LD-1TR Software-Defined Transceiver

The LD-1TR is a NEW 5-Watt (nominal output) HF / MF transceiver for Amatreur Radio operators. It's based on the LD-1B2 software defined receiver (in fact, there's an LD-1B2 inside it and it looks just like an LD-1B2) but there's an LD-1TX 5-Watt transmitter module inside the box. Like the LD-1B2, its low cost and high performance make it a great addition to any ham shack. Small in size, it is also ideal for portable operation using a notebook computer. It does require a host computer, either desktop or notebook (or even a netbook) with Windows XP, Vista, or Windows 7; a souncard with a stereo line-in connector; and SDR signal-processing software (HDSDR is recommended, download it at no cost). The current host software and firmware may be downloaded on the Downloads page.

"Wav" format demonstration files, recorded using Winrad, are also available on the Downloads page. These may be played back using Winrad, and will let you experience the LD-1 before you buy.

The LD-1TR has a very nice extruded aluminum enclosure with an attractive black anodized finish.

Here's a video demonstrating the LD-1B with Winrad 1.6.1 software. The antenna was an MFJ Super Hi-Q Loop, and the soundcard was an E-Mu 0202. To order an LD-1B, go to the Lazy Dog Store.

	LD-1TR Hardware: The LD-1TR hardware includes a DDS I/Q local oscillator, quadrature sampling modulator (QSM), push-pull power amplifier, and a set of six, relay-switched lowpass filters. It works like the LD-1B2 receiver, but in reverse. Modes include AM, FM, CW and SSB. Most digital modes can also be used, through third-party software.(Back to Top)
	Host Software: The host's SDR software, which is available from several third-parties at no cost, performs IF signal processing and demodulation. Compatible modes include AM, FM, SSB, CW, and in some cases DRM. "Soundcard" modes such as PSK31 are available using appropriate software and a second soundcard or Virtual Audio Cable. HDSDR (similar to Winrad) is preferred, because of its transmitter support features and because the LD-1TR software installation package includes a DLL which connects it with HDSDR's controls so the operator can change the LO frequency either from Winrad or from the LD-1 control panel. A standalone LD-1TR control application is also included in the installation package to let you use your LD-1TR with other SDR software, such as Rocky. (Back to Top)
USB-Controlled Frequency-Agility: The SDR software has a tuning range of 48 kHz, 96 kHz or 192 kHz, depending on the soundcard's sample rate. The tuning range is centered at the LO frequency, so the crystal-controlled LO found in many low-cost SDR's restricts the frequency coverage to a single 96-kHz range. The LD-1TR uses a synchronized pair of direct digital synthesizer (DDS) chips as its quadrature LO, resulting in extreme frequency agility. The LO frequency is selected via a USB connection, either from the LD-1TR's control panel (shown above) or directly from HDSDR. When the LO frequency is changed, one of the eight receiver preselector filters and one ofe the six transmitter lowpass filters are automatically selected. These control functions are performed by a microcontroller. The microcontroller's firmware may be updated by the user via the USB cable. (Back to Top)
Soundcard Considerations: Like any SDR which relys on a host computer and soundcard, the LD-1TR's performance is dependent on the performance of the soundcard. An expensive professional-grade soundcard like the Delta-44 is NOT required. The LD-1B performs very well with a Creative SB1090 USB sound adapter, which is available for $50 - $75 dollars and is ideal for portable use with a notebook PC. For transceive operation, two soundcards are required. The PC's internal soundcard can be used as one of them, for mic input ans speaker or headphone output, with no performance degradation. The other, which should be of reasonably high-quality (SB-1090, SB-1095, E-Mu 0202 or similar) is used as an interface between the LD-1TR and the PC. (Back to Top)
Performance: The LD-1TR's performance has not been fully characterized, but after using the prototype for several months with an MFJ Super High-Q loop antenna, an SB1090 sound adapter, and HDSDR, it can be described as comparable to the performance of Yaesu FT-817 in terms of sensitivity and out-of-band signal rejection. The power output is 5 Watts or more from 160 meters to 20 meters, and slightly less above 20 meters. The SDR software provides a spectrum-analyzer-like graphical display of all signals within the tuning range, and the operator can instanly tune to any signal with a single mouse click. The IF bandwidth is highly adjustable, as are the AGC characteristics. After operating the LD-1TR with HDSDR, going back to a non-SDR transceiver feels like flying blind. (Back to Top)
Professionally Designed For Amateurs: The LD-1B was designed by a lifelong ham with degrees in Electrical Engineering from Rose-Hulman Institute of Technology and Purdue University, and 30+ years of industrial and academic experience, so you can rely on its technical soundness. It is built on a high-quality PC board using dedicated power and ground planes as well as extensive decoupling to minimize EMI and EMC problems. (Back to Top)

Specifications
Frequency Coverage:	100 kHz - 30 MHz
Sensitivity:	0.18 µV for 10 dB signal-to-noise ratio at 10 MHz
Image rejection:	Comparable to Amateur-grade receivers
Overload Characteristics:	Comparable to Amateur-grade receivers
Power Supply:	6 - 14 VDC "wall-wart" with 2.1 mm x 5.5 mm male connector, available seperately
Rear Panel:	3.5 mm stereo output jack, 3.5 mm stereo input jack (for planned transmitter module when available), 3.5 mm "stereo" accessory jack, USB mini-B for connection to host, SMA female antenna connector, and 2.1 mm x 5.5 mm coaxial female power connector (center positive).
Front Panel:	Power switch (push-on, push off), green LED power indicator, red LED mute / transmit indicator
Dimensions:	1.1875 x 3.125 x 7.0 HWD (overall)