Weak Signal

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NeeLi1454
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Weak Signal

Post by NeeLi1454 » Thu Feb 04, 2016 6:00 am

Hi,

I live in the UK (South Yorkshire) and I am trying to fix an issue with a weak signal to a TV on the 2nd floor.

I have the following set up.

Wide Band roof aerial pointed to Belmont Transmitter. In the living room the guy who put up the aerial also installed a booster (ProCeption - Pro PSU 11F MK2. http://www.amazon.co.uk/PROception-12v- ... B002L64B3S).
This feeds then into a Humax DTRT-1000 HD Digital TV Recorder. The Humax shows an average signal strength of 55 - 65%. And works great on all channels.
The Humax has a feature to boost the signal for the RF Coaxial output which goes via a 10 metre (32 feet) run of cable to a Sharp 32" FreeView TV on the 2nd floor.

The Sharp TV is tuned to Belmont using the Channel IDs but the channels break up quite bad. It shows a signal of around 5% on the Sharp TV which has no boosting features built in I can find.

So my question is. What is the best way for me to boost the signal to give a good signal to the 2nd floor TV?

I have had thoughts that because there is already a booster involved from when the aerial coax cable enters the house that adding a second booster might not work?

If this is possible... What would be the best route to go with a booster fit for this job?

Thanks

w9wi
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Re: Weak Signal

Post by w9wi » Thu Feb 04, 2016 6:59 am

Are you sure the RF output on the Humax is the same signal coming in on the antenna?

The RF coaxial output on a U.S. DTV box usually transmits only one channel, downconverted to analog standard definition, so one could watch digital signals on an analog TV. If you connected a digital TV to this output, you'd get little or no signal from any digital station.

If you're sure the RF coaxial output is passing through everything that's coming in on the antenna... I would say either:

- The Humax is broken. It claims to be passing through all the digital signals, but it isn't.
- There's something wrong with your 10m of coaxial cable. It shouldn't be knocking signals down that much.

I think what I would try.. is to disconnect the coax going into the Humax from the booster.. and the cable going from the Humax to the second TV.. and connect those two coaxes together. (with a "barrel" connector, although they may call it something else in the U.K.) Does the second TV work now? If it does.. the problem is the Humax. If it doesn't.. the problem is the 10m of coax.

Coax is more likely to fail at either end, that's where I'd start looking for faults. If you're lucky you can just replace the connector on one end & you'll be in business.
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Doug Smith W9WI
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KPJL FM
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Re: Weak Signal

Post by KPJL FM » Thu Feb 04, 2016 9:37 am

Use a splitter after the first booster, to feed both TV's, should work better. Any time a passive device can be used, the better.
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Deep Thought
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Re: Weak Signal

Post by Deep Thought » Thu Feb 04, 2016 10:04 am

The manual is unreasonably silent about what that RF output does, but if it is anything like the old VCRs it does not pass through the input unless the unit is offline. Otherwise you're going to get one RF-modulated channel version of whatever is on the composite video output. I suspect the same is true here, and that would explain the very low levels on OTA channels at the second TV since all you are getting is whatever leaks past the internal switching and/or is picked up by the coax cable. The solution is to bypass the box as mentioned above.
Mark Mueller • Mueller Broadcast Design • La Grange, IL • http://www.muellerbroadcastdesign.com

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Re: Weak Signal

Post by Kelly » Fri Mar 25, 2016 7:54 am

Remember too, DTV tuner manufacturers incorrectly label their devices in the setup menu as "signal level", where it's actually signal quality. It's frequently confusing to consumers. Even viewers geographically close to a transmitter site have experienced low signal readings. Nine times out of ten, the low signal (signal quality) is actually caused by multipath or bandwidth/equalization restrictions. Using an amplifier to 'boost' the signal many times makes the problem worse. That, and make sure the amplifier and any splitters is rated for DTV reception with bandwidth out to 2Ghz. Many older cable amplifiers and splitters only cover to 500Mhz.
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Shane
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Re: Weak Signal

Post by Shane » Fri Mar 25, 2016 2:44 pm

If you can see the Belmont transmitter (with your eyes) you are possibly getting too much signal. In which case you may want to lose the boosters and maybe even use attenuators.

I live about 1-1/4 mile from all the major TV signals in my city and on a digital TV or on a converter I get pretty darned good reception using a push-pin - the kind you use on a bulletin board - stuck into the 'F' jack. Using an antenna often causes trouble.

We're also very close to about a jillion 100kw FMs mostly from the same site. So I removed the collapsible "stick" antenna from one of my FM radios to help it deal with the overload. Then I took the stick, fully collapsed to about 6 or 8 inches long and hung it on the push pin on the TV. With that it can also pick up other local stations about 15 miles away.

Too much signal can be a bigger problem than too little.

In an earlier time (analog TV) I lived in a neighborhood that was "shaded" from this same site. TV reception with just an indoor antenna was horrible because of ghosts just as strong as the main signal! I had to get cable in order to watch local TV. (I also had reason to suspect some of the interference was leakage from the cable system.)

We don't get ghosts on digital TV but the multipath that produced them is still with us and just causes the digital signal to break up or be otherwise unusable.
Mike Shane, CBRE
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