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K3 6/10M pre-amp

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Gary Gregory-2

K3 6/10M pre-amp

Wonder when we will see release of an internal 6/10M pre-amp?

73

Gary

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*Elecraft K3
P3 Panadapter
KPA500FT
KAT500FT**

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Fred Smith-2

Re: K3 6/10M pre-amp

I wouldn't hold my breath.

73,
Fred/N0AZZ
K3 Ser # 6730--KX3 # 2573--K2/100 # 6470-KAT100
P3/SVGA--KPA500--KAT500--W2

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Gary Gregory
Sent: Sunday, July 07, 2013 5:31 AM
To: Elecraft List
Subject: [Elecraft] K3 6/10M pre-amp

Wonder when we will see release of an internal 6/10M pre-amp?

73

Gary

--
*Gary - VK1ZZ
Skype: Gary.VK1ZZ
http://www.qsl.net/vk1zz
Motorhome Portable
The Shack*
*Elecraft K3
P3 Panadapter
KPA500FT
KAT500FT**

*
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Version: 2013.0.2904 / Virus Database: 3204/6470 - Release Date: 07/06/13

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Gary Gregory-2

Re: K3 6/10M pre-amp

I'm not. But I did a post from Elecraft stating it was possible IF enough
wanted it.

I am over 'add on boxes' for now to fix a problem that should have been
done sooner, not later.

Just thinkin'

73

On 7 July 2013 20:49, Fred Smith <[hidden email]> wrote:

> I wouldn't hold my breath.
>
>
> 73,
> Fred/N0AZZ
> K3 Ser # 6730--KX3 # 2573--K2/100 # 6470-KAT100
> P3/SVGA--KPA500--KAT500--W2
>
>
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Gary Gregory
> Sent: Sunday, July 07, 2013 5:31 AM
> To: Elecraft List
> Subject: [Elecraft] K3 6/10M pre-amp
>
> Wonder when we will see release of an internal 6/10M pre-amp?
>
> 73
>
> Gary
>
> --
> *Gary - VK1ZZ
> Skype: Gary.VK1ZZ
> http://www.qsl.net/vk1zz
> Motorhome Portable
> The Shack*
> *Elecraft K3
> P3 Panadapter
> KPA500FT
> KAT500FT**
>
> *
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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>
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> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2013.0.2904 / Virus Database: 3204/6470 - Release Date: 07/06/13
>
>

glenb

Re: K3 6/10M pre-amp

Hello,

I have had a different experience with regards to the 6M performance.

I was always told for years that the 6M performance on rx was pretty poor.
After I got a K3 recently, I found
the internal preamp to be pretty good. But, I had a DEMI 6M preamp, so I
installed it in a small die cast box
and bought male BNC connectors and made it mate exactly to the back of the
K3. Then used the 12 volt out to
power the DEMI preamp. The DEMI preamp is better than the internal one, but
not by a large margin. With
BOTH preamps on, is only marginally better. I plan on adding cutoff relays
like the PR6 later.

Background: I do weak signal 6M work, with 104 countries worked in 6 years
down here in the black hole of southwest
GA. Antenna: 7x7 LFA at 120' and 85'.

73's

Glen K4KV
Moultrie, GA

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]]On Behalf Of Gary Gregory
Sent: Sunday, July 07, 2013 6:54 AM
To: Fred Smith
Cc: Elecraft List
Subject: Re: [Elecraft] K3 6/10M pre-amp

I'm not. But I did a post from Elecraft stating it was possible IF enough
wanted it.

I am over 'add on boxes' for now to fix a problem that should have been
done sooner, not later.

Just thinkin'

73

On 7 July 2013 20:49, Fred Smith <[hidden email]> wrote:

Jack Berry

Re: K3 6/10M pre-amp

In reply to this post by Gary Gregory-2

It's on the order page now. Same price for any of the three pre's including the old 6 pre, new 10 pre and new combo 6/10 preamp. $159.95 if memory serves.

On Jul 7, 2013, at 5:30 AM, Gary Gregory <[hidden email]> wrote:

> Wonder when we will see release of an internal 6/10M pre-amp?
>
> 73
>
> Gary
>
> --
> *Gary - VK1ZZ
> Skype: Gary.VK1ZZ
> http://www.qsl.net/vk1zz
> Motorhome Portable
> The Shack*
> *Elecraft K3
> P3 Panadapter
> KPA500FT
> KAT500FT**
>
> *
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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Iain MacDonnell - N6ML-2

Re: K3 6/10M pre-amp

It's not internal, though.Wayne did state that that would not be feasible.

http://elecraft.365791.n2.nabble.com/K3-Combined-6-and-10mtr-preamp-td7572734.html

73,

~iain / N6ML

On Sun, Jul 7, 2013 at 6:05 AM, Jack Berry <[hidden email]> wrote:

> It's on the order page now. Same price for any of the three pre's including the old 6 pre, new 10 pre and new combo 6/10 preamp. $159.95 if memory serves.
>
> On Jul 7, 2013, at 5:30 AM, Gary Gregory <[hidden email]> wrote:
>
>> Wonder when we will see release of an internal 6/10M pre-amp?
>>
>> 73
>>
>> Gary
>>
>> --
>> *Gary - VK1ZZ
>> Skype: Gary.VK1ZZ
>> http://www.qsl.net/vk1zz
>> Motorhome Portable
>> The Shack*
>> *Elecraft K3
>> P3 Panadapter
>> KPA500FT
>> KAT500FT**
>>
>> *
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
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>> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
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Jim Low man

Re: K3 6/10M pre-amp

In reply to this post by glenb

I know that this has probably been discussed before, but just how bad is
the K3 on 6m/10m?
Hopefully, the KX3 doesn't suffer this fate as well.

It's one thing to spend another $160 on the 6m/10m preamp, but it also
requires the KXV3A at another $120.
Yes, that would also provide the ability to use a second antenna, have
access to the IF out and support a transverter.
The most likely of these features that I would use is the transverter
output to get on 222 MHz.
But there's so little activity on that band in this area for some
reason, even in contests, that I question the expense of the transverter
and antenna.

73 de Jim - AD6CW
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Fred Smith-2

Re: K3 6/10M pre-amp

In reply to this post by glenb

Glen the internal preamp did not work on 6m. Your antennas are your largest
asset by far, wish I had them. About any radio with 6m would perform very
well with your setup but my FTDX-5000MP and Icom's spoiled me on the high
bands.

If you do a lot of weak signal work a mast mounted preamp and hardline would
do wonders for you. I enjoy weak signal VHF myself and a close friend Mike
K0AZ was the first true Zero land call with 6m DXCC some time back. He is
one of my go to guys and has been very helpful over the years with 50 yrs.
of experience to call upon.

73,
Fred/N0AZZ
K3 Ser # 6730--KX3 # 2573--K2/100 # 6470-KAT100
P3/SVGA--KPA500--KAT500--W2

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Glen
Sent: Sunday, July 07, 2013 7:49 AM
To: Gary Gregory
Cc: elecraft
Subject: Re: [Elecraft] K3 6/10M pre-amp

Hello,

I have had a different experience with regards to the 6M performance.

I was always told for years that the 6M performance on rx was pretty poor.
After I got a K3 recently, I found
the internal preamp to be pretty good. But, I had a DEMI 6M preamp, so I
installed it in a small die cast box and bought male BNC connectors and made
it mate exactly to the back of the K3. Then used the 12 volt out to power
the DEMI preamp. The DEMI preamp is better than the internal one, but not
by a large margin. With BOTH preamps on, is only marginally better. I plan
on adding cutoff relays like the PR6 later.

Background: I do weak signal 6M work, with 104 countries worked in 6 years
down here in the black hole of southwest GA. Antenna: 7x7 LFA at 120' and
85'.

73's

Glen K4KV
Moultrie, GA

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]]On Behalf Of Gary Gregory
Sent: Sunday, July 07, 2013 6:54 AM
To: Fred Smith
Cc: Elecraft List
Subject: Re: [Elecraft] K3 6/10M pre-amp

I'm not. But I did a post from Elecraft stating it was possible IF enough
wanted it.

I am over 'add on boxes' for now to fix a problem that should have been done
sooner, not later.

Just thinkin'

73

On 7 July 2013 20:49, Fred Smith <[hidden email]> wrote:

> I wouldn't hold my breath.
>
>
> 73,
> Fred/N0AZZ
> K3 Ser # 6730--KX3 # 2573--K2/100 # 6470-KAT100
> P3/SVGA--KPA500--KAT500--W2
>
>
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Gary Gregory
> Sent: Sunday, July 07, 2013 5:31 AM
> To: Elecraft List
> Subject: [Elecraft] K3 6/10M pre-amp
>
> Wonder when we will see release of an internal 6/10M pre-amp?
>
> 73
>
> Gary
>
> --
> *Gary - VK1ZZ
> Skype: Gary.VK1ZZ
> http://www.qsl.net/vk1zz
> Motorhome Portable
> The Shack*
> *Elecraft K3
> P3 Panadapter
> KPA500FT
> KAT500FT**
>
> *
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net Please help support this email
> list: http://www.qsl.net/donate.html
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2013.0.2904 / Virus Database: 3204/6470 - Release Date:
> 07/06/13
>
>

--
*Gary - VK1ZZ
Skype: Gary.VK1ZZ
http://www.qsl.net/vk1zz
Motorhome Portable
The Shack*
*Elecraft K3
P3 Panadapter
KPA500FT
KAT500FT**

*
______________________________________________________________
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No virus found in this message.
Checked by AVG - www.avg.com
Version: 2013.0.2904 / Virus Database: 3204/6470 - Release Date: 07/06/13

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Fred Smith-2

Re: K3 6/10M pre-amp

In reply to this post by Jim Low man

Jim

The KX3 has no problems with the high bands works perfect, mine does anyway
it's just the K3 and only 6/10m with it.

73,
Fred/N0AZZ
K3 Ser # 6730--KX3 # 2573--K2/100 # 6470-KAT100
P3/SVGA--KPA500--KAT500--W2

.

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Jim Lowman
Sent: Sunday, July 07, 2013 12:29 PM
To: [hidden email]
Subject: Re: [Elecraft] K3 6/10M pre-amp

I know that this has probably been discussed before, but just how bad is the
K3 on 6m/10m?
Hopefully, the KX3 doesn't suffer this fate as well.

It's one thing to spend another $160 on the 6m/10m preamp, but it also
requires the KXV3A at another $120.
Yes, that would also provide the ability to use a second antenna, have
access to the IF out and support a transverter.
The most likely of these features that I would use is the transverter output
to get on 222 MHz.
But there's so little activity on that band in this area for some reason,
even in contests, that I question the expense of the transverter and
antenna.

73 de Jim - AD6CW
______________________________________________________________
Elecraft mailing list
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2013.0.2904 / Virus Database: 3204/6470 - Release Date: 07/06/13

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Keith Heimbold

Re: K3 6/10M pre-amp

In reply to this post by Fred Smith-2

I think a preamp with the K3 is an absolute necessity out here in Southern California with a small six element antenna for 6m. I use one both the PR6 and the Collins Laboratory preamp I purchased from Dr Jack Smith. Both work great.

Btw, I have not heard before anyone on the east coast refer to their location as a black hole for 6m. This is definitely a first for me. When you live in Southern California and you get the chance to DX to Europe about one or two days every decade.

Keith
AK6ZZ

Sent from my iPhone please excuse typos

On Jul 7, 2013, at 10:37 AM, "Fred Smith" <[hidden email]> wrote:

> Glen the internal preamp did not work on 6m. Your antennas are your largest
> asset by far, wish I had them. About any radio with 6m would perform very
> well with your setup but my FTDX-5000MP and Icom's spoiled me on the high
> bands.
>
> If you do a lot of weak signal work a mast mounted preamp and hardline would
> do wonders for you. I enjoy weak signal VHF myself and a close friend Mike
> K0AZ was the first true Zero land call with 6m DXCC some time back. He is
> one of my go to guys and has been very helpful over the years with 50 yrs.
> of experience to call upon.
>
>
> 73,
> Fred/N0AZZ
> K3 Ser # 6730--KX3 # 2573--K2/100 # 6470-KAT100
> P3/SVGA--KPA500--KAT500--W2
>
>
>
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Glen
> Sent: Sunday, July 07, 2013 7:49 AM
> To: Gary Gregory
> Cc: elecraft
> Subject: Re: [Elecraft] K3 6/10M pre-amp
>
> Hello,
>
> I have had a different experience with regards to the 6M performance.
>
> I was always told for years that the 6M performance on rx was pretty poor.
> After I got a K3 recently, I found
> the internal preamp to be pretty good. But, I had a DEMI 6M preamp, so I
> installed it in a small die cast box and bought male BNC connectors and made
> it mate exactly to the back of the K3. Then used the 12 volt out to power
> the DEMI preamp. The DEMI preamp is better than the internal one, but not
> by a large margin. With BOTH preamps on, is only marginally better. I plan
> on adding cutoff relays like the PR6 later.
>
> Background: I do weak signal 6M work, with 104 countries worked in 6 years
> down here in the black hole of southwest GA. Antenna: 7x7 LFA at 120' and
> 85'.
>
> 73's
>
> Glen K4KV
> Moultrie, GA
>
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]]On Behalf Of Gary Gregory
> Sent: Sunday, July 07, 2013 6:54 AM
> To: Fred Smith
> Cc: Elecraft List
> Subject: Re: [Elecraft] K3 6/10M pre-amp
>
>
> I'm not. But I did a post from Elecraft stating it was possible IF enough
> wanted it.
>
> I am over 'add on boxes' for now to fix a problem that should have been done
> sooner, not later.
>
> Just thinkin'
>
> 73
>
> On 7 July 2013 20:49, Fred Smith <[hidden email]> wrote:
>
>> I wouldn't hold my breath.
>>
>>
>> 73,
>> Fred/N0AZZ
>> K3 Ser # 6730--KX3 # 2573--K2/100 # 6470-KAT100
>> P3/SVGA--KPA500--KAT500--W2
>>
>>
>>
>> -----Original Message-----
>> From: [hidden email]
>> [mailto:[hidden email]] On Behalf Of Gary Gregory
>> Sent: Sunday, July 07, 2013 5:31 AM
>> To: Elecraft List
>> Subject: [Elecraft] K3 6/10M pre-amp
>>
>> Wonder when we will see release of an internal 6/10M pre-amp?
>>
>> 73
>>
>> Gary
>>
>> --
>> *Gary - VK1ZZ
>> Skype: Gary.VK1ZZ
>> http://www.qsl.net/vk1zz
>> Motorhome Portable
>> The Shack*
>> *Elecraft K3
>> P3 Panadapter
>> KPA500FT
>> KAT500FT**
>>
>> *
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net Please help support this email
>> list: http://www.qsl.net/donate.html
>> -----
>> No virus found in this message.
>> Checked by AVG - www.avg.com
>> Version: 2013.0.2904 / Virus Database: 3204/6470 - Release Date:
>> 07/06/13
>
>
> --
> *Gary - VK1ZZ
> Skype: Gary.VK1ZZ
> http://www.qsl.net/vk1zz
> Motorhome Portable
> The Shack*
> *Elecraft K3
> P3 Panadapter
> KPA500FT
> KAT500FT**
>
> *
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
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> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2013.0.2904 / Virus Database: 3204/6470 - Release Date: 07/06/13
>
> ______________________________________________________________
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Jim Brown-10

Re: K3 6/10M pre-amp

On 7/7/2013 11:10 AM, Keith Heimbold wrote:
> I think a preamp with the K3 is an absolute necessity out here in Southern California with a small six element antenna for 6m.

Whether a preamp is needed depends entirely on your own noise level, and
as another post noted, the antenna gain. With a 4-el Yagi on a fairly
long boom (3-el SteppIR), I definitely DO need a preamp. I use an ARR
GasFET at the K3 patch point that I bought long before the K3 existed.
There's an easy way to figure out if you need a preamp. If the noise
level increases by at least 6-7 dB when you connect the antenna, you
don't need a preamp.

> Btw, I have not heard before anyone on the east coast refer to their location as a black hole for 6m. This is definitely a first for me. When you live in Southern California and you get the chance to DX to Europe about one or two days every decade.

Your surely have that right. Out here in the SF Bay Area, I've NEVER
heard EU on 6M, and there have been VERY few Es openings this season.
The last good one was the first day of the June ARRL VHF contest. At
the same time that we watch the east coast working EU, the Caribbean,
and each other. In six seasons, I've worked 13 countries on 6M with
500W and that SteppIR. Out here, DXCC on 6M is something you do in a
lifetime from a high QTH with a BIG antenna. I know that K6QXY and K6KLY
have done it, and it took them a LONG time.

73, Jim K9YC
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Edward R Cole

Re: K3 6/10M pre-amp

In reply to this post by Gary Gregory-2

Been a lot of discussion on this topic so I decided to make some
"real" MDS measurements comparing my K3/10 (4340) and KX3 (475). I
hope the columns read clear for everyone (I can create some charts on
my website, if not):

Test set up: XG3 + JFW 30-dB step attenuator + 6-inch of RG-58 w/BNC's
The XG3 is installed in a Hammond "diecast aluminum" enclosure with
BNC feedthru adapter so the unit is fully shielded (I have made MDS
measurements using additional 20-dB coaxial attenuator to -157 dBm
+/- 2 dB. That was using double-shielded coax whereas today's tests
were using ordinary RG-58 (so adds a little uncertainty on the
minimum signal). MDS detector are my "ears" so that makes a bit more
subjective for absolute measurements.

Both radios tuned with 2.8 KHz bw in USB, Elecraft's MDS spec is done
at bw = 500-Hz.

50.120 MHz
Level (dBm) K3+PRE KX3+PRE(30-dB) K3 (no preamp)
XG3 off S1 S0 S0
-73 S9+5 S9 S8
-107 S3 S4
-123 --- S1/S2
-130 S1 below MDS
ANT S2 S2/S3 S0
(slight rise in noise in speaker)

28.200 MHz
Level (dBm) K3+PRE KX3+PRE(30-dB)
XG3 off S1 S0
-73 S9+5 S9
-107 S4 S3
-123 --- S0
-133 S1 Below MDS

I also checked frequency using the K3 as reference (has EXREF) and
the KX3 was 50-Hz higher than the K3 on 6m and 40-Hz higher on 10m (I
have not done the temperature calibration for the KX3). I did not
measure freq drift after transmitting.

One would state that the K3 looks better than the KX3 for receiver
sensitivity (yet the KX3 hears 6m much better - hmmm?)

73, Ed - KL7UW
http://www.kl7uw.com
[hidden email]
"Kits made by KL7UW"

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Scott Manthe-2

Re: K3 6/10M pre-amp

Maybe the signals are louder on the KX3, which would fool people into
thinking it was more sensitive? I've always thought my K3 was adequate
on 6 meters. Not gangbusters, but certainly adequate.

73,
Scott, N9AA

On 7/8/13 6:09 PM, Edward R Cole wrote:

> Been a lot of discussion on this topic so I decided to make some
> "real" MDS measurements comparing my K3/10 (4340) and KX3 (475). I
> hope the columns read clear for everyone (I can create some charts on
> my website, if not):
>
> Test set up: XG3 + JFW 30-dB step attenuator + 6-inch of RG-58 w/BNC's
> The XG3 is installed in a Hammond "diecast aluminum" enclosure with
> BNC feedthru adapter so the unit is fully shielded (I have made MDS
> measurements using additional 20-dB coaxial attenuator to -157 dBm +/-
> 2 dB. That was using double-shielded coax whereas today's tests were
> using ordinary RG-58 (so adds a little uncertainty on the minimum
> signal). MDS detector are my "ears" so that makes a bit more
> subjective for absolute measurements.
>
> Both radios tuned with 2.8 KHz bw in USB, Elecraft's MDS spec is done
> at bw = 500-Hz.
>
> 50.120 MHz
> Level (dBm) K3+PRE KX3+PRE(30-dB) K3 (no preamp)
> XG3 off S1 S0 S0
> -73 S9+5 S9 S8
> -107 S3 S4
> -123 --- S1/S2
> -130 S1 below MDS
> ANT S2 S2/S3 S0 (slight rise in noise
> in speaker)
>
> 28.200 MHz
> Level (dBm) K3+PRE KX3+PRE(30-dB)
> XG3 off S1 S0
> -73 S9+5 S9
> -107 S4 S3
> -123 --- S0
> -133 S1 Below MDS
>
> I also checked frequency using the K3 as reference (has EXREF) and the
> KX3 was 50-Hz higher than the K3 on 6m and 40-Hz higher on 10m (I have
> not done the temperature calibration for the KX3). I did not measure
> freq drift after transmitting.
>
> One would state that the K3 looks better than the KX3 for receiver
> sensitivity (yet the KX3 hears 6m much better - hmmm?)
>
> 73, Ed - KL7UW
> http://www.kl7uw.com
> [hidden email]
> "Kits made by KL7UW"
> ______________________________________________________________

Edward R Cole

Re: K3 6/10M pre-amp

In reply to this post by Gary Gregory-2

To respond to Scott's comment:

My experience is that the K3 with internal preamp (PRE on) is not
able to hear weak signals as well as the KX3 (with its preamp set to
30-dB gain). This is an accepted condition by Elecraft and they
responded by providing the PR6 and now expanded this to 10-12m with the PR6-10.

I suspect (but have no technical evidence) that maybe the K3 is too
low in overall system gain at 6m. The PR6 or other external preamps
provide this (plus lowering system NF).

MDS is good alternative to noise figure (NF) measurements. The PR6
is cited by Elecraft providing -143 dBm sensitivity at bw=500 Hz. NF
claim is 0.7 dB with 0.5 typical; PR6 gain = 18 dB.

The K3 is cited at MDS of -136 dBm at bw=500 Hz. This is adequate
information for calculating equivalent NF. -136 dBm is equivalent to
a NF =11 dB at bw =500 Hz into a 290K termination. Adding the PR6
brings this down to -145.6 dBm. Pretty close to what Elecraft claims.

My measurements were with bw=2.8 KHz (-130 dBm), so correcting for
bw: 10Log(2.8/0.5) = 7.5 dB this would result in -137.5 dBm
MDS. Considering I am doing this by ear it comes pretty close to the
Elecraft spec for the K3 with internal preamp. What was a surprise
is the KX3 observed MDS was 3-dB worse than the K3 at -127 dBm
(-134.5 dBm corrected for bw).

My measurements do not match on-air experience?? Only conclusion is
that the test set up is not providing a stable output. XG3 is a
great tool for checking performance but maybe sensitive to loading
(just guessing). Probably the best I can achieve with equipment at
hand. Hope the math was entertaining - HI.

73, Ed - KL7UW

---------------------------------
From: Scott Manthe <[hidden email]>
To: [hidden email]
Subject: Re: [Elecraft] K3 6/10M pre-amp
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Maybe the signals are louder on the KX3, which would fool people into
thinking it was more sensitive? I've always thought my K3 was adequate
on 6 meters. Not gangbusters, but certainly adequate.

73,
Scott, N9AA

73, Ed - KL7UW
http://www.kl7uw.com
[hidden email]
"Kits made by KL7UW"

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wayne burdick

Re: K3 6/10M pre-amp

Administrator

Typical KX3 MDS with preamp on is about -138 to -140 dBm in a 500-Hz bandwidth, on all bands.

If a KX3 is measuring -134 dBm MDS in this bandwidth, chances are there's a measurement error, or the ATU has been left in-line at an impedance other than that of the source RF generator, etc.

73,
Wayne
N6KR

On Jul 9, 2013, at 9:15 AM, Edward R Cole <[hidden email]> wrote:

> To respond to Scott's comment:
>
> My experience is that the K3 with internal preamp (PRE on) is not able to hear weak signals as well as the KX3 (with its preamp set to 30-dB gain). This is an accepted condition by Elecraft and they responded by providing the PR6 and now expanded this to 10-12m with the PR6-10.
>
> I suspect (but have no technical evidence) that maybe the K3 is too low in overall system gain at 6m. The PR6 or other external preamps provide this (plus lowering system NF).
>
> MDS is good alternative to noise figure (NF) measurements. The PR6 is cited by Elecraft providing -143 dBm sensitivity at bw=500 Hz. NF claim is 0.7 dB with 0.5 typical; PR6 gain = 18 dB.
>
> The K3 is cited at MDS of -136 dBm at bw=500 Hz. This is adequate information for calculating equivalent NF. -136 dBm is equivalent to a NF =11 dB at bw =500 Hz into a 290K termination. Adding the PR6 brings this down to -145.6 dBm. Pretty close to what Elecraft claims.
>
> My measurements were with bw=2.8 KHz (-130 dBm), so correcting for bw: 10Log(2.8/0.5) = 7.5 dB this would result in -137.5 dBm MDS. Considering I am doing this by ear it comes pretty close to the Elecraft spec for the K3 with internal preamp. What was a surprise is the KX3 observed MDS was 3-dB worse than the K3 at -127 dBm (-134.5 dBm corrected for bw).
>
> My measurements do not match on-air experience?? Only conclusion is that the test set up is not providing a stable output. XG3 is a great tool for checking performance but maybe sensitive to loading (just guessing). Probably the best I can achieve with equipment at hand. Hope the math was entertaining - HI.
>
> 73, Ed - KL7UW
>
>
> ---------------------------------
> From: Scott Manthe <[hidden email]>
> To: [hidden email]
> Subject: Re: [Elecraft] K3 6/10M pre-amp
> Message-ID: <[hidden email]>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Maybe the signals are louder on the KX3, which would fool people into
> thinking it was more sensitive? I've always thought my K3 was adequate
> on 6 meters. Not gangbusters, but certainly adequate.
>
> 73,
> Scott, N9AA
>
>
> 73, Ed - KL7UW
> http://www.kl7uw.com
> [hidden email]
> "Kits made by KL7UW"
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

Edward R Cole

Re: K3 6/10M pre-amp

In reply to this post by Gary Gregory-2

>Date: Wed, 10 Jul 2013 00:12:45 -0800
>To: Wayne Burdick <[hidden email]>
>From: Edward R Cole <[hidden email]>
>Subject: Re: K3 6/10M pre-amp
>
>Wayne,
>
>I re-tested on 50.120 and was able to reduce the -107 dBm signal
>from the XG3 down to -135 dBm at 2.8-KHz bw. Correcting for
>bw=500-KHz this results in -142.5 dBm. This is barely detectable so
>lets say -140 dBm for copyable CW. Adjusting the step attenuator
>further did not change the signal so suspect -135 dBm is the lowest
>level I can generate with the current setup. -135 dBm is equivalent
>to NF=4 dB. That is surprisingly low for the BDR performance which
>usually requires a trade-off with MDS.
>
>Bypassing the ATU did not change the level so I guess the ATU was
>already adjusted to 50-ohms.
>
>I did adjust the pitch up to about 700-Hz which made the signal
>easier to hear. The other day it was probably about 400-Hz.
>I did not verify the 0-dBm output of the XG3 but would not expect
>there to be significant level above zero.
>
>The K3+PR6 or other Gasfet preamp will exceed the KX3 so still the
>preferred setup for 6m-eme will be the K3. Still -140 dB is no
>small achievement for the KX3. My summer project includes getting
>the 6-element 6m yagi installed and 800-1000w 6m sspa QRV for eme/ms.
>
>thanks for a really sweet little radio.
>
>Ed - KL7UW
>
>
>> > At 08:31 AM 7/9/2013, you wrote:
>> >> Typical KX3 MDS with preamp on is about -138 to -140 dBm in a
>> 500-Hz bandwidth, on all bands.
>> >>
>> >> If a KX3 is measuring -134 dBm MDS in this bandwidth, chances
>> are there's a measurement error, or the ATU has been left in-line
>> at an impedance other than that of the source RF generator, etc.
>> >>
>> >> 73,
>> >> Wayne
>> >> N6KR
>
>73, Ed - KL7UW
>http://www.kl7uw.com
>[hidden email]
>"Kits made by KL7UW"

Joe Subich, W4TV-4

Re: K3 6/10M pre-amp

Ed,

>> Bypassing the ATU did not change the level so I guess the ATU was
>> already adjusted to 50-ohms.

I have not checked the KX3 schematic but based on the K2 and K3
"bypassing" the ATU only adjusts it to a stored condition that the CPU
'thinks' represents 50 Ohms. I've seen several of the other rigs be
very far off when the ATU is bypassed and known 50 Ohm load attached.

I would always "tune" into a known 50 Ohm load before switching the
ATU to bypass - or in the case of the K3 use the RX IN - before making
any measurements if the radio under test has an ATU installed.

73,

... Joe, W4TV

On 7/10/2013 1:32 PM, Edward R Cole wrote:

>
>> Date: Wed, 10 Jul 2013 00:12:45 -0800
>> To: Wayne Burdick <[hidden email]>
>> From: Edward R Cole <[hidden email]>
>> Subject: Re: K3 6/10M pre-amp
>>
>> Wayne,
>>
>> I re-tested on 50.120 and was able to reduce the -107 dBm signal from
>> the XG3 down to -135 dBm at 2.8-KHz bw. Correcting for bw=500-KHz
>> this results in -142.5 dBm. This is barely detectable so lets say
>> -140 dBm for copyable CW. Adjusting the step attenuator further did
>> not change the signal so suspect -135 dBm is the lowest level I can
>> generate with the current setup. -135 dBm is equivalent to NF=4 dB.
>> That is surprisingly low for the BDR performance which usually
>> requires a trade-off with MDS.
>>
>> Bypassing the ATU did not change the level so I guess the ATU was
>> already adjusted to 50-ohms.
>>
>> I did adjust the pitch up to about 700-Hz which made the signal easier
>> to hear. The other day it was probably about 400-Hz.
>> I did not verify the 0-dBm output of the XG3 but would not expect
>> there to be significant level above zero.
>>
>> The K3+PR6 or other Gasfet preamp will exceed the KX3 so still the
>> preferred setup for 6m-eme will be the K3. Still -140 dB is no small
>> achievement for the KX3. My summer project includes getting the
>> 6-element 6m yagi installed and 800-1000w 6m sspa QRV for eme/ms.
>>
>> thanks for a really sweet little radio.
>>
>> Ed - KL7UW
>>
>>
>>> > At 08:31 AM 7/9/2013, you wrote:
>>> >> Typical KX3 MDS with preamp on is about -138 to -140 dBm in a
>>> 500-Hz bandwidth, on all bands.
>>> >>
>>> >> If a KX3 is measuring -134 dBm MDS in this bandwidth, chances are
>>> there's a measurement error, or the ATU has been left in-line at an
>>> impedance other than that of the source RF generator, etc.
>>> >>
>>> >> 73,
>>> >> Wayne
>>> >> N6KR
>>
>> 73, Ed - KL7UW
>> http://www.kl7uw.com
>> [hidden email]
>> "Kits made by KL7UW"
>
> ______________________________________________________________
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>