KX3 AM-breakthrough

[Bruce Beford-2]

Peter,

I have heard from some afflicted with this, that the situation can be helped
in a few ways.

#1- reduce the overall system gain. Turn off unneeded preamps, turn on
attenuator.

#2. Often, the interfering signal has been identified as a SW BC station
_below_ the Amateur band in use. In these cases, a high pass filter may
help. The output LPF of the rig will not reduce the incoming, lower
frequency, interference. This would imply a switchable (or otherwise
tunable) HPF, provided by the user, and switched in as needed. Less than
ideal, but may be helpful in some situations.

#3. engage the 8KHz Rx shift.

Note that this does not affect all operators, in all situations. When it
does, however, it can be quite debilitating to RX. The 8 KHz shift does
seems to help in most cases, but should be used only when needed, as Wayne
has previously said.

73,
Bruce
N1RX

> This thread has moved way beyond my technical level.  As I understand, the
> problem arises in locations where there are very strong broadcast
> stations, well outside the ham bands.  Presumably a bandpass filter
> doesn't help -- is it that the mixing products are occurring in the
> antenna?  Wouldn't the solution then be in the antenna, in the form of
> directional nulls or stub filters?

>     Peter W0LLN



______________________________________________________________
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

[vk2rq]

It has been noted by some that enabling the 8kHz shift means that the KX3 dual watch feature can not be used at the same time.

Perhaps it is also worth noting that if the KX3 RX I/Q output is connected to a PC running an SDR application such as NaP3, then the PC can be used as a second receiver and you can access this dual watch type of functionality even with the 8kHz IF shift enabled.

73,
Matt VK2RQ

On 31/07/2013, at 6:05 AM, "Bruce Beford" <[hidden email]> wrote:

> Peter,
>
> I have heard from some afflicted with this, that the situation can be helped
> in a few ways.
>
> #1- reduce the overall system gain. Turn off unneeded preamps, turn on
> attenuator.
>
> #2. Often, the interfering signal has been identified as a SW BC station
> _below_ the Amateur band in use. In these cases, a high pass filter may
> help. The output LPF of the rig will not reduce the incoming, lower
> frequency, interference. This would imply a switchable (or otherwise
> tunable) HPF, provided by the user, and switched in as needed. Less than
> ideal, but may be helpful in some situations.
>
> #3. engage the 8KHz Rx shift.
>
> Note that this does not affect all operators, in all situations. When it
> does, however, it can be quite debilitating to RX. The 8 KHz shift does
> seems to help in most cases, but should be used only when needed, as Wayne
> has previously said.
>
> 73,
> Bruce
> N1RX
>
>> This thread has moved way beyond my technical level.  As I understand, the
>> problem arises in locations where there are very strong broadcast
>> stations, well outside the ham bands.  Presumably a bandpass filter
>> doesn't help -- is it that the mixing products are occurring in the
>> antenna?  Wouldn't the solution then be in the antenna, in the form of
>> directional nulls or stub filters?
>
>>    Peter W0LLN
>
>
>
> ______________________________________________________________
> 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
Please help support this email list: http://www.qsl.net/donate.html