LPD433

"SRD" redirects here. For other uses, see SRD (disambiguation).

In telecommunication, a low-power communication device, also short-range device (SRD) is a restricted radiation device, exclusive of those employing conducted or guided radio frequency techniques, used for the transmission of signs, signals (including control signals), writing, images and sounds or intelligence of any nature by radiation of electromagnetic energy. Examples: Wireless microphone, phonograph oscillator, radio-controlled garage door opener, and radio-controlled models.

Low Power Device 433 MHz (LPD433) transceiver radios are short range, licence free communication devices authorized for use in many parts of the world. In some countries, however, voice is not allowed over LPD. They operate in the UHF band from 433.075 MHz to 434.775 MHz with 25 kHz channel spacing, for a total of 69 channels. These devices are frequency modulated (FM) with a maximum legal power output of 10 mW. LPD devices must only be used with the integral and non-removable antenna. LPD was introduced to reduce the burden on the eight PMR446 channels over shorter ranges (less than 1 km) . Channels 1 to 14 are UK Amateur repeater outputs and channels 62 to 69 are UK Amateur repeater inputs.

Channel	Frequency (MHz)	Channel	Frequency (MHz)	Channel	Frequency (MHz)
1	433.075	24	433.650	47	434.225
2	433.100	25	433.675	48	434.250
3	433.125	26	433.700	49	434.275
4	433.150	27	433.725	50	434.300
5	433.175	28	433.750	51	434.325
6	433.200	29	433.775	52	434.350
7	433.225	30	433.800	53	434.375
8	433.250	31	433.825	54	434.400
9	433.275	32	433.850	55	434.425
10	433.300	33	433.875	56	434.450
11	433.325	34	433.900	57	434.475
12	433.350	35	433.925	58	434.500
13	433.375	36	433.950	59	434.525
14	433.400	37	433.975	60	434.550
15	433.425	38	434.000	61	434.575
16	433.450	39	434.025	62	434.600
17	433.475	40	434.050	63	434.625
18	433.500	41	434.075	64	434.650
19	433.525	42	434.100	65	434.675
20	433.550	43	434.125	66	434.700
21	433.575	44	434.150	67	434.725
22	433.600	45	434.175	68	434.750
23	433.625	46	434.200	69	434.775

In ITU region 2 (the Americas), the frequencies that LPD433 uses are within a band allocated to amateur radio. In the United States LPD433 radios can only be used under FCC amateur regulations by properly licenced amateur radio operators. The conflicting allocations have been something of a nuisance to US amateur operators due to use of the equipment by European tourists in the U.S.

Some European licence-free LPD transceivers also include Short Range Device 860 MHz (SRD860), which have a maximum legal power output of 5 mW. SRD has a total of 126 channels in five bands.

Band A	868.00625 MHz -> 868.59375 MHz	48 Channels
Band B	868.70625 MHz -> 869.19375 MHz	40 Channels
Band C	869.41250 MHz -> 869.63750 MHz	10 Channels
Band C2	869.31250 MHz -> 869.38750 MHz	4 Channels
Band D	869.70625 MHz -> 869.99375 MHz	24 Channels

See also

• DASH7
• PMR446
• Part 15
• ISM band

References

•  This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on 2022-01-22.
• NTIA Manual of Regulations and Procedures for Federal Radio Frequency Management