[Elecraft] K3: Choosing which filters to buy

[Joe Subich, W4TV]

> Are those filters I've listed above all I can fit in the K3's 
> main receiver? I think I read that it had 5 filter slots. I'm 
> not sure if the KBF3 fills one of these slots. If not, should 
> I consider an alternative additional filter?  

The KBF3 General Coverage RX Filter Module is not a 
first IF filter - it is a front end bandpass filter module - 
and does not use one of the five "filter slots." 

If you are planning to use the 12 KHz filter for AM, I do 
not know that also need the 6 KHz filter unless you are 
planning for ESSB use in the future. 

> 2. Can users distinguish the difference between the 2.7KHz 5 
> pole filter and the 2.8KHz 8 pole filter when using the K3? I 
> understand the skirts of the 8 pole filter's passband will be 
> steeper but is this noticeable?

Yes, when the band is crowded and you have very strong signals 
+/- 1.5 KHz or more.  However, for 90%+ of CW and digital 
(RTTY) operation you will not notice the narrower first IF 
filter.  The 500 Hz 5-pole filter is a suitable alternate to 
the 400 Hz 8-pole at a slightly lower cost.  

My K3 has the FM, 2.8 KHz, 500 and 200 Hz filters.  I see no 
need for the 6 KHz filter and rarely use the 200 Hz filter (but 
I expect to use it on 80/160 in the contests).  I can't see a 
need for any of the other filters but I'm keeping my options 
open with regard to a 1.5 or 1.8 KHz narrow SSB filter (or the 
variable width filters if/when they are available).  

73, 

   ... Joe, W4TV 
 



> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Shane White
> Sent: Wednesday, June 25, 2008 9:06 AM
> To: elecraft at mailman.qth.net
> Subject: [Elecraft] K3: Choosing which filters to buy
> 
> 
> 
> 1. I plan to configure my K3 with the following filters -
> 
> Stock 2.7KHz
> KBF3 General Coverage RX Filter Module
> AM 6KHz
> FM 12KHz
> CW 400Hz 8 pole (uncertain about this filter)
> 
> Not having much CW experience and my current radio only using 
> a 2.7KHz wide filter for CW (Rx only), I'm not sure which 
> narrow filter to equip the K3 with. What's recommended for 
> someone who will only use CW intermittently and not for 
> contesting? (General purpose use I suppose). It's worth 
> mentioning that I'm yet to learn morse but certainly 
> appreciate it's worth and plan to use it. 
> 
> Are those filters I've listed above all I can fit in the K3's 
> main receiver? I think I read that it had 5 filter slots. I'm 
> not sure if the KBF3 fills one of these slots. If not, should 
> I consider an alternative additional filter?  
> 
> 2. Can users distinguish the difference between the 2.7KHz 5 
> pole filter and the 2.8KHz 8 pole filter when using the K3? I 
> understand the skirts of the 8 pole filter's passband will be 
> steeper but is this noticeable?
> 
> Thanks,
> Shane
> VK5ABQ
> -- 
> View this message in context: 
> http://www.nabble.com/K3%3A-Choosing-which-filters-to-buy-tp18
111978p18111978.html
Sent from the Elecraft mailing list archive at Nabble.com.

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