What might be low-level IMD3 in K3.
When used with 13 dB KPA-500 the
power is 25W.
K3 IMD might be considerable lower than
KPA-500 IMD3 of -35dB. So this is the result?
How about 400Wout and 300W?
Lower output might give a clean signal
when power is not primordial.
Benny OH9NB
Hello All,
I checked my K3's TX IMD today(K3 SN:1302), from 5W to 110W. Very good
TX IMD when I set the output power to 35w( 50db), but very poor when I set
it to 100w or 110w(20~18db).
Any one can help?
I have about 10 photos for this test, if interest I can send via email
offline.
I have measured myself however didn´t come up
with as poor and/or as good numbers.
What could be interesting is with what and how
did you measure.
/ Jim SM2EKM
-
chen dave wrote:
Hello All,
I checked my K3's TX IMD today(K3 SN:1302), from 5W to 110W. Very good
TX IMD
Hi Jim,
I use K3 internal 2 tones test function + SDR-IQ+ SpectraVue3. If need
I can use HP RF spectrum monitor to test it.
http://photo.blog.sina.com.cn/u/1411826944 for test photos.
73 de ba4rf,David
2010/4/4 Jan Erik Holm sm2...@telia.com
I have measured myself however didn´t
On Apr 4, 2010, at 4/46:50 AM, chen dave wrote:
I use K3 internal 2 tones test function + SDR-IQ+ SpectraVue3.
Are you ignoring the crest factor of the two tone test signal?
To get 100 watts average RF power from a two tone signal, the
instantaneous peak power has to be nearly 200
I did change subject to TX IMD only.
People has measured down to -24 dB. As I recall ARRL first
had a lower figure but somehow it got revised.
My own measurements show that it´s not usable above 100W.
I would keep it at 80W or lower, something seems to happen
above 80W.
No artifacts, I can hear
Jan Erik Holm wrote:
Anyway I will rest my case. I have written about this before
and I can clearly see that Elecraft ain´t interested so
why should I waist my time.
73 Jim SM2EKM
You obviously are not happy with the rig. My K3 works fine. The IMD
gets a bit worse over 100W but then
Jan Erik Holm wrote on Monday, January 26, 2009 8:52 AM
As you say, it´s getting rare these days with radios in the
-30 to -40 dB bracket. And we are just going to be content
with it? No not IMO.
Jan,
I agree in the context of Amateur Service radios.
The time might come perhaps sooner than
Is there a sweet spot to which one can adjust the power output for minimum
IMD, if so, how would you do it easily? I presume you would need another rx or
spectrum analyser. And I bet it changes with antenna reflections, ie from one
end of the band to the other.
I dare say a lot of K3s are
David Cutter wrote:
Is there a sweet spot to which one can adjust the power output for
minimum IMD, if so, how would you do it easily? I presume you would need
another rx or spectrum analyser. And I bet it changes with antenna
reflections, ie from one end of the band to the other.
I
Not doubting your TX IMD report in PSK. But I typically see ~-32dB IMD when
checking PSK at 50W.
-
73,
Greg - AB7R
Whidbey Island WA
NA-065
On Mon Jan 26 7:58 , Julian, G4ILO sent:
David Cutter wrote:
Is there a sweet spot to which one can adjust the power
There is something that has been puzzling me for the last 17
years.
In November of 1991, QST reviewed the Yaesu FT-990, which
used a 13.8 vdc PA. Worst case measured 3rd order IMD
was -38 dB, 5th order was -47 dB. This measurement was at
100 watts output. The review is available on ARRL's
Gregory Fischer wrote:
Not doubting your TX IMD report in PSK. But I typically see ~-32dB IMD
when
checking PSK at 50W.
You are probably right to doubt it. Such a difference made me try a test
again, on a different band. I got a different set of results. Probably it is
better to use a
David,
Sorry for being slow to reply.
You wrote:
Is there a sweet spot to which one can adjust the power output for
minimum IMD,
In general terms the short answer is that there might be. If the two tone
signal driving an amplifier under test is very 'clean' in terms of odd order
IMD
One factor that affects IMD is power supply voltage variation under
load. The standard PS cable that comes with the K3 drops several tenths
of a volt at max power. Add that to power supply regulation and
internal voltage drop in the K.
On my unit, the voltage reading on the K3 display goes from
-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Dave
Hachadorian
Sent: Monday, January 26, 2009 11:42 AM
To: Elecraft reflector
Subject: Re: [Elecraft] TX IMD
There is something that has been puzzling me
HI Julian and Greg,
I see some difference in measured IMD in various software using the same
equipment. I also notice a difference in going narrow on receive. Of
coarse the transmitter's IMD isn't changing, but the the recorded result.
Still useful for testing as long as you compare apples to
One factor that affects IMD is power supply voltage variation under
load. The standard PS cable that comes with the K3 drops several tenths
of a volt at max power. Add that to power supply regulation and
internal voltage drop in the K.
In addition to lowering the AWG size, I am using a Lambda
...@mailman.qth.net]on Behalf Of Jay Bromley
Sent: Monday, January 26, 2009 3:58 PM
To: Julian, G4ILO; elecraft@mailman.qth.net
Subject: Re: [Elecraft] TX IMD
HI Julian and Greg,
I see some difference in measured IMD in various software using the same
equipment. I also notice a difference in going
: Re: [Elecraft] TX IMD
There is something that has been puzzling me for the last 17 years.
In November of 1991, QST reviewed the Yaesu FT-990, which
used a 13.8 vdc PA. Worst case measured 3rd order IMD
was -38 dB, 5th order was -47 dB. This measurement was at
100 watts output
Yes of course, however this cable is supplied by Elecraft
and is part of the high performance kit.
My own PS has a 0.06V drop RX TX and that is good enough!
/ SM2EKM
---
Alan Bloom wrote:
One factor that affects IMD is power supply voltage variation under
load. The standard PS cable
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