Comparison of cheap RF modules with ASK modulation. Part 3. Results for receivers.

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 last part with conclusions.

Part 3. Receivers.

Table content:

• The 1st band: center F, MHz; Bandwidth, MHz; L, dB - Center frequency in MHz of the main receiving band and it's width in MHz. Maximum level of attenuation of RF-source while receiver can receive useful signal without any noises;
• The 2nd band: center F, MHz; Bandwidth, MHz - Center frequency in MHz of the second receiving band and it's width in MHz (if it presents);
• The 3rd band: center F, MHz; Bandwidth, MHz - Center frequency in MHz of the third and others receiving bands and their width in MHz (if it presents);

Index number: RX315-1

Current consumption	Dimensions, mm	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
7mA	30x14x8 (w/o pins)	Fc=316,5MHz, dF=3,3MHz L>50dB	N/A	N/A

It was a 433 MHz module. Even if it was described as 315MHz or it was in the set of 315MHz RX/TX modules – it was 433MHz always (see the RX433-4 Module). But I’ve liked this module – it has only 1 band and very good sensitivity. As a disadvantage, it has high power consumption – 7 mA. The receiver is a regenerator, and it has an analog comparator (LM358) on the output.

So, I tried to make it to able to receive 315MHz signals. To do that one should increase both coil’s inductances in 1,37 times.  I took the coil from the broken TX315-1 module. So, the “small” coil from that module fits ideally as an antenna one. But the generator coil is not so easy to replace. I cut away the old wire from it (it was primed in the plastic) and I took the wire from the “big” coil from the TX315-1 module and winded it on that “core”. But the required inductance has appeared only when this coil had been primed in the wax. 

So, this remake could be completed if you have some equipment to check the receiving frequency.

Index number: RX315-2

Current consumption	Dimensions, mm	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
4mA	30x13x4	Fc=316,0MHz, dF=2,0MHz L>50dB	Fc=438,5MHz, dF=1,0MHz L=20dB	N/A

It's a 315 MHz module. It has a blue PCB with a white mask and mark “WirelessCom DL-RMX2013” on the back side. Chip has no any marks. CE pin should be connected to VCC to operate. 

The module has very good sensitivity, but it has a parasitic band too. 

By the way – I ordered very similar module with “Dl-RXC2015 v.2.0” mark and it had come defective – it hasn't operated at all.

Index number: RX315-3

Current consumption	Dimensions, mm	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
<1mA	11,5x17x6	Fc=317,0MHz, dF=4,0MHz L=10dB	Fc=340,0MHz, dF=4,0MHz	N/A

It's a 315MHz module.  It has a blue PCB with “LC-technology” mark on the back side. Chip has 480R mark (SYN480R). Very poor sensitivity and selectivity. But the supply current is low.

Index number: RX315-4

Current consumption	Dimensions, mm	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
<1mA	18x8x2	Fc=315,0MHz, dF=5,0MHz L>50dB (both with spiral and pin antennas)	N/A	N/A

It's a 315MHz module. It has a blue PCB with “H5V3M” mark on the back side. The module has very good sensitivity and only one band. In addition, it has low supply current too.

Index number: RX315-5

Current consumption	Dimensions, mm	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
<1mA	12x10x6 (w/o pins	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

It's a 315MHz module.  It has a green PCB without any marks. It has a very good sensitivity, but poor selectivity – 4 bands in the range from 315 to 340 MHz. SHUT pin should be disconnected. 

Index number: RX433-1

Current consumption	Dimensions, mm	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
<1mA	30x8,5x5 (w/o pins)	Fc=434,1MHz, dF=0,7MHz L>50dB	Fc=420,5MHz, dF=1,0MHz	Fc=447,0MHz, dF=1,0MHz

It's a 433MHz module.  It has a blue PCB without any marks. Chip has no marks too. Only “WL433” mark on the SAW. Very good sensitivity. But there’re 3 bands. Altogether it’s a not bad module.

Index number: RX433-2

Current consumption	Dimensions, mm	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
<1mA	21,5x9x6	Fc=434,8MHz, dF=1,0MHz L=30dB	N/A	N/A

It's a 433MHz module. But seller described it as a 315 MHz. It has a blue PCB with “LR45B” mark on the back side. Chip has no marks. I think it’s one of the best modules in the case of selectivity. But sensitivity is average, many other modules have better one. But if one cares about jam-protection - it’s the best choice.

Index number: RX433-3

Current consumption	Dimensions, mm	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
<1mA	43x11,5x5 (w/o pins)	Fc=432,5MHz, dF=5,0MHz L=25dB	Fc=420,0MHz, dF=1,0MHz	Fc=447,0MHz, dF=1,0MHz

It's a 433MHz module. It has a green PCB with “RXB6 2.0” mark on the back side. Don’t be fooled by this cute metal cover – it’s one of the worst modules. Chip is SYN500R. There’re 3 bands. The main band is too wide – 5,0 MHz. Sensitivity is poor. And in addition, it’s the biggest module I got.

Index number: RX433-4

Current consumption	Dimensions, mm	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
7mA	30x14x8 (w/o pins)	Fc=435,5MHz, dF=4,3MHz L>50dB	N/A	N/A

It's a 433MHz module. It has a green PCB with “MX-RM-5V” mark on the back side. It has no synthesizer, the receiver is a regenerator. This module could be remade to 315MHz (see the RX315-1). It has a high sensitivity and only one band. But it has a high power consumption – 7 mA as a disadvantage.

Index number: RX433-5

Current consumption	Dimensions, mm	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
<1mA	18x12x2	Fc=435,5MHz, dF=2,0MHz L>50dB	N/A	N/A

It's a 433MHz module. It has a blue PCB with “H5V4D” mark on the back side. Attention! The module can be unstable and begin to self-oscillate. Similar the 315MHz module (the RX315-4) has more stability.

Index number: RX433-6

Current consumption	Dimensions, mm	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
<1mA	35x10x8	Fc=435,8MHz, dF=0,3MHz L=30dB	N/A	N/A

It's a 433MHz module. It has a blue PCB with “SRX882 V1.1” mark on the back side. It is the only superheterodyne from all modules I got. Chip is PT4303-S. CS pin should be connected to VCC to operate. This module brought me to a doubt. It must have 433,9MHz as center frequency by calculations, but it has almost 436MHz. But it received signals from the 433MHz wireless doorbell very well. Maybe my method of measuring is wrong, but with the other modules, this method showed believable results. Anyway, it’s the best module in case of selectivity. The sensitivity is average, but enough. As a disadvantage, it has relatively big dimensions.

    The 1st part with methods described.

    The 2nd part with transmitters results.

    The last part with conclusions.