tv coax plugs

[Bill Wright]

The mad house.

Bill

[tony sayer]

In article , Bill Wright scribeth thus

Do you get a card from Prince Phil to tell you to get a fecking move on to fit a few more;?...

As he is won't to do;!...

[tony sayer]

Having misspent my younger years in the TV trade and having done quite a bit of rigging..

The number of times I've seen a Belling Lee plug fitted like that as it ought be around 10 or so. I swear blind those times were whilst I was working at Pye TVT on some studio OB equipment.

The usual way was to wrap the braiding around the cable outer PVC and then as long as there was enough to fill up the collet clamp part then that was good enough.

I did ask the tight barsteward for a soldering iron so as to solder them but he won't give us one and told us to nip the plug onto the inner core of the co-ax with side cutters which wasn't ideal. Some people never bothered with that even.

As to the soldered or not it did work surprisingly l well if it wasn't soldered and it did work OK at UHF frequencies due to Capactive reactance being more effective at those frequencies rather than at VHF Band one and Three as there was never a strong ITV signal in the Cambridge area..

IMHO life would have been better if Belling Lee had never invented the damm thing anyway like the SCART plug and the abominable so called UHF plug the PL259 used in some PMR applications.

In all the simple F plug was a much better idea.

[Ian Jackson]

In message , Bill Wright writes

As they say, "Practice makes perfect".

[Graham.]

I d>> >I'd expect far greater losses from an un-soldered joint at Band V >> > I replied

Apart from a missing comma after "view", I stand by what I said.

Surley my use of the word "given" shows that I conceed that the statement that follows is true, ie cable losses are much higher at UHF (than at VHF).

The point I was making is that an oxidised coaxial inner inserted into a coaxial plug may well be open circuit as far as DC is concerned, but the capacitor so formed (I would estimate 5-10pF) will, acording to the equasion 1 / 2*pi*f*C, have progressivly lower Xc (expressed in Ohms) as the frequency increases.

Such a termination will therefore contribute a fraction of the attenuation at 500MHz than it would at 50MHz (to use my origanal comparason between Band IV and Band I).

[Terry Casey]

Fair enough but if I could misinterpret it then so could others, so a more detailed explanation might help someone else who might more easily be confused.

It certainly does no harm to spell it out in detail, particularly in uk.d-i-y where the average reader will not be expected to have a good grasp of RF theory and practice.

In uk.tech.digital-tv, where this thread also appears, I would expect a better level of understanding in general, but it still isn't mandatory!

[John Rumm]

Its not thought ;-) every "I'd expect far greater losses from an un-soldered joint at Band V"

To which Graham in effect replied:

"It's a commonly held view, but it's wrong."

What seems to have got everyone's knickers in a twist is the added comment

" *given* that feeder losses are so much greater at UHF,"

(my emphasis on "given") - i.e. he is acknowledging that the feeder looses will be much higher, but this is a point unrelated to the effect of frequency on poor connections (which will better "jump" small open circuits due to the lower reactance of the capacitor formed)

[John Rumm]

I have seen loads of BL plugs with the inner unsoldered - but a length of inner left protruding from the centre pin of the plug. In effect making it behave somewhat like a F connector with the co-az itself doing the final connection.

[Mike Tomlinson]

En el artículo , Bill Wright escribió:

I was impressed with the speed at which an aerial fitter fitted the plug. Mind you, he had the proper tool for stripping the end of the cable - it cut the outer insulation, the braid/foil, and the inner insulation all to the right length in one go.

[Davey]

Yeah, that's cheating. It's only valid if done with a blunt penknife. This is, after all, a D-I-Y group.

[Bill Wright]

That is often because the inner moves along the cable a bit, sometimes. And it is unlikely that the protruding inner will contact the inner connector of the socket, unless it is very bent.

Bill

[Bill Wright]

I would never do it like that. My coax plugs were lovingly hand-fitted.

Bill