Apparently I need some help in trying to use this dBV capability with on the
air signals.
For example, using it as an AGC off relative S-meter with digital readout
to run some antenna pattern checks for skewness etc.
I've used it just fine in lab type measurements with a constant signal
source.
I've used it just fine in lab type measurements with a constant signal
source.
Which is precisely what it was designed for.
Is the reference value of AFV used in the dbV calculation the last one taken
at the instant one leaves the menu entry?
It is the last one. It might be the last one
Hi Brian,
The dBV and AFV functions were designed primarily for use with steady
state lab signals to test receiver sensitivity etc. We added these two
displays to speed our final test of the K3 in production, and as an aid
to do this in the field with simple tools like our XG2 test
I've independently measured the linear range of the DBV function as just
over 60 dB, which is quite impressive. You can see the plot at
http://www.cliftonlaboratories.com/elecraft_k3_noise_blanker_and_crystal_dsp_filtering.htm.
That page also provides measured filter response curves using the
On Thu, 18 Sep 2008 05:36:40 -0700 (PDT), alsopb wrote:
First question. What is meant by stable value of AFV?
Here's what I see for a bunch of AFV edited values one after another with no
change in K3 settings.
1579,1688,1598,1624,1696,1613, 2168,1758,1425.
The range is 6db.
Sure. It's audio,
Lyle Johnson wrote:
We have a total of three characters available, and we wanted to express
that this was a dB value, and it was voltage based. So we used dBV.
Into a linear load, and I presume we have one here[A], there is no
difference between dB relative to a voltage, using the 20
Would it be useful to call it Vdb, i.e. a voltage measurement not
necessarily using the 1V RMS standard reference?
73,
Geoff
GM4ESD
On Tue, 16 Sep 2008 15:40:04 -0700, Lyle Johnson wrote:
Maybe dBv stands for dB variable, not dB with respect to a volt.
Not with respect one volt, but
Lateral thinking. Sounds good to me
David
G3UNA
From: Geoffrey Mackenzie-Kennedy [EMAIL PROTECTED]
Date: 2008/09/17 Wed AM 09:33:31 BST
To: Elecraft Discussion List elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 dbV in 2.38
Would it be useful to call it Vdb, i.e. a voltage
On 2008-09-17 00.26, Lyle Johnson [EMAIL PROTECTED] wrote:
The K3's dBV function is a *relative* measure. It must be set to
whatever reference you wish by first using AFV. The calculation
measurement is true RMS. It is used for measuring things like MDS, AGC
slope, roofing filter
The K3's dBV function is a *relative* measure. It must be set to
whatever reference you wish by first using AFV. The calculation
measurement is true RMS. It is used for measuring things like MDS, AGC
slope, roofing filter attenuation and so forth.
So what's the correct procedure for
You should be able to use the AFV readings instead of the voltage
measured with a DMM across the speaker - then using those values, enter
them into the calculations in the XG2 manual for calculating MDS.
73,
Don W3FPR
Björn Mohr wrote:
On 2008-09-17 00.26, Lyle Johnson [EMAIL PROTECTED]
Into a linear load, and I presume we have one here[A], there is no
difference between dB relative to a voltage, using the 20 log10,
voltage, formula and dB relative to the power corresponding to that
voltage using the 10 log10. power, formula.
That's only true if the source and load
Brian,
You have to let the AFV value stabilize first, and then the dBV shows the
value compared to the last AFV value. Page 36 of the manual shows more
details.
73 's Steef PA2A
K3 1184
- Original Message -
From: alsopb [EMAIL PROTECTED]
To: elecraft@mailman.qth.net
Sent: Tuesday,
Hi Steff,
Thanks reply.
Try this. Set your K3 up to display dBV. Turn your K3 off. Turn the K3
on. Look at the value. Wait. See if it ever changes from +99.9. It never
does here.
This works:
Have any other parameter displayed in the VFO B area. Turn rig off. Turn
it on. That
.
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of alsopb
Sent: Tuesday, September 16, 2008 4:50 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 dbV in 2.38
Hi Steff,
Thanks reply.
Try this. Set your K3 up to display dBV
The K3's dBV function is a *relative* measure. It must be set to
whatever reference you wish by first using AFV. The calculation
measurement is true RMS. It is used for measuring things like MDS, AGC
slope, roofing filter attenuation and so forth.
This function has been in the K3 for a
Maybe dBv stands for dB variable, not dB with respect to a volt.
Once you get used to it, the relative reference can be of some benefit.
For example, set dBV to 0.0 at the bandwith peak and then the dBV
reading gives you a direct reference to how many dB down from the filter
peak you are when
Maybe dBv stands for dB variable, not dB with respect to a volt.
Not with respect one volt, but voltage based, using the 20log rather
than the power-based 10log conversion.
AFV is AF Voltage and corresponds to the voltage you would measure
across the speaker with AF GAIN set to max. Units
On Tue, 16 Sep 2008 15:40:04 -0700, Lyle Johnson wrote:
Maybe dBv stands for dB variable, not dB with respect to a volt.
Not with respect one volt, but voltage based, using the 20log rather
than the power-based 10log conversion.
Hold on a minute. We cannot sit over in our little corner and
Jim Brown wrote:
...
Hold on a minute. We cannot sit over in our little corner and pretend
that the rest of the world does not exist. That's how we got into
trouble with the KIO3.
dBV is a voltage measure with a reference of 1V RMS. It's an
international standard. If a K3 function does
On Sep 16, 2008, at 5:07 PM, Augie Hansen wrote:
Jim Brown wrote:
...
Hold on a minute. We cannot sit over in our little corner and
pretend that the rest of the world does not exist. That's how we
got into trouble with the KIO3.
dBV is a voltage measure with a reference of 1V RMS. It's an
] K3 dbV in 2.38
On Tue, 16 Sep 2008 15:40:04 -0700, Lyle Johnson wrote:
Maybe dBv stands for dB variable, not dB with respect to a volt.
Not with respect one volt, but voltage based, using the 20log rather
than the power-based 10log conversion.
Hold on a minute. We cannot sit over
On Sep 16, 2008, at 5:38 PM, Joe Subich, W4TV wrote:
I suppose when Wayne has time, he can modify the display
driver to light two fewer segments so the V is v.
That is probably no good either.
dBv is the deprecated version of dBu. It was changed from dBv to dBu
because it was too easy to
If you reference to a full scale meter reading or A/D converter clipping
level, a standard that is in use is dBFS (or dBfs).
We have a total of three characters available, and we wanted to express
that this was a dB value, and it was voltage based. So we used dBV.
73,
Lyle KK7P
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