Can't get TV while neighbours are.

Treecrest14 · Senior Member

Can't get TV while neighbours are.

Phil C · Guru

Gday Glen, have you tried turning the knob marked attenuator? Im not sure what the big one does, but attenuator is like a volume control for the signal. See what happens.

Cheers

Magnarc · Guru

An attenuator is an electronic device that reduces the power of a signal without appreciably distorting its waveform. An attenuator is effectively the opposite of an amplifier, though the two work by different methods. While an amplifier provides gain, an attenuator provides loss, or gain less than 1.

So an attenuator would appear to directly affect the signal. I have one on the home tv as our signal is too strong for the tv, it reduces the signal, so maybe try tweaking the attenuator knob and see how you go???

-- Edited by Magnarc on Thursday 24th of December 2015 12:07:33 PM

aussie_paul · Guru

https://youtu.be/du3srqykknw

Aussie Paul. smile

valiant81 · Guru

Hi Treecrest14;

Have you tryed retuning your television or taking your tv in to the house and connecting your set to the outside antenna, maybe something like poor cable or a crook flylead, may be the answer. It could also be that your antenna is not pointing the correct way. May be a problem with your neighbours caravan blocking your parth for your television signal and only showing up when his caravan is in the signal parth. The digital signal is funny like that. There are many ways around the problem ways around the problem. Better antenna, move your antenna to a higher place, or do what others have done and invest in satillight television!!

If you feel adventuress try disconnecting the cable from your batwing antenna and with a multi meter try and see if you have 12 Volts DC at the end of your coax cable. No 12 Volts = the amplifier in your antenna not working and no television signal.

-- Edited by valiant81 on Thursday 24th of December 2015 12:49:21 PM

Treecrest14 · Senior Member

Thanks for all replies:

Phil - yes have turned the knob and the blue lights do go out etc.
Paul - have watched the video, but to no avail.
Magnarc - wasn't aware about reducing the signal by the accentuator - thanks
Valiant81 - When we get home, will try the multi meter and take the TV into the house to check it works.

Noticed that the blue lights are affected by my hand being near the controlling knob. They go off! So my be it is the Surelock that is faulty. Valiant81's idea will prove that.
Forgot to mention it works some of the time, but never get as many channels as other cavaneers nearby.

laurieoz · Senior Member

Does it have anything to do with LED lights turned on in the van?

valiant81 · Guru

Hi Treecrest14;
Over the years i've had a few caravans in for antenna reception problems, most have been user operation faults ( forgeting to turn on the little light that tells you that your amplifier is operating ) and others, like poor connections at one end or the other of the coax cable.

Manufactured problems like staples through the coax cable that led to the antenna on the roof of the caravan, intermittantly blow the fuse for the television, this fault took ages to track down and was fixed once and for good, one the coax cable was replaced. This was a three hour job and the final bill worked out to be close on $400. Including parts and labour.

One other caravan that the owner had spent well over 100k on and had again poor reception, this fault was traced back to there being no 12 DC Volts at the end of the coax cable that fed the antenna on the roof. This fault was traced back to a incorrectly wired splitter ( why do manufactures install splitters in very hard to get at places ). Once the splitter was reconnected correctly every thing worked. That took just one 1 hour. I've even seen people use 300 Ohms twin feed wire ( even with coax pal plugs on the ends, and once or twice i've seen people use speaker wire off a old table lamp.

Other problems have been the incorrect antenna ( EG, UHF antenna/ amplifier and VHF ONLY signal ). Others have been that the customer has moved camp and forgotten to retune his television.

Treecrest your problem dose sound like you have poor quality cable to cause the type of problems that you are talking about. Remenber not all coax cable are the same and all manufacturers will take the quickest and easy way out, and use the cheapest cable that they can buy in bulk, or get poorly payed staff in to do the install that cable.

For digital television, the recommended coax cable is what in the industry is called RG6 quad sheild cable. The quad sheild cable also has to have a gas injected polythene dielectric. This sounds and is important, cheap coax dosen't have this polythene and some manufactures use just plain old plastic. Alot of houses were wired in the early days of color television with all types ( air spaced coax was one ) of coax cable and alot was not up to the specification for reliable digital reception and had to be replaced, caravan manufactures are just starting to catch on.

Also with coax try and avoid sharp bends ( nothing onder 4~5 inches ) and under no circumstances squash the coax, this is a big no no. Staples, and any thing that can squash the cable are a big no no. One other important thing is to use the correct fittings ( F connectors, splitters, wall plates amd amplifiers all have to be 'F' type. Gone are the days of the old screw and saddle connections, This may have been ok for color television , but for for digital television again no.

Tomcat · Senior Member

Our TV sometimes has reception problems when the leds are on even the outside one. Switch them off and all ok.

Treecrest14 · Senior Member

Laurie - Van lights don't make any difference. Trying today with no lights on
Valiant81 - Have taken cover of Surelock and when I move the cable coming into the unit, the blue lights go off and on. Tells me that there is a wiring issue! Will have to get a TV guy to sort it out when we get back home.

Thaks everyone for your suggestions etc.

Glen holidaying @ Hopetoun WA.

PeterD · Guru

Treecrest14 wrote:
Have a Cormal with the Batwing Antenea and an inline Jack Surelock booster. Even though I get 4 bue lights (indicating good strength), the TV doesn't get the channel. Glen

When you say "Batwing Antenea" do you mean a Jack antenna or a Winegard antenna. People tend to call Winegards bat wing antenna.

Bill B · Guru

PeterD wrote:

When you say "Batwing Antenea" do you mean a Jack antenna or a Winegard antenna. People tend to call Winegards bat wing antenna.

From the picture in the original post it is a Jack aerial.

Delta18 · Guru

One has to ask the obvious silly question....have you re-tuned the tv channels

for a new location? You need to do this every time you move a significant distance.

tastourer · Member

"and once or twice i've seen people use speaker wire off a old table lamp."

That is not a problem at all. Figure 8 cable has an impedance of 75 ohms and is a balanced feeder.

03_Troopy · Guru

tastourer wrote:
"and once or twice i've seen people use speaker wire off a old table lamp."
That is not a problem at all. Figure 8 cable has an impedance of 75 ohms and is a balanced feeder.

The impedance characteristics of figure 8 wire at transmission frequencies could be wide and varied depending on size of conductor, distance apart the conductors are, dielectric characteristics of the insulation etc. How did you arrive at your figure of 75, just out of curiosity?

tastourer · Member

The impedance characteristics of figure 8 wire at transmission frequencies could be wide and varied depending on size of conductor, distance apart the conductors are, dielectric characteristics of the insulation etc. How did you arrive at your figure of 75, just out of curiosity?

How did you arrive at your figure of 75, just out of curiosity?

The ARRL Handbook

03_Troopy · Guru

OK, I just had a quick look in chapter 22, component data references, and couldn't see mention of figure 8 wire. But if you go to this Link Transmission Line Calculator, and play with a few figures, you can see how even very small variation in manufacturing tolerances has a pretty big effects on the impedance values. Because fig 8 wire is not intended to be used as a transmission line, the variations in insulation types and thickness, along with conductor thickness, will vary the characteristic impedance of the cable at different frequencies by a great deal. The bottom line is, as far as using it as a TV signal feeder, it is rather dodgy.

BUt, in a pinch, if you only had a piece of wet string as the only other alternative, I guess you could use it. biggrin

The Phantom · Guru

Glen holidaying @ Hopetoun WA.

Being in Hopetoun might have a bit to do with it.

The Phantom