Terrestrial Reception: Articles, etc

Ulsterman 1690

Mainly written for DX enthusiasts but some good recommendations on aerials

Coaxial cables The Good The Bad and the UGLY :mad:

For cheapskates

Lots more

Seen the last one before.
Stickified anyways for now and if anyone has non commercial weblinks to add-feel free.
If you want to add your own site, pm a mod first.

Telefís

13th Sept 2005

Just wondering - does anyone have the faintest idea as to where I can get my hands on some decent 'copper-on-copper' coaxial cable, as pictured on top in the image below:



Nowhere sells it!
I've rung around five places alone today including electrical wholesalers, but everywhere just sells the cheap black so-called 'satellite cable' with silver paper inside.
Anyone know of an Irish store/supplier in the Dublin/North-East area that sells it at a reasonable price?

It seems the only people that use it is Sky! All independent installers appear to be gangsters (for once the term is not applicable to Sky ) using the cheap stuff because they can get away with it, while Sky as a major supplier can't.

There's some decent UK websites that sell it, but charge €40-€50 for delivery alone!
A 100m reel only costs €38-40 taking the exchange rate into account.

Any help at all would be much appreciated, thanks.

Ulsterman 1690

Have you tried Maplin (Belfast/Dublin/Blanchardstown/Cork/Limerick/Galway

Their catalouge lists both CT100 and CT125 cables

byte

http://www.satellite.ie/acatalog/Digital_coaxial_cable_CT_100_.html

This guy sells it online, email to see how much he'd sell you 100m roll for.

mansell2

Have Phillips STB 2 months old, "flat" type of aerial looking direct over the sea to Wales , very good analogue picture on all 5 channels.Tuned my STB and it displays Wenvoe during the search although I am sure I am picking up Presely.
Very good on all BBC digitals but all ITV (CH 51 ). Signal strength is 75% give or take but ITV = Signal quality poor/none.
How can my signal quality be so bad with such a strong signal? Tried swinging my aerial but no good.

Anybody got any thoughts? Gorey-- just sth of Tara hilll

Booms

@ mansell2.
have you looked at ch51 on your tv to see what's present on that channel? could be one of your other boxes producing a signal on thta channel.

@ telefís.
B+Q have 25m rolls of double-copper, solid dielectric coax.

OFDM

Doe anyone havea rundown on the different types of cables? For instance the difference between:
RG-6
RG-58
RG-59
RG-216

when it comes to impedance and shielding?

watty

http://www.universal-radio.com/catalog/cable/coaxperf.html

RG58 is very basic 50 Ohm coax. Useful for < 500W HF or VHF
RG59 is similar, but 75 Ohm

RG6 is American spec of a cable not unlike CT100. A double screen 75 OHm cable.

Some Equivalents

Type 	Center Conductor 	Cond. Type 	VOP¹ 	O.D. 	Replacement
RG-174/U 	7x (.0063") 	Stranded 	65% 	.100" 	LMR-100A
RG-316/U 	7x (.0067") 	Stranded 	68% 	.110" 	LMR-100A
RG-58/U 	20 AWG 	Solid 	66% 	.195" 	LMR-195
RG-58A/U 	19x (.0071") 	Stranded 	65% 	.195" 	LMR-195
RG-58C/U 	19x (.0071") 	Stranded 	65% 	.195" 	LMR-195
RG-59CATV 	22 AWG 	Solid 	78% 	.242" 	
RG-6 CATV 	.040" 	Solid 	82% 	.300" 	
RG-8X 		Stranded 	78% 	.242" 	LMR-240
RG-213 	13(7x.0296) 	Stranded 	65% 	.405" 	LMR-400
RG-214/U 	13(7x.0296) 	Stranded 	66% 	.405" 	LMR-400

RG216 is kind of next up from RG-213, which is a lot more common.

LMR 400 is also a widely used better equivalent of RG213.

RG213 is 50 Ohm very heavy cable.

But last repeater I installed used even heavier cable (forget part) only a few dB loss over the 120ft run from 90ft up mast to the equipment at 434MHZ. I used hacksaw, pipe cutters and file to cut, trim and fit compression fitting N-Plugs (only type of connector available). Might have been LMR600


Use Google.

See
http://www.andrew.com/products/trans_line/heliax/default.aspx


Especially see http://www.ocarc.ca/coax.htm

Ulsterman 1690

How can my signal quality be so bad with such a strong signal?

interference ?
multipath ?

pjq

Is this CT100 cable ? Ther is more detail on their 120db cable

http://www.toci.de/xtcommerce/product_info.php?info=p58_50m-Koax-100db.html

L1011

Its using aluminium, it ain't CT100. CT100-equivalents are copper on copper, braid on tape.

byte

I notice that there are 2 layers of foil, a layer on either side of the braid. Have never seen this cable "in the flesh" though.

watty

It is a cheap type of cable. Never seen ANY coax with an outer foil layer.. I've minature silver plated, hardline, heliax, rigid 10kW etc everything.

watty

This is the ONLY recommended set top aerial for UHF:

The picture below is only a typical sample. Many variations and makes/ models exist. B&Q, Homebase, Expert and all other TV sellers should have something like this

http://www.maplin.co.uk/images/full/L56af.jpg



Broad alumimum strip near one end and about 3 to 4 half sized "knitting needles" all on a plastic boom on the stand. Usually about 3 to 5 rods as a reflector at the end near the broad aerial strip where coax cable comes from.

These are widely available from €5 Euro to €10. More expensive or amplified aerials SET TOP aerials are not worth it, it this is not good enough, it needs to be in attic, or else you need a real TV aerial in Attic on outside.

Amplifiers have TWO uses:
1) Preamplify signal about 1.2m below aerial on a large mast to make up for loss in the coax cable to TV.

2) Boost the signal for a passive multi Tv set splitter (which may be built into the amplifier or a separate passive splitter).

They will not make a bad signal better, only a higher up or larger aerial will.

The basic set top aerial will work much better on an upstairs window sill pointing at transmitter. Even in TV room, it will work better at the window. You can add extension coax (use satellite grade cable, as this works better than an amplifier and cheap cable.) If the coax cable to the set top aerial is over 25m long, then add a low noise pre amp /booster. If there are different gains, pick the lowest. i.e. 14dB is better than 20dB. A 20dB gain pre-amp will overload.


If you are on VHF for RTE1 & RTE2 you still need one of these above for UHF TV3 & TG4, they are not on VHF anywhere.

Use a VHF /UHF splitter/diplexor to combine this aerial with an existing VHF aerial or a VHF only "rabbits ears" (Two long V rods, adjustable). If the "rabbits ears" is for UHF also it has a useless loop beside the VHF rods. it is hard to get the Rod only kind now, but they are better for VHF TV and will also help VHF/FM radio or DAB reception. Essentially any UK DAB aerial will work as an Irish VHF TV aerial.

ronan.michael@g

Tristrame wrote:

Seen the last one before.
Stickified anyways for now and if anyone has non commercial weblinks to add-feel free.
If you want to add your own site, pm a mod first.

I have a webcam -- www.camstreams.com/live cams/scenery/Irish Traffic - Wicklow. Busy junction - almost 11,000 hits in about 5 months. Is this of interest? Love the Arklow site - beautiful action! Cheers Michael r.

staker

you might find it of interest to know that independent sky installers are not all gangsters! having worked for sky direct myself,now installing independently,i can assure you the same standards apply to both sectors. without meaning to offend any professionals, the gangsters know who they are and constantly undermine the good works done by the large majority!!!
i buy all my rg6 rated cable off city electrical factors in cork,maybe they have a depot in dublin....

Telefís wrote: »

13th Sept 2005

Just wondering - does anyone have the faintest idea as to where I can get my hands on some decent 'copper-on-copper' coaxial cable, as pictured on top in the image below:



Nowhere sells it!
I've rung around five places alone today including electrical wholesalers, but everywhere just sells the cheap black so-called 'satellite cable' with silver paper inside.
Anyone know of an Irish store/supplier in the Dublin/North-East area that sells it at a reasonable price?

It seems the only people that use it is Sky! All independent installers appear to be gangsters (for once the term is not applicable to Sky ) using the cheap stuff because they can get away with it, while Sky as a major supplier can't.

There's some decent UK websites that sell it, but charge €40-€50 for delivery alone!
A 100m reel only costs €38-40 taking the exchange rate into account.

Any help at all would be much appreciated, thanks.

watty

FM, DAB and Internet streaming audio in one box:
http://gizmodo.com/gadgets/home-entertainment/blik-radiostation-dab-wi+fi-and-fm-radio-all+in+one-333230.php

No Satellite, DRM or Worldspace though.