Future... If you ever decide to add a TV and it's 7.5db gain on each output.

Actually, it's ~15 dB gain with ~7-8 dB insertion loss per port. The net gain is around 7.5 dB for a typical four-port distribution amp with a 15-16 dB amp at its input.

All consumer distribution amps with multiple outputs follow the same scheme. One amp, followed by no splitter, a two-port, a four-port, eight-port, etc. Each time the signal is split in half, an insertion loss of 3.5-4 dB is incurred.

Your site specifically states 7.5db gain per port. I guess I was misinformed.

Not misinformed, just under-informed. ;)

Things on the website are often greatly simplified....

"7.5 dB Gain per port"

So when I read this it doesn't mean what it says?:confused::confused::confused:

It means what it says, but it is a simplification.

Using the Channel Master series as another example for comparison of specs:

3410
A one port distribution amp does not contain a splitter, so its gain is 15 dB.
http://www.channelmaster.com/Antenna..._p/cm-3410.htm

3412
A 2-port distribution amp contains an amp with a gain of 15 dB and a 2-way splitter with a loss of 3.5 dB per port, for a NET gain of 11.5 dB per port.
http://www.channelmaster.com/Antenna..._p/cm-3412.htm

3414
A 4-port distribution amp contains an amp with a gain of 15 dB and a 4-way splitter with a loss of 7 dB per port, for a NET gain of 8 dB per port.
http://www.channelmaster.com/Antenna..._p/cm-3414.htm

Just to male it even more confusing, PCT International not only makes the CM distribution amps with the stupid hard-to-read black labels, they also make the mini drop passive return CATV amps with white labels that are equivalent.
http://www.pctstore.com/RF_Amplifier...fiers_s/58.htm

OK, bought the CM3412 and hooked up one of the outputs to the TV upstairs and then switched it to the TV downstairs. It added a few more channels (33 total, up from 21 or so) to the upstairs TV. It also added a few more to the TV downstairs (18 total up from 8 or so). I'm wondering why there could still be such a discrepancy. Is it possible that some of the cabling being used on the downstairs route is not up to snuff? Any ideas?

Which direction did you pick for the 4221, 260 or 115?

Where is the 3412 located, near the antenna or further downstream?

Tell us how long the cable runs are starting at the antenna, then down to the splitter or 3412, then to each TV. Is it like this?

Give us a list of channels at each TV; it does sound like the 3412 made an improvement.

Yes. It is also possible that there is a hidden splitter or defect on that run. You can check that by running a temporary length of known good coax downstairs.

Do you have any way to measure the signal strength with one of your TVs?

I tried 260 first, then 115 (current direction and the setup used to pickup # of channels listed in my previous post).

3412 is right off of the antenna (maybe 6 feet of cable away at most).

Very similar, I'd say it's closer to this:

Note: Up to this point, I have not had both 3412 outputs hooked up to both paths. I have been switching between paths where the coax 50 ft enters the junction box. After I verify that I can get all the channels I want on the downstairs TV, I plan to run the extra 50 ft coax and truly split the signal to both paths.

Also, is it possible that the 25 feet of coax cable that I run through the wall on the 1st floor to the TV would degrade the signal if it weren't 75 ohm quad shielded? I read somewhere that this was important. I bought this years ago, and I'm not sure if it is 75 ohm quad shielded or not.

I will pull the list when I get home for both TVs.

I tried looking for this option on my 1st floor TV, but couldn't find anything after experimenting or googling the TV. My TVs are listed below. Maybe someone can help me locate a way to check it.

• Vizio M552I-B2 (1st floor TV)
• LG 42LD550 (2nd floor TV)

Here's the channels I get on each of the TVs. Each TV has it's own tab. On the 2nd floor TV, the channels highlighted in green are ones that the 1st floor TV doesn't pick up.

50 + 20 + 6 = 76 ft
50 + 60 + 25 = 135 ft
difference of 59 ft; about 3 dB for UHF,
approx. the same as a 2-way splitter loss

So if you inserted a 2-way splitter in the 2nd floor line after the 3412, the 2 TVs should be getting about the same signal strength. If not, there is another loss that exists in the 1st Floor line.
The attenuation loss is about the same for regular coax as it is for quad. The quad has an extra layer of shield to reduce pickup of interference; you don't need it for most applications.

Do you have AC power for the 3412 in the attic?

LG 42LD550
http://www.lg.com/us/support-product/lg-42LD550
When selecting DTV or Cable DTV input signal in Manual Tuning, you can view the on-screen signal strength monitor to see the quality of the signal being received.

http://forum.tvfool.com/attachment.p...4&d=1453348228

I'm having trouble downloading your Google doc of channels. I think I would need to log on before it would allow my me to download it; I have had this trouble before.

OK, got your 1st Floor list using View Only at Google Docs. A lot of signals coming in the back of the antenna.

http://forum.tvfool.com/attachment.p...5&d=1453422015

And the 2nd Floor
http://www.rabbitears.info/search.ph...pe=dBm&height=
click on callsign to see networks

http://forum.tvfool.com/attachment.p...6&d=1453426856

Sorry, it's taken me so long to respond.

Yes, I have the 3412 plugged into an outlet in the attic using the AC adapter that came with the 3412. The AC adapter is connected to the unit via a coax cable.

I went ahead and used the instructions you posted to get the signal strength/signal quality readings for each channel on the LG 42LD550 (2nd Story TV). Here they are:

http://forum.tvfool.com/attachment.p...3&d=1453771288

Reminder: Green is channels I get on the 2nd Floor TV but not on the 1st Floor TV. Bolded Channels are the ones that I actually WANT to get on both TVs.

I am not sure what the difference is between "Signal Strength" and "Signal Qualtiy" as called out on my LG 42LD550 TV.

Also, the weird thing to me is that is that the main channels that I want to get on the 1st Floor TV, but only get on the 2nd Floor TV (WSOC-TV, WTVI-HD, WTVI-MV, WTVI-Ct) all have "Signal Strengths" on the 2nd Floor TV of 89% or higher. In fact, there are stations that I got on both TVs, for which the signal strength on the 2nd Floor TV is lower than 89%. Doesn't really make any sense to me.

Also, can you confirm that "front" and "back" of antenna is as I think in the picture below?

http://forum.tvfool.com/attachment.p...1&d=1453771974

No problem; it takes time to do it right. And it's going to take time for us to digest your results and think of an intelligent helpful comment.:)
Every manufacturer does it a little differently. The percent scale is only relative, not absolute, but it is very useful for comparisons. The signal strength is similar to the NM dB or Signal pwr dBm scales on your tvfool report. The Signal Quality is probably SNR (Signal to Noise Ratio).
Your labels are correct.
It doesn't make sense yet to me either.

There are three possibilities. The loss in the coax line to the first floor is more than estimated. As a test, run a temporary coax line to the 1st floor to bypass the in-wall coax run.

The 1st floor tuner is more sensitive to overload than the tuner in the 2nd floor TV. Try inserting various values of attenuation between the antenna and the input of the 3412. A 2-way splitter has a loss of 3.5 dB, a 4-way 7 dB.
https://www.antennasdirect.com/store...ttenuator.html
http://www.3starinc.com/drop_in-line_attenuator.html
http://mjsales.net/collections/atten...ant=1083705673
•Attenuation values 1, 3, 6, 8, 10, 12, 16, 20dB (FAM)
click on 1 dB for other values; the up and down arrows are faint

The tuner in the 1st floor TV is less sensitive than the tuner in the 2nd floor TV. To test this theory you would need to move the 2nd floor TV down to the 1st floor.

Is it safe for me to assume that you do a tuner rescan of the 1st floor TV after a change?

For "Signal Quality", I assume 100% is the ideal? Almost every station was at that value, so it looks like I don't have any signal quality issues.

My observation below would seem to cast some doubt on the first possibility, wouldn't it?


I will have to look into the other 2 possibilities. Finding a cable long enough, or a short enough path for my existing coax could be an issue. I could possibly run from the antenna straight to the wall the 1st Floor TV is mounted to, but I'm guessing I'd run into some 2X4s going down 2 stories. If only I could get signal strength readings from the 1st Floor TV.

Yes.