HC12 Antenna Help

Well I am trying to get the most out of this module and I need to change the antenna from a passive one to an active one . Any suggestions ?

Expl0siv3Man79:
Well I am trying to get the most out of this module and I need to change the antenna from a passive one to an active one . Any suggestions ?

Can you tell us, in relation to the HC12, what an 'active' antenna actually is ?

I have experiemented with similar radio modules and used the HC12, but I do not understand what you mean by an active antenna.

As far as I know active antennas need to be powerd externally

Expl0siv3Man79:
As far as I know active antennas need to be powerd externally

I guess they do.

So why do you think you need a powered antenna, and indeed how do you apply power to it and for what benefit ?

I think you are confused, in the realm of UHF radio modules, such as the HC12, antennas are passive and for very good reasons.

It would have been better to say why you think you need a better antenna.

The range provided by the non powered antennas is around 1 km . I would like to get more than that . It’s not a must for me but if it is possible then why not

What are you trying to increase with an active aerial.
Transmit power (maybe illegal) or receive sensitivity (maybe useless).

Tell us more about the types of antennas you're using (both of them).
And how/where this link is being used. For your RC plane?
Leo..

Illegal? Isn't the 433mhz frequency legal ?

An active antenna is for receive-only. They have an FET to match an extremely short antenna impedance to the receiver input impedance and to provide some amplification. The Heathkit active antenna I built from a kit has a short collapsible antenna rod and a tuned, band switched amplifier. It connects to a short wave receiver.

If you ever transmit into an active antenna, kiss it good by!

Paul

Expl0siv3Man79:
Illegal? Isn't the 433mhz frequency legal ?

In some parts of the World and under specific conditions, then yes its legal to use the 433mhz frequency.

You can improve the receiver performance of the HC12 by 6 db by reducing the serial data rate to 2400 bps or less.
Thats about all you can realistically do unless you want to use a directional gain antenna like a yagi , but you will need one with an IPEX20279 connector to plug into the coaxial socket on the HC12 board.
What are you trying to achieve?

I want it for a small weather station .

The size/shape of the aerial is very important for range.
What are you currently using.
Leo..

Expl0siv3Man79:
The range provided by the non powered antennas is around 1 km . I would like to get more than that . It's not a must for me but if it is possible then why not

Do you live on a big farm, and NEED the range.
Or do you live in a town/village, and just want this frequency for yourself.
Leo..

Expl0siv3Man79:
Illegal? Isn't the 433mhz frequency legal ?

Sometimes but it comes with restrictions, one of which is the power you are permitted to radiate. This is normally given as ERP, effective radiated power, so it applies to both antenna gain and power output.

Also while operating a type approved transmitter might be legal building your own or sticking an amplifier on the output to increase the power makes the thing not type approved and so illegal.

Expl0siv3Man79:
Well I am trying to get the most out of this module and I need to change the antenna from a passive one to an active one . Any suggestions ?

The range provided by the non powered antennas is around 1 km . I would like to get more than that . It's not a must for me but if it is possible then why not.

I want it for a small weather station.

So although your current setup for the weather station is OK, you apparently 'need' to go further, which begs the obvious question, why ? Is the weather station on the move ?

Would it not save us all a heap of time if you prepared to reveal in detail what you project actually is and where in the World you are based ?