Elecraft K160RX - Manual (Page 10)

10
Using the K160RX
Receive Antenna Preamp and Attenuator Settings
Preamp and attenuator settings can be different for the receive antenna. For example, if you use a low-
noise, low-gain receive antenna on 160 m, you might want the preamp to be on whenever the receive
antenna is on, but off when you select the main antenna for receive. The K2 saves preamp and attenuator
settings for the receive antenna ON and OFF cases on a per-band basis.
160-Meter Frequency Selection
You can switch to 160 m using B A N D + / B A N D - . To use direct frequency entry, add a leading zero (e.g.,
0 1 8 0 5 ). This distinguishes between the 160-meter band (1.8 MHz) and 17-meter band (18 MHz).
High Current (HI CUR) Warning
If you see a HI CUR warning when operating on 160 meters at over 5 watts, it may be due to low supply
voltage. For operation above 5 watts on 160 meters the supply voltage should be 12.0 volts or higher on
key-down (or when using
T U N E ). The voltage can be checked using the D I S P L AY button. With
batteries and some power supplies, the voltage on transmit may drop from 13 or 14 volts to 12 volts or
lower on transmit. In this case you should reduce power to less than 10 watts.
Operating Considerations
160 meters– or "top band" as it is sometimes called– is the only Amateur band in the LF range (300 kHz-3
MHz). At these frequencies, low-power operation is particularly challenging. First of all, it can be difficult
to erect a full-size antenna. A quarter-wave vertical cut for 1825 kHz would be roughly 128 feet (44 m) tall,
and a dipole would be nearly the length of a football field. In addition, 160 meters is often plagued by
atmospheric noise, particularly in summer.
You'll probably find 160 meters most rewarding if you do the following:
1. Put up the largest possible antenna, and use a high-e
f f i ci e ncy a nt enna t une r i f you don’ t ha ve r oom f or
a resonant system. The Elecraft KAT2 and KAT100 ATUs will tune most wire antennas on 160
meters. (These ATU options also include an SWR bridge, providing more accurate power readings
than the K2's internal RF detector.)
2. Use a low-noise receiving antenna (the K160RX option can help here).
3. Listen very late at night and into the early morning hours for DX, especially in winter months.
4. Become familiar with the informal 160-m band plan (see www.arrl.org), including the DX windows.
5. Watch QST and other publications for 160-meter contest announcements. You'll find many more
stations on the band during contests, and they'll try very hard to copy you, regardless of how much
power you're using. 160-meter operators are among the most skilled you'll find on any band.
6. Kilowatt amplifiers are the rule, not the exception, among 160-m ops. If you use your K2 "barefoot" (5
to 10 W) you'll have to work hard for your QSOs, but you'll definitely get a pat on the back for it.