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rabbit73 7-May-2017 2:22 PM

2 Attachment(s)
Quote:

Originally Posted by Bigbear (Post 57916)

Yes. The last time I measured one, it performed well.
Quote:

Thanks rabbit for the diagram. Now the only problem is finding a UVSJ. All the links I find lead to discontinued products.
They are getting hard to find. Solid Signal is out and mjsales.net is out. There are some on Amazon and ebay. Antennas Direct still has them:
https://www.antennasdirect.com/store...Combiners.html

Inside the Antennas Direct UVSJ housing:

http://forum.tvfool.com/attachment.p...1&d=1494170120

MCM also has one, but I have received mixed reports about its reliability. Maybe I'll have to order one and test it.
http://www.mcmelectronics.com/product/33-2230

http://forum.tvfool.com/attachment.p...1&d=1494251768

If it gets any worse, we will have to make one like in the GE 34792 Attic Antenna:

http://forum.tvfool.com/attachment.p...9&d=1494003888

http://forum.tvfool.com/attachment.p...0&d=1494003908

I have used the conventional terms for top and bottom of the board. The top is where the components are mounted and the bottom is where the ground plane is located. In actual use, the coax connector faces down.

The GE 34792 Attic Antenna includes a REAL UVSJ, not shorting stubs, to keep the UHF and VHF signals separated before combining. Each section of the antenna has its own balun. The UVSJ and the well designed reflector are responsible for the good performance of this antenna.

Here is a circuit of a UVSJ by SM0HX (amateur radio callsign for a ham in Sweden). The UVSJ UHF/VHF Separator-Joiner belongs to the filter family of Diplexers. All UVSJs are Diplexers, but not all Diplexers are UVSJs; Diplexer is the more general term. A HLSJ is also a Diplexer, but for VHF-Low and VHF-High.

http://forum.tvfool.com/attachment.p...1&d=1494003982

The UHF highpass filter section has 3 series capacitors and 2 shunt inductors. The VHF lowpass filter section has 3 series inductors and 2 shunt capacitors.

Here are the curves for the Radio Shack UVSJ:

http://forum.tvfool.com/attachment.p...2&d=1494007033

Original post in RCA ANT751 thread:
http://forum.tvfool.com/showpost.php...1&postcount=40

ADTech 7-May-2017 4:34 PM

Quote:

Originally Posted by Bigbear (Post 57916)

Yes, it is. It passes power on the UHF port.

If you happen to have a RS store still open in your 'hood, you might be able to score one locally. Do call ahead, though, inventory is pretty spotty in the remaining retail stores.

Our UVSJ is still in production and is available. ;)

rabbit73 7-May-2017 7:25 PM

1 Attachment(s)
Here are the curves for the Antennas Direct UVSJ:

http://forum.tvfool.com/attachment.p...1&d=1494193827

Bigbear 8-May-2017 6:27 PM

thanks AD tech. but any idea where I can score one of your UVSJ's in NW Vermont?
Will the UVSJ allow me to install it at the pole ,connecting my existing antenna to the VHF side, and the new antenna to the UHF port, and run one cable into the house.

Very important question. Will sending a signal boosted by 30Db do physical harm to my Roamio?

ADTech 8-May-2017 8:11 PM

Quote:

thanks AD tech. but any idea where I can score one of your UVSJ's in NW Vermont?
You would have to order it, it is not stocked in any stores. Amazon, Solid Signal, our website, etc.

Quote:

Will the UVSJ allow me to install it at the pole ,connecting my existing antenna to the VHF side, and the new antenna to the UHF port, and run one cable into the house.
Yes, BUT you will only be able to amplify either the UHF-only signals from the UHF-only antenna or amplify everything. This is an important constraint and will not allow you to amplify ONLY the VHF as recommended.
Quote:

Very important question. Will sending a signal boosted by 30Db do physical harm to my Roamio?
No, it will not cause any harm to the tuner. Worst case, it will simply not work very well, if at all, as long as the overload condition persists.

Bigbear 9-May-2017 10:46 AM

Thanks
How do I order from your website? It's not obvious as to how.

Update: After removing the Roamio from the distribution amp, the issue with WCAX is lots better so I am thinking of leaving things as they are. If the over load were harming my DVR, then.....


Thanks for everything all

ADTech 9-May-2017 10:51 AM

Quote:

How do I order from your website? It's not obvious as to how.
Well, one would click on the button that says "Add to Cart", then "Checkout" on the next page that loads. ;)

Bigbear 9-May-2017 10:58 AM

Thanks I see that, but can't find a UVSJ, or where it may be located. The only combiner I can find is this https://www.antennasdirect.com/store...Combiners.html

I think I need the UVSJ to combine the signals in my basement after the power injector for the antenna pre amp.

ADTech 9-May-2017 11:19 AM

UVSJ stands for "UHF/VHF Signal Joiner" Same device, you have found the correct item. Marketing decided to call it what they did, we've been using the common acronym for it. Sorry for any ambiguity. ;)

Bigbear 9-May-2017 12:44 PM

Thanks
I was looking for a smaller one to mount in the basement. I was lead to believe that the Antenna Direct would not pass power to my antenna pre amp.
I think I was told to mount the UHF antenna pointer to my local channels and run a separate cable into the house and combine the cables "down stream" of the amps power tap. Is this not correct?

Thanks
Bear

ADTech 9-May-2017 1:18 PM

Quote:

was lead to believe that the Antenna Direct would not pass power to my antenna pre amp.
Please re-read my previous statements, they address this question.

Quote:

I think I was told to mount the UHF antenna pointer to my local channels and run a separate cable into the house and combine the cables "down stream" of the amps power tap. Is this not correct
That will work PROVIDED your existing VHF antenna also picks up the local VHF channel, even when aimed at Montreal. If it does not, then that station will be lost unless extraordinary measures are taken (custom components).

Bigbear 9-May-2017 5:45 PM

Thanks, I'm getting a little lost in the technology. I understand analytical chemistry instruments, but your world is foreign to me.
I have one local VHF channel that I currently can get ( quite well via the back side of my antenna). In looking at my signal analysis chart I notice that CTV channel 6 from Montreal is not shown. It comes in quite well with my current set up.
So this proposed setup using an un powered UHF antenna pointed at 111 degrees true azimuth will work.
The remaining confusion is regarding the power pass diagram for the signal combiner. It indicates the power will not be shunted to my existing antenna, correct? My assumption is that my existing antenna will be connected to the VHF input of the combiner. Am I way off base?

Thanks for your patience.

Bear

rabbit73 9-May-2017 7:11 PM

4 Attachment(s)
Many years ago TV sets had separate inputs for VHF and UHF. The UHF/VHF Separator Joiner was developed to separate the UHF and VHF signals coming from the antenna to feed the separate inputs for two tuners. There were also UVSJs that would combine two 300 ohm antennas for a 75 ohm input TV. Some TVs had two 2-screw 300 ohm inputs, and some had a 75 ohm coax input for VHF and a 2-screw input for UHF where you could mount a UHF loop.

Separate tuners for UHF and VHF. To tune to a UHF channel, you would set the VHF channel selector to U, and then rotate the UHF dial. The output of the UHF tuner was sent to the input of the VHF tuner:

http://forum.tvfool.com/attachment.p...1&d=1494355873

The 2 screws in the center are for VHF and have the internal antenna connected. The 2 screws on the right are for a UHF antenna:

http://forum.tvfool.com/attachment.p...1&d=1494356524

This UVSJ combines a UHF and a VHF antenna for a 75 ohm coax input TV:

http://forum.tvfool.com/attachment.p...1&d=1494355873

This UVSJ separates the UHF and VHF signals from a 75 ohm all-band antenna for a TV with separate 300 ohm UHF and VHF inputs:

http://forum.tvfool.com/attachment.p...1&d=1494355873

The common use these days is to combine a UHF antenna with a VHF antenna for the single input of current TVs, but the UVSJ is a reciprocal device that can be used to combine UHF and VHF signals OR separate UHF and VHF signals.

The UVSJ UHF/VHF Separator-Joiner belongs to the filter family of Diplexers. All UVSJs are Diplexers, but not all Diplexers are UVSJs; Diplexer is the more general term. A HLSJ is also a Diplexer, but for VHF-Low and VHF-High.

ADTech 9-May-2017 7:24 PM

Quote:

In looking at my signal analysis chart I notice that CTV channel 6 from Montreal is not shown.
Click on the "Pending" button. Industry Canada never fully updated their records that transfer into the FCC's system (which are subsequently picked up by this site's data gathering), apparently, when the Canadian digital transition took place

Also, make sure you are not confusing the virtual (displayed) channel number with the real channel number. For antenna purposes, we have to use the "real" channel number. CBMT-DT, for example, is operating on channel 21, not 6.

rabbit73 9-May-2017 8:01 PM

1 Attachment(s)
Quote:

In looking at my signal analysis chart I notice that CTV channel 6 from Montreal is not shown. It comes in quite well with my current set up.
CFCF CTV from Montreal is on real channel 12, virtual channel 12.1, unless all my research resources are wrong.
https://en.wikipedia.org/wiki/CFCF-DT

http://www.rabbitears.info/market.ph...&callsign=cfcf

https://en.wikipedia.org/wiki/CTV_Television_Network

http://forum.tvfool.com/attachment.p...1&d=1494360023

rabbit73 9-May-2017 8:40 PM

4 Attachment(s)
Quote:

So this proposed setup using an un powered UHF antenna pointed at 111 degrees true azimuth will work.
The remaining confusion is regarding the power pass diagram for the signal combiner. It indicates the power will not be shunted to my existing antenna, correct? My assumption is that my existing antenna will be connected to the VHF input of the combiner. Am I way off base?
You are not off base, you are correct. If you can not find a UVSJ with power pass on the VHF side, you must use two coax down leads like this:

Code:

                DB2E > coax > grounding > coax >
                                block          \
                                              UVSJ > splitter > TVs           
                                                /
VHF > preamp > coax > grounding > coax > power >
ANT                    block            inserter

If you can find a UVSJ with power pass on the VHF side, this would be the setup:

Code:

DB2E > coax >
              \
            UVSJ > coax > grounding > coax > power > splitter > TVs           
present      /              block          inserter
VHF > preamp >
Ant

If you look closely at the Radio Shack UVSJ, you can see the DC pass arrow going to the UHF port. This would allow you to insert a preamp between the UHF antenna and the UVSJ to amplify the UHF signals, but not the VHF signals, which is not what you need.

http://forum.tvfool.com/attachment.p...1&d=1494369089

The power pass for the Antennas Direct UVSJ is also to UHF.

The label on the Radio Shack pkg is misleading:

http://forum.tvfool.com/attachment.p...1&d=1494370999

It is described as a splitter for two components, which is not correct.

The Holland UVSJ passes DC to the VHF port, but there is no arrow:

http://forum.tvfool.com/attachment.p...1&d=1494470497

Notice that it says Separator so that it doesn't get confused with a splitter, as happened here on this thread, creating a heated discussion:
http://www.avsforum.com/forum/25-hdt...-combiner.html

Inside:

http://forum.tvfool.com/attachment.p...1&d=1494470497

I will try to find a UVSJ with power pass on the VHF side. If I can find one I will send it to you. Meanwhile, do a test with temporary coax lines and a second antenna for UHF to see if the plan will work.

Bigbear 12-May-2017 11:00 AM

After reading other posts about poor reception, how much does being surrounded by trees contribute to my issue? There are lots of trees between me and Mt Mansfield.

ADTech 12-May-2017 12:26 PM

Quote:

Originally Posted by Bigbear (Post 57938)
After reading other posts about poor reception, how much does being surrounded by trees contribute to my issue? There are lots of trees between me and Mt Mansfield.


That would have been good to know much sooner. I did point out (twice) that we didn't know any details about your signal path (among other things).

If trees are in the signal path, take any prediction made by the simulator and throw it out the window. Then, go outside and stomp on it a few times. For good measure, dig a hole and bury it. Then put a really big rock on top of it. The simulator's predictions are dead and buried since they are useless and no longer apply.

I've personally visited a location what was less than 5 miles from a million watt UHF tower, and measured a >50 dB reduction in signal power when moving a mere 50 feet from a spot with LOS to one behind a mature wet silver maple tree. When the wind blew, the signal looked like it had gone through a shredder and reception failed.

Bigbear 12-May-2017 1:29 PM

Ok, I'm sorry that I omitted the thing about the trees. Most of them are not mine so there is nothing to do about it other than to install the antenna on a 200' tower.
It must still be an issue with the roamio as the issue is with it only, and not the other 2 TV's in the system.
Guess I'll monitor for a while as by taking the Roamio off the distribution amp things have gotten better.

Again sorry, and thanks for all your help.

Tower Guy 12-May-2017 1:54 PM

the combination of trees and a mis-aimed antenna is killing you. One or the other by itself only works sometimes.


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