Re: Re: K3 AM operation with "FM" roofing filter?

[Dave Lowenstein-2]

No interest in ESSB and little interest in phone, but for casual AM use,
could the "FM" roofing filter be used or is it necessary to purchase both
AM & FM filters to be able to receive and transmit on all modes?

73,
Dave
N7AF


On Tue, 22 May 2007 09:16:06 -0700 wayne burdick <[hidden email]>
writes:
> Actually you could do ESSB at even wider bandwidths, say up to 4.5 or
>
> even 5 kHz, but the exact specs are TBD.
>
> tnx
> Wayne
_______________________________________________
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 Manthe]

I too would be interested in knowing this. I'm on a budget and it would
be nice to save some $$ initially by buying only the FM filter and using
the DSP to limit bandwidth in AM. Any possibility of this?

Thanks,
Scott, N9AA

Dave Lowenstein wrote:
> No interest in ESSB and little interest in phone, but for casual AM use,
> could the "FM" roofing filter be used or is it necessary to purchase both
> AM & FM filters to be able to receive and transmit on all modes?
>
> 73,
> Dave
> N7AF
>
>  
_______________________________________________
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

[Dave Lowenstein-2]

Does anyone know the answer to this?  Can the "FM" roofing filter be used
when transmitting AM to save the cost of an additional filter for a
rarely used mode?

On Tue, 22 May 2007 22:17:46 -0500 Scott Manthe <[hidden email]> writes:

> I too would be interested in knowing this. I'm on a budget and it
> would
> be nice to save some $$ initially by buying only the FM filter and
> using
> the DSP to limit bandwidth in AM. Any possibility of this?
>
> Thanks,
> Scott, N9AA
>
> Dave Lowenstein wrote:
> > No interest in ESSB and little interest in phone, but for casual
> AM use,
> > could the "FM" roofing filter be used or is it necessary to
> purchase both
> > AM & FM filters to be able to receive and transmit on all modes?
> >
> > 73,
> > Dave
> > N7AF
> >
> >  
>
>

_______________________________________________
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

[Eric Swartz - WA6HHQ]

Hi Dave,

The short answer is a 'qualified' yes. The wider FM filter can be used
for AM transmit and receive, since the DSP limits the AM bandwidth, but
there will be two issues.

1. On receive you will be subject to AGC blocking (de-sense) from nearby
signals inside the 13 kHz FM filter's bandwidth but outside the DSP's AM
bandwidth. (Typically those over S9+20 to 30.)

2. On transmit we will not guarantee that there will not be an increase
in close in spurious signals inside the FM filter bandwidth. Normally
the AM filter reduces any undesired transmit signals outside of its
bandwidth.

So for casual AM listening, or AM transmission on a non-crowded band
this might be OK. But we recommend the AM filter for any regular AM
transmit usage.

73, Eric   WA6HHQ
Elecraft

Dave Lowenstein wrote:
> Does anyone know the answer to this?  Can the "FM" roofing filter be used
> when transmitting AM to save the cost of an additional filter for a
> rarely used mode?
>  

_______________________________________________
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

[Dick Dickinson]

 ...wait for variable filter(s)?

Regards,
Dick - KA5KKT/4

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Dave Lowenstein
Sent: Thursday, May 24, 2007 10:31 AM
To: [hidden email]
Subject: Re: [Elecraft] Re: K3 AM operation with "FM" roofing filter?

Does anyone know the answer to this?  Can the "FM" roofing filter be used
when transmitting AM to save the cost of an additional filter for a rarely
used mode?


_______________________________________________
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

[Greg - AB7R]

I've not put this on the FAQ yet, but yes you can use the FM filter for AM.
But be advised it will degrade performance some with reguard to selectivity.
In transmit, the DSP will work with the filter and determine the TX BW.  The
exact specs on this are not yet available.

73
Greg
AB7R


-----Original Message-----
From: [hidden email]
[mailto:[hidden email]]On Behalf Of Edward Dickinson
III
Sent: Thursday, May 24, 2007 8:26 AM
To: 'Dave Lowenstein'; [hidden email]
Subject: RE: [Elecraft] Re: K3 AM operation with "FM" roofing filter?


 ...wait for variable filter(s)?

Regards,
Dick - KA5KKT/4

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Dave Lowenstein
Sent: Thursday, May 24, 2007 10:31 AM
To: [hidden email]
Subject: Re: [Elecraft] Re: K3 AM operation with "FM" roofing filter?

Does anyone know the answer to this?  Can the "FM" roofing filter be used
when transmitting AM to save the cost of an additional filter for a rarely
used mode?


_______________________________________________
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

[ab2tc]

There seems to be some confusion whether one can use the FM filter to receive AM with the *current* firmware or if this is a future enhancement. I need to clarify this as I am in the process of ordering more filters.

Knut - AB2TC

Greg - AB7R wrote

I've not put this on the FAQ yet, but yes you can use the FM filter for AM.
But be advised it will degrade performance some with reguard to selectivity.
In transmit, the DSP will work with the filter and determine the TX BW.  The
exact specs on this are not yet available.

73
Greg
AB7R

<snip>