CB questions

Be useful if it WAS a conductor, but as alumina, its not only a bloody good electrical insulator, its usable to about 1900 C

Steve

How come the capacitance between all these little bits isn't sufficient to make the impedance of the ground plane essentially the same as if they were all welded together, at the RF of interest ?

Steve

No idea, all I do know is that RF sensitivity of aerials and aerials in general can get a bit weird so maybe it just doesn't work like that, for a start some part of my brain is making noises about phase shifting of signal through a capacitor, which would play havoc with reception.

(Checks)

Yep, current through a capacitor lags the input by 90 degrees so you'd get signal cancellation and addition problems. You'd probably end up with a tuned resonator too what with dodgy cables ;-)

There are several compounds (obviously, I wasn't thinking of alumina). I was referring to the transparent one that forms near-instantly on aluminium metal. If it is not conductive I'd be mighty surprised.

G6ILE... Haven't transmitted on an amateur band for years. Am I right in thinking that we don't have to pay £15/year anymore and even as a Class B I have access to HF now? I'm a little out of touch...

That's true, but to look at the net effect you have to consider the phasor diagram of the situation. You'll have capacitive reactance, and inductive reactance as well as resistance.

There'll only be an appreciable phase shift if the reactive components of the impedance are significantly higher than the resistive component of the impedance.

AFAIR an antenna IS a resonant system.

Steve

That's the same aluminium oxide. Al2O3. None of the hydroxides are appreciably conductive either as far as I can tell.

Steve

Only playing devil's advocate, because people have asked me, what IS the point these days in being a radio am ? Back in the day, people became highly competent in RF engineering, built their own rigs to do this and that. These days it seems that you buy it all in and - do what ? That I can't do by email or net or with a wi-fi card and a Pringles can ?

Steve

None. Somewhat like driving a 101. :-)

Lee D

I'd imagine you have an equal chance of winning the lottery. What a random observation. Have they locked you in the workshop again?

Lee D

True

But , you might get a chance to talk to a SIX year on air

DieSea

Ah, but the 101 (frequently) forces you to the maintenance/problem solving stuff. You can't BUY a new 101, in perfect working order.

Steve

Hmm. Should've paid more attention in chemistry lessons, evidently.

What a monumental lack of curiosity. Don't you want to know, as a radio amateur ? Or do you just like making long distance phone calls ?

Steve

Even when brand new 101s were pretty hopeless. They had to have the route made easier for them on the acceptance trials. Robbie

Donno these days, back when I was active it was before mobile phones and CB. It was very useful on canals when working a flight of locks to keep in touch with the boat and give advance warning of boats coming the other way so you could have locks set correctly.

Dabbled a bit with RTTY, still have a Creed 444 teleprinter. Must get that back on the air but I doubt many people use RTTY on 2m or 70cm these days. Can I as a Class B transmit RTTY on HF?

Built the terminal units for RTTY, a 10GHz wideband FM set, though never found anyone to talk to!

Good question, it was "self education" for me but I'd always been interested in electronics and making things justa progression from that. You can still dabble but technology has moved on and TBH it's not so easy to build stuff for modern data comms from from simple and cheap components.

Voice and CW still exist but the latter you have to learn and it seems to me that many of todays youngsters are so used to instant results they don't want to put the effort in.

You'd have a mess, hence wanting to avoid it, and you don't want to go introducing a tuned resonator into the mix, whether the aerial is already one or not!

It's the challenge, it's seeing how good you can get something to work.

I used to keep a cb setup in the boot of my car if I was going to be somewhere nice and high up for a few hours. Set up the CB and see what's happening. If the atmospheric conditions are good you can get some surprising results.

As a means of reliable communication, they're rubbish, but they have charm. Faffing about with PL plugs and the like, it's crap, but it has results.