to diplex or not to diplex OTA

[ciurca]

Has anyone done good signal level testing before and after diplexing their OTA with SAT signal? I've read conflicting results. Some say no problem, some say you lose some OTA signal.

[dettxw]

Works great for me, I've done it with the Zinwell 6x8 and the SWM8 using discrete diplexers. Tried using the OTA inputs on the SWM8 but it attenuated the signals too much so went back to the discrete diplexers. Have since upgraded my OTA antenna so really should try it again. I'm close to the transmitters so was using just a set-top antenna in the attic, but installed a regular UHF/high VHF HD antenna just to see if it made any difference.
(Have an Air Fioce Base between me and the transmitters, sometimes get dropouts and not sure if the air traffic has any possible affect)

What kind of signal strength are you getting now and what is your distance from your transmitters?

[carl6]

You have an HR23, which has broad band internal tuners and does not use an external B-Band Converter (BBC). If you are using SWM, you can diplex. If you are not using SWM, then you will not be able to diplex OTA without loss of both OTA and some satellite signals. They use the same frequencies and will conflict head-on with each other.

If you had an older model DVR (HR20, HR21, HR22) that used the BBCs, then you could try a work around that moves the BBC to the far side of the diplexing. That would normally work, but the HR23 doesn't use the BBC so you can't use this workaround.

[Grentz]

Using a SWM I have not had too much trouble at all. No real change in signal strengths.

[ciurca]

Yes, brand new installation with swm. Can I diplex the OTA and SAT right after the dish, before the SWM power inserter?

Here's my setup now....... House built with 1 rg6 run to attic which splits to 5 rooms, 1 rg6 run to bonus room over garage. Those two runs go to outside box.
(A third run is into my garage for cable modem only, but that's beside the point)

Installers split the signal from dish to Bonus room and to attic (which is then split to all other rooms but bonus room). Power inserter is in bonus room.

Right now my OTA antenna is in attic, with power preamp, ran through eaves, hid inside of corner edging of siding, back into crawlspace, and up to family room AM-21. This works great, but I need to get the OTA to the bonus room now, for my wife's shows to DVR for her treadmill sessions)

What I would like to do is pull the OTA signal back outside, and then diplexed right after the dish. I just don't know what this does to the SWM.

[ciurca]

Okay, here's what's now in my mind.

Dish -> Power inserter -> then OTA and dish signal diplexed to 2 way splitter -> to bonus room and to attic splitter -> then every TV un diplexed to receivers.

[carl6]

Okay, here's what's now in my mind.

Dish -> Power inserter -> then OTA and dish signal diplexed to 2 way splitter -> to bonus room and to attic splitter -> then every TV un diplexed to receivers.

That should work. I have no experience trying to diplex before the PI, but your suggestion here, to do it right after the PI, should be no problem.

[dettxw]

Just for you I went into the attic and switched an antenna output back to the SWM internal diplexer so I could compare signal strengths vs. an external diplexer. I hadn't tried this since I got a bigger antenna - the little one was OK with external diplexers but through the SWM I lost some channels entirely.

For me, 13-15 miles from the transmitters using a Channel Master CM2016 HDTV VHF High Band and UHF Antenna all the UHF-based stations come through at 100% according to the HR20-700 OTA signal meters. This is using either an external diplexer or the internal one in the SWM.

However, my VHF signals get attenuated from 100% using the external diplexer to lower values using the SWM:

KOCO ABC virtual 5 real 7 - 80-85%
KWTV CBS virtual 9 real 9 - 90-95%
OETA PBS virtual 13 real? - 70-75%
(still UHF 32 according to Wikipedia but not sure that is correct)


So the moral of the story is that the SWM may attenuate you OTA signal strengths.
If yours are low to begin with then you may need a bigger antenna or maybe an amp to make up for the loss.

[ciurca]

Carl, thanks for the input. Now do you recommend any specific branded diplexers? Also, should I preamp the OTA, or would the PI on the circuit help with that frequency?

Thanks in advance.

[David MacLeod]

I lost 10% across the board when I tried using the swm8 ota in.
used diplexer between pi and sws-4 splitter.

[dettxw]

My names not carl, but FWIW a Perfect Vision PVDP3 (http://www.solidsignal.com/prod_display.asp?prod=PVDP3) and Radio Shack unit (no part number available, bought when they sold DirecTV gear in '98) work equally well for me.

Lots of other choices at Solid Signal, or, you can even pick something up quickly at your local Lowe's.

[BattleZone]

My names not carl, but FWIW a Perfect Vision PVDP3 (http://www.solidsignal.com/prod_display.asp?prod=PVDP3) and Radio Shack unit (no part number available, bought when they sold DirecTV gear in '98) work equally well for me.

I would NOT recommend either of these between the power inserter and the dish. The PVDP3 is only rated for 750 mA of power at 12V, and the crappy Radio Shack ones aren't even rated (and have proven to be lousy in the field).

I recommend the Holland DPD2, which is rated to handle 2 full amps. We use these with DishProPlus Dish Network receivers, which also pump out a lot of power, because the cheaper 750 mA models burn out quickly.

[carl6]

I agree with not putting anything between the antenna and the diplex, at least not for starters. Put a diplexer AFTER the PI and insert your ota signal. Put diplexers at your receivers and split it back out. See what you've got. If it's good, stop there (if it ain't broke, don't fix it).

Most amplifiers require power which is sent over the coax. If it essential to amplify the ota signal, use the amplified output of the amplifier as your input to the diplexer.

[texasbrit]

I use the SWM8 internal diplexer with no signal problems. But what people forget is that the SWM splits the signal between the two SWM outputs, so if all your DVRs/receivers with OTA tuners are off just one of the SWM outputs you are throwing away 50% of the signal. If you use both SWM outputs like I do, you don't have this wasted signal.

[Grentz]

I would NOT recommend either of these between the power inserter and the dish. The PVDP3 is only rated for 750 mA of power at 12V, and the crappy Radio Shack ones aren't even rated (and have proven to be lousy in the field).

I recommend the Holland DPD2, which is rated to handle 2 full amps. We use these with DishProPlus Dish Network receivers, which also pump out a lot of power, because the cheaper 750 mA models burn out quickly.

To back these up, I use the Holland DPD2 diplexers on my SWM setup and they are working great. I use them all after the PI though.

[David MacLeod]

this may not be an issue for you but I had 1 HR2x unit that acted flaky with diplexing. I used channel master combiner ( http://www.solidsignal.com/prod_display.asp?prod=CM4002IFD ) for the initial diplex in and all issues were solved.

[ciurca]

Guys, thanks for everyone's input. I am definately putting the diplexer after the the PI.

I'm thinking......channel master for the combining, and the perfect vision for the 4 tv's on the split out.

[harsh]

So the moral of the story is that the SWM may attenuate you OTA signal strengths.It would appear that the OP has an SWM LNB as opposed to an external SWM. Are you working with an external SWM.

[RobertE]

Personally, I'd avoid diplexing anything if at all possible.

[harsh]

Personally, I'd avoid diplexing anything if at all possible.It will be interesting to see if diplexing interferes with MoCA.

[ciurca]

I have a SWM LNB......what kind of monkey wrench does that throw into the mix?

[bobnielsen]

I have a SWM LNB......what kind of monkey wrench does that throw into the mix?

None that I can see, other than possible future issues depending on how Directv implements MoCA for networking via coax.

[David MacLeod]

just remember it is not, in any way, a supported configuration and any trouble calls may cost you due to it.

[ciurca]

just remember it is not, in any way, a supported configuration and any trouble calls may cost you due to it.

I understand, and am prepared to undo any reconfiguration if needed.

Great, now I need to learn everything about MoCa......

[Grentz]

It will be interesting to see if diplexing interferes with MoCA.

You shouldnt even need to diplex OTA with it, just put the two on the same line with a combiner and you would be good. MoCA is around 1ghz which is higher than OTA channels.

[harsh]

MoCA is around 1ghz which is higher than OTA channels.This may be on the crossover slope depending on the diplexer.

[ciurca]

FWIW, I just got around to moving the coax and diplexing my OTA.

All worked fine, just lost some signal strength. What was around 90% is now around 83%, and one dropped to around 75%. I shouldn't have problems though, it seems the signal increases at night, which is when shows are dvr'd.

[ShrikeT]

Not for OTA, but I've diplexing in cable internet using a pair of these guys,

http://www.techtoolsupply.com/index.asp?PageAction=VIEWPROD&ProdID=786

I placed it after my 2-way SWM splitter, and it's only sending the internet up to one room, where I have my cable modem and an HR22. It's been working fine for nearly 7 months now, no signal drop on my DTV or internet. It was pretty funny when the DTV technician came out today to fix an alignment issue and was shocked that it actually worked:D

[Grentz]

From what I have heard, the DPD2 can just handle a bit more voltage and is a tiny bit better on the high freq. signals.

[BattleZone]

Most diplexers are rated for a max of 750mA of power (and some are entirely unrated). The DPD2 is rated for 2 full amps.

[ShrikeT]

Yeah, I went with the STVC because I needed to make sure it passed 33Mhz on the CATV side for my cable modem's upload channel. The DPD2 says it only passes down to 40Mhz on the CATV side. I didn't even consider that it would need to handle that much current on the Sat side lol. Ah well, it's been working for a while now without melting, so I think it's fine.