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post #151 of 180 Old 07-21-2017, 05:20 PM
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Originally Posted by esdwa View Post
Anyone know best way to setup the 2-CH Micromod to be used along with OTA antenna?

I have tried to lower output level signal to -30 but it still masks some of my OTA channels.
Result is both my LCD TVs (with built in ATSC tuner) are catching the modulator channels but not all OTA ones (less than half which is really bad).

I looked at local channel list on FCC website
https://www.fcc.gov/media/engineering/dtvmaps
to set modulator frequencies away from occupied by OTA but this webstite do not show ch.frequencies.

I guess I am missing something here and I appreciate suggestions.
You could try using the old higher channel numbers in the 60's no longer assigned to TV broadcasting - there is a smaller chance of spurious signals being generated below a selected channel, and the wider spacing from the OTA channels may reduce interaction with them.

Here is a web page with the frequencies:

http://www.csgnetwork.com/tvfreqtable.html

PVI setup seems to go by the frequency at the center of the channel - 473 MHz for ch 14, etc.

Last edited by Channel99; 07-21-2017 at 05:28 PM.
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post #152 of 180 Old 07-21-2017, 05:32 PM
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Anyone know best way to setup the 2-CH Micromod to be used along with OTA antenna?
First off, you will need an amplifier on your antenna..not for gain, but for reverse isolation. Otherwise you'll risk backfeeding the modulator to the antenna and radiating to your neighbors. Not good if you have prurient Tv interests.

Second, you should have a lowpass channel filter to prevent incoming rf interference from affecting the desired modulated channels.
Just because there is no Tv channel listed for your area, it doesn't mean something else may be using the frequency, such as wireless mics or cellular. See: https://www.parts-express.com/channe...ilter--180-780

You also need to make sure you're not sending too much RF power into your Tv..doing so can and will eventually fry the front end of the tuner.

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post #153 of 180 Old 07-21-2017, 05:37 PM
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Are you combining the output of the MicroMod 2 with your OTA signals via a splitter, or are you using the "pass through" Coax input on the MicroMod to add the OTA stations?
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post #154 of 180 Old 07-21-2017, 05:57 PM
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Originally Posted by esdwa View Post
Thanks Ron,
I see 3, 6 and 12dB models. Should I stick to 3dB or get 6 or 12dB one and then have some leverage on boosting modulator output if signal is too weak?

Sent from my SM-N910T3 using Tapatalk
On my SDR modulator, I have it set to output -25 dBm average power and then I use a 40 dB attenuator. So three 12 dB attenuators stacked assuming the Micromod is really at -30 dBm.

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post #155 of 180 Old 07-21-2017, 06:16 PM
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Good point. I actually thought not use the mix input on modulator but run OTA and modulator output into 2-1 splitter (reversed) and then feed the TV.
I was told by PVI tech that this is common practice use by installers instead of using Mix In for the same reason I report.

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post #156 of 180 Old 07-21-2017, 06:20 PM
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Quote:
Originally Posted by bdfox18doe View Post
First off, you will need an amplifier on your antenna..not for gain, but for reverse isolation. Otherwise you'll risk backfeeding the modulator to the antenna and radiating to your neighbors. Not good if you have prurient Tv interests.

Second, you should have a lowpass channel filter to prevent incoming rf interference from affecting the desired modulated channels.
Just because there is no Tv channel listed for your area, it doesn't mean something else may be using the frequency, such as wireless mics or cellular. See: https://www.parts-express.com/channe...ilter--180-780

You also need to make sure you're not sending too much RF power into your Tv..doing so can and will eventually fry the front end of the tuner.
...but after this post, I seriously reconsider following the author suggestions.
The last thing I would want to do is to cause interference and/or risk damaging my gear.

Thank you!

Sent from my SM-N910T3 using Tapatalk
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post #157 of 180 Old 07-22-2017, 03:27 AM
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this is what I use to combine OTA antenna and PVI modulators: it has a separate input for antenna and 2 modulators: output is unity gain

https://www.amazon.com/550BID-Channe.../dp/B00006JPEH

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post #158 of 180 Old 07-22-2017, 10:55 AM
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Quote:
Originally Posted by bdfox18doe View Post
First off, you will need an amplifier on your antenna..not for gain, but for reverse isolation. Otherwise you'll risk backfeeding the modulator to the antenna and radiating to your neighbors. Not good if you have prurient Tv interests.

Second, you should have a lowpass channel filter to prevent incoming rf interference from affecting the desired modulated channels.
Just because there is no Tv channel listed for your area, it doesn't mean something else may be using the frequency, such as wireless mics or cellular. See: https://www.parts-express.com/channe...ilter--180-780

You also need to make sure you're not sending too much RF power into your Tv..doing so can and will eventually fry the front end of the tuner.
My planned eventual setup will be similar with OTA antenna channels and MicroMod channels merged (either using the MicroMod Mix In, or a reversed 2-way splitter) > Tivo Bolt > TV.

I'm also planning to use the OTA antenna coax to create a MoCA network for Tivo, and will therefore need to use a point of entry filter at the antenna ( https://www.wiredathome.com/holland-...al-networking/ ) to prevent backfeeding my network traffic out of the antenna. Will this also prevent backfeeding the modulator, or is it blocking the wrong frequencies?

Where does the low pass filter go exactly? Is it going to block my MoCA network traffic?

If I need to use an amplifier to prevent backfeeding the modulator, would this also prevent backfeeding my internet traffic, making the use of the MoCA filter unnecessary?
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post #159 of 180 Old 07-22-2017, 09:09 PM
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Quote:
Originally Posted by esdwa View Post
...but after this post, I seriously reconsider following the author suggestions.
The last thing I would want to do is to cause interference and/or risk damaging my gear.

Thank you!

Sent from my SM-N910T3 using Tapatalk
Sorry to post this in the open thread, but I wanted to let you know I did reply to the Private Messages you sent me about the D-VHS thing we were discussing. The replies must not be showing in your Tapatalk for some reason. I haven't been getting proper PM notifications on here in awhile. I sent you a reply to the e-mail address you had given me previously too just now. Let me know if you don't receive that!
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post #160 of 180 Old 07-23-2017, 09:22 AM
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dB Questions

Apologies for what are, I'm sure, very elementary questions. I'm something of an AV novice and find dB pretty confusing. The MicroMod manual says that the -10 dBm setting is equivalent to 45 dBmV. Does this make sense? It seems like you'd need an impedance over 300 ohms for this to be true. Or am I totally missing something?

I read a post on here that said the "ideal" for analog TV is 0 dBmv at the tuner, but in practice around 6dB is preferred to allow for signal variation. Are these numbers still valid for digital (QAM and ATSC)? Does the TV itself cause any attenuation before the tuner?

So, assuming the 45 dBmv is an accurate conversion of -10 dBm, if I set the MicroMod to -30 dBm, that should result in 25 dBmv, and than if I use 20 dB attenuation, that should be 5dBmv at the TV tuner. Does that sound good?
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post #161 of 180 Old 07-23-2017, 04:56 PM
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I was lucky enough to get my hands on a Silicon Labs evaluation board for the Si2183 which is their latest chip that decodes all the digital televisions standards (except for ATSC). Here's a set of measurements for 256QAM (which requires the most signal) from -75 dBm to -35 dBm. -75 dBm was the lowest signal level without errors. -45 dBm seems to be the point of diminishing returns. -45 dBm is equal to 3.75 dBmv.











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post #162 of 180 Old 07-24-2017, 06:54 AM
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Originally Posted by dr1394 View Post
I was lucky enough to get my hands on a Silicon Labs evaluation board for the Si2183 which is their latest chip that decodes all the digital televisions standards (except for ATSC). Here's a set of measurements for 256QAM (which requires the most signal) from -75 dBm to -35 dBm. -75 dBm was the lowest signal level without errors. -45 dBm seems to be the point of diminishing returns..
Wow!! Thanks. Great info. I'm very jealous of your measurement capabilities.

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-45 dBm is equal to 3.75 dBmv
Now that's a conversion I can understand. I still don't see how PVI are getting 45 dBmv from a setting of -10 dBm. I guess 6.25 dBmv isn't worth worrying too much about though.
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post #163 of 180 Old 07-24-2017, 12:19 PM
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I would try more attenuation. If that doesn't work, then the output of the Micromod may be too "dirty". That is, it's signal is not entirely confined to one channel.

http://www.markertek.com/product/ppf...nuator-pad-3db

Ron
Is there any advantage using the PPFAM rather than just FAM attenuators for this application (I already have some FAM attenuators I could use)?
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post #164 of 180 Old 07-24-2017, 01:28 PM
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Is there any advantage using the PPFAM rather than just FAM attenuators for this application (I already have some FAM attenuators I could use)?
The difference between PPFAM and FAM is just rated operating frequency. PPFAM goes up to 2150 MHz while FAM only goes to 1000 MHz. So FAM attenuators are entirely appropriate for this application.

http://www.picodigital.com/product-details.php?ID=FAM

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post #165 of 180 Old 07-29-2017, 12:58 PM
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Question ATSC Modulator plus OTA

Ok, going through these threads on Modulators has given me a headache, but I have a vague idea of what I need now. To preface here's what I'm trying to do.

I have a house with crummy Internet, and we've sworn off Cable TV for various reasons. So our current setup involves local OTA and a Roku piped into a cheap RF Modulator so that all the TVs in the house can see the one video stream our Internet can handle. However recently we've begun upgrading our TVs from old CRTs to modern LCD flat pannels, and I've realized that the old Analog RF modulation looks like crap on these new TVs. So I naively thought that it'd just be a simple matter of just getting whatever cheap HDTV RF Modulator to replace the Analog RF Modulator, but as I've quickly learned things are far more complicated and expensive.

I have a shallow budget so I can't afford dropping $1000+ on AV equipment, preferably I'd like to spend $500 or less. So I'm looking for advice on what Modulator to get and any other steps I should take to make sure I'm not washing out my OTA channels and broadcasting Netflix to my neighbors. It'd also help if you can tell me if I need to worry about getting an HDCP stripper.

I'm currently looking at these two Modulators:
$299 Stellar Labs HD ATSC RF Modulator (I've heard this one has a lot of compatibility issues due to audio codecs and sync issues)
$495 PVI VeCOAX MINIMOD-2 (Only other ATSC Modulator I could find remotely in my price range)

PS: Is ProVideoInstruments a good seller?
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post #166 of 180 Old 07-29-2017, 05:48 PM
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Originally Posted by japzone View Post
Ok, going through these threads on Modulators has given me a headache, but I have a vague idea of what I need now. To preface here's what I'm trying to do.

I have a house with crummy Internet, and we've sworn off Cable TV for various reasons. So our current setup involves local OTA and a Roku piped into a cheap RF Modulator so that all the TVs in the house can see the one video stream our Internet can handle. However recently we've begun upgrading our TVs from old CRTs to modern LCD flat pannels, and I've realized that the old Analog RF modulation looks like crap on these new TVs. So I naively thought that it'd just be a simple matter of just getting whatever cheap HDTV RF Modulator to replace the Analog RF Modulator, but as I've quickly learned things are far more complicated and expensive.

I have a shallow budget so I can't afford dropping $1000+ on AV equipment, preferably I'd like to spend $500 or less. So I'm looking for advice on what Modulator to get and any other steps I should take to make sure I'm not washing out my OTA channels and broadcasting Netflix to my neighbors. It'd also help if you can tell me if I need to worry about getting an HDCP stripper.

I'm currently looking at these two Modulators:
$299 Stellar Labs HD ATSC RF Modulator (I've heard this one has a lot of compatibility issues due to audio codecs and sync issues)
$495 PVI VeCOAX MINIMOD-2 (Only other ATSC Modulator I could find remotely in my price range)

PS: Is ProVideoInstruments a good seller?
You need to search for the "MicroMod 2" used models we've all been buying off eBay recently. You might not need two channels right now, but you could always hook up a DVD or Blu-Ray player to the second input to give you another option. It might have a little bit of a learning curve vs the other units, but you will be well within your budget.
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post #167 of 180 Old 07-29-2017, 05:59 PM
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You need to search for the "MicroMod 2" used models we've all been buying off eBay recently. You might not need two channels right now, but you could always hook up a DVD or Blu-Ray player to the second input to give you another option. It might have a little bit of a learning curve vs the other units, but you will be well within your budget.
Indeed tempting, though since it is used I can't expect a warranty or return right? Also do these properly remove DHCP? Couldn't find a definitive answer to that beyond vague 'it works for me' comments. Finally, should I do anything special to make sure I don't accidentally backfeed into my antenna and overpower low power stations?
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post #168 of 180 Old 07-31-2017, 03:21 AM
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Quote:
Originally Posted by japzone View Post
I have a house with crummy Internet, and we've sworn off Cable TV for various reasons. So our current setup involves local OTA and a Roku piped into a cheap RF Modulator so that all the TVs in the house can see the one video stream our Internet can handle. However recently we've begun upgrading our TVs from old CRTs to modern LCD flat pannels, and I've realized that the old Analog RF modulation looks like crap on these new TVs. So I naively thought that it'd just be a simple matter of just getting whatever cheap HDTV RF Modulator to replace the Analog RF Modulator, but as I've quickly learned things are far more complicated and expensive.
Wouldn't it be more cost effective to put a Roku in each room? (And easier to implement remote control of the replay controls?)

Or do you need to strictly enforce 'one player' so that multiple users don't try (and fail) to stream simultaneously?
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post #169 of 180 Old 07-31-2017, 06:19 AM
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Wouldn't it be more cost effective to put a Roku in each room? (And easier to implement remote control of the replay controls?)

Or do you need to strictly enforce 'one player' so that multiple users don't try (and fail) to stream simultaneously?
Pretty much the latter since the internet connection sucks. Plus the benefit would be that every screen could see that one stream if they wanted. Already been doing it for years now using an Analog RF Modulator and it's worked pretty well. Family members actually enjoy the fact that they can go into a different room like the kitchen and still watch the show/movie while they do other things.
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post #170 of 180 Old 07-31-2017, 07:00 AM
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Originally Posted by japzone View Post
Pretty much the latter since the internet connection sucks. Plus the benefit would be that every screen could see that one stream if they wanted. Already been doing it for years now using an Analog RF Modulator and it's worked pretty well. Family members actually enjoy the fact that they can go into a different room like the kitchen and still watch the show/movie while they do other things.
Both entirely sane and sensible reasons

Good luck with your modulation quest!
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post #171 of 180 Old 10-03-2017, 06:46 PM
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I managed to snag a MicroMod 2 off ebay last week for $500. It was said to have come from a store (hh greg?) but I am not sure because it was set to DVB-T when I first powered it on. At first I thought I had to move to Europe to use it, but thankfully the option to switch it to ATSC was available in the front panel menus (apparently cannot be done from the web interface). I was able to get it mostly configured from all the pointers in this thread. I have RF1 set to 797mhz (ch 68) and RF2 set to 803mhz (ch 69). After tweaking the bit rate and audio settings I am able to connect it to my whole house coax splitter-amp and re-scanning all the TVs in the house finds my two ATSC modulated channels. The only problem I have i that is does not seem to be sending the settings on the Input->Encoder Out Param page. The TVs see the channel as 68-253 and none of the Service Provider, Program Name, Short Name, etc. options seem to be sent down the wire. Can someone share their settings on how to get these populated properly?

Two caveats on the modulator now that I have it working:

1. Be very careful when hooking this up to a TV or your antenna distribution system. As mentioned somewhere in this thread, too much signal can cause damage to a TV. I managed to fry the front end of the tuner in my beloved Panny plasma when I first hooked the modulator up to my antenna system. Once it was cooked, the TV would not receive any UHF high channels. Luckily I had a spare tuner module for this TV so I was able to rip the old one out and solder the new one in, fixing the problem. I have set the power output of the modulator to -30 and added 40db of inline attenuators between the output of the modulator and the modulator in port of my whole house antenna system.

2. There is roughly a 1 second delay added to the stream as it gets encoded, send down the wire and decoded by the TV. This was never an issue with older analog NTSC modulators so be aware if you are coming over from that world. If you are using this to send out your DVR to the whole house and sending remote control signals back to your head-end, be prepared to wait 1 second to see the result of key presses on the remote.

Last edited by AlienWarlock; 07-29-2018 at 07:34 AM.
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post #172 of 180 Old 10-19-2017, 11:45 AM
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[...] At first I thought I had to move to Europe to use it,
That's a good one

Quote:
but thankfully the option to switch it to ATSC was available in the front panel menus (apparently cannot be done from the web interface).
That is correct. Standard selection only from front panel within given firmware capability. However, web interface has to be used ot flash alternate firmware to cover other modulation standards. Refer to manuf. instruction.

Quote:
I was able to get it mostly configured from all the pointers in this thread. I have it RF1 set to 797mhz (ch 68) and RF2 set to 803mhz (ch 69). After tweaking the bit rate and audio settings I am able to connect it to my whole house coax splitter-amp and re-scanning all the TVs in the house finds my two ATSC modulated channels. The only problem I have i that is does not seem to be sending the settings on the Input->Encoder Out Param page. The TVs see the channel as 68-253 and none of the Service Provider, Program Name, Short Name, etc. options seem to be sent down the wire. Can someone share their settings on how to get these populated properly?
Well, that's just the way it works. Some program information are not being transmitted.

Quote:
Two caveats on the modulator now that I have it working:

1. Be very careful when hooking this up to a TV or your antenna distribution system. As mentioned somewhere in this thread, too much signal can cause damage to a TV. I managed to fry the front end of the tuner in my beloved Panny plasma when I first hooked the modulator up to my antenna system. Once it was cooked, the TV would not receive any UHF high channels. Luckily I had a spare tuner module for this TV so I was able to rip the old one out and solder the new one in, fixing the problem. I have set the power output of the modulator to -30 and added 40db of inline attenuators between the output of the modulator and the modulator in port of my whole house antenna system.

2. There is roughly a 1 second delay added to the stream as it gets encoded, send down the wire and decoded by the TV. This was never an issue with older analog NTSC modulators so be aware if you are coming over from that world. If you are using this to send out your DVR to the whole house and sending remote control signals back to your head-end, be prepared to wait 1 second to see the result of key presses on the remote.
The delay is caused mostly by modulator MPEG-2 encoder electronic circuits. The nature of MPEG-2 and higher encoding schemes requires collection of several consecutive picture frames , queuing it into encoder pipeline from which a encoded compressed frames are created on the output. Depending on the encoder pipeline buffer size, it may result in delay from fraction to multiple of the second. Generally the higher encoder compression ratio available+larger frame buffer the longer encoding process is taking. An the contrary the decoding compressed MPEG stream takes much less time vs. encoding process.

Until we have "quantum" computers serving as encoders at our disposal, the delay will be there whether we like it or not.

Last edited by esdwa; 10-19-2017 at 11:53 AM.
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post #173 of 180 Old 10-25-2017, 04:12 PM
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I have a question for one of our resident technical experts. Do these HHGreg units have the capability to set the TSID of the streams they are sending out? In my case I'm trying to combine a couple of local channels off satellite that I can't pick up OTA into my existing antenna setup with my unit. I just picked up an HDHomeRun device and I've been told that they detect channels and assign guide data based on the TSID. (This might be accurate or not, I haven't tested it yet). My thinking was if I was able to make the modulator send out the stream with the correct TSID for the station I'm modulating (the TSID info came from rabbitears.info) that it would correctly recognize my modulated local channel and let me have correct guide data for it? Am I way off base, or could this possibly work (if these modulators can do that)?
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post #174 of 180 Old 12-06-2017, 05:33 AM
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post deleted: I believe the issue will be resolved

thanks

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post #175 of 180 Old 01-09-2018, 10:57 AM
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Hi, I tried to read through the whole thread, but my experience with modulators dates back to the analog days. Could I just check that my understanding is correct? Sorry if some of these are basic questions.

I’m looking to distribute the HDMI output of a Fios STB to all the TVs in the house, which have QAM tuners. It sounds like the VeCOAX product will do this, correct? Even for content protect flagged / HDCP channels like HBO?

For this application, where I’m using the HDMI input, is there any difference in output quality between the PVI MiniMod 2 and the more expensive MicroMod 3?

Do people find that attenuators are needed, or is starting with the lowest output level via the menus typically okay (with 6-8 outlets)?

Is it feasible to insert the modulated output right on to the same cable carrying the Fios signal? Or is there insufficient free room for something like that? Back in the analog days, I remember needing a notch filter to clear a place on the spectrum for the modulated channels. Is anything similar needed for QAM? Or will that disrupt the Fios signal so much that modulating onto a different cable is much preferable?

I’m assuming for my application I should modulate to QAM, but should I be modulating to ATSC instead? Would modulating to ATSC help avoid a conflict with the Fios signal, or do they occupy the same frequency space?

Thank you very much.
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post #176 of 180 Old 01-15-2018, 05:56 PM
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I’m looking to distribute the HDMI output of a Fios STB to all the TVs in the house, which have QAM tuners. It sounds like the VeCOAX product will do this, correct? Even for content protect flagged / HDCP channels like HBO?
VeCOAX will handle HDCP. I was able to test it with the the HDMI output of my old Oppo 981hd playing a DVD of a major motion picture without issue. I also had it hooked to the HDMI output of my Tivo premiere. I don't think the content protection flag would matter.

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Do people find that attenuators are needed, or is starting with the lowest output level via the menus typically okay (with 6-8 outlets)?
I would start with attenuators and see what the signal meter shows at each tv and remove them later if necessary. I had problems with damaging a TV tuner with the VeCOAX signal as described above.

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Is it feasible to insert the modulated output right on to the same cable carrying the Fios signal? Or is there insufficient free room for something like that? Back in the analog days, I remember needing a notch filter to clear a place on the spectrum for the modulated channels. Is anything similar needed for QAM? Or will that disrupt the Fios signal so much that modulating onto a different cable is much preferable?

I’m assuming for my application I should modulate to QAM, but should I be modulating to ATSC instead? Would modulating to ATSC help avoid a conflict with the Fios signal, or do they occupy the same frequency space?
I am not familiar with Fios but if you are able to connect it directly to your TV and view clear QAM channels then you may be able to combine the VeCOAX QAM modulated signal onto the same coax as Fios. But if I were going to try that I would set the VeCOAX modulation to the highest frequency available in the menu and then hope that Fios is using frequencies below that. A notch filter would work to clear some spectrum on your coax but would likely kill reception of some Fios channels. I would get a notch filter that closely matches the frequency of the modulated channel that you are trying to use.

The better option would be to send your in-house modulated signal on a separate coax from Fios and then possibly combine that signal with an OTA antenna and notch filter. In that case you would use ATSC modulation on the VeCOAX since most TVs can't do both ATSC and QAM at the same time.
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post #177 of 180 Old 06-12-2019, 08:31 PM
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I have RF1 set to 797mhz (ch 68) and RF2 set to 803mhz (ch 69). After tweaking the bit rate and audio settings I am able to connect it to my whole house coax splitter-amp and re-scanning all the TVs in the house finds my two ATSC modulated channels. The only problem I have i that is does not seem to be sending the settings on the Input->Encoder Out Param page. The TVs see the channel as 68-253 and none of the Service Provider, Program Name, Short Name, etc. options seem to be sent down the wire. Can someone share their settings on how to get these populated properly?

Well I am back to sort-of answer my own question. I figured out how to get the channels to show the right virtual channel and program name entered through the config page. You have to turn on VCT Insert on the TS Config page.





So it was all working great but, I guess I forgot to save the configuration because it all got reverted after a power outage. I set VCT Type to TVCT and checked the box. The VCT is displaying but it is wrong... My physical channels are 68 and 69 and I wanted the VCT to be 68-1 and 69-1, but now they are showing as 104-1 and 105-1. I tried messing with the Modulation mode and carrier frequency but that didn't seem to have any effect. I can't find any official documentation that says what Modulation modes 1 thru 3 represent (4 is CABLE MODE as seen in the one manual that I found). Does anyone know or have a better manual for this beast?
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post #178 of 180 Old 06-15-2019, 07:05 PM
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It's almost as if it's encoding the virtual channel numbers in octal (base 8): 68 decimal is 104 octal, and 69 decimal is 105 octal....

I realize that doesn't help; just an interesting observation. I wonder if RF 63 would come out as VC 77....
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post #179 of 180 Old 06-16-2019, 08:13 PM
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I guess you were on to something with the octal, but it still does not make sense. I got the VCT to display 68-1 and 69-1 again for my channels by entering in 0x44 and 0x45 as the major channel numbers. So for some reason you need to subtract 24 from the desired VCT number that you want displayed on the TV. Here is my Channel 2 encoder out page:





Here is my modulator page: (I'm using physical channels 68 & 69 so 797MHz and 803MHz are at the center of those two channels)



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post #180 of 180 Old 06-17-2019, 05:31 PM
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I guess that makes sense, sort of; 0x44 is 68 decimal, 0x45 is 69 decimal, and now that I think about it 0x68 is 104 decimal and 0x69 is 105 decimal. It's weird that you have to enter the channel numbers in hex instead of decimal (since decimal is what you're going to see on the TV) to get it to work, but at least it does work.
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