Avoiding cordless phones on the 900 MHz ham band
by: kb9mwr

Cordless phones are typically spaced every 30, 60 or 100 kHz. It depends on the manufacture.   Channels that end in "00" or "000" seem to be very hard hit by cordless phones, and other Part 15 stuff.. Most hams have taken to use "splinter" (12.5 step) channels that end in "5", such as 927.9625, etc  to cut down on the interference potentials.  100 kHz each side of a known signals seems to be reasonable.

A quick look:

927.4800

Cordless Phone

927.4850

 

927.4875

 

927.4900

 

927.4950

 

927.5000

Nat calling simplex (PL 151.4)

927.5050

Cordless Phone

927.5100

Cordless Phone

927.5125

 

927.5150

 

927.5200

 

927.5250

 

927.5300

 

927.5350

 

927.5375

 

927.5400

Cordless Phone

927.5450

 

927.5500

 

927.5550

 

927.5600

 

927.5625

 

927.5650

Cordless Phone

927.5700

Cordless Phone

927.5750

 

927.5800

 

927.5850

 

927.5875

 

927.5900

 

927.5950

 

927.6000

Cordless Phone

927.6050

 

927.6100

 

927.6125

 

927.6150

 

927.6200

 

927.6250

Cordless Phone

927.6300

Cordless Phone

927.6350

 

927.6375

 

927.6400

 

927.6450

 

927.6500

 

927.6550

 

927.6600

Cordless Phone

927.6625

 

927.6650

 

927.6700

 

927.6750

 

927.6800

 

927.6850

Cordless Phone

927.6875

Cordless Phone

927.6900

Cordless Phone

927.6950

 

927.7000

 

927.7050

 

927.7100

 

927.7125

 

927.7150

 

927.7200

Cordless Phone

927.7250

 

927.7300

 

927.7350

 

927.7375

 

927.7400

 

927.7450

Cordless Phone

927.7500

Cordless Phone

927.7550

 

927.7600

 

927.7625

 

927.7650

 

927.7700

 

927.7750

 

927.7800

Cordless Phone

927.7850

 

927.7875

 

927.7900

 

927.7950

 

927.8000

 

927.8050

Cordless Phone

927.8100

Cordless Phone

927.8125

 

927.8150

 

927.8200

 

927.8250

 

927.8300

 

927.8350

 

927.8375

 

927.8400

Cordless Phone

927.8450

 

927.8500

 

927.8550

 

927.8600

 

927.8625

 

927.8650

Cordless Phone

927.8700

Cordless Phone

927.8750

 

927.8800

 

927.8850

 

927.8875

 

927.8900

 

927.8950

 

927.9000

 

927.9050

 

927.9100

 

927.9125

 

927.9150

 

927.9200

 

927.9250

 

927.9300

 

927.9350

 

927.9375

 

927.9400

 

927.9450

 

927.9500

 

927.9550

 

927.9600

 

927.9625

 

927.9650

 

927.9700

 

927.9750

 


While this is still not fool proof,  I believe it's better. Also and use DPL protection, if possible. DPL because some if these cordless phones send out short bursts of various (sometimes) matching PL tones as part of their  sub-audible security code handshake.  It's a shame the RSS/Radio doesn't support a 6.25 kHz step!