Splitters, Attenuators, Filters, Diplexers, Other Signal Gear

[robman50]

ok so?
old yagi (uhf/vhf/fm) ->combiner ->preamp?
______________________/\
new cm4228hd (uhf)-----|

[majortom]

robman, replace 'combiner' with 'UVSJ', and u should be OK.
That's basically what I do here except in addition I place my homemade
VHF Hi pass filter between the UVSJ output and the preamp input, to kill
the FM Band entirely. I'm not interested in anything below VHF CH 7.

[robman50]

I just looked at the 7777 and the yagi is on 'VHF seperate input' and the 4228hd is on 'UHF or combined' but the switch is set to Combined.
Could that cause the problem? maybe I just have to change the switch?

[flavoie]

Keep setting as combined input since it looks like you want UHF channels from both antennas. Combine both antennas using a splitter combiner if you wish to retain VHF channels, or uvsj if you wish to filter out VHF entirely like majortom. Then input the combiner output into the UHF(combined) input on the 7777. Leave the 7777 VHF(separates) input unused.
EDIT: you'd actually want a uvsj after the combiner output to kill off all VHF. Or set the cm7777 as Separates...

[majortom]

Yep I didn't notice u have the cm 7777 with the input switch. Ya have to open it up to flop the switch I think. I don't have one myself but the installation notes sheet should let you know which way it is set at the factory by default. Depends on what ur trying to do as to which way to set it.

[robman50]

I would like to use both the VHF and UHF bands just incase after the CRTC deadline of the analog to digital switch that they may put some digital stations on the VHF band.
Also what is a UVSJ? I don't think I've heard that one before.

[rabbit73]

roger1818:

That FMFool report is missing all of the problem stations for Channel 6 here in Ottawa. tvlurker published a list of all FM stations here in Ottawa and summarized the likely problem ones here.

Thanks for the link to the FM station list.

The lowest high power stations are the CBC at 90.7 and 91.5 MHz with 84 kW each.

That's even worse than I thought!

[flavoie]

robman50, then use a normal 2:1 splitter to join the antennas before the cm7777. You will keep all VHF and UHF bands this way. A common splitter is also called a splitter combiner. It can be used one way to split or the reverse way to combine signals like what you'd do here.
EDIT 2: I edited my post #1294 for better clarity

[ProjectSHO89]

If you set the input switch to "Combined" on a 7777, you will get NOTHING from the VHF port since the switch physically disconnects it...

[flavoie]

If you combine both antennas using a 2:1 combiner, and put the output of it on the Combined 7777 input, Of course you're not getting anything from the VHF input of the 7777; you're not using it in this case.

And the combined cm7777 will amplify the VHF band that the antennas pick up.

[ADTech]

..along with all the distorted signals due to typical phase cancellations and other gremlins that often occur in such a "joining" of like-band antennas ...

[roger1818]

The topic of combining antennas has been thoroughly discussed in the thread Stacking, Ganging, Combining TV Antennas. Please read over that thread and move the discussion there.

[majortom]

Motivated by Adtech's comment about a Winegard splitter in this thread.
http://www.digitalhome.ca/forum/show...1&postcount=18

Wanted to see if I could measure the loss of a Radio Shack 2 way splitter I had in the junk bin. I came up with a loss of 4 dB at CH 69 (800 MHz). Not bad considering the bad rep R/S has and all.
The one I tested says
ARCHER
2 Set UHF/VHF/FM
Hybrid Splitter / Combiner

Here's what I did. Mother in law used to have Satellite till they moved to a new place a couple years ago. They had an Echostar DVR-625 rcvr that she gave me when they moved, since they don't have satellite any more. I never played with it until today and it turns out that receiver has 2 RF Modulators in it.

TV1 CH 3 or 4 60 - 72 Mhz
TV2 
-Air   21-69    512 - 806 Mhz
-Cable 73-125

Set the TV2 modulator to CH 69, and plug in to the Comm test set, measures -47 dBm. Insert the two way splitter, with port 1 going to a TV, and port 2 going to the comm test set. Comm test set now measures -51 dBm, for a net insertion loss of 4 dB on CH 69 for the supposedly crappy R/S Splitter.
Same test using an ARCHER 4 Way Splitter and I measure 10 dB insertion loss (-57 dBm on any of the 4 outputs)
Not too useful as a satellite receiver since I don't subscribe to satellite, but makes a great NTSC signal generator
I'll bet Bell sells the same receiver.

[PanaMark]

I purchased one from Save n Replay and was wondering if this model of splitter is DC power passive on all ports.
I think it is, but would like some kind of confirmation.

[hoopitup2000]

The Solid Signal website states "No Power Pass" for the 3214.