Re: KX3 vs FT817 - how do the "inside dimensions" compare?

Posted by wayne burdick on Oct 23, 2011; 5:17pm
URL: http://elecraft.85.s1.nabble.com/KX3-vs-FT817-how-do-the-inside-dimensions-compare-tp6919846p6922411.html

Hi Jim,

The K3 comes with very narrow ham-band filters, standard. These  
provide the excellent SWL rejection that you're referring to, which is  
especially important in a down-conversion superhet design. To obtain  
full SWL coverage, the K3 user can install the KBPF3 option, which  
adds wider filters that cover the entire range of 0.5-30 MHz. This has  
no impact on ham-band performance, as the wider filters are only  
switched in when you tune well outside the ham bands.

The KX3 has a different receiver architecture, similar to direct  
conversion but with quadrature channels (I/Q) to allow for single-
signal reception. This architecture doesn't involve a large I.F., so  
there are fewer images to deal with in both RX and TX mode. This  
lightens the requirements for band-pass filtering. As a result, the  
KX3's band-pass filters can include ham and nearby SWL bands without  
any need for tuning.

The K1, KX1, and K2 have tuned ham-band filters that provide coverage  
of most nearby SWL bands.

73,
Wayne
N6KR


On Oct 23, 2011, at 9:58 AM, Jim Lowman wrote:

> After almost 50 years of being a ham, I see that the conventional  
> wisdom
> of NOT including general coverage in a receiver has been refuted.  
> It was
> thought to be at the expense of performance on the ham bands.
>
> How have modern design techniques overcome this limitation?
>
> 73 de Jim - AD6CW
>
> On 10/22/2011 10:11 AM, Wayne Burdick wrote:
>> Hi TR,
>>
>> The KX1 is our smallest radio, with TFR (trail-friendly) format and  
>> an
>> attached paddle, like the KX3. It also uses a DDS VFO and SSB/AM
>> receive, providing SWL coverage in addition to the ham bands.
>>
>> 73,
>> Wayne
>> N6KR
>>
>>
>>
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