HF/MF radio module

Hardware
1

I am searching for a module that connect two devices with the lowest possible frequency. The data bandwidth is not a crucial factor; even 1 kb/s is sufficient, and 0.2 kb/s is acceptable. However, I require a long-range capability and a powerful transmitter with the lowest feasible frequency. My budget for both the transmitter and receiver modules is under $1000. I need one transmitter and one receiver for one-way data transmission. Do not suggest 433 MHz :smiley:

P.S. The receiver should have a compact size, for example, 10x10x10 cm is okay, 20x20x20 cm isn't. The size of the transmitter is irrelevant.

2

what's the distance ? is frequency the most important part?

Lora could be a candidate and your budget would not suffer much

3

I'm no expert, but when asking for advice re radio modules, you should also state which country you are in and/or the country you intend to operate the radio in as each country has different rules/regulations on what frequencies are available and what you can do at those frequencies.

4

Whats 'long range' ?

10M ?
100M ?
100kM ?

And what is the environement between transmitter and receiver ?

So 434Mhz would be OK ?

5

Around 10 km, probably without direct LOS (trees). Lora would cover that distance but it's 433 MHz at lowest, and i need lower frequency (preferably lower than 100 MHz)

6

morse code over VLF ?

7

Consider that I have no limitations

8

If it could be done in aforementioned budget and size limitations, I would consider that solution

9

Wrong.

LoRa device spec is down to 137Mhz.

1 Like
10

Why do you 'need' a lower frequency ?

11

Because electronic warfare systems suppress 433 MHz frequency

12

I am curious if you would consider using a HAM (amateur radio operator) radio in digital mode with the correct license. Do you have any suggestions for the approximate frequency you would prefer? Is the 2200 meter band a low enough frequency?

1 Like
13

You plan to engage in electronic warfare with something built from an Arduino?

The forum will not help you if you are planning something illegal or designed to kill or injure people.

14

You might want to provide further details on your project as my interpretation of the above is that your project may be intending to circumvent EW systems which would be a red flag for me.

15

So you want to operate comms in an area where, presuambly the owners of the area, have gone to a deal of trouble to prevent normal comms from working ?

Simple on\off ?

16

2200m is great but I'm afraid I won't be able to pull this off. I'm looking into 30-100 MHz frequencies.

17

I missed this before my previous post and am not willing to help anyone bypass electronic warfare systems. Iā€™m out of here.

18

And then add the antennas and what will the size be? Or are you not including the antennas

19

Antennas included.

20

Please spend a few minutes researching antennas for the frequencies you are interested in.