UHF switch box

[ed731pdh]

Well, it arrived today, made by Philex, weights 193g.  According to specs on box, 75 ohms, high isolation, frequency range of 5 to 1750mhz with a minimum loss of 4db.

Trials start shortly.

[Terry]

A minimum loss of 4dB?

A 5 - 865MHz two-way splitter usually has a loss of only 3.7dB* so what on earth are they doing?

Increasing the upper limit to 1750MHz ups the stakes somewhat but it is, after all, a simple switch.

I will probably come across a couple of CATV two-way switches in the next couple of weeks (final clearance of old house) - there are two types, one is rotary with a large lever protruding from the front and the other type is like yours with press buttons on the top.

If I find them, I'll take them back to Hykeham and see what I can find out about them, though finding a suitable signal source may be a problem.

* It is becoming increasingly difficult to find 860MHz splitters these day because every one seems to want to sell the 2.4GHz type. Beware! Some of these have horrendous losses which make a complete mess of a simple distribution system.

If you are pushed, the PROview splitters sold by Toolstation aren't toobad but you will still take a 1dB hit on any splitter.

The full range of PROview splitters with a full specification, including an 862MHz range, can be found on pages 41 & 42 of Blake UK's pdf catalogue but I'm not impressed. Decent splitters should have maximum losses of 4dB (2-way), 8dB (4-way) and 11dB (8-way) that these splitters fail to meet.

Taylor Bros still sell 860MHz versions but, unlike Toolstation, you can't just pop round to your local branch for them.

[ed731pdh]

It may not work yet for that very reason, the new aerial put up still struggles to get Midhurst from 8 miles away, but the old one that's been there ten years, a log periodic with a booster on the back as part of the construction, was pointed towards Crystal Palace, 40 miles away and pulled in a fantastic signal. For some reason Midhurst is p*** poor even though the stats say we are in a prime receiving area.

[ed731pdh]

The new arrangement, that still stuggles only on certain channels.  You can see the old log periodic pointing towards CP, under the FM radio aerial.

[Terry]

I'm not too happy with that aerial.

The directors nearest the camera seem to be in closely spaced pairs with a long space between each pair - if so, that is definitely wrong - they should be approximately equally spaced.

It's difficult to see from the photograph but that looks suspiciously like an aerial sold in the 'sheds' that has the directors punched out of thin sheet and has a folded dipole that looks strangely as if it is made from a length of flexible rule!

Being so close to a main transmitter I would expect much better results. I suggest you get the installer back to sort it. Ask him to show you the signal level measurements so that you can see that they are reasonable with no unexpected troughs (but bear in mind that not all muxes will be transmitted at the same level - you can check that in advance).

If he doesn't have a signal level measuring instrument, that would point to him being a cowboy - not all of them stick to the cheapest contract aerials!

By the way, have you checked that the coax is properly terminated? And if it is RG6 (bonded aluminium foil screen) or the superior PF100 type (copper foil screen) or even something completely different?

[pwdrive]

Antenna....Triax T band ?

Lawrence.

[Terry]

Could be - this is the TRIAX Unix 52 LTE T Band:



Note the regular director spacing and how it contrasts with the aerial in the previous post.

[pwdrive]

http://www.trade-works.co.uk/aerials-for...erial-p454

Lawrence.

[ed731pdh]

The aerial is marketed as a UTE400 mobile band rejector type. We have had terrible grief in the area here since Feb since the major phone operators upgraded the main mast. The chief signal culprit is Vodafone, since they have boosted the signal the television has been bloody poor, not helped that the television frequencies for this area butt up against the mobile frequencies. Have tried a filter inline that has mopped up some of the interference but not all.

Aerial was tried pointing towards CP and Heathfield, no problems at all with signal strength and quality, point back towards Heathfield and the majority of channels are OK but some like Freeview 23 would occasionally go bitty. Cable is solid copper centre core with exterior copper braid/foil type, same type I use on the 1.2m dish feed from the bottom of the garden (40yds away).

Anybody remember the good old days of UHF? Just point and watch? Digital is a royal pain in the a&$e.

[Terry]

I must admit that I've never come across this unusual director spacing before!



If you haven't already done so, use this handy calculator.

At the bottom there are links to the signal profile and to maps. Because it shows every single building, I prefer to use the OS map at its largest scale. Drag the pointer to your house and see if the signal profile shows up any problems.