Initial Impressions of the RX-320 by Chuck Olson, WB9KZY

Ten-Tec has recently released the RX-320 PC radio. I purchased mine directly from Ten-Tec at the beginning of September, 1998. I requested delivery by US Mail and I received my radio 3 days later. UPS is a hassle for me here on the Island, so it's really neat that Ten-Tec will ship via the Postal Service.

This radio IS the often mentioned but rarely seen "black box". The front panel is solid black except for the Ten-Tec logo. Download this file back.jpg (14k) for a picture of the rear panel of the RX-320.

The RX-320 includes the following:

  • The radio itself (firmware version 1.06)
  • Windows control software (version 1.25)
  • 9 pin serial cable
  • a hefty wall wart power supply with a 2.5 mm coaxial connector
  • a black finish collapsable whip antenna
  • the manual


    • 10/6/98 - I forgot these two items:
  • a stereo audio cable (1/8 inch stereo mini phone plugs)
  • an RCA phono plug (to attach an exterior antenna)


    • The manual mentions a warranty card - I didn't get one with the radio but after sending an email to Ten-Tec they mailed one to me.

    I also received a sample copy of Popular Communications which is both a nice touch and possibly an indication that Ten-Tec is trying to broaden their target market to include SWL listeners as well as their customers among ham radio operators.

    The software is easy to install and works well for me with my 486 and Windows 3.1. The software does have some omissions such as no control over AGC selection OR access to all of the 34 bandwidths that the DSP provides but I assume that Ten-Tec will be adding this type of stuff to future revisions of the software. The user really will need a mouse to use all the features of the software although this isn't really a big deal for most windows users. The radio can be controlled from the keyboard, except for the filter selection, the memory and the spectrum display. I hope that Ten-Tec adds keyboard control of these items in later versions of the program because I normally have my mouse on COM1 and I use COM2 for my internal modem so I have to run the program mouseless for now. The exit from the program should be an Alt-F then X to conform with all the other Win 3.1 programs that I use. Also, the Alt-Q to exit spec'd in the manual doesn't work for me. Tom Cooper's (W1EAT) DOS program [rx320.zip (48k)] gives me full keyboard control of the radio and since I'm normally using DOS anyway, it's very convenient.

    My computer / monitor are fairly noisy (electrically and audibly) but I did also try the radio with a laptop and found that it works quite well providing that I used the external antenna input - this seemed to isolate the radio from the computer a little.

    The manual seems to already be slightly out of date (some of the screen shots show a 6 Khz maximum filter width while the actual control software has an 8 khz maximum filter width). The technical details are few, no schematics - the manual is mostly a review of the control software and a tutorial by author Joseph J. Carr on Shortwave listening.

    I couldn't resist opening the radio up - There are two circuit boards inside - the top board (called the RF board) has all the coils, caps and other good stuff needed to convert the RF signal down to the DSP IF. Here is a picture [rf.jpg (52k)] of the RF board of the RX-320. There is also a lot of circuitry on the bottom of the board (surface mounted) including 3 ICs: A TL082 op amp, a 74LS390 dual counter and an MC145170D1 PLL chip from Motorola.

    The bottom board (called the DSP board) has the all the DSP and control chips. Here is a picture of the DSP board [dsp.jpg (52k)]. The DSP chip is the Analog Devices ADSP-2101 in a socketed 68 pin chip carrier package. The A/D and D/A functions are handled by an Analog Devices AD1847 soundport CODEC chip which is in a socketed 44 pin chip carrier package. The version 1.06 firmware is contained in a 28 pin socketed DIP EPROM. The top of the DSP board also has a voltage regulator and the audio amplifier chip. The bottom of the DSP board has 4 chips including 3 digital logic chips (an 74HC14, 74LS00 and 74HC574) along with the RS-232 interface chip (Analog Devices ADM232AARN).

    The bottom line for me is that the RX-320 is a really nice radio that will only get better as new software and firmware is released by Ten-Tec and others.

    Check out our: Washington Island BOOKS
    go back to the:TOP PAGE
    Link back to: Ham Radio kits