More SDR and Knob Issues

Steve, K9ZW, is testing out his Flex-6700 and comparing it to an IC-7800.user1_pic3266_1337358910

He’s posting his experiences on his blog “With Varying Frequency – Amateur Radio Ponderings” and it makes for some interesting reading. The 6700 looks like it might be a game-changer when it comes to Amateur Radio.

But Flex isn’t the only SDR manufacturer offering radios with amazing specs at competitive prices. (And yes Sparky $7000 for a FlexRadio is competitive to a $8200 FTdx5000MP.)

The blade RF is a new one to me and looks interesting as does the Indian-designed Anan-100D. These radios are selling at a fraction of the price of the 6700.

This is a great time for experimentation in Amateur Radio. SDR holds promises of radio performance at rockbottom costs that may change Amateur Radio forever. The biggest argument against SDR is the ergonomics (“It doesn’t have a knob!”) and the need for a semi-robust computer.bladeRF_cropped-38-0-0-0-0

Both of those arguments were made in different ways in the 60s when SSB came to the Amateur Radio bands. Critics (and there were many) said SSB sounded too mechanical and drove up the price and complexity of their radio equipment. Both arguments were true enough and faded away as the superior communications ability of SSB made evangelists out of the early adaptors.

And so it is with SDR.

The contesters (which on big contest weekends are legion) who I dare suggest constitute a majority of the “active Hams” who are on HF these days have not embraced SDR for one reason and one reason only IMHO. And that’s the issue of the knob.T_ANAN-100D Front

Contesters need rigs that have rock solid front-end design. They don’t much care what the transmitter sounds like as evidenced by some of the really dirty output of some well-known contesters especially in the hands of guys who set up their audio by ear. And let’s face it, a 100 watts is a 100 watts regardless of what kind of rig emits it.

Bad audio or distortion or broad signals can happen regardless of the rig but based on personal experience I sure like the way a Flex sounds compared to many other radios. Using the panorama display on the Flex 1500 you can see the other guy’s signal so clearly and dirty transmitters show up right away.

But back to the front-end and that’s where SDR has swept away the competition. In Sherwood Engineering’s Receiver Test Data page of the top 11 radios six are true SDR radios and I’m not sure about the Ten Tec Argonaut and Eagle but they may qualify as well (any rig that gets “better” after a software upload is SDR IMHO).

BTW Ten Tec has four radios in the top 11 and Flex has three while Elecraft have both of their radios listed in the top 11. I made it the top 11 to include my Flex 1500 🙂

So what’s the knob issue?FlexControl_420x356

When you’re operating at 2 am the FlexRadio configuration has a nasty habit under the hands of a sleepy operator of suddenly changing frequency.

The reason is the Flex SDR window and the contest logging software are usually running on the same computer and configured with both windows open on the same monitor. The FlexKnob (which satisfies most of the lack-of-a-knob complaints) locks to the SDR window but the computer mouse does not. That means if the computer mouse activates the SDR window and you begin to type a call sign thinking you’re in the contesting logging window the SDR software thinks you’re asking for a frequency (or worst a band) change and off you go in mid contact.

Now an experienced SDR contester (like yours truly) never…almost never…rarely… okay occasionally has this happen and a small programming change isn’t going to fix this issue because the mouse is needed on occasion to change parameters on screen (because the FlexKnob can’t do everything)  in the SDR software and then moved back into the logging program to start typing. This takes a certain amount of brain functioning which may not be available at 2 am.

There are ways around this but nothing beats a big box rig with a big heavy tuning knob and no active software on the computer screen with the exception of the logging program when it comes to stable, predictable operating after midnight.220px-Collins_KWM-1

But take a second look at Sherwood’s list of rigs (He focuses on how a rig behaves when confronted with a big signal 2 kHz away from a lesser desired signal which is a big deal when contesting.) and notice how many really big, expensive and relatively new rigs that didn’t make the top 11 or even the top 20. There are some seriously P.O. big box contest operators out there who own one of these dinosaurs.

Any rig, even a QRP rig with virtually no front end or a second hand mobile rig can be used in a contest if (a) you can attenuate signals coming into the rigs non-existant front end (a bad antenna will do but an attenuator switch is better) and you only operate out on the band edges away from the cut and thrust of the main action.

But if you want to be competitive then you’ve got to have a rig capable of dancing withe the elephants and that means having a rig with superior front-end characteristics. That’s where SDR is at home.

The future of radio is SDR and the knob issue (and competing software windows) will get fixed. You’ll notice I don’t include the need for a computer when it comes to SDR as an issue for contesters. Why?


First every contesting station has a computer for logging. A laptop with enough firepower to run SDR can be had for the same price as a computer used for photo editing ($500 or so). Bigger remains better for now.300px-RaspberryPi

I say that because pretty soon you’re going to be able to run your SDR on a $35 Raspberry Pi computer (if you can’t already) and for the most part, once you setup your software parameters at the beginning of a contest there’s no need to change anything but frequency, bandwidth and maybe volume which you can do with a FlexKnob on a Flex radio or by using a small box interface between you, the operator, and your SDR rig.

BTW you can operate your SDR on 80-meter AM Sparky 🙂

This entry was posted in FlexRadio, SDR Radio by Peter West. Bookmark the permalink.

About Peter West

I am retired. I'm invested into bike riding, guitar playing, yoga and Ham Radio. I am a former photojournalist, newspaper and magazine editor and public relations practitioner with national, regional and local experience. A long-time member of Toastmasters International and an active Amateur Radio (Ham) operator here in Canada I am taking on new challenges.

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