[Elecraft] Current buy configuration

[Randy Farmer]

Regardless of whether you get a P3, the KXV3A should be installed in ANY 
K3 build from day one. It's extremely valuable for running external 
receive antennas and/or the installation of bandpass filters, step 
attenuators, etc. between the transmit antenna and the main receiver 
input. If you ever need an accessory such as one of the MFJ-1026 or 
Timewave ANC-4 boxes to combat local noise you can easily patch it into 
the receive line without worrying about the noise canceller T/R relay 
switching giving you problems if you have the KXV3A installed. And you 
might someday want to get an external VHF transverter. Having the KXV3A 
makes adding a transverter a snap. The KXV3A (the only version now 
available) is required to support the P3.

I put the 8-pole roofing filters in my K3, but that was primarily 
because I installed the second receiver and planned to use it for 
diversity reception in 160 meter contest conditions. The 2.7 kHz filters 
are perfectly adequate for operation in virtually any normal environment 
short of Field Day or contest operation with huge antennas. Since you're 
also planning to get the KRX3, you can order a pair of 2.7 kHz units 
with matched offsets at build time for a nominal extra fee, which I 
would recommend. Unless you do a lot of CW band scanning, the 1 kHz CW 
filter probably won't find much use. The 2.7 kHz filter will work just 
fine for wider bandwidth CW operation.

I would substitute the 13 kHz FM filter for the 6 kHz filter for AM use. 
The 6 kHz filter limits your recovered audio bandpass to 3 kHz, just a 
very small bit wider than you can get using normal SSB demodulation on 
AM signals. If you want "broadcast quality" AM audio, the wider filter 
would probably be a better choice. Note that the AM receive (and 
transmit) bandwidth is limited by the K3's DSP processing and you won't 
get the full 6.5 kHz audio range on AM that a 13 kHz filter would imply.

73...
Randy, W8FN

On 4/6/2014 10:41 AM, David Cole wrote:
> As a result of all of you helping me better understand the K3 here is
> what I have come up with as a buy list for a K3 purchase.
>
> I wonder if anyone would not mind looking it over, with an eye towards
> suggestions to me if you see something I missed.
>
> Also a few questions first:
>
> 1.  Do I need something for the KXV3A Upgrade, or is the original item
> included with the K3?
>
> 2.  Is there really much of a difference between the stock 2.7 filters,
> and the 2.8, 8 pole filters for SSB?  I will never be on an island doing
> a DXpedition.  Could I save a few bucks and not get the 8 poles for both
> RX's?
>
> Buy Info follows:
>
> Basic Rig:
> K3/100-F K3 	K3 Xcvr
> KAT3-F		K3 ATU
> KRX3-F		Second RX
> KBPF3		Gen Coverage Module
> KTCX03-1	K3 TXCO (Is this really needed?)
> KDVR3		Digital voice recorder
> KUSB		USB Cable for connection to Linux box
>
> Panadaptor:
> P3-F
> KXV3A (See question above)
>
> Filters:
> MAIN RX Only
> AM:
> KFL3A-6K	AM Filter, only in Main RX
>
> All filters below are in Both Main RX and Sub RX
> SSB:
> KFL3A-2.8	2.8, 8 Pole Replacement filter, RX, plus Sub RX
> KFL3A-2.1	2.1, 8 Pole
>
> CW:
> KFL3A-1K	1 K, 8 Pole
> KFL3A-400	400 Hz, 8 Pole
>
> I may replace the 1K filters with 700 Hz filters, I am still mulling
> this over, any thoughts would be appreciated.
>