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Chasing the numbers

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Gary D Krause

Chasing the numbers

Since the K3 is at the top of the list now and the K2 isn't far behind, I've
been wondering how the numbers really affect what we hear. If a ham were to
sit down in front of all the top rigs, blind folded and not allowed to touch
them, would he or she be able to pick out the one with the best receiver by
just using his or her ears? Lets assume that this ham has good hearing and
that every rig is set the same. I realize that people have different reasons
for picking a rig and that it isn't always based on lab tests otherwise we
would all own the same rig assuming money is not a factor :-) But is there
really a difference in the lab numbers as close as they are or are we just
chasing numbers?

Gary,
N7HTS

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Don Wilhelm-4

Re: Chasing the numbers

Gary,

Those better numbers will allow you to copy weaker signals than a
receiver with a poorer numbers.
So there is something to it other than just chasing numbers.
Will the average ragchewing ham notice a difference - maybe, but that is
not the type who typically dig for weak signals. The DXer, the
contester, and many QRP hams will dig for those weak ones,

73,
Don W3FPR

Gary D Krause wrote:

> Since the K3 is at the top of the list now and the K2 isn't far
> behind, I've been wondering how the numbers really affect what we
> hear. If a ham were to sit down in front of all the top rigs, blind
> folded and not allowed to touch them, would he or she be able to pick
> out the one with the best receiver by just using his or her ears?
> Lets assume that this ham has good hearing and that every rig is set
> the same. I realize that people have different reasons for picking a
> rig and that it isn't always based on lab tests otherwise we would all
> own the same rig assuming money is not a factor :-) But is there
> really a difference in the lab numbers as close as they are or are we
> just chasing numbers?
>

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Darwin, Keith

RE: Chasing the numbers

In reply to this post by Gary D Krause

I've done this, or as close to it as I can get. Yes, there is a big
difference.

I hook up 2 rigs to the same antenna and then feed their audio outputs
(speaker outs) into a mixing board. I adjust the audio to give the best
S/N ratio on the rig and then trim each channel on the mixer to get both
rigs at the same level in the headphones. I can then listen to one rig
or the other (or one in each ear) by just sliding volume faders up and
down or hitting a mute button. In this way, I'm using the same antenna,
tuning the same signal at the same time and listening on the same
headphones. The only difference is the rig itself.

I've done this test with various combinations of R4A, 2B, IC-735,
TS-830s, TenTec Omni V, K1 and K2.

What I've found is that the differences between rigs are shown more
clearly with this sort of rapid A/B testing. You can really hear the
differences in AGC action, IF passband width, frequency response,
distortion levels and general grunge or harsh sound. There really is a
difference. No, we are not just chasing numbers.

- Keith N1AS -
- K2 5411.ssb.100 -
- K3 Wave 3 -

-----Original Message-----
If a ham were to sit down in front of all the top rigs, blind folded and
not allowed to touch them, would he or she be able to pick out the one
with the best receiver by just using his or her ears?
... is there really a difference in the lab numbers as close as they are
or are we just chasing numbers?

Gary,
N7HTS
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Darrell Bellerive-2

Re: Chasing the numbers

Keith,

I would be interested in reading about your observations on the differences
between receivers. Please consider posting them to the reflector.

Darrell

On Thursday 28 February 2008 09:01, you wrote:

> I've done this, or as close to it as I can get. Yes, there is a big
> difference.
>
> I hook up 2 rigs to the same antenna and then feed their audio outputs
> (speaker outs) into a mixing board. I adjust the audio to give the best
> S/N ratio on the rig and then trim each channel on the mixer to get both
> rigs at the same level in the headphones. I can then listen to one rig
> or the other (or one in each ear) by just sliding volume faders up and
> down or hitting a mute button. In this way, I'm using the same antenna,
> tuning the same signal at the same time and listening on the same
> headphones. The only difference is the rig itself.
>
> I've done this test with various combinations of R4A, 2B, IC-735,
> TS-830s, TenTec Omni V, K1 and K2.
>
> What I've found is that the differences between rigs are shown more
> clearly with this sort of rapid A/B testing. You can really hear the
> differences in AGC action, IF passband width, frequency response,
> distortion levels and general grunge or harsh sound. There really is a
> difference. No, we are not just chasing numbers.
>
> - Keith N1AS -
> - K2 5411.ssb.100 -
> - K3 Wave 3 -
>
> -----Original Message-----
> If a ham were to sit down in front of all the top rigs, blind folded and
> not allowed to touch them, would he or she be able to pick out the one
> with the best receiver by just using his or her ears?
> ... is there really a difference in the lab numbers as close as they are
> or are we just chasing numbers?
>
> Gary,
> N7HTS
> _______________________________________________

--
Darrell Bellerive
Amateur Radio Stations VA7TO and VE7CLA
Grand Forks, British Columbia, Canada
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Gary D Krause

Re: Chasing the numbers

In reply to this post by Darwin, Keith

Thanks Keith, that's good to know. I only have two other rigs to compare my K2
with and they are older rigs that I bought in the eighties. I believe they are
both single conversion designs and I swear that I can sometimes hear weak
signals better on them than on my K2 but, the K2 has much better filtering.
Maybe my brain does a better job of filtering.

On Thu, 28 Feb 2008 10:01:22 -0700
"Darwin, Keith" <[hidden email]> wrote:

Vic K2VCO

Re: Chasing the numbers

In reply to this post by Gary D Krause

Gary D Krause wrote:
> Since the K3 is at the top of the list now and the K2 isn't far behind,
> I've been wondering how the numbers really affect what we hear. If a
> ham were to sit down in front of all the top rigs, blind folded and not
> allowed to touch them, would he or she be able to pick out the one with
> the best receiver by just using his or her ears?

The biggest issue is close-in dynamic range. When you notice this the
most is in a contest, when you are trying to work a station surrounded
by others. A receiver that's poor in this area will present you with
pops and other noises in the passband when there are loud signals nearby
which you may not be hearing. These noises cover up weak signals and add
to operator fatigue.

Another situation is when there are a lot of CW signals at various
pitches. A poor radio presents you with mass of distorted signals and
it's hard to pick out the one you want. One of the things I really like
about the K3 is that signals seem to stand out and you can use your
'brain filter' to differentiate.

If you mostly ragchew with reasonably strong signals in uncrowded bands,
it probably won't matter too much. But it's nice to know that the
capability is there if you ever need it.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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Darwin, Keith

RE: Chasing the numbers

In reply to this post by Darrell Bellerive-2

-----Original Message-----
From: Darrell Bellerive [mailto:[hidden email]]

Keith,

I would be interested in reading about your observations on the
differences between receivers. Please consider posting them to the
reflector.

-------------------------

I did my comparisons a few years ago so what follows is my recollection
of my tests.

Omni V vs. 830s.

The TenTec rig had a harsher, more distorted sound on CW and SSB. It
had a noticeably tighter passband resulting in less splatter and of
frequency noise as well as a more bandwidth limited sound. My Omni V
with twin Inrad 2.8 KHz filters sounded almost as good as the 830s with
it's stock SSB filters. The Omni with stock filters was noticeably
narrower than the 830s. It was clear that part of the 830s' great sound
was the wide receiver passband. From an AGC point of view, both rigs
were similar with aggressive AGCs with no real slope.

830s vs. K2

This test was done during a CW contest. The 830s with twin 500 Hz
filters had less selectivity than the K2. The aggressive flat-top AGC
of the 830s amplified the background noise so it "sounded" S-9.
Consequently, the rig was always screaming at me. If it wasn't loud
signals, it was loud band noise between the signals. The K2, with it's
sloping AGC, allowed the background noise to stay in the background.
Overall, the rig was just quieter and cleaner to listen to. Also, the
K2 receiver did a better job of keeping things clean between stations.
The holes between 2 big stations sounded like holes in the K2. In the
830s, those holes were filled with garble, grunge, junk.

Drake 2B vs. K2

The Drake is a fabulous sounding rig. Very clean, smooth, sweet.
Unfortunately, it has a very aggressive AGC so you'll never hear a quiet
band as the AGC ramps up the gain when there is no signal to provide a
constant full-blast noise floor. Filtering, of course is not nearly as
good as the modern K2, but fidelity and sonic quality is better. The
wide filtering made strong SSB signals a joy to listen to and CW stuff
came through very clean and pure. Still, for AGC reasons, I found the
K2 to be more relaxing to listen to in general even though it didn't
sound as good.

I also recorded CW signals and examined their waveform. The Drake's AGC
was rather slow to kick in so the leading edge of each dot/dash had a
1/2 to 1 cycle spike that was 2x the height of the rest of the signal.
After a cycle, the AGC had caught up and the rest of the waveform was
much more controlled. Interestingly, this leading edge spike of sorts
did not add any nasty artifacts to the audio. After seeing it on the
screen, I could hear it in the audio but the little edge at the
beginning was not bothering at all. The K2, on the other hand had no
such edge and in the headphones did sound a bit smoother than the 2B's
CW tone.

Omni V vs. K1

I had a K1 for a while and compared it to the Omni V. K1 sounded much
(much) better. Smooth, pure, nice. Of course the AGC caused loud
signals to pop and the filtering was not nearly as good, but the K1 sure
sounded nice. My recollection is that the K1 sounds better than the K2
(less IF noise, for instance) but I never had both rigs at the same time
so I can't say for sure.

- Keith N1AS -
- K2 5411.ssb.100 -
- K3 Wave 3 -
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N2EY

Re: Chasing the numbers

In reply to this post by Gary D Krause

-----Original Message-----
From: Gary D Krause <[hidden email]>

> I've been wondering how the numbers really affect what we hear. If a
ham were to sit down in front of all the top rigs, >blind folded and
not allowed to touch them, would he or she be able to pick out the one
with the best receiver by just >using his or her ears? Lets assume that
this ham has good hearing and that every rig is set the same. I realize
that people >have different reasons for picking a rig and that it isn't
always based on lab tests otherwise we would all own the same rig
>assuming money is not a factor :-) But is there really a difference in
the lab numbers as close as they are or are we just >chasing numbers?

IMHO:

It depends on what you are doing.

Under good conditions (decent signal strength, not a lot of QRM or QRN,
etc.), you won't hear much difference between a K3 and any other
half-decent rig.

It's when things are less-than-good that the differences really begin
to show. Like when you're trying to dig out an S1 signal next to an
S9+40 signal. Or when the band is full of signals of all kinds and
strengths, but you only want to hear one of them. Etc. What tough
conditions do is to show up the weaknesses in a rig.

There's also the inability to set every rig the same. Filter responses
and DSP settings vary all over the place, as do gain controls, notches,
etc.

The numbers show what can be measured objectively. But that's not the
only measure of a rig. What really shows the quality of a design is a
combination of the numbers and other factors, like how tiring is it to
operate the rig, how well it makes contacts of the kind you like to
make, etc.

IOW, for me, the real test is this: How much fun do you have with the
rig?

73 de Jim, N2EY

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S Sacco

Re: Chasing the numbers

Very broad topic here.

One thing that you might very well notice about the different
receivers, is how much different they sound, one from another, even in
a situation where you're listening to a single signal on an otherwise
clear band.

Audiophiles would know the correct buzz-words, but tube receivers tend
to sound "warm" because of the characteristics of tubes (somewhere,
I'd read that tubes emit even-numbered harmonics, and transistors,
odd-numbered harmonics...I have NO IDEA if that's true).

I have an ICOM R-71A, which is pretty nice, but the audio sounds
"mushy". Apparently, there's a mod available for that, but I'm not
going to bother with it; I'll be selling the R-71A and some other
stuff to get a 2nd K3.

I used to have an ICOM IC-756ProII. I loved the LCD display, and, of
course, the band scope, but I never could actually LIKE the audio.
The CW always sounded somewhat "hollow"; it was hard to describe.
Prior to my ordering the K3, I had several discussions with long-time
friend KR2Q. Doug had the perfect description for the ProII's audio:
he called it "flutey".

I have a Drake C-Line, with the Sherwood mods in the R4C. I *seem*
to recall briefly setting up the R4C alongside the ProII, and being
astonished at the difference in how they sounded. (The R4C was the
clear winner). I don't know why I didn't compare them for a longer
period; perhaps I didn't want to disappointed in my ProII. I'm still
trying to figure out what to do with the C-Line. I might sell that,
too.

Previous to the ProII, I had Yaesu FT-1000MP. I always liked the
sound of the Collins mechanical filters in it.

Back in my days at contest station K2GL, I spend a lot of time behind
a Collins 75A-4, and loved how that sounded (tubes, and Collins
mechanical filters). We also had Drake TR-7A's, and as much as I
loved the 75A-4, I disliked the Drake twice as much, especially under
weak-signal conditions.

Anyway, these comparison would not necessarily tell you what's "best",
except for what's most pleasing to listen to under those non-demanding
conditions. It *DOES* make a difference, especially when you become
used to the differences between what radios CAN sound like, and should
be part of any purchase decision.

I'm sure that you would be able to hear the difference between those radios.

Listening to JA's coming in over the pole on 20 M right now. They
sound good on the K3.

Hope this helps a little.

73,

Steve NN4X

On Thu, Feb 28, 2008 at 4:34 PM, <[hidden email]> wrote:

> -----Original Message-----
> From: Gary D Krause <[hidden email]>
>
> > I've been wondering how the numbers really affect what we hear. If a
> ham were to sit down in front of all the top rigs, >blind folded and
> not allowed to touch them, would he or she be able to pick out the one
> with the best receiver by just >using his or her ears? Lets assume that
> this ham has good hearing and that every rig is set the same. I realize
> that people >have different reasons for picking a rig and that it isn't
> always based on lab tests otherwise we would all own the same rig
> >assuming money is not a factor :-) But is there really a difference in
> the lab numbers as close as they are or are we just >chasing numbers?
>
> IMHO:
>
> It depends on what you are doing.
>
> Under good conditions (decent signal strength, not a lot of QRM or QRN,
> etc.), you won't hear much difference between a K3 and any other
> half-decent rig.
>
> It's when things are less-than-good that the differences really begin
> to show. Like when you're trying to dig out an S1 signal next to an
> S9+40 signal. Or when the band is full of signals of all kinds and
> strengths, but you only want to hear one of them. Etc. What tough
> conditions do is to show up the weaknesses in a rig.
>
> There's also the inability to set every rig the same. Filter responses
> and DSP settings vary all over the place, as do gain controls, notches,
> etc.
>
> The numbers show what can be measured objectively. But that's not the
> only measure of a rig. What really shows the quality of a design is a
> combination of the numbers and other factors, like how tiring is it to
> operate the rig, how well it makes contacts of the kind you like to
> make, etc.
>
> IOW, for me, the real test is this: How much fun do you have with the
> rig?
>
> 73 de Jim, N2EY
>
>
> _______________________________________________
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> Elecraft web page: http://www.elecraft.com
>

k4tmc

Re: Chasing the numbers

In reply to this post by Gary D Krause

Gary,

Based on your scenario, it would take me a few hours operating a contest to
make a decision, but I feel confident that I could pick the better receivers
out of the group, "for my purposes."

Now, this may not be the same selection that someone else makes. However, if
you have a large enough group of operators and ask them to pick the best 2 or
3 rigs, over a period of time, you should arrive at the best rig.

Relative to the specification numbers. They are part of the equation. One
of my criteria for a good receiver is its fatigue factor (sorry, there are no
none numbers for this parameter, its all subjective). But, the numbers
associated with the AGC parameters, the blocking characteristics, the IMD numbe
rs,
etc., all add up to affect that fatigue factor. Other things that you do not
normally see in the published data are the specific characteristics/parameters
of the components, processors and circuits that pass the audio portion of the
signal. For me, these can have significant impact on my fatigue factor.
Someone else has mentioned the TS830. I had one for several years, and did
numerous mods, including INRAD filters in both IF's. Until I started using a K
2, it
was my standard reference rig. Subsequent rigs (TS850 and FT1000MP, both
with INRAD filters) never approached the 830's low fatigue factor. But both of

those newer rigs had better numbers.

So, what does all of this mean? The low fatigue factor allows your brain to
do more of the signal processing. The "strange noises" that some rigs
generate impact your brain's ability to process the audio. As a result, the be
tter
number rigs have a better chance of having a low fatigue factor, but it is not
a guarenteed situation. As they say...YMMV.

73,
Henry - K4TMC
**************
Ideas to please picky eaters. Watch video on AOL
Living.

(http://living.aol.com/video/how-to-please-your-picky-eater/rachel-campos-duffy
/2050827?NCID=aolcmp00300000002598)
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DaveVK

RE: Chasing the numbers

In reply to this post by Gary D Krause

Hi Gary,

I agree with your comments. I seem to like radios that have better audio resolution and sound good rather than have good specs. That's why I like using my K2 - it sounds great with headphones. It has a great tone. All other radios have been moved on and the K2 is my main rig.

I don't care about the specs so much but it is a bonus.

Here in VK we don't suffer from strong close-in signals like OPs in EU so these things matter less. One of the reasons I've ordered a K3 is because guys were raving about how good they sound, not because of the dynamic range etc.

I don't know if elecraft have gone to great lengths to engineering the K2 audio or whether it was a technological accident. But if it sounded like fuzzy tin box I would have sold it years ago regardless of it's specs.

Dave
VK2NA

> Message: 33
> Date: Thu, 28 Feb 2008 09:47:08 -0700
> From: "Gary D Krause" <[hidden email]>
> Subject: [Elecraft] Chasing the numbers
> To: "Elecraft" <[hidden email]>,
> Message-ID: <[hidden email]>
> Content-Type: text/plain;charset=iso-8859-1;format="flowed"
>
> Since the K3 is at the top of the list now and the K2 isn't far behind, I've
> been wondering how the numbers really affect what we hear. If a ham were to
> sit down in front of all the top rigs, blind folded and not allowed to touch
> them, would he or she be able to pick out the one with the best receiver by
> just using his or her ears? Lets assume that this ham has good hearing and
> that every rig is set the same. I realize that people have different reasons
> for picking a rig and that it isn't always based on lab tests otherwise we
> would all own the same rig assuming money is not a factor :-) But is there
> really a difference in the lab numbers as close as they are or are we just
> chasing numbers?
>
> Gary,
> N7HTS

Alan Bloom

RE: Chasing the numbers

In reply to this post by Darwin, Keith

On Thu, 2008-02-28 at 11:06, Darwin, Keith wrote:

> I did my comparisons a few years ago so what follows is my recollection
> of my tests.

...

> Drake 2B vs. K2
>
> The Drake is a fabulous sounding rig. Very clean, smooth, sweet.
> Unfortunately, it has a very aggressive AGC so you'll never hear a quiet
> band as the AGC ramps up the gain when there is no signal to provide a
> constant full-blast noise floor.
...
> I also recorded CW signals and examined their waveform. The Drake's AGC
> was rather slow to kick in so the leading edge of each dot/dash had a
> 1/2 to 1 cycle spike that was 2x the height of the rest of the signal.
> After a cycle, the AGC had caught up and the rest of the waveform was
> much more controlled. Interestingly, this leading edge spike of sorts
> did not add any nasty artifacts to the audio.

I had a 2B many years ago. The thing that absolutely amazed me about
that radio is that you could run full QSK with the AGC enabled. I never
saw another receiver that could do that.

Al N1AL

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