Antenna for 434 MHz ASK RF transmitter module?

Hi,
I have these few questions regarding aerials that can be used with a 434 MHz ASK RF Transmitter module.
https://electrosome.com/wp-content/uploads/2014/10/MO_SAWR.pdf  (data sheet of the transmitter)

1)The recommended length for the antenna is 17 cm,which is a quarter of the wavelength.
Will using a 34 cm antenna(half wavelength) enhance the range of transmission? Will it get even better for 3/4 th and full wavelength long antennas?

2)Should the antenna be a monopole? Can I use a helical one instead(picture attached)? What are the ideal dimensions of a helical antenna(with respect to its wavelength) for maximum range ?
Should the antenna of the receiver be of the same type or can I have a helical transmitter antenna and monopole receiver antenna ,both of same length?

3)Does Copper traces on the printed circuit board between the antenna pin of the transmitter and the actual antenna,add to the total length of the antenna? If the answer to the previous question is yes,can using coaxial cables to connect the antenna pin to the antenna prevent this from happening?

4)Should the antenna be installed perpendicular relative to the plane of the circuit board?Has it got anything to do with grounding or anything? Should the antenna be grounded too and if so how?(I am a bit confused with this part)

5)Can having the antenna in close proximity to step down transformers and ics ,produce undesired results?


Picture of Antenna for 434 MHz ASK RF transmitter module?
rickharris2 years ago

1)The recommended length for the antenna is 17 cm,which is a quarter of the wavelength.

Will using a 34 cm antenna(half wavelength) enhance the range of
transmission? Will it get even better for 3/4 th and full wavelength
long antennas?

In principle if you go to a full wave length your at maximum efficiency. However in practical terms you need to adjust the antenna to account for other stray influences.

2)Should the antenna be a monopole? Can I use a
helical one instead(picture attached)? What are the ideal dimensions of a
helical antenna(with respect to its wavelength) for maximum range ?

Should the antenna of the receiver be of the same type or can I have a
helical transmitter antenna and monopole receiver antenna ,both of same
length?

Coiling the antenna up will shorten the range. Effectively your making an external tuned circuit that will effect the performance. The shape of the transmitted wave form will approximate a doughnut if the antenna is vertical.

3)Does Copper traces on the printed circuit board
between the antenna pin of the transmitter and the actual antenna,add to
the total length of the antenna? If the answer to the previous question
is yes,can using coaxial cables to connect the antenna pin to the
antenna prevent this from happening?

Yes see answer 1. Coax cable will a) reduce the possibility of power being radiated from the antenna cable and so increase the available power at the antenna. b) It will also act as a match to ensure maximum power is transmitted into the antenna - BUT this requires some sophisticate equipment to make sure everything is working at max efficiency. for example you need to minimize the standing wave that will appear in the coax if the cable and antenna are not perfectly matched together.


4)Should the antenna be
installed perpendicular relative to the plane of the circuit board?Has
it got anything to do with grounding or anything? Should the antenna be
grounded too and if so how?(I am a bit confused with this part).

The antenna position depends on the expected transmission profile you want. generally for best reception you would mount it vertical and on a suitable ground plane, ( a conducting surface) a high as you can manage. Simply having an insulated mount on a conducting plate will suffice.

5)Can having the antenna in close proximity to step down transformers and ics ,produce undesired results?.

This is only going to transmit milliwatts. Your not going to have any issues with its effect on other circuits around it. You don't say what your end aim is. i assume max range.

Now with such a small output power you will be far better off directing as much power in the direction you want it to go rather than maximizing the antenna performance, which is hard to measure anyway.

https://www.instructables.com/howto/paraboloc+anten...

One of these will give good results and the parabolic reflector may be as simple as a wok lid.

https://www.instructables.com/howto/Cantenna/

many people get good results extending the range of mobile phones to many Km using this idea.

Making antenna is so complex that most design is done experimentally on a suck it and see basis. and in the end you will only know what you have by testing it in the field. At 434Mhz the buildings around you and the terrain have a much greater effect than the design of the equipment.

Good luck.




Adarsh_tronix (author)  rickharris2 years ago

Thank you so much..But would you be kind enough to answer just two more related questions?

1)Can I have a half wavelength transmitter antenna and a quarter wavelength receiver antenna?(This occurred to me because commercial FM transmitters used by radio stations have huge antennae whereas the receiver antennae at the user's end are much smaller).

2)Could you check if the way I've connected the antenna to my circuit board is okay?(picture attached)

antenna.jpg

Commercial stations are using lower frequencies and so longer wavelength and antenna.

You can try different antenna you won't hurt much.

your connection looks OK.

Take heed of my earlier post re setting up antenna. it's hard to do without being able to measure the transmitted power or SWR

Adarsh_tronix (author)  rickharris2 years ago

Alright..so trial and error it is..Thanks rickharris.