[Elecraft] AF1: First Impressions

[Don Wilhelm]

  Robert,

The form factor is quite different.  The AF1 is a standalone filter that 
can be used with any receiver, and the KAF2 mounts inside the K2.  The 
switch on the AF1 permits selection of no filter, low pass only, one 
filter stage, or two filter stages, and the center frequency is 
continuously varaible using the control.
With the KAF2, the low pass filter is in all the time (unless you 
operate the switch inside the K2), and the center frequency is set to 
whatever you adjust it to - presumably your sidetone pitch.

In other words, the AF1 has more controls available from the "Front 
Panel" than the KAF2.
If you set the AF1 center frequency to your sidetone pitch and do not 
touch it after that, and never use the switch selection that bypasses 
the filter, then the two will be the same "in the ear".

73,
Don W3FPR

On 1/3/2011 5:58 PM, Robert G. Strickland wrote:
> Don...
>
> I take your answer to say that "in the ear" there's no significant 
> difference. What difference there is in the form factor and various 
> adjustments. Yes?
>
> ...robert
>
>
> On 1/3/2011 22:41, Don Wilhelm wrote:
>> Robert,
>>
>> The AF1 is an audio filter, not DSP based, so it is comparable to the
>> KAF2. The AF1 has the added advantage of a variable center frequency.
>> Yes, the KAF2 also has a variable center frequency (with 2 pots), but it
>> is not a "Front Panel" control, once it is set, it cannot be varied at
>> will.
>>
>> 73,
>> Don W3FPR
>>
>> On 1/3/2011 5:06 PM, Robert G. Strickland wrote:
>>> Is the audio filtering of the AF1 any different from the audio filters
>>> of the K2 DSP unit? Is this just a matter of the AF1 being an outboard
>>> unit focused on audio filtering compared to the K2DSP unit being
>>> inboard [specifically for the K2] and using digital signal processing?
>>>
>>> ...robert
>>>
>>>
>>> On 1/3/2011 21:50, dl9hda wrote:
>>>> Hi,
>>>>
>>>> same here. Poor performance.
>>>>
>>>> 73 - Holger, DL9HDA
>>>>
>>>>
>>>> Am 03.01.2011 22:23, schrieb Ken Alexander:
>>>>> Wow! All of that is just with the AF-1? I think I have a lot more
>>>>> tweaking to do because I wasn't getting that kind of performance with
>>>>> it. I'll keep trying and let you know.
>>>>>
>>>>> Thanks for the demo.
>>>>>
>>>>> 73 - Ken, VE3HLS
>>>>>
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>