Frequently Asked Questions

Why is the maximum power of the ADT-200A limited to just 50W?

There is a number of reasons:

  • There is simply no space for a bigger power supply and the heat dissipation is critical.
  • Power amplifier, harmonic wave filters and antenna switch are designed for 50W.
  • A 3dB power gain can be achieved by using an intelligent preprocessing of the speech signal.
  • The sender provides just 50W, but continuously!

Can I control an external power amplifier?

Yes, the control signals are available. Some power amplifiers will require an external adapter to adjust the signal levels. The adaptive predistortion can be extended to the PA, if a signal attenuated by ca. 50dB is fed back from the PA to the input "Ext_Monitor".

Is a Spectrum Monitoring function available?

The spectrum can be displayed with the available resolution on the transceiver display. Higher resolution can be achieved by connecting the transceiver via USB port to a PC. The maximum bandwidth is up to 30MHz provided that the preselector is switched off.

Is remote control via CAT possible?

There are two ways to remote control the transceiver:

  • Via USB interface, controlled by a PC
  • Via LAN using an optional Web Server Module which is installed into the transceiver. This gives the possibility to operate a remote station via an internet connection. (between two ADT-200A devices).

An actual CAT interface is not available, because there is no standardization.

How is it possible to achieve a dynamic range of 112dB with a resolution of just 14 bits?

It is correct that a 14-bit AD-Converter exhibits an effective signal to noise ratio of only 75dB. However, this value comprises for the whole bandwidth of 32MHz. By filtering appropriately and therefore reducing the bandwidth B, a process gain of P = 10*Log10(32MHz/B) can be achieved. With B=2400Hz, the process gain results in ca. 41dB, therefore the dynamic range is increased to 75 + 41 = 116dB.

Is a broadband IF output available?

Since the Rx converts directly to 0Hz, there is no traditional IF available. For DRM reception, the signal is converted to an IF of 12kHz. This IF can also be used for signal analysis with a sound card.

Will the software be available as open source?

The source code will not be available, because the cost of the necessary development tools exceeds the cost of a transceiver by a multiple. Additionally, the code could be misused for commercial purposes.

Are updates available, and what is the cost?

Software updates with new functions will be free and can be downloaded via website. Software options (see above) will be with costs.

With 4 Rx and 4 Tx VFO's, can I set each one to a different band and work cross band?

Yes, the VFO's can all be set to the same or to different bands, independant from its Rx-frequencies. The user must keep in mind, that each selection of a band will also switch in the appropriate halfband filter in the preselector.

There are various programs that switch bands and frequencies quickly - such as the new ALE digital mode. Will it be possible to switch the VFOs quickly using external computer CAT control?

The TRX is prepared for remote control. The ADT-200A has its own proprietary data base, which means that the remote terminal (PC) has to learn the possible settings and options from the ADT-200A.

In the future, ADAT will publish a document with the control codes so that other programs may be updated to operate the ADT-200A.

Will you be offering a small Amplifier in the future? 50W seems quite low under the Solar conditions that we have to live with for another year or two.

There are many commercially available Power Amplifiers, which work fine with 50W input.

QSK has been advertised by several vendors. But when a good CW operator tries the QSK it sometimes is not very useful. How is the ADT-200A QSK implemented with AGC? can you hear the other station in between dits sent at say 30WPM?

The AGC will not be affected by the transmit signals, so you can hear even weak signals between dits. This is also enhanced by the very fast T/R switching time of less than 10ms. The ADT-200A has been carefully engineered so that, unlike some other SDR radios, the ADT-200A will not have long T/R delays caused by software or firmware.

Will the CW waveform be conditioned so that it is very smooth and has no clicks or harmonics? Some modern rigs allow the attack and decay times of the CW waveform to be adjusted from 2ms to 8ms. Will the ADT-200A have any adjustments in the menu for CW?

The Tx CW signal will be shaped by means of a special filter to prevent out of band clicks. The cutoff of this filter is adapted to the keyer speed. In case of a manual key, its cutoff is optimized for approximately 30WPM.

There is a strong interest in "Enhanced SSB" (ESSB) where the Tx bandwidth is 2.7Khz. Some ESSB operators use 4Khz to 6Khz bandwidths. Will the ADT-200A allow wider Tx bandwidths?

The transmit voice bandwidth is limited by regulation to 2.7kHz here in IARU Region-1. The Tx cutoff frequencies of the ADT-200A are user selected for 100, 200, 300Hz for the lower end, and 2400, 2700, 3000Hz for the upper limit as standard. ESSB operators may contact ADAT Engineering for possible modifications to the firmware to accommodate wider Tx bandwidths consistent with the regulations in their home country.

Will you allow Tx on any frequency that the VFO can generate? In the United States stations are allowed to operate outside the standard Ham bands if they are properly certified for Military Affiliate Radio System (MARS) operation. Will you allow MARS operation outside the normal bands?

The Tx frequencies are limited to the HAM bands. Tx frequencies outside the HAM bands are possible upon special request with proper station identification consistent with the regulations of their country.

Is there any provision for connecting a PS/2 or USB computer Keyboard to the ADT-200A for digital modes or CW?

Yes, there is an input for a PS/2 compatible keyboard. For USB, an small adapter is needed.

Automatic fine tuning was listed for SSB. Will the automatic feature also help "Zero Beat" in CW?

Zero Beat can be accomplished by simply pressing the F-TUNE button.

Will the PA shut down if it senses a very bad mismatch to the Antenna?

There is a supervision for an VSWR and, in addition, a over current shut down feature.

Will the PA shut down if it senses an Over Voltage (> 15VDC?)

The ADT200A is powered from the wide range AC input (90…240Vac). Yes, the internal power supply monitors for over voltage and unwanted other power conditions.

How does the ADT-200A compare with the Elecraft K3?

The Elecraft uses an analog concept with a DSP in the last IF. The ADT-200A is a radical new design that departs from the past. If you want a rig that is state-of-the-art, you should carefully consider all the features the ADT-200A.

Why should I purchase a rig that uses (SDR) Software Defined Radio technology?

Generally said, SDR technology is an exciting alternative to the conventional design concepts. SDR offers much more flexibility and is open for simple future upgrades and deployment. ADAT hopes that Hams will have many different designs from which to choose. This is an exciting time to be alive and in the Ham Radio hobby. As the new Solar Cycle begins to pick up steam, the ADT-200A will be at the head of the line to take on all the opportunities for new modes and new DX.

What are the benefits of the ADT-200A direct digital conversion design?

The direct digital design has the big advantage, there is no need for noisy synthesizers, spurious analog mixers, and restrictive and expensive crystal filters. This technology allows a drastic reduction of the component count and offers a much better reproducibility and a higher reliability, red with conventional analog designs.

Amateur and Commercial RF design engineers have been searching for a technology that would meet the ultra high speed needs of a Direct Digital Conversion radio. In 2007 the necessary chips and control electronics have finally been merged into the exciting new ADT-200A rig. The ADT-200A is the *first* Amateur Radio equipment to incorporate these sophisticated state-of-the-art technologies. There are some direct conversion *receiver only* designs that demonstrate the value of this architecture. However, none of the receivers has been combined with a leading edge transmitter and control firmware to form a full Ham Radio piece of equipment. You have a unique opportunity to own a rig that no one has ever been able to purchase in the past. The ADT-200A is a breakthrough design.

Digital chips have advanced since last year with you first designed some of the circuits. Will the ADT-200A have modern chips that are the best available?

The ADT-200A chipset has been updated several times since it was first designed. Each of the design decisions were optimized to create a cost effective rig consistent with leading edge modern design. Faster chips with more bits are not needed to reach a high level of performance that is cost effective.

Many rigs are de-rated (operated at lower than full power) when running digital modes. For example, digital SSTV using EasyPal recommends that you operate some rigs at 1/4 of their full power (25w). How will the ADT-200A handle digi modes with continuous tones such as RTTY and SSTV?

The ADT-200A is designed to deliver the rated output (50W) at continuous operation.

If I want to connect an Automatic Antenna Tuner (ATU) will there be any provision for communicating with the ADT-200A. In some rigs there can be a direct RS232 connection from the rig to the ATU to change bands and initiate tuning.

The ADT-200A has a 9pin D-sub connector as an universal interface. ADAT intends to build a small external box which serves as an interface to different peripheral units like Amplifier, ATU etc. In the case of unmanned remote controlled rig, there is also a possibility of operating bands switching and rotors etc. Please watch our website for new announcements.