Topband: RE: Topband Digest, Vol 6, Issue 20

WD4K WD4K2 at Charter.net
Tue Jun 24 12:52:33 EDT 2003


This Orion testing has gone from questionable to absolutely ridiculous.
Isn't anyone here going to question statements of personal opinion cloaked
as fact??  What credibility can one give to any claim from a "non objective
lab" environment; info based on someone's questionable "good ears", and
questionable techniques. This "the best-list" is already suspect in many
areas, as others have pointed out, any of which destroy any credibility of
the entire "report". This lowers the bar for accuracy and reliability to the
Joe Gunn antenna range tests and claims.
I have two 1000MP's, one of which was the original radio tested by QST, both
fully Inrad loaded and have years of experience with them.. I also have a
new Orion sitting side by side for AB comparisons.  In a previous post I
described my initial AB comparisons of the two after receiving the Orion. I
will stand by my years of experience with the MP's. The Orion is so superior
to my beloved MP's that there is NO comparison. I love my MP's, always have
and was very skeptical about how much better the Orion would be, considering
the dollars involved. I started using Yaesu rigs in the 70's with the first
twins and have had a bunch of good radios since, so I am a little biased
toward their products because of years of a dependable and quality product.
I can say beyond a doubt that the Orion is worth every green hard earned
dollar and the best rig I have ever had my hands on.
Not sure of someone else's agenda and I mean no disrespect to anyone else,
but these observations are WAY off. Especially the "too difficult to use
theory" The MP has difficult menus to find, interpret and set. The menus are
in "phonetic-ease" and take time to find, reading glasses and a cheat sheet
and get reset, plus NO memory settings for general rig setup. Come'on, this
is a no brainer that makes me think there are more personal issues here than
objective "findings". The Orion is light years ahead of the MP menu process
as well as most other features. That flawed statement alone leads me to
believe something in this new "testing" is afoul. Personally I have no
leanings toward Ten Tec or anyone else..this Orion is the only piece of Ten
Tec gear that I own...so no blind fanatic here, just fair objective personal
observations. I don't have enough kahunas to proclaim that MY opinions are
the standard on which all others should base their buying decisions.
I previously said that using the Orion next to the MP was like comparing the
Space Shuttle to a Cessna...I stand by that. I will be anxious to hear the
real lab testing yet to be done vs the CB radio like testing and comments
from the "good ears" folks at Jo Gunn labs. This seat of the pants Orion
testing is beginning to be as humorous and just about as credible as HiFi
SSB "audio engineering experts". But, in their defense, they are having fun
with their equipment which is great, however this Orion factless testing is
very obviously designed to bias the opinions of the general ham community
and affect someone's buying decision and financial investment which I
personally believe is over the line. IF it was based on fact, fine...but it
isn't. Hopefully it won't be too long before we, including yours truly, will
get to see the real numbers and hear the opinions of real lab tests. Until
then, I have to look at the opinions of all of these wobbly knobbers with
real skepticism. Maybe their wives found out how much they spent and they
have to have a "reason" to send back the radio to save face:) HI  Who
knows??
Tommy


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Sent: Tuesday, June 24, 2003 9:14 AM
To: topband at contesting.com
Subject: Topband Digest, Vol 6, Issue 20


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Today's Topics:

   1. Re: Re: Weak signal receivers (John Buck)
   2. RE: Omni VI+ A/B Test results (Tony Reynolds)
   3. Re: Re: Weak signal receivers (Tree)
   4. CM6RCR (Steve Lawrence)
   5. Re: Omni VI+ A/B Test Results (Michael Tope)
   6. RE: Omni VI+ A/B Test results (Ford Peterson)
   7. Re: RE: Omni VI+ A/B Test results (Tom Rauch)
   8. FT-757 (Carl)
   9. Re: RE: Omni VI+ A/B Test results (Keith Jillings)
  10. =?iso-8859-1?Q?Re:_Topband:_Re:_Weak_signal_receivers?=
       (=?iso-8859-1?Q?i4jmy?=)


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

Date: Mon, 23 Jun 2003 10:19:34 -1000
From: John Buck <kh7t at arrl.net>
To: Tom Rauch <w8ji at contesting.com>, topband at contesting.com,
   Jim Reid
 <kh7m at arrl.net>
Subject: Re: Topband: Re: Weak signal receivers
Message-ID: <3EF760D6.5020301 at arrl.net>
References:
	<20030618.144802.-1928155.12.k6se at juno.com><3EF0E8B3.60201 at arrl.net>
	<000f01c3363f$dddd1900$2d8001d8 at akorn.net> <3EF20606.6010109 at arrl.net>
	<006101c33725$9df06180$168001d8 at akorn.net>
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Message: 1

Tom,

Thanks for the tutorial that helps to clarify the various sources of
noise and interference.  I absolutely agree with your conclusion that
the goal is to be able to copy weak signals without artifacts caused by
overload.

I believe that I was guilty of sloppily using the term noise to refer to
all unwanted stuff showing up in my audio while trying to listen to weak
signals instead of correctly separating antenna noise, external spurious
noise, receiver noise
and receiver generated intermod products.

I agree that much of the "DX pileup noise" is probably due to
transmitters."   However, I have noticed that the noise rise effect is
noticeably  less and signal to noise ratio is better when using K2,
Omni, Orion than when using  IC 735, TS120, TS530 and others.  I think
this is more than the an operator perceived effect described below.

So my conclusion remains that some of the apparent noise is generated in
the receiver in the presence of multiple strong signals.  Of course the
artifacts you describe are there also.  Perhaps your ears and
instrumentation are more discriminating that mine.  Also perhaps some of
the noise that shows up as bleeps and bloops in the narrow CW case
appear more similar to random noise when generated by a large number of
mixed ssb signals.

A difference in our observation base is that you appear to be looking at
narrow band cw and I have been looking primarily at SSB bandwidths.  I
also agree that my K2 does not have the excess gain necessary for a very
quiet receive antenna.  I think this was a design goal to minimize
"excess" gain before the mixers and filter consistent with adequate
noise figure.  It is fine for use with conventional transceive antennas.
 I have been looking at 40 meters and up and with dipole and beams.

Your explanations are logical with good separation of the various
effects.  And perhaps we are both attacking the  "I want to hear a loud
background noise that must show my receiver has sufficient gain" folklore.

Is it possible that my "noise" rise in a strong signal power environment
observation is a phase noise in the receiver fault?  Again not the same
as a front end amplifier/mixer non linearity cause.

Aloha,
John KH7T
 I did not Snip Tom's text here as I believe his words deserve  careful
reading.
The initial quotes are from my original message.  -- John

Tom Rauch wrote:

>>The context that I was using is that nonlinear front ends cause a lot of
low level mixing products in the pass band in the presence of multiple large
signals in the front end.
>>
>>
>
>With a front end problem, the non-linear artifact is almost always easily
identifiable spurious signals. All sorts of odd signals (like mixes of BC
stations) are present that "aren't really there" when listening on a better
receiver. I suppose there are rare cases where an overloaded receiver might
generate something that sounds like noise, but signal levels would have to
>be phenominal...like multiple local extermely strong transmitters.
>
>The common effect of poor IM3 dynamic range in CW pileups are musical
bleeps and bloops that sound like real CW signals with sloppy sending. This
is best described as like listening to the Novice bands of the 60's and 70's
with the receiver BFO turned off. All sorts of uncipherable CW signals with
otherwise good tone are heard, they sound exactly like normal CW signals
>otherwise.
>
>Drake R4C's under SN 18000 or so had a very bad case of this, probably the
worse in history of modern receivers. The most problematic Drake (with FET
>second mixer) had the narrowest front end used in any commercially
manufactured receiver, and was one of the worse ever for overload problems.
>
>
>
>>I agree that the noise we all hear should be external to the receiver.
But in many cases it is not.  A prime example is a heavy DX pile up.  When
many people are calling the band noise appears to rise.
>>
>>
>
>Most composite noises I have tracked down actually comes from low-level
transmitter stages, not synthesizers. I spent some time looking at various
rigs because I like to duplex (transmit while receiving) even with close
>splits.
>
>Some rigs have heavy composite transmitter noise. In the FT1000D, the noise
is mostly from a stage back in the early transmitter IF system. The same is
>true for a few Ten Tecs I have tested.
>
>On occasion I've seen dominant synthesizer noises. The rare FT1000MP can
have broad rough hissing noise when transmitting, occasionally with many
buzzy spurious signals. (Someone posted something a few years ago on this
>reflector about a cure.) Pileups generally wind up with at least a few
nasty transmitters causing problems, but I've never heard it as "noise"
There commonly are clicks, occasional hissing rigs, and spurious thumps and
bumps
>from poor VCO switching (most commonly from 775DSP's).
>
> > partially due to nonlinearities in the transmitters outside the
>
>
>>receiver, but is also partly due to nonlinearities in the receiver front
end including phase noise.
>>
>>
>CW transmitters can be as non-linear as we like, as long as rise and fall
times are good. Non-linearity aggrivates key clicks, not noise.
Non-linearity can actually reduce AM noise!
>
>>the line receivers such as Ten-Tec and K2 as a lack of gain even though
>>the weak signals pop up with
>>a better signal to noise ratio than many other receivers.
>>
>>
>
>The K2's and TT's I have looked at actually did have "low gain" compared to
other receivers. While that is prefectly OK in noisy locations or when using
transmitter antennas for receiving, it makes them poor performers in quiet
>locations (especially those with very directive receiving antennas). One
odd thing with the only K2 I tested was even though gain increased with the
internal preamp, noise figure did not improve. I think I measured around
>10dB or more NF, about what the mixer and post mixer amp should do, and it
didn't change significantly with the preamp on. That meant K2 IM3 DR was
significantly worse with the internal preamp on.
>
>There is a human effect that, if the signal is over a certain S/N
threshold, attenuation (less gain) appears to make a signal "stand out"
more. This only works with signals that are already above noise a reasonable
amount. It gives a false operator impression S/N has increased, because the
removal of AGC action reduces noise fill between signal-on periods. Some of
us don't do as well at ignoring noise when reading weak signals, so less
gain (and the resulting reduction in AGC) helps.
>
>>By the way, a receiver front end must not only be super linear for the
power range of the desired signal but must be able to maintain that
linearity for all of the power presented by all other (large) signals in
>>the front end pass band.
>>
>>
>
>That's a good point. It is the peak power of all the signals present that
pushes a receiver towards overload. That's why contests are a good test.
Many receivers that roll-along perfectly fine on SSB or CW moderate strength
>nearly clear channel operation are horrible in contests or for weak signal
work.
>
>I think what we will see is operators who want to reach down into the noise
and dig the weakest possible signal out with the best possible copy will
disagree with the choice of operators who like a receiver to "sound
>quieter".  Some operators will disagree with other operators choices.
>
>If a receiver of the same bandwidth as another sounds quieter with noise,
it almost certainly isn't going to make copy better on noise floor signals.
Unless you have the very rare grossly overloaded or saturated receiver,
noise is all external to the receiver. It is all inside the filter passband
of the narrowest filter in the system. Birdies, IM, and spurious *signals*
(which do not sound like noise) are different, of course.
>
>My opinion is a receiver has to let me copy weak signals very well. Then it
has to not overload, and generate phantom signals. All other things are far
down the list.
>
>73 Tom
>
>
>
>



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

Date: Mon, 23 Jun 2003 17:56:16 -0400
From: "Tony Reynolds" <kb8jvh at reydata.com>
To: <topband at contesting.com>
Subject: Topband: RE: Omni VI+ A/B Test results
Message-ID: <02a401c339d2$466a68c0$0100a8c0 at reydata>
References: <200306231601.h5NG0vBP006176 at contesting.com>
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Here is the updated list of receivers checked so far at K6SE, in order
from best to worst:

1)  Yaesu FT-1000MP (with INRAD mod)
1)  Elecraft K2 (tied for first place)
3)  Kenwood TS-830S
3)  Kenwood TS-870S (tied with the TS-830S)
5)  Yaesu FT-1000MP (without the INRAD mod)
6)  Yaesu FT-757
7)  Icom IC-775DSP
8)  Ten-Tec Omni VI+
9)  Icom IC-756
10) Ten-Tec Orion

Ya had me going till the FT 757. I had one of those for many years. It was
the worst rig I've ever owned for dynamic range and phase noise. It's
frontend is just crushed under even moderately busy band conditions. How can
it be as good as the near perfect TS-830s? Not even in the same league in my
book.

Tony
KB8JVH


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

Date: Mon, 23 Jun 2003 17:02:22 -0500
From: Tree <tree at kkn.net>
To: topband at contesting.com
Subject: Re: Topband: Re: Weak signal receivers
Message-ID: <20030623220222.GA6205 at kkn.net>
In-Reply-To: <3EF760D6.5020301 at arrl.net>
References: <000f01c3363f$dddd1900$2d8001d8 at akorn.net>
	<3EF20606.6010109 at arrl.net> <006101c33725$9df06180$168001d8 at akorn.net>
	<3EF760D6.5020301 at arrl.net>
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Message: 3


> So my conclusion remains that some of the apparent noise is generated in
> the receiver in the presence of multiple strong signals.

In band signals have IMD products - which can get pretty bad.  On most
receivers I have seen, they are down about 30 or 35 db - when doing just
two signals.  If you get a bunch of them (or a lot of QRN), then it's a
mess.  Cranking the RF gain down will often improve it to 50 db or less.

Tree
------------------------------

Date: Mon, 23 Jun 2003 18:55:58 -0700
From: Steve Lawrence <smlx at earthlink.net>
To: Top Band List <topband at contesting.com>
Subject: Topband: CM6RCR
Message-ID: <000B82E0-A5E7-11D7-BD95-0003931129C6 at earthlink.net>
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Message: 4

Anyone have suggestions on getting a 160 card from CM6RCR.? I've used
the QRZ.com address and again when it changed still without success
after several months.

My next try will be to see if WF5E can work his magic. Other
suggestions appreciated.

Tks & 73, Steve WB6RSE

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

Date: Mon, 23 Jun 2003 20:10:01 -0700
From: "Michael Tope" <W4EF at dellroy.com>
To: <1000mp at mailman.qth.net>, <topband at contesting.com>,
   <TenTec_Orion at yahoogroups.com>, <elecraft at mailman.qth.net>,
<k6se at juno.com>
Subject: Re: Topband: Omni VI+ A/B Test Results
Message-ID: <057c01c339fe$1d2e5d00$0100a8c0 at 1800XP>
References: <20030622.123945.-1837811.8.k6se at juno.com>
Precedence: list
Message: 5

How weak were the signals that you guys were listening to? I am wondering
if your ranking is just simply a measure of which receivers have the best
noise figure. It would be interesting to repeat the test with an LNA in
front
of the receivers to see if its simply a matter of total RF gain and noise
figure, or if there is more to it than that. In any case, a super weak
signal
test is only one part of the dynamic range equation. If ranked by intercept
point, the order and makeup of the list might be different.

73 de Mike, W4EF.................................

>
> My friend is now seriously considering buying a used FT-1000MP or an
> Elecraft K2.
>
> Here is the updated list of receivers checked so far at K6SE, in order
> from best to worst:
>
> 1)  Yaesu FT-1000MP (with INRAD mod)
> 1)  Elecraft K2 (tied for first place)
> 3)  Kenwood TS-830S
> 3)  Kenwood TS-870S (tied with the TS-830S)
> 5)  Yaesu FT-1000MP (without the INRAD mod)
> 6)  Yaesu FT-757
> 7)  Icom IC-775DSP
> 8)  Ten-Tec Omni VI+
> 9)  Icom IC-756
> 10) Ten-Tec Orion
>
> I've located a Yaesu FT-1000D and an Icom IC-746 PRO locally that I hope
> to test soon.  I'm still looking for an Icom 756 PRO II to test.
>
> 73, de Earl, K6SE
> _______________________________________________
> Topband mailing list
> Topband at contesting.com
> http://lists.contesting.com/mailman/listinfo/topband



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

Date: Mon, 23 Jun 2003 22:37:02 -0500
From: "Ford Peterson" <ford at cmgate.com>
To: <topband at contesting.com>
Subject: Topband: RE: Omni VI+ A/B Test results
Message-ID: <002501c33a01$e03342e0$6400a8c0 at Office2>
References: <200306231601.h5NG0vBP006176 at contesting.com>
	<02a401c339d2$466a68c0$0100a8c0 at reydata>
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> Here is the updated list of receivers checked so far at K6SE, in order
> from best to worst:

It seems to me that this list is quite meaningless without the inclusion of
the other popular radios.  Any hand picked (either intentional or not)
collection of radios will exhibit quite a bit of variation in the sorting of
this list.  Specifically, radios excluded from the list include...

1000D
756PROII
746PRO
746 (with filters of course)
a host of other quality equipment

Specific radios can exhibit varying degrees of misalignment.  Likewise,
tweaking ATT, PBT, and DSP controls can make an obvious difference.  Without
an exhaustive list of accessories, tuning procedures, controlling on-the-air
environment, and modifications included in the test, the situation is
repleat with opportunities to simply get the list all out of order.

What does it all mean?

Ford-N0FP
ford at cmgate.com


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

Date: Tue, 24 Jun 2003 06:53:26 -0400
From: "Tom Rauch" <w8ji at contesting.com>
To: "Tony Reynolds" <kb8jvh at reydata.com>, <topband at contesting.com>
Subject: Re: Topband: RE: Omni VI+ A/B Test results
Message-ID: <002601c33a3e$d8038ac0$2f8001d8 at akorn.net>
References: <200306231601.h5NG0vBP006176 at contesting.com>
	<02a401c339d2$466a68c0$0100a8c0 at reydata>
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Reply-To: Tom Rauch <w8ji at contesting.com>
Message: 7

> Ya had me going till the FT 757. I had one of those for many years. It was
> the worst rig I've ever owned for dynamic range and phase noise. It's
> frontend is just crushed under even moderately busy band conditions. How
can
> it be as good as the near perfect TS-830s? Not even in the same league in
my
> book.

Hi Tony,

Phase noise and dynamic range/overload problems have any effect in a test
like Earl's. We won't hear phase noise unless a strong close by signal is
present, just as we won't hear overload.

I've found ability to dig out weak signals with noticeable antenna noise is
a lot different than a bench test with only a signal generator on the
receiver input.

I suspect manufacturers and filter vendors almost never worry about group
delay errors, which are critical for copying signals near noise. This
problem results in a variable time for "things" to pass through the receiver
system, with lower pitched frequencies we are hearing taking a different
amount of time to pass through the system than higher pitch signals. What
happens is one sideband of the CW signal is delayed a different amount than
the other sideband, resulting in what sounds like ringing or excessive
softening of the rise and fall. Noise pulses are also subjected to the same
uneven time delays with respect to frequency in the passband we hear,
stretching out noise pulse duration.

How many filters have you seen rated for group delay errors, or how often is
it mentioned? I'd bet almost no one looks at it, even though it can be
critical. My 751A totally blows away a stock R4C or 75A4 for selectivity and
overload by close signals and looks much better for noise floor, but the
250Hz filters are unusable for working noise floor signals if there is any
rough noise present. The 500Hz filters in the 751A are barely acceptable.
Because of that, I never use the 751A for working weak signals. All the
sensitivity in the world does no good when the filters ping on every noise
pulse, and CW sounds mushy.

Aside from "ringing" or group delay errors, some receiver detectors seem to
blend noise and signal together making it impossible to copy noise floor
signals. I am not positive, but I *think* much of this is detector
non-linearity or intermod. I always observe receivers with a lot of headroom
in detectors and audio systems work better for me in receiving weak signals.

It would be great to come up with a lab test protocol for weak CW signals in
noise!

73 Tom

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

Date: Tue, 24 Jun 2003 06:12:53 -0500
From: Carl <k9la at gte.net>
To: topband at contesting.com
Subject: Topband: FT-757
Message-ID: <3EF83235.9020007 at gte.net>
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Message: 8

All,

I agree with Tony KB8JVH's comment about the FT-757. I had one of those,
and it was a excellent example of a receiver not handling strong signals
very well. Perhaps that's a typo in the list. Or maybe it was a "good"
one - which I just don't think is "typical".

Carl K9LA

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

Date: Tue, 24 Jun 2003 12:26:00 +0100
From: Keith Jillings <keithj at dsl.pipex.com>
Cc: topband at contesting.com
Subject: Re: Topband: RE: Omni VI+ A/B Test results
Message-ID: <3EF83548.7080403 at dsl.pipex.com>
In-Reply-To: <002501c33a01$e03342e0$6400a8c0 at Office2>
References: <200306231601.h5NG0vBP006176 at contesting.com>
	<02a401c339d2$466a68c0$0100a8c0 at reydata>
	<002501c33a01$e03342e0$6400a8c0 at Office2>
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Message: 9

Ford Peterson wrote:


> Specific radios can exhibit varying degrees of misalignment.  Likewise,
> tweaking ATT, PBT, and DSP controls can make an obvious difference.
Without
> an exhaustive list of accessories, tuning procedures, controlling
on-the-air
> environment, and modifications included in the test, the situation is
> repleat with opportunities to simply get the list all out of order.
>
> What does it all mean?

In the final analysis, it means I don't buy anything in a hurry!   After my
youthful years of being spoiled with an excellent site with room for plenty
of
antennas (but before the era of the topband reflector), I have for the past
15
years had a "postage stamp" and can't work 160 from home at all.   But when
I
come to move to my "retirement home", neighbouring agriculture and friendly
farmers will be a critical consideration, and the new rig will be whatever
is at
the top of this list.   (I've already had a dabble from the "second QTH" up
in
the Welsh hills. )

Right now, it's an FT1000MP with the W8JI mods.   That, to me, is the key
information I take away from this.   If the list changes and something else
goes
to the top, that will become my "retirement new rig".


Keith
--
Keith Jillings
G3OIT   GW3OIT   G-UTSY at EGMC

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

Date: Tue, 24 Jun 2003 13:45:13 +0200
From: =?iso-8859-1?Q?i4jmy?= <i4jmy at iol.it>
To: =?iso-8859-1?Q?kh7t?= <kh7t at arrl.net>
Cc: =?iso-8859-1?Q?kh7m?= <kh7m at arrl.net>
Cc: =?iso-8859-1?Q?topband?= <topband at contesting.com>
Cc: =?iso-8859-1?Q?w8ji?= <w8ji at contesting.com>
Subject: =?iso-8859-1?Q?Re:_Topband:_Re:_Weak_signal_receivers?=
Message-ID: <HGZHZD$AE036870E232257570405D639DA11F5F at libero.it>
Content-Type: text/plain; charset=iso-8859-1
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Message: 10

Although linearity is inherent of the specific device and different
amplifiers behave differently, the admissible output level of an amplifier
to keep constatnt its charachteristics of linearity is also related and
inversely proportional to the number and to the amplitude of the input
signals. This concept is for example well known in RF wideband TV amplifiers
where the final effect of applying a lot of modulated carriers of different
level at the input is a reduction of the final S/N on each amplified video
signal if the levels aren’t accordingly reduced. If such a disturbance can’t
be named noise in the strict sense, nevethless it does affect the quality of
a signal up to the point to mask it.

73,
Mauri I4JMY




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

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