RECEIVER PERFORMANCE

#1:  "YOU NEED TO ENJOY USING THE RADIO."

As long as it is "good enough", which many of today's radios are,

"measurements" are only secondary in the choice of a radio.

The MOST impotant performance criteria today is NOT a measurement!

The radio does not have to have the highest ranking on the receiver performance list,

it only has to be "good enough".

 

 I'm sure many engineers will dispute this point.

• To some extent, that is fair, but at some point you are "majoring in minors."
• Again, the performace measurements only have to be "good enough."



Also Of Importance:  "Creature Comfort"

1. User friendly operation of main features?
2. User friendly operation of software menus?
3. Audio Quality, both on receive and transmit.
4. Size, weight, color... may be important to some Op's.

LIKE A HIGH PERFORMANCE RACE CAR:

• Powerful Engine (Performance)
• Good Handling

YOU NEED BOTH.  Which one is more important depends on the race track.

• A Drag Racer's most important need is a Powerful Engine
• A Formula 1 car's most imporant need is good handling
• Both only need to ge "good enough" in the other dicipline

 THE SAD REALITY OF ALL TRANSCEIVERS CURRENTLY ON THE MARKET:

• ALL Transceivers (no exceptions) have at least one major issue (usually more than one).  These issues are disturbing to many operators.  In some cases these issues can over-shadow the high performance measurements of that radio.  THEREFORE, YOU SHOULD BEWARE OF PERFORMANCE LISTS!
• Whether these issues are disturbing to  YOU  will depend on how you use the radio and which "Creature Comfort" features are important to you.

"RECEIVER PERFORMANCE MEASUREMENTS"

This is probably the subject that interests everyone the most!

Performance can be measured in many ways and a quick glance at the test results from the ARRL, Sherwood Engineering, or others, reveals many diverse measurements.  It is difficult for most of us to understand what all of these measurements mean, and how much they impact the radio's performance.

Moreover, we have read lots of articles on performance over the years and although some have tried to point out what is important, very few have ever touched on  "how much performance do we need?

Most older popular receiver measurements are not important today.  

In the 70's and 80's we were interested in things like:

• Sensitivity
• Selectivity
• IP3  (Intercept Point)

These measurements are not very meaingful.  It's not that they are not important; we just don't have problems in these areas anymore.  All modern radios are good enough. They all have ample sensitivity, with their crystal or DSP filters they are selective enough, and the Intercept Point was actually never very meaningful, anyway. Specifically, you can move the IP3 up by adding attenuation and down by adding pre-amplification.

THE MOST IMPORTANT RECEIVER MEASUREMENT TODAY IS "DYNAMIC RANGE" (DR); SPECIFICALLY DR3 (DR for 3rd Order IMD).  This indicates how well the receiver will perform IN THE PRESENCE OF DISTURBING SIGNALS (with exceptions).

To have an accurate evaluation of a radio's performance, similar to how it will perform under adverse band conditions, especially under contest conditions, it is important to measure DR3 with close in signals (typically 2 kHz).

Although DR3 is the most important measurement, it is not the only indication of performance.  Other factors may also contribute to receiver performance degradation. 

There are several sources of Receiver Performance Measurements.

Among these are The ARRL Lab Reports and Rob Sherwood's Receiver Performance List.

For more on these, see:  Performance Lists

FOR AN EVEN BETTER OVERVIEW on transceiver performance, see (and listen to) Rob Sherwoods PRESENTATIONS. 

Other potential sources of problems, especially on recent new products are problems with the effect of pulse noise on the AGC, spurs, and audio clarity. For more on this, see "Other Problems".