sharing my experiences in getting my OTA setup tweaked, as I've done similar, going in a slightly different direction.

Those HDHR's are sweet and really made my setup fly. I got a refurb direct from SD for half price and scored another deal on a new one some time soon after. Both are dual tuners, so I have 4 signals coming in, one HDHR connected to a single antenna. They are in my office closet, jacked into my 8-port router. Wife and I both have laptops, so now we can have TV anywhere we take the laptops, thanks to wi-fi. We get all the big networks; ABC, CBS, NBC, FOX & PBS. Mix in all the subchannels and a couple of other networks and it's a pretty decent selection.

Ok, so the next best thing to the microwave is the DVR, right? I think so! That was the next step. Being that I already had a Home Theater PC previously....or at least a sad attempt at one, it was time to revisit. This time I build a shoebox version; it's dead quiet and can playback 1080p BluRay. Scoring deals, I had about $300 in it. It's running Windows 7. Windows Media Center is included and that's what handles the the DVR management duties. Once I loaded the HDHR drivers, WMC found the tuners and scanned for the stations. Then it downloaded the necessary TV guide. WMC records locally and has a function to archive to a server. (Yes, I have a Windows Home Server in a closet with plenty of disk space.) There, the recorded content can be shared with other WMC PC's, if you want to watch elsewhere. The DVR functionality is the best I've seen compared to the dish companies.

Outside of that, I have an app called Media Browser that is customized to present our movie collection. I've diced that up into kids movies and uhm, PG+ for the adults...not to be confused with adult movies! For a year or so, we also used the Netflix app for some streaming movies, but have since unsubscribed from that. But my point is that everything runs under a seamless interface that is pretty wife and kid friendly. My 6 yr old can take our Harmony One remote and dial up about anything, from PBS to a Disney flick.

Yes, I spent a little money on some hardware, but I haven't spent any for a while now. Not paying $75/mth for sat service makes that pretty easy though. I did build my own PC's, but for not much more, a person could buy comparable plug-n-play devices to do the same. If you're reading GUM's post and considering cutting the cable for OTA, you're probably a little smarter than the rest anyway! :D

I'm thinking through the cable cutting process. At this point the leading contenders are a Myth HTPC and HDHomeRun. I ran across a new-in-the-box HDHR - it's white and has 2 plugs in the back. Is this like the 1st one(s) you have? Any reason to go for new new? Or is the dual input preferable in your mind?

Do you have your Myth box up and running? My Linux experience is limited although I have poked around the Mythbuntu site a bit.

My setup is relatively simple. We currently have DirecTV (two HR24 receivers) and 98% of everything on both DVRs is watched on a Samsung LN-T4053H. (I also have a Panasonic DMR-EZ27 DVD recorder there.) Am I correct in assuming that a Myth setup can play our 2% on the other TV with a low-end computer attached to it?

I have an uninstalled DB4 antenna as well. I have some questions about that for a later date/another thread.

Thanks for any pointers or clarifications.

That is a very cool way to set up antennas for the teckie!

I have been looking at similar equipment for my display. There is nothing I would rather eliminate than that evil rotor, however in my business location I receive from five markets. I just booked nine demo/installations this weekend at a show. Five of them dont even have a computer and the other 4 think cat 5 is one less than six. Realy! So unfortunatly I will be purchasing ten rotors on my next supply run. Nine to install and one to cover the DOA.

Thanks for sharing your ideas. They are very inovative.

As I mentioned previously, I own three of the white HDHR-Dual units and one HDHR3-US (black). I have seen no difference in tuner sensitivity. In my multi-antenna system, the white dual input unit offers the flexibility to connect different antenna sources to each tuner... so my nod goes to the older model.

I have a MythTV system running on a Zotac box... with some proprietary video/audio driver support issues remaining. I'm still in the learning curve. My XP box is still my reliable PVR/DVR. My best advise is to depend on the MythTV and Ubuntu forums for guidance on minimum hardware recommendations.

As much as I am biased toward open-source solutions, the industry is inclined toward proprietary systems. Netflix has implemented digital rights management security that is closed/proprietary and therefor has no support in Linux or any other open-source OS. Therefor, I am still using the WIN-7 or XP machines to access Netflix. EDIT: Many disk player include Internet media access functionality. Our new Sony BlueRay player has Netflix functionality included, so one more 'weak string' that held me captive to MS has been cut.

@signals unlimited, You're absolutely correct, there is a limited group that would find this solution easy to understand and implement.

GroundUrMast gives a really good explanation of the benefits of the HDHomeRun box with and without a separate antenna on each box. I have two of the new HDHR3 units -- one Dual and one Tech -- fed from one attic antenna thru a splitter. I bought the Tech model at reduced price from Adorama.

He also mentions "I like the signal quality metering that is provided with the utility software, it reports relative signal strength, signal quality and symbol quality. Not as good as a pro-grade ATSC signal analyzer but a step or two above any other consumer equipment signal indication."

I thought I'd point out that the Tech model has some really nice engineering-ish features. For example, even the simple display in the Config program shows more than just the "percentage" data. The Dual version is on the left, and the Tech version is on the right (Win7 version):

Attachment 443

Note the signal strength is shown in dBmV -- for this station it's 23 dBmV, or more than 14000 microvolts. The Signal Quality of 31.1 dB is, I assume, a Signal-to-Noise Ratio (SNR). Note, too, the "Plot" button at the right in the Tech version. It plots what they call a "constellation" although I think it's more a histogram than a classic ATSC constellation. On a cable signal the Tech version does plot a true QAM constellation.

The Tech Config User Manual shows many other screens with a wealth of info. It's a very useful unit especially if you like to get at many details of the signal. I run both of my HDHR boxes with eyeTV on a Mac, although I often use a Win7 laptop.

Linux Script
 

Here is a script that works well on a basic Linux box. The function is similar to the Windows batch file in post #5, giving you the function of a PVR/DVR. Edit variable values as needed.

Note that this script also adds tuner locking. This prevents another user, script or application from interrupting the tuner while it's recording. The lock key is the recording time stamp variable, so it's not impossible to override the lock if the need arises.

Use "cron" or "at" to launch the script at the correct time.

Several new products are now being offered by Silicon Dust. The HDHR Plus appears intriguing. http://www.silicondust.com/products/...run/hdhomerun/

The ability to trans-code MPEG-2 to H.264 makes streaming to WiFi connected phones, tablets and pads easy and practical. Even remote site antenna & tuner situations become more practical, given the reduction in bandwidth required.