This is a small radio set, as in just a tad larger than a mint tin. What you get: The radio set SW-3B is a lightweight, rugged, miniature, single-conversion transceiver that operates (transmits) on three Internationally allocated high frequency bands within the Amateur Radio Service - 40M, 30M and 20M. It may be powered with any stable DC source between 8 and 15 VDC. Power consumption in is minimal . With the backlight on (display illuminated), the radio draws ~43 mA. With backlight off, it draws only ~37 mA (@13.8 VDC). Actual current used will vary slightly based ion input voltage. The radio set SW-3B also offers broadband reception from 5 to 16 MHz in the so-called shortwave bands. This broadband feature also allows reception of WWV on 5, 10 and 15 Mhz for frequency check, time and weather reports. Reception of International Shortwave Broadcasts using USB mode is possible with careful tuning. A relative S meter is provided. The unit is all digital. The VFO control provides for tuning in 10 Hz, 100 Hz. 1kHz, 100KHz increments. The RIT/XIT function permits receiver offset tuning in 10 Hz increments and transmitter offset tuning in 100 Hz increments. In addition to manual tuning via the rotary encoder, eight memories per band are provided to store frequency/mode. Changing between stored Memory and the VFO is by a pushbutton. Changing between Memory locations is via the Tune (VFO) knob. A slide switch is used to change between bands. Unlike other small form factor radio sets, the SW3B offer sbioth a volume control (AF Gain) and an RF Gain control. Unit is equipped with an audio-derived AGC loop. Placement of the operator controls and connectors only on the sides of the chassis clearly puts this radio in the class generally known as Trail Friendly. With both the top and bottom of the chassis free of control ports, you may place the radio set upright, on a stand or tilt the radio set for the best viewing angle and not impact any connections. While seemingly a minor detail, this flexibility is a nice touch for operating in the field. The high-contrast digital display is large enough to easily read in bright sunlight and it has a backlight for viewing at night. The backlight may be turned off during daylight operations for a ~15+% saving in current draw on receive. The backlight may be set to on, off or AUTO. In AUTO mode, the unit will light the display for 10 seconds on any command input, such as adjusting the VFO. After 10 seconds with no operator input, the display backlight will extinguish. The receiver is single conversion, with a crystal ladder filter to reduce noise and adjacent signal interference. The Beat Frequency Oscillator (BFO) operates at 4.914 MHz. The BFO injection signal to the second mixer signal is provided directly by the Si5351 DDS source. Very clever and ensures the BFO signal tracks the VFO exactly.. The filter may be set for narrow (CW/CWR) and wide (USB/LSB). This bandwidth change is controlled by a simple pushbutton and is automatic, depending on the mode selected. Receiver performance is impressive, with Minimum Discernible Signal (MDS) levels of 0.1 to 0.2 microvolts (-127 dBm @ 50 ohms) typical. The transmitter is a classic Master Oscillator/Power Amplifier (MOPA) type fed directly by the DDS system. The transmitted signal passes through several filters to reduce harmonic content in the output. 5 watts nominal @ 12.8 VDC is easily obtained. The transmitter final amplifier (PA), is a robust IFR510 MOSFET (or in earlier radios, an 2SC2078) transistor (Q3). The PA is protected from high VSWR by a Zener diode, type 1N4756A in the earlier models. The antenna is attached via a BNC connector mounted on side of the unit. The internal keyer supports iambic keying via a set of operator-supplied paddles. Use of a straight key is supported as well. (See operation manual for more on keys). A keyer memory allows automated calling of CQ w/Operator callsign at the push of a button. Operating on a DC input between 8 and 15 Volts DC, the radio transmits with a nominal power of five watts output with 12.8 DCV applied. The power input is protected against reverse polarity. External power supplies should be able to provide up to 2 amperes of current with no AC ripple. A simple battery pack made up of eight "AA" (or 10 NiMH) batteries provides ample power. Power used on RX - ~37mA (back light off) ~43 mA w/backlight. Power used on TX - ~800 mA,.use of AA batteries (NiMH or alkaline) provide more than enough power for a long afternoon and chsing DX. Please note that the unit transmitted power output drops off with lower input (supply) voltage. Radio does not have nor has the space to allow internal battery or antenna tuner. No internal speaker. this shows how tight the internals are - this is the older 3B1 board. (HT AE5X, John) The newer CW-3B3/2020 has no variable caps. the only adjustment is for settring the displayed DCV on the screen. not a lot of menus on this rig. RIT (receiver offset tuning) and XIT (transmit offset tuning) is offered as is CW and CWR. Add a set of earbuds, a battery pack and a key - attach a resonant antenna and you are good to go. I used a QRPGUYs end Fed Half Wave tuner with this. (QRPGuys EFHW 40m-15m or 80m only Mini Tuner - QRPGuys) The radio sells for $188 USD. Shipping time to arrival is about a month right now. The rig is popular enough that there is 0 stick. Dale Yu, BA4TB, has indicated the next back will be out near the end of Aug. Dale works this in addition to his day job, so things may seem slow, but he is paddling as fast as he can and still have a life.... The units are made, in batches, on a commercial manufacturing line, so are good quality devices. Vendor website There are multiple videos reviews on this unit on UTOOB should this be of any interest. I've just sent the full technical manual to Dale for review prior to release here in the NA market. Dale gave a radio to use to take photos and make measurements for the tech manual - full disclosure. I'm selling my -9200 radio as the SW3B blows it away in so many areas - both size and technical specs. Ping me if you have any questions. Edit to add I've posted my technical manual on a separate page here. SW3B HF qrp tranciever techncial and Operations manual
