K3 BCB reception weak

[N4LQ-2]

Is sensitivity very low below about 1000khz in the BC band or is it just me?
It really drops off there and I can only pick up a couple of really strong
stations below that. I did install the KBF3. Does that attenuate the BC
band?
I did make sure the ATU was in bypass.
Steve Ellington
[hidden email]

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Scott Prather-2]

Steve: The K3's PIN diode T/R switch displays quite a bit of attenuation in
the broadcast band, especially below about 1 MHz (I've measured 18 dB
attenuation at 500 kHz).

The only solution I'm aware of is to install the KXV3. With the external
antenna input provided on this interface (which bypasses the PIN diode T/R
switch) the K3 is an excellent performer on the BCB.

Scott
N7NB

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of n4lq
Sent: Thursday, July 17, 2008 12:29 PM
To: [hidden email]
Subject: [Elecraft] K3 BCB reception weak

Is sensitivity very low below about 1000khz in the BC band or is it just me?

It really drops off there and I can only pick up a couple of really strong
stations below that. I did install the KBF3. Does that attenuate the BC
band?
I did make sure the ATU was in bypass.
Steve Ellington
[hidden email]

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[N4LQ-2]

Wow. Thanks Scott. That made all the difference!
I have a real problem here with WHAS on 840khz. This is a 50kw station and
it totally overloads the K3. I use an ICE BCB filter inline with the rig
just so it can be used on HF. Some rigs are less affected by this station
but not the K3. What I really need is a series tuned trap for 840khz but I
guess that would need to be home brewed and installed in the front end.
Steve Ellington
[hidden email]
----- Original Message -----
From: "Scott Prather" <[hidden email]>
To: "'n4lq'" <[hidden email]>; <[hidden email]>
Sent: Thursday, July 17, 2008 9:28 PM
Subject: RE: [Elecraft] K3 BCB reception weak

> Steve: The K3's PIN diode T/R switch displays quite a bit of attenuation
> in
> the broadcast band, especially below about 1 MHz (I've measured 18 dB
> attenuation at 500 kHz).
>
> The only solution I'm aware of is to install the KXV3. With the external
> antenna input provided on this interface (which bypasses the PIN diode T/R
> switch) the K3 is an excellent performer on the BCB.
>
> Scott
> N7NB
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of n4lq
> Sent: Thursday, July 17, 2008 12:29 PM
> To: [hidden email]
> Subject: [Elecraft] K3 BCB reception weak
>
> Is sensitivity very low below about 1000khz in the BC band or is it just
> me?
>
> It really drops off there and I can only pick up a couple of really strong
> stations below that. I did install the KBF3. Does that attenuate the BC
> band?
> I did make sure the ATU was in bypass.
> Steve Ellington
> [hidden email]
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>
>
> No virus found in this incoming message.
> Checked by AVG - http://www.avg.com
> Version: 8.0.138 / Virus Database: 270.5.1/1559 - Release Date: 7/17/2008
> 6:08 PM
>
>
>

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[wayne burdick]

N4LQ wrote:

> Is sensitivity very low below about 1000khz in the BC band or is it
> just me?
> It really drops off there and I can only pick up a couple of really
> strong
> stations below that. I did install the KBF3. Does that attenuate the BC
> band?
> I did make sure the ATU was in bypass.
> Steve Ellington
> [hidden email]

Hi Steve,

All PIN diodes, including those used in the K3's T-R switch, are
susceptible to increasing intermodulation as the applied signal
frequency decreases. We selected diodes that perform very well at low
frequencies, but as a precaution, we designed the T-R switch to have a
high-pass response below 1 MHz. At 500 kHz, the roll-off is around 15
to 20 dB. At 1.5 MHz, the roll-off is only a dB or so. We feel that
this is a good tradeoff.

There's a note about this in the Owner's Manual (in Rev. C, it's on the
right side of page 36). But I'll also add this to the Specifications
page.

73,
Wayne
N6KR

---

http://www.elecraft.com

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com