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

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

Don Rasmussen
So would operation without the AM filter be bad enough
to roughly approximate, say, a Heath DX100? Just about
the same as would suit me just fine but if not maybe I
need a wider filter? My guys are hard to please and I
know they're not going to be happy with the new rig's
weight already. ;-)

=====

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

 

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

ab2tc
Hi,

I am still confused as to whether I can *receive* AM with the FM roofing filter with the *current* firmware. Can someone please give me an authoritative answer on this? I have just received the FM filter and the included note seems to imply that I have to wait for an firmware update. I am not asking whether I can get more than 3kHz audio BW on AM with but just simply if it will work?

Knut - AB2TC

wb8yqj wrote
So would operation without the AM filter be bad enough
to roughly approximate, say, a Heath DX100? Just about
the same as would suit me just fine but if not maybe I
need a wider filter? My guys are hard to please and I
know they're not going to be happy with the new rig's
weight already. ;-)

=====

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

 

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

Ken Wagner K3IU
Wondering why you don't just install it, configure it, and try it?
73,
Ken K3IU

ab2tc wrote:

> Hi,
>
> I am still confused as to whether I can *receive* AM with the FM roofing
> filter with the *current* firmware. Can someone please give me an
> authoritative answer on this? I have just received the FM filter and the
> included note seems to imply that I have to wait for an firmware update. I
> am not asking whether I can get more than 3kHz audio BW on AM with but just
> simply if it will work?
>
> Knut - AB2TC
>
>
> wb8yqj wrote:
>  
>> So would operation without the AM filter be bad enough
>> to roughly approximate, say, a Heath DX100? Just about
>> the same as would suit me just fine but if not maybe I
>> need a wider filter? My guys are hard to please and I
>> know they're not going to be happy with the new rig's
>> weight already. ;-)
>>
>> =====
>>
>> 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
>>
>>  
>>
>> _______________________________________________
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>>
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>>
>>
>>
>>    
>
>  
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Re: K3 AM operation with "FM" roofing filter?

Don Brown-4
In reply to this post by ab2tc
Hi

The short answer is - YES

I have the FM in slot 1 but do not have the AM filter. I have the 2.8 Khz in
slot 3 and the 400 hz filter in slot 4.  I get 3 KHz bandwidth with the FM
filter on AM broadcast stations.  If I crank the bandwidth above 2.8 Khz the
K3 switches to the FM filter but it is limited to 3 KHZ with the current
firmware.


Thanks

Don Brown
KD5NDB

K3 S/N  0575

--------------------------------------------------
From: "ab2tc" <[hidden email]>
Sent: Saturday, April 12, 2008 4:24 PM
To: <[hidden email]>
Subject: Re: [Elecraft] K3 AM operation with "FM" roofing filter?

>
> Hi,
>
> I am still confused as to whether I can *receive* AM with the FM roofing
> filter with the *current* firmware. Can someone please give me an
> authoritative answer on this? I have just received the FM filter and the
> included note seems to imply that I have to wait for an firmware update. I
> am not asking whether I can get more than 3kHz audio BW on AM with but
> just
> simply if it will work?
>
> Knut - AB2TC
>
>
> wb8yqj wrote:
>>
>> So would operation without the AM filter be bad enough
>> to roughly approximate, say, a Heath DX100? Just about
>> the same as would suit me just fine but if not maybe I
>> need a wider filter? My guys are hard to please and I
>> know they're not going to be happy with the new rig's
>> weight already. ;-)
>>
>> =====
>>
>> 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
>>
>>
>>
>> _______________________________________________
>> 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
>>
>>
>>
>
> --
> View this message in context:
> http://www.nabble.com/Re%3A-K3-AM-operation-with-%22FM%22-roofing-filter--tp14077620p16656659.html
> Sent from the Elecraft mailing list archive at Nabble.com.
>
> _______________________________________________
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Re: K3 AM operation with "FM" roofing filter?

ab2tc
In reply to this post by ab2tc
Thanks, that answers the question unequivocally. That means that it has merit to open up the radio and install the general coverage option and the FM filter without waiting for the back-ordered 1.8kHz filter. I assume they mean business when they say that filters have to be installed ordered by bandwidth wide -> narrow, so I have to move lone 2.7kHz filter installed now. Is it OK to leave the 2nd slot open, just in case I find that I have to install the 6kHz at some later stage?

Knut - AB2TC
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RE: K3 AM operation with "FM" roofing filter?

Dick Dievendorff
You can leave gaps.  Just configure the missing filters at 0 bandwidth and
don't enable them for any mode.

Dick, K6KR


-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of ab2tc
Sent: Saturday, April 12, 2008 4:17 PM
To: [hidden email]
Subject: Re: [Elecraft] K3 AM operation with "FM" roofing filter?


Thanks, that answers the question unequivocally. That means that it has
merit
to open up the radio and install the general coverage option and the FM
filter without waiting for the back-ordered 1.8kHz filter. I assume they
mean business when they say that filters have to be installed ordered by
bandwidth wide -> narrow, so I have to move lone 2.7kHz filter installed
now. Is it OK to leave the 2nd slot open, just in case I find that I have to
install the 6kHz at some later stage?

Knut - AB2TC

--
View this message in context:
http://www.nabble.com/Re%3A-K3-AM-operation-with-%22FM%22-roofing-filter--tp
14077620p16656672.html
Sent from the Elecraft mailing list archive at Nabble.com.

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

Joe Subich, W4TV-3
In reply to this post by ab2tc

Knut,

> I am still confused as to whether I can *receive* AM with the
> FM roofing filter with the *current* firmware. Can someone
> please give me an authoritative answer on this? I have just
> received the FM filter and the included note seems to imply
> that I have to wait for an firmware update. I am not asking
> whether I can get more than 3kHz audio BW on AM with but just
> simply if it will work?

The unequivocal answer is - it will work but with only 3KHz
audio under the current firmware (DSP ver 1.58).  My factory
built K3 was delivered with MCU 1.78/DSP 1.58 and the FM
filter).  With the current public firmware, FM is not functional
and AM audio is limited to 3 KHz (even with the FM filter).

Wayne has said publicly that both FM and wider AM (to 5 or 6 KHz
audio response - 10 to 12 KHz IF bandwidth ) is coming in the next
version.  

73,

   ... Joe, W4TV
 


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

KK7P
> Wayne has said publicly that both FM and wider AM (to 5 or 6 KHz
> audio response - 10 to 12 KHz IF bandwidth ) is coming in the next
> version.  

The firmware under test increases the IF response to 10 kHz bandwidth.
bu the AF response is still only about 4 kHz.  AF response will
(eventually) increase to about 5 kHz, but not 6 kHz.

73,

Lyle KK7P

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