Bruce85 wrote:IanB wrote:Bruce85,
Sounds like you have got interference rather than a weak signal.
You don't say what your in wall cabling is like
The cabling, all of which is RG6 quadshield coaxial, was installed in early 2007 by a qualified antenna installer. The installer did not feed the cable inside the walls and ceiling. Instead, he laid it from rooftop to the adjoining shed, where it is attached to a two-way signal splitter (F-connector style). There is an iron roof covering the splitter, but air and
water can come in from the sides, which are exposed.
Okay, that sounds like one place to fully inspect carefully.
One of the RG6 quadshield coaxial cable that is connected to the splitter travels underneath the patio rooftop -- I'd say between 20 and 35 metres -- then makes its way to the loungeroom via a hole that was drilled into the wall. A few other coaxial cables travel alongside it -- one for internet, one for pay TV and one old coaxial cable that was here when I moved in.
My room is close to the splitter, so its RG6 coaxial cable doesn't need to travel far.
I'm slightly confused here
. You have a 2 way splitter. One run goes 20-35 meters to the lounge, which is
not where the BW is. Second run is much shorter and goes to the BW in your room. Please confirm this!
On Wednesday I noticed that the fly-lead I created for my room -- RG6 quadshield coaxial cable with crimp style f-connectors placed on each end -- was not working as well as the gold-plated PAL fly-lead that I bought from a store. Saying that, it providing better signal quality and better signal strength than the PAL cable when I tested it last week. I just tested the two again -- this time I've made sure there's no other major cable crossing them -- both of them are working at the exact same value. I take it this means I must have failed to strip the shielding correctly before I crimped the F-connectors? I suppose this is quite possible as I use a basic economy stripper. I didn't pull the first layer of shielding back over the black rubber.
With most crimp style F-connectors, you just circumcise the sheath and braid, leave ~5mm of dielectric with the foil intact and then expose ~10mm of centre conductor. Then ram the connector trunk up between the braid and the foil. If the connector is the right size for the cable there should not be enough gap to fold the braid back over the sheath.
IanB wrote:How does the power injector fit into the cabling, is it in series with the Beyonwiz
It's located in the loungeroom. It has a little green light on it. Not sure of its brandname.
So it is not involved in the cable from the splitter to the BW.
A possible problem with the antenna amplifier could be the power supply filter capacitors. When these fail you get hum in the system. With analogue TV you get slowly rolling vertical light and dark patches, with Digital you cannot see any such obvious effect, but it can effect the signal adversely.
IanB wrote:What is your location/postcode
4123
~15Km South East of Brisbane central? I'm not familiar with Brisbane, but others on the forum may well be. I am surprised you need an amplifier in what I believe to be a suburban area. But there are pockets around Melbourne that prove very difficult to get unassisted reception, so I won't/can't judge.
IanB wrote:How is the quality of the analogue broadcasts when connected to the RF output of the Beyonwiz
The VHF channels are very good,
with the ABC being the worst of them. The UHF channels are worse than the ABC.
So they are not perfect. DTV is a prick to diagnose because of the digital cliff, i.e. it either works or it does not. Analogue gradually fades away to snow as the signal quality and strength degrade. This at least gives you something to work with without having special test equipment.
IanB wrote:As you say moving the fly lead causes changes in the problem. This would indicate poor connection of the shield somewhere. The cable is supposed to be a transmission line, resisting adjacent interference. If the shield is not contiguous and of high quality then interference can get into the cable.
That's what I was thinking.
Can things like power cords and speaker cable cause interference when they are really close-by?
This is what high quality quad shielded RG6 coax is all about. Cheap coax is less immune. Poor joints and fittings negate the noise immunity of the whole coax system.
Would a properly crimped F-connector on a perfectl stripped RG6 quadshield coaxial cable be immune to any noise that could be produced by a power cord and speaker cable?
Speaker cables almost certainly, power cables pretty likely. Nothing on earth will be immune to something like an arc welder in the vicinity however.
Edit: The fly-lead I created for my room is playing up again! I guess I stuffed it up. Is there any way to test the signal quality of a coaxial cable with a digital multimeter?
Well, there is the normal continuity, end to end. And the isolation centre conductor to shield.
A simple effective crackle tester can be made with an AA battery and a set of headphones. Wire the lot including the cable under test in series. Wiggle the joints and cable near the joint, listen for crackles in the head phones. Crackles indicate bad connections. F type connectors need to be screwed into a good quality barrel connector for the test to be useful, the end screw will be naturally crackly for this test when not screwed up tight.
One very important consideration when making F type connector cables to the clean the centre conductor with >800 grade wet and dry abrasive paper. There is generally a lacquer coating that must be completely removed.
Out of interest, could the problem with my home made fly-lead be due to it having F-Pal connectors attached to the F-connectors? I needed to put these on it so that it can fit into the female Pal sockets of the Beyonwiz and wall outlet. I read on DTVforum.info that these things can cause problems. If so, then it would explain why the cable works perfectly on the Foxtel STB -- I don't use the F-Pal connectors when connecting it to the Foxtel STB.
Like all things these days you can buy crap or quality, and it is hard to tell the difference visually.
