[Scales]

Was just going by what I remember from my old days of radio work. If I am wrong... My apologies, had a few beers since then.

[zukenutter]

You know stuff all scales, pull your head in buddy

[bumstein]

Well personally, I thank everyone who popped their contributions in!!

I know stuff all!

Scales, Fritter, Samwich and all involved, big thumbs up to all of you!! Yep, some opinions differed but that's the fun of it all most importantly, it works now and as I digest more of your input I might be able to get it working much more efficiently..

Cheers all!!

[Samwich]

Any time

[Blakey]

fritter wrote:

Quote:

And Impedence is not the same as resistance

Please check your facts before posting statements like this. A given impedance can most easily be described as anything presenting a resistance at it's terminals. In it's simplest form this would be just a resistor. Generally however it will be a combination of resistance, capacitance and inductance and ohms law applies. Thus externally, an impedance at a particular frequency looks just like a resistor. That is why impedance is measured in ohms.

No your wrong impedance is completly different to Resistance, only the concept is the same.

Impedance is the AC's equivelant to DC's Resistance.

Resistance is R Ohm's and
Impedance is Z Ohm's

Impedance incorperates AC Reactance into the Ohm calculations. yes for a resistor that has no "Reactance" their impedance and resistance is the same.

impedance uses frequency for working out the true Ohm's of a Capacitor and Inductor. if you where to just try and find a resistance of them the inductor would be quite large as its just a big coil of wire and the capacitor would be Huge to OL unmeasurable.

Impedance is a Complex number with the same Unit's as Resistance. and it is also the Frequency domain ratio of the Voltage to the current.

If what you have said is correct then i could easily add impedance to resistance. but no you cant as impedance is a Vector of resistance and reactance. so one can not simply add resistance to impedance.

The only time what you have said would be true would be if the entire circuit was only resistors. Then yes they would be the same is there is no reactance or phase lag in the AC circuit.

and that is very basic electrical knowledge

[GeckoXL7]

^^ Takes me back to Tafe, been a long long time.

Im embarrassed of what i said about testing the cable...

Think i should go back and read all my Radio, amplifier, power supply, ac and dc circuit etc etc study books?

[Scales]

zukenutter wrote:

You know stuff all scales, pull your head in buddy

Lol cheers dude.
I can see this getting out of hand. I am staying out of it cos it's Shit I learnt 10+ years ago. And even then I was probably wrong lol. Take all forums info with a grain of salt i say no matter who provide the info. Buyer beware. Etc. Etc.

[Joe]

Mattmorgo wrote:

Where's your power supply from I've seen a few sierras now with the exact same symptons from low power supply. Tapping into the cigarette lighter accessories plug isn't enough.

Is this true?
I'm about to wire up my UHF and i thought 12v would be enough to power it

[VAXXi]

Depends on the unit, but most "consumer" radios are well within the cigarette lighter's amp rating. If you go to bigger radios, then yes - you might have a problem.

Also, some people say it's better to draw power directly from the battery in order to have a clean and stable power input, which also can be important to radios.

[Blakey]

considering the highest wattage you can have without a license is a 5W then they cant really draw much more then 5W of power. and considering a 12V cigaret lighter point is around 120W that would be perfectly fine. that's 10A i doubt you will find even a large radio that draws that much power.

[VAXXi]

Not true. What you're saying is 5 W of power goes in, 5 W of power goes out, which would be 100% efficiency and "in this house we obey the law of physics".

For example, a radio I have can go up to 60W on transmit, but it draws up to ~11 amperes at the nominal 13.2V (close to 140 W).

[Joe]

soooo is that a yes or no

[VAXXi]

For 90% of common radios out there, the cig supply is enough (I believe even the Jimny has 15A max on that power feed).

[Joe]

Sweet thanks guys ill get stuck into that on the weekend

[Blakey]

Pff physics I only obey the Laws of THERMODYNAMICS!!

But yes you are right it was more of just an example a 5w radio no matter how inefficient will not draw the 120w to more that the socket can supply.