XPost: uk.radio.amateur
From: Rambo@thisaintreal.org
On Sat, 19 Aug 2017 18:06:12 +0100, Brian Reay wrote:
>On 19/08/17 16:25, Rambo wrote:
>> On Sat, 19 Aug 2017 15:22:26 +0100, Brian Reay wrote:
>>
>>> On 19/08/17 13:05, Ian Jackson wrote:
>>>> In message , Gareth's Downstairs Computer
>>>> writes
>>>>> On 19/08/2017 10:34, Jimbo wrote:
>>>>>>> sexes).
>>>>>> when I was newly licensed and poor I used 75 ohm TV coax and
>>>>>> belling lee
>>>>>> connectors on HF and got away with it .......
>>>>>>
>>>>>
>>>>> And it was standard on 145MHz. (QQV03-10 anyone?)
>>>>
>>>> Actually, the original B&L connector is a pretty good 75 ohm match up to
>>>> 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot
>>>> >500MHz. With 75 ohms, the problem is maintaining the structural return
>>>> loss constant while having enough PTFE insulation to hold the pin in
>>>> place. Some are only really good to around 200Mhz. Of course, for most
>>>> purposes, both are usable to much higher frequencies.
>>>>
>>>> And mixable!
>>>
>>> Well, the B&L connectors are used for TV which covers well into the 100s
>>> of MHz. There is also the F connector, another 'cheap and cheerful'
>>> beast, used beyond 1GHz. I've not done any measurements but it obviously
>>> performs were enough for the task demanded of it.
>>>
>>> Both the B&L and F connector suffer (as do all connectors) problems if
>>> not fitted correctly but they are more prone to being 'bodged'. The B&L
>>> is, for example. prone to issues with poor braid bonding while the F
>>> connector, which uses the centre conductor as the pin, tend to be prone
>>> to the 'pin' not aligning etc. I believe the F connector is used in the
>>> US where we would, generally, expect to see a B&L connector. I believe
>>> the B&L is virtually unknown in the US. I was contacted by a US amateur
>>> some time back who had acquired a bit of UK kit (KW?) which had B&L
>>> sockets. He'd not seen them before. I sent him some plugs etc.
>>>
>>> Of course, there is nothing 'magic' about 50 ohm coax or the connectors
>>> we 'normally' use on our radios. If we were to stick to using 75 ohm
>>> coax and B&L connectors the world wouldn't end. Likewise, if you mixed
>>> 50 ohm and 75 ohm, while you may be able to measure a slight difference,
>>> chances are, in real terms, it wouldn't make much difference to the
>>> overall set up performance- at least unless you were doing something
>>> 'exotic'. You'd be more likely to notice the impact of a poorly fitted
>>> 'correct' connector in an all 50 ohm system.
>>>
>>> I tend to favour N types but I've not change all the connectors on my
>>> radios. The 'first' patch lead as whatever the radio needs on one end
>>> and required N type to connect to rest on the station on the other. The
>>> same for my mobile set ups.
>>>
>>> I also have a good collect of, quality, interseries, adaptors etc and a
>>> set of the correct connectors for my Bird power meters and dummy load
>>> etc. Through in a few home brew special adaptor leads for things I don't
>>> have adaptors for and I can interconnect virtually anything.
>>>
>>>
>>>
>>>
>> Oh! has he finished? I dozed off for a moment there.
>>
>
>That short attention span probably contributes to your problems studying
>and acquiring technical knowledge. That accounts for your problems with
>the Advanced Exam and lack of other qualifications.
>
>You should really have tried to seek help earlier, you could perhaps
>have improved it and achieved at least some worthwhile qualifications.
>
Perhaps if you should refrain from your self indulgent monologues and
also take a break from fretting about others, and actually post
something of interest, you wouldn't come across as such a dull
crushing repetitive bore.
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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