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The RX320 Experience

The Ten Tec RX320
 
 

A few years ago,there was a novel idea to build a totally self standing radio  using a computer to control all functions.This has been done before by Rockwell -Collins and others in the military and governmental service sectors,but not for general public usage. First came a company called WinRadio from Australia , I think ,that  offered a pc radio card mounted on a ISA board. While this was effective ,two things happened, First,they offered an all band receiver in this format,which is good in some ways and not in others. Two, they  obviously back then could not build a complete  HF and VHF\UHF receiver on one tiny ISA board.
There appeared once again  another product by Icom,The PCR1000,which  had a lot to offer,but it too fell short as it was an all in one receiver as well.However, it was an out of pc receiver which helped in some ways to cut down internal noise from the computer.



Then in the late 1990's ,there was a company in Tennessee called Ten Tec that already had vast experience in amateur radio design and also some military communications experience. They designed  from the ground up a radically new receiver. Deciding that if shortwave was going to be effectively  listened to via the pc,they  did not build an all in one receiver. Instead,they focused on the HF band performance ,and the results were nothing but spectacular.The first thing  I noticed when I opened the box up from Universal Radio was  the size. Roughly 6 inches by 6 inches,and standing about 2 and a half inches tall,this was not the size of any table-top  receiver by any means. The second impression I had was how did they pack all of the performance of this radio into such a tiny package. The answer to both lies in the  somewhat new technology of DSP. Digital Signal Processing has come a long way in the years it has been available. Gone are the days of massive boxes filled with heat producing components that age with each  voltage applied to various parts.An example would be the 34 IF filters available in the radio. Using older components such as Murata filters ,this would require a  vast amount  of space to install. That's not all this radio has to offer either.
A full list of available features  follows here.



Features and Specifications

Dual VFO's for tuning two stations

Unlimited memories for tuning favorite frequencies. Can save tuning mode,station name,bandwidth filter,and agc rate.
 

34 IF filters from 300 hz to 8 khz.
(depending on  controller software used from 5 to all can be used  at one time )

Frequency range
100khz -30Mhz

Operating Modes
AM,USB,LSB,CW

Sensitivity
.64 uV in AM
.3 uV in SSB

Dynamic range
90db

IF rejection
>60db

Image rejection
>60db

Passband Tuning

audio line out speaker out jacks

50 ohm antenna input through an RCA jack(would prefer so239 or BNC for this)



The Experience

First,depending on your computer setup, this will be very easy or somewhat hard to do. In my case,I had some conflicts with the modem  using the same IRQ's as the radio. The usual port settings for the radio will be selectable on all  control programs.However using Com Ports 2 and 4,or 1 and 3 is inadvisable. The internal modems usually use Com2, so using Com4 would probably create a IRQ conflict. I did find out through installing the radio on the Com1 port that my modem was somewhat defective,at least in Windows assigning it a port. Once the problems were solved,installing this radio is very easily done. All you do is plug in the serial cable,plug in the powersupply, which is very heavy  and powerful, install the software and it's up and running. The radio comes with Ten-Tec's software which is  a Windows  compatible  program. You can use Win3.1 to Win95\98.

I think in XP ,you will have to use the WIN98 compatible program setting. In Windows Vista,there were issues with various third party controllers. In Windows 7,if you have the top grade versions such as Professional,Enterprise,or Ultimate, there is a neat virtual computer ability to run in what is called XP mode. I found most controllers will work in XP mode.The most interesting thing about the  RX320 software is that TenTec offers the code for the controller,which Icom never did. This enabled others to write their own software for the radio controller. The result was that  now there are several outstanding programs for use with this radio.



Using the radio

Working the radio is a dream ,for the first time a pc controlled radio that has all these features and is meant specifically
for shortwave listening is now available. Using the various Win 98 control programs was nice and easy for most part.
I ,however like to use Linux,and it was a bit of a problem getting the control program I found to work.
The answer lies in the software not telling the  program about flowcontrol to the serial port.so with the stty command, I was able to get it to work.Here is a link to directions for installing RX320-0.4.2 for linux. The latest build for rx320 is rx320-0.6.2,it will run on xclass-0.8.3 or higher. The link below is for instructions on installing in RedHat 7.1 or 7.3,installation in RH 8 or 9 will probably be different than this,according to some who have tried it. Installation in Mandrake will definitely be different as Mandrake 9.1 installs by default xclass-0.6.3-9. To use this rx320 controller it will be neccessary to remove the original xclass rpm and reboot to make sure all the libraries for version 6.3 are gone,or else you will end up with parse errors like I did. Thanks go to Hector Pereza for cluing me in what to look for and for forcing installation to look for the updated xclass libraries.Here is the link for the rx320 controller.


Now in 2010, a far as Linux controllers go, there may be a few issues with the newer distributions.In particular,the x86_64 versions may have problems compiling.I have a few patch files that Mr. Peraza was kind enough to go over and alter to ensure install on these versions of Linux.

RX320 controller program page

RX320-install notes

I LOOOOOOVE this program.

 

Here is a screenshot  of the desktop in Mandrake Linux 9.1 using the BlackBox desktop environment while listening to the radio.

Pic of rx320 controller

Screenshot taken using KSnapshot
 

As you can see,the Linux program has all the available features of the  radio  on one  screen. The bandwith control is from the 300 hz to the 8 khz setting.The Passband control is  complete and the range is 3 khz total. The left and right arrow keys on the keyboard can control the tuning knob up and down in whatever increments are selected. I keep my vfo on 1 khz tuning rate. The page up and page down keys will then work for a 10 khz tuning step rate. Just perfect for AMBC stations.



The Verdict

My opinion is  this,for $300 USD,this radio  far outperforms anything else for this price.That includes most older used tabletop receivers ,and any portable out there today.
One thing I noticed right away was how sensitive it is to noise.Besides the computer ,which I have a couple of solutions below ,the area in which you place the antenna can make or break this radio.I just moved into a house not too far from where I was living,yet at this location,the difference in performance was phenomenal,to say the least. My first couple of nights using the radio here I was hearing Radio del Pacifico on 4975 khz like it was almost a BBC broadcast from Europe.Considering that it isn't a very strong station to begin with , that blew my mind. The next night I got to hear Radio Uganda signing on . I think the first thing this radio needs is a coax fed antenna. The second thing it will need is some kind of balun to avoid getting noise from around the feedline to the radio.My first few nights here,I could hear stations allright ,but I had a nasty noise level in some of my times at the controls. All I did was get an old so239 chassis mount and run some wire from center post to out back and a groundwire to a faucet from the chassis mount hole,fed it with some rg58u and was up and running the second day here at the new place.

Recently I tried an old trick I had almost forgotten about.I got an old cylinder-type tv balun that goes from 75 ohms to 300 ohms. I put it on a wooden base of sorts with two screws. With one of the 300 ohm leads,I attached the ground wire to an outside faucet.The other lead was connected to the end of the 150 foot longwire.Some RG59u was used to go from the transformer to the radio.The difference was downright scary .I thought my radio was dead for a minute,it was that quiet. I started tuning around and signals popped in very clear and noise free for the most part.The second thing I did was try an experiment. I took the MFJ 901b antenna tuner out of line and tried to see what it would do . The radio performed just fine in between 700 khz and 30 mhz without having to retune an antenna tuner.I tuned in stations from San Antonio to Philadelphia,from Brasil to South Africa,and the impression I got was that the first year I had it ,living in an apartment robbed me of some damn good dx. A lot of signals that were perhaps s-4 on the old setup are now at least s-8 or better at times,depending on propagation of course.

Now,three things I don't like about the radio. They are actually very simple things ,nothing fancy . I would like an rf gain to be instituted at some time. Using a good external antenna,there are bound to be some stations that can swamp the receive section.RHC from Cuba is a good example ,as is Radio Marti. An RF gain control would help matters a lot .The second thing is get rid of the crappy pcb mounted rca antenna jack. A pc radio really needs to be fed by a high grade of coax which isn't gonna be light at all. The weight of the coax is going to destroy the jack after some time of use.A nice idea would be a so239 or at the least a BNC connector.The last thing would be to make it easier to use this radio on a network without all the fancy tricks and hoops of having to search for software. A second serial port or even a usb port would be nice.Make it a usb 1 port even for older pc's to use .Those are my only real complaints. Things like synchronous detection can wait . I've gone without it ever since I started this hobby ,it isn't that big of a deal for me . .

Now for those wondering about how well it does in an urban area . There are a few tips I have for you. First ,if you live close to downtown,then you may have to contend with some MW stations interfering with the radio in some ways.You may need to get a high pass filter specifically made to cut out frequencies below 2 mhz. Sometimes a bit shorter antenna will help too.Outside the immediate urban area there should be no problems whatsoever using this very good radio to hear whatever you wish to hear. There has been some argument as to how sensitive it is compared to other tabletops such as the Icom R-75 and others,but from what I can tell offhand , I think it will hold it's own in that department.I would highly suggest using a nice grade of coax to connect your antenna to the RX320. Using wire antennas directly to the radio will usually bring in a lot of computer generated interference. I find most of the noise is going to be made by the monitor itself and not the actual pc. That is,unless you have a fairly cheap power supply . In that case ,yank that out and replace with a higher grade power supply .Nothing drives me more crazy then hearing my mouse and keyboard clinking away in the radio's audio.

Where to get it?

 Universal Radio

 TenTec

 dxtra.com

Controller software is available here

 A collection of RX320 controllers for Linux and Windows

Clifton Turner's popular RX320 software