The KSYN3A synthesizer module is a completely new design that improves on the original KSYN3 and the performance of the K3 in several ways:
Low Frequency (500 kHz) Receive:
With a KSYN3A installed, the K3 VFO can be tuned as low as 100 kHz. Sensitivity will be very good around the 600-meter band (470 kHz) if a KBPF3 filter and the KXV3 modules are installed and the antenna is connected to either the RX ANT IN or XVTR IN jack on the rear panel. The RX ANT IN and XVTR IN both bypass the transmit-receive (TR) switch and its associated high pass filter which would greatly attenuate the low-frequency signals. However, below 300 kHz sensitivity starts to decrease quickly because the receiver in the K3 was optimized for use on higher bands. Typical sensitivity at 300 kHz will be about -100 dBm. The preamp should be turned off because it is not useful at these low frequencies; it will only increase noise level.
Ultra-Low Phase Noise:
The KSYN3A significantly improves the K3's already excellent receive and transmit phase noise at close carrier spacing. This in turn not only improves the K3's top performing close spaced receive dynamic range, yielding even better weak signal detection in the presence of strong signals.
Faster CW break-in and more accurate CW element timing.
Excellent Mechanical Stability:
The KSYN3A is virtually immune to both physical vibration and magnetic coupling, and operates over a very wide temperature range.
Basic K3s have one synthesizer. If you have the optional KRX3 Subreceiver installed in your K3 there will be two synthesizers and you must order a second KSYN3A Upgrade kit. If your K3 has both synthesizers, they both must be the same type.