Disclaimer. Anything in this article is a private opinion guaranteed by Universal Declaration of Human Rights (UDHR). The author doesn’t impose it to anybody. Parameters are shown in this article are relative, and don’t reflect standard parameters of this type of the devices. If one would use different methods of measuring (or different types of measuring devices), the result different. The author doesn’t bear any responsibility for any consequences related to devices described in this article, including a lost profit. Decisions made by a reader are implemented at his own risk. Manufactures who think they are defamed can present their own refutations and the author will publish them with (or without) changing his own opinion.
The 1st part with methods described.
The 2nd part with transmitters results.
The 3rd part with receivers results.
Part 4. Conclusions
The best way to get a good RX/TX device is to buy more expensive and complicated device or DIY.
But everybody wants to buy cheap modules and get good parameters. It can be acquired, but one should check these devices by himself. Many modules I ordered as a 315MHz came as a 433MHz. Many modules were unstable or even broken.
From modules below I cannot point to the best module and recommend it to somebody. Each module has its own disadvantages.
Summary table for transmitters modules:
Number, photo and sizes (in mm)
|
Current consumption in transmission mode
|
F1, MHz
L, dB (More is better)
|
F2, MHz
L, dB (less is better)
|
F3, MHz
L, dB (less is better)
|
19x18x7 (w/o pins)
|
10mA
|
-66dB
|
-70dB
|
-78dB
|
11,5x11,5x6
|
10mA
| -68dB |
N/A
|
N/A
|
10x10x3
|
Sp.ant.: 7mA
Pin ant.: 8mA |
Spiral antenna: 315,05Mhz
-72dB Pin antenna: 315,05Mhz -70dB |
Spiral antenna: 630,0Mhz
-97dB Pin antenna: 630,0Mhz -96dB |
N/A
|
12,5x17x4 (w/o pins)
|
47mA
|
Main band:
433,79MHz -44dB 2 parasitic side bands: 447,35 and 420,23MHz -88dB |
867,79MHz -83,5dB
|
1301,64MHz
-74,0dB |
| Comments: Maybe it has the bad matching with the antenna. | ||||
19x18x7 (w/o pins)
|
47mA
|
433,180MHz
-55dB |
867,444MHz
-67,5dB | -57,5dB(!) |
11,5x15x6
|
16mA
| -66dB |
N/A
|
N/A
|
11,5x15x7
|
88mA
| -56dB Pin antenna: 433,9Mhz -51dB |
Spiral antenna: 867,84Mhz
-95dB Pin antenna: 867,84Mhz -95dB |
Spiral antenna: 1301,8Mhz
-93dB Pin antenna: 1301,8Mhz -82dB |
Comments: Good module with powerful output.
| ||||
19x18x7 (w/o pins)
|
Sp.ant.: 107mA
Pin ant.: 119mA | -51dB Pin antenna: 433,95Mhz -52,5dB |
Spiral antenna: N/A
Pin antenna: 867,51Mhz -73dB |
Spiral antenna: 1301,3Mhz
-77dB Pin antenna: 1301,3Mhz -87dB |
Comments: Parameters are like in the TX433-4 module. But it has more current consumption and not good spectrum of harmonics.
| ||||
11x15x3
|
65mA
| -52dB Pin antenna: 433,95Mhz -67dB |
Spiral antenna: 867,84Mhz
-96dB Pin antenna: 867,51Mhz -93dB |
Spiral antenna: 1301,92Mhz
-96dB Pin antenna: 1301,3Mhz -90dB |
Summary table for receivers modules:
Number, photo and sizes (in mm)
|
Current consumption
|
1st band, center F, MHz
Bandwidth, MHz L, dB (more is better) |
2nd band, center F, MHz
Bandwidth, MHz |
3rd band, center F, MHz
Bandwidth, MHz |
x18x7 (w/o pins)
|
7mA
| L>50dB |
N/A
|
N/A
|
 
30x13x4
|
4mA
| L>50dB |
Fc=438,5MHz, dF=1,0MHz
L=20dB |
N/A
|
NB: Similar module with “Dl-RXC2015 v.2.0” mark had come defective – it hasn't operated at all.
| ||||
11,5x17x6
|
<1mA
|
Fc=317,0MHz, dF=4,0MHz
L=10dB |
Fc=340,0MHz, dF=4,0MHz
|
N/A
|
18x8x2
|
<1mA
|
Fc=315,0MHz, dF=5,0MHz
L>50dB (both with spiral and pin antennas) |
N/A
| N/A |
Comments: The module has the very good sensitivity and only one band. In addition, it has low supply current too.
| ||||
12x10x6 (w/o pins)
|
<1mA
|
Fc=316,8MHz, dF=1,5MHz
L>50dB (both with spiral and pin antennas) |
Fc=319,0MHz, dF=1,2MHz
L>50dB |
+2 bands near 340,0MHz, dF about 1-1,5 MHz
|
30x8.5x5 (w/o pins)
|
<1mA
|
Fc=434,1MHz, dF=0,7MHz
L>50dB |
Fc=420,5MHz, dF=1,0MHz
|
Fc=447,0MHz, dF=1,0MHz
|
21,5x9x6
|
<1mA
|
Fc=434,8MHz, dF=1,0MHz
L=30dB |
N/A
|
N/A
|
Comments: It’s one of the best modules in the case of selectivity. But the sensitivity is average.
| ||||
43x11,5x5 (w/o pins)
|
<1mA
| L=25dB |
Fc=420,0MHz, dF=1,0MHz
|
Fc=447,0MHz, dF=1,0MHz
|
Comments: One of the worst modules. It has 3 bands. The main band is too wide – 5,0 MHz. The sensitivity is poor. And in addition it’s the biggest module I got.
| ||||
30x14x8 (w/o pins)
|
7mA
|
Fc=435,5MHz, dF=4,3MHz
L>50dB |
N/A
|
N/A
|
18x12x2
|
<1mA
|
Fc=435,5MHz, dF=2,0MHz
L>50dB |
N/A
|
N/A
|
35x10x8
|
<1mA
|
Fc=435,8MHz, dF=0,3MHz
L=30dB |
N/A
|
N/A
|
So, I can highlight some modules in the transmitters:
- TX315-2 or TX315-3 – Others are worse;
- TX433-6 is better with spiral antenna for high-power cases;
- TX433-4 is better for pin antenna for high-power cases;
- TX433-3 is better for low-power cases.
And in receivers:
- RX315-2 if there’s enough power supply;
- RX315-4 if the low power consumption is important;
- RX433-1 if the high sensitivity is required;
- RX433-2 or RX433-6 if the high jam-protection is required.
And in addition, it wasn't obvious for me (I used these modules for the first time) if there’s no useful signal in the air, the output of the receivers has a chaotic signal (it tries to receive any weak signal, and it cause a noise on the output pin as a result). Unpleasantly, the transition to useful signal in most cases could be detected only by a long pause after a packet transmitted. It should be considered if you design your own devices using this types of RF modules.
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