If you ask owners of the same radios how the radio works you can get a wide range of answers. We often find owners don't notice a radio performs poorly compared to other radios even when the radio has known major defects or shortcomings.  This is why we have to be very careful asking opinions about radios.

Why the Difference in Opinion?  

Sometimes we become emotionally attached to our toys. After all, we invest time and money in our hobby. We have a right to enjoy what we worked for. Sometimes this colors our opinion.

I remember the first new radio I every bought. I carefully asked all the right questions and received the answers I was looking for. I received my very first brand new radio, and it was an expensive radio. After years of home brewing or buying second or third hand gear I finally was in a position where I could afford a brand new high end radio.

I loved the large digital readout. The receiver sounded great. People gave me glowing reports; the transmitted audio sounded wonderful. Then the second or third day came along.

After a few days of SSB ragchews and barefoot  CW contacts I finally listened to some weak DX. My local noise floor is way down near S1, even on 160 meters. I heard a weak but easily readable signal in the area where DX normally hangs out, and I was shocked to hear it was VE1ZZ. I wondered why Jack was only S-3 instead of his normal S-9 + signal. Then I tuned up the band a little bit, and there was Jack again but this time his normal S-9 signal strength. Puzzled by this, I did my customary crosscheck of using a totally different type of radio to look for the same spurious signal. Was I surprised  when the second weak signal from Jack wasn't there at all on my old IC-751A!

Then I tried transmitting on my big amplifier. It was a single 8877 with 4000 volts on the anode. This required reducing the power output of my 150 watt radio to about 50 watts. I reduced the power, loaded up, and was all set to transmit. As soon as I touched the key the amplifier tripped right off. It gave me a "grid current overload" fault. How could that be? I loaded up to only 25mA of grid current.

I advanced the loading control on the amplifier and hit the key again. Now the amplifier dumped because of an SWR fault.

Out to the shop I went, new radio in hand. I quickly discovered the receiver would actually hear signals on an unselected VFO when the unselected VFO and active VFO were close in frequency! While the spurious response was 50 or more dB down (depending on VFO spacing), it was enough to cause spurious signal responses on a VE1 a few thousand miles away on 160 meters! This was not good. Making matters even worse, the transmitter had the same spurious response. I could generate, with the right VFO spacing, spurious signals spaced at the VFO separation and on both VFO frequencies.

Then I looked at the transmitter power and my life suddenly got worse. I discovered the transmitter, on a good peak detecting meter I used for pulsed transmitter measurements, had a leading edge power spike of 250 watts or more! Worse yet it had this same power spike when the power control was reduced to 50 watts. No wonder it was tripping the very fast fault detection circuits in my amplifier.

A call to the manufacturer revealed they knew about these issues. They said I was stuck with the power spike, but the receiver and transmitter spurious responses were caused by leakage through a solid state switch that selected or deselected the unused VCO's. They could cure by making a modification that turned off the unused VCO's (the front panel calls them VFO's) if I was willing to give up QSK.

Why didn't others notice the problems?

If we have a noisy location, work only strong signals on SSB, have small antennas, and run low power almost any radio will be good enough.
The better our location, the better our antennas, the more power we run, and the more we operate congested bands the more important radio performance becomes.  When I was in strong SSB ragchews, when I wasn't working split frequency, and when I didn't have the low-drive amplifier with fast protection circuits on, everything looked great.

This is probably how many others used that radio, and those were the people I relied on for advice. If I never worked weak signal DX from a quiet location, never operated close to other people, didn't work much CW, and didn't have a fast protection system in my amplifier I probably would not have noticed the serious flaws in that $3000 dollar radio.

What's important to you?

People make some pretty stupid subjective claims. Some have even claimed an $8000 radio with a close-spaced signal dynamic range defect is bothered by other signals because it "hears better, and so it hears the defective signals where other lesser receivers will not".  Others will claim they changed receivers and suddenly noise was greatly reduced. Actually that's all just rubbish. 

Virtually any radio today has plenty of sensitivity. Virtually every radio made in the last 20-30 years will "hear" way down into ambient noise at the quietest location when on a reasonable antenna, even when the antenna is just an ordinary old dipole. For many years internal receiver noise has not set the limit of hearing weak signals. For the same general filter selectivity, virtually all radios produce a signal-to-noise ratio determined solely by the signal-to-noise ratio at the antenna.

What sometimes fools people is the AGC slope at low levels or raw gain of the receiver. If one receiver has a bit less sensitivity than another and we listen to fair signals, the lower gain receiver (or a receiver with less AGC loop gain) will provide an illusion that S/N ratio has improved. This is because the gain between signals is not nearly so high. We actually don't have better S/N ratio, the background noise between signal peaks just doesn't pump up so high. Years ago receivers had an RF gain control that was used just for this purpose. Today we can remove a preamp or add an attenuator pad. Today the RF gain control virtually NEVER controls the RF gain!! In the modern rig is is generally an IF gain control that is mislabeled or incorrectly named. 
 

What is the difference?

Other than bells and whistles 99% of us never use and transmitter power output the only consistent benchmarks are the bandwidth performance of the receiver and the transmitter.

When we buy a less expensive "does everything radio", like a compact portable or mobile rig, we generally get the worse end of modern transmitter and receiver bandwidth performance range. Strong close-frequency stations, even when they have no transmitter defects, will bother the receiver. The transmitter will also bother others much more than necessary when we are strong.

Filtering is also important.  A few radios totally omit conventional analog IF filters, depending exclusively on DSP filters. These receivers, whether $800 or $8000 rigs, almost always provide significantly poorer close-spaced performance than similar radios using conventional crystal or mechanical IF filters.

If we never operate close to other strong signals, if we have high local noise, if we use small antennas and/or low power, and if we operate wide bandwidth modes we aren't nearly as likely to appreciate good quality.

ARRL reviews have now improved. The ARRL now tests and reports performance at closer spacing. It is worth looking at ARRL reviews, especially at close-spaced IM3 dynamic range and transmitter IM distortion. ARRL numbers are more useful now, although the review text is often chock full of hyperbole.

Also look at the following links on this site for  receivers  and transmitters.

since 10 Mar 2007