OTAfool not sure if you got answered as this thread has branched off
That's true...probably a contributor to that...:rolleyes:
Anyway. Back to the drawing. Why do you have the DC injector where it is?
Can you place that closer to the antenna as the downlead comes in to the house? Then connect the "TV" side of the injector to the 4 way Splitter input. That would eliminate the need for them three DC Blocks.
One more note, if your truly only using 2 of the 4 outputs from a 4-Way Splitter, you should be terminating
the two unused ports with 75 Ohm terminations. Finally, I'd make sure to tie the ground of the DC Injector to the Gnd of the 4 way splitter (assuming they are right next to each other), and ultimately to a decent Gnd point (short a Gnd length as possible).

nice going MT;)

My current set-up is RG6 40ft from antenna into basement and another 20ft to HTPC. Antenna is a DB8 mounted on a 10ft eaves mount.

I tried to set-up with no preamp and then with a 7778 before going to the 7777. I simply couldn't pull in CityTV without it. I'm located at 10th line and Britannia in Mississauga.

My HTPC is WMC but I believe that WinTV has a signal strength indicator plus I can use my 26" Sony as a guide. Tomorrow I am going to rerun a single line to the htpc and try updating the drivers on the 2250 Hauppauge.

Will keep everyone posted.

G20, I use 3 2250s in my TV server. They are a sensitive card, and I have had times when my TV received channels fine, but the tuners didn't. Adding an attenuator in line, brought the missing channels in. I'm also using a 7777, but with a 4221 not 4228 (DB8).

Do you have your 7777 set for separate or unified mode?

Make sure it's set for separate, and terminate the VHF input. This will "eliminate" (9 will still come in probably) the chance of a booming 5 or 9 analog coming down the line to your tuner. That may get you some channels back on the tuners. If that doesn't solve your problem, try an attenuator on the line going to the PC, or add an extra splitter on the PC line before the tuner card (terminate the unused port).

G20 there are 2 components to the CM 7777 preamp and power supply/amp. You cannot have anything between them.

No, this is not correct. You can have components between the power inserter and the amplifier module provided they are properly selected.

A splitter (or diplexer) that passes power on at least one port may be used to provide the requisite power to the amplifier module. In the diagram posted above, G20 uses an all-port DC PASS splitter with DC BLOCKs on the other ports to serve this purpose. The other alternative would have been to select a splitter with a single DC PASS port.

No, this is not correct. You can have components between the power inserter and the amplifier module provided they are properly selected.

A splitter (or diplexer) that passes power on at least one port may be used to provide the requisite power to the amplifier module. In the diagram posted above, G20 uses an all-port DC PASS splitter with DC BLOCKs on the other ports to serve this purpose. The other alternative would have been to select a splitter with a single DC PASS port.
That is encouraging. Will keep everyone updated on my results.

Attached is a photo of the OTA set-up:

http://i51.tinypic.com/34xm7o1.jpg

I want to run 2 X CM4221HD antennas (one for TO and one facing towards Buffalo). Does the CM7777 pre-amp have 2 inputs for both UHF antennas or will I have to combine both first?

I want to run 2 X CM4221HD antennas (one for TO and one facing towards Buffalo). Does the CM7777 pre-amp have 2 inputs for both UHF antennas or will I have to combine both first?
I believe you will need to combine first

http://pimages.solidsignal.com/CM-7777_5_zoom.jpg

Below is my proposed layout. Will keep everyone posted on the result be end of week. Anyone see any potential issues?

Should I place the UVSJ before the DC passthrough?

http://i56.tinypic.com/30mvfw0.jpg

That looks fine, and be sure to cap any unused RF ports. :)

That looks fine, and be sure to cap any unused RF ports. :)

But if something doesn't go right, don't forget about terminated vs unterminated (http://www.digitalhome.ca/forum/showpost.php?p=1201834&postcount=1180) options... :o

And depending on levels, he may want the VHF/UHF splitter ahead of both receivers?

If the purpose of the UVSJ is to attenuate unwanted VHF, it should be installed between the amplifier and the antenna for most effective results. Cap the VHF port with a 75 ohm terminator.

Guys I beg to differ on CM 7777 install methods, please read;
http://www.solidsignal.com/pview.asp?mc=03&p=CM-7777&d=Channel-Master-CM7777-Titan2-VHFUHF-TV-Antenna-Preamplifier-with-Power-Supply-(CM7777)&c=Pre-Amplifiers&sku=02057207774

Install instructions;
http://www.solidsignal.com/p/?p=2710&d=channel-master-pre-amp-installation-instructions-cm-7777-cm-7778&mc=03

Particularly the part that says; Be sure not to place any devices in-line between the pre-amp and power supply, says nothing about properly selected.

Even with using power pass thru splitters, where does the manufacturer say you can do this? Or is this a 'hack'? My opinion; The final boosted signal product is on the 'to TV' on power supply not in the middle of the 'preamp loop'. loop should always be closed, splitters at the end only.

hi all;
I think i have come to the resolution that i need a preamp. I jsut don't know which one. I have a 4221hd (newer) aimed at buffalo properly grounded. I have a 50ft run of RG6 to 25+25 of RG59. Basically 100ft of cable. I tested the TV after the RG6 run and i get everything digital except NBC and ION. I am pretty happy with those results. So...which pre-amplifier should I install at the end of the 100ft run?

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d3cf4a04f40f1da

Rats. I've been trying to disengage from this, but I can't help myself...


Particularly the part that says; Be sure not to place any devices in-line between the pre-amp and power supply, says nothing about properly selected.


It is absolutely possible. The most common requirements of the intermediate devices are that [1] that they provide DC continuity (are "power passing"), [2] they do not load the power supply, and [3] obviously they should have minimum loss across the frequency band of interest.

Properly chosen, however, you can even violate [2]. If you have a single power supply capable of supplying sufficient current and with compatible voltage, you can safely and reliably power more than one amplifier from a single supply.

It is something akin to a "simplex" powering arrangement. The concept leverages the facts that the intrinsic RF impedance of the transmission line is very low (75 Ohms), that RF is AC (Alternating Current), and that we can carry that AC on a steady state DC offset or bias, mainly the power supply voltage.

Circuit design concepts go something like this. At the power supply end, the RF Transmission path passes in and out, with as little RF loss as possible. Connected to the center conductor, through a nominaly higher than 75 ohms resistance, is a voltage source (a device that optimally puts out a constant voltage independent of load, up to its current limit). At the amplifier end, through similarly higher resitance, the DC Voltage is filtered and becomes the +V (internal power) connection for the internal gain stage. The RF output (AC) from that gain stage is coupled to the center conductor at the low 75 ohm impedance. The shield, or ground, is common to both the AC and the DC current paths.


Even with using power pass thru splitters, where does the manufacturer say you can do this? Or is this a 'hack'? My opinion; The final boosted signal product is on the 'to TV' on power supply not in the middle of the 'preamp loop'. loop should always be closed, splitters at the end only.

If we understand and accept the above, then it becomes clear that the highest amplitude RF is available immediately at the amplifier output. Its amplitude will be reduced by any intermediate coax (down lead) connecting to the power supply, and by whatever RF loss there is through the power supply (or "power injector") component. Hopefully, though, the designer has kept this loss to less than .5 dB.

If we have a splitter that is power passing on one port, we can connect its common port to the amplifier output, the "power passing" downstream port to the powered downlead (the coax to the power supply), and the other downstream port to some other downlead or interconnecting coax. To the extent the splitter has identical AC response on both (downstream) ports, then exactly the same RF is presented on the two downstream ports.

It is not a hack, it is basic electrical engineering.

I hope this helps the understanding of why it is possible...

paperthin,

Before ya did anything else, I would scrap the two 25 ft runs of RG-59. Actually, cut the connectors off and throw 'em away so noone else can use it either;) Replace them both with new RG-6 runs and new connectors. Since ur almost happy with what ya got now, let us know what happens after replacing them two runs.

tballister,
for what it's worth, agree it's feasible. I only shy away from the concept because...
a.) it's not necessary.
b.) adds needless complexity.

Should always keep things as simple as possible to avoid chasing down issues later...
Keeping in mind ultimately they have to support an end user, of course they are going to
recommend the simplest configuration (KISS). That's my take on what the author of the mfr's
instruction sheet is getting at, when they say not to put other components in the DC Path.

MajorTom;
I would if it wouldn't be such a huge hassle. Eventually I want a second TV so i can use the existing network of cable that exists (even though it is inferior). My plan is at the 75ft mark use a splitter (tBD later) when I do purchase a second TV. Would a Preamp not help my solution? If so which one? I know your answer is the most correct and I made the attempt to get that wire through the walls, but failed. With the current 100ft run I get 60% of what i should get.

Right Major T wise words, when someone says ‘ I am having trouble’ we default to vendor config first , get is solved then move forward. Possible or not, when the vendor does not support it, it's a hack.

paperthin,
is the existing 25 ft RG-59 in ur walls now? IS that the issue, pulling the cable thru walls (Drywall??). Should be able to get it from point a-point b...

In any event, if ya really wanna try a pre-amp, from ur tvfool, local signals are pretty strong in ur area, so I'd go with the bare minimum gain, and good performance with strong signals present...Think the general consensus around here would be like the HDP269 in the pre-amp chart of post #1.:).
Ultimately, ya need to read them first couple posts, analyze the pre-amp chart, compare that to what ur up against, and make a decision...