[Elecraft] K3: FM Filter for AM?

[Bob Naumann]

Can someone explain why this restriction exists?

*Why* can't you transmit through a 2.1 filter for example. *Why* is it
precluded? 

I don't want a 2.7 or a 2.8 filter tying up one of the too few filter slots.

W5OV

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Joe Subich, W4TV
Sent: Friday, October 08, 2010 11:07 AM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] K3: FM Filter for AM?


On 10/8/2010 9:30 AM, Don Wilhelm wrote:
 >
 > You can use the FM filter to receive AM, but not for transmit.  To
 > transmit AM, you must have the 6 kHz filter, so you will have to
 > sacrifice one filter.

Repeating one of my complaints about the K3 .... there is no reason
that the FM filter should not be usable for AM (or ESSB) transmit.
The filter response is well into its stopband for the IF image.  I've
checked both of my K3s on a spectrum analyzer (by telling the K3 the
FM filter was 6 KHz wide) and there is no measurable/detectable
transmit image.

73,

    ... Joe, W4TV


On 10/8/2010 9:30 AM, Don Wilhelm wrote:
>    Bill,
>
> You can use the FM filter to receive AM, but not for transmit.  To
> transmit AM, you must have the 6 kHz filter, so you will have to
> sacrifice one filter.
>
> 73,
> Don W3FPR
>
> On 10/8/2010 9:11 AM, Bill Henderson wrote:
>> Hi
>>
>> I already have the 250Hz, 400Hz and 2.7 KHz filters fitted to both
>> receivers. I plan to add 2.1KHz or 1.8kHz filters some time I in the
future.
>>
>> In the nearer future I intend adding the 2m module to my K3. Since this
will
>> be used for local traffic I understand that I need to add an FM filter on
>> the main receiver. Since this is a wide filter can I use it for AM as
well?
>> If not then I would "need" 6 filters with only 5 slots available.
>>
>> I am a black box operator. If I find more than one switch on that box I
>> burst into tears. So please bear this in mind in your answers.
>>
>> Tia
>>
>> Bill
>> GM0VIT
>>
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