A 2.7 kHz 5-pole filter is included with each K3 and each KRX3. (See the K3 price list/order form at http://www.elecraft.com/elecraft_prod_list.htm#k3)
You may replace that 2.7 kHz 5-pole filter with a 2.8 kHz 8-pole filter at the time of initial order for an additional amount that is slightly less than a new 2.8 kHz filter. (see the KFL3A-2.8_2.7sw item on the K3 order form). If you're ordering both main and sub, you should consider "matching" the filters if you decide on the 2.7 kHz 5-pole filters. (see KFLMATCH on the order form). Matching is not required for two 2.8 kHz 8-pole filters. A 2.7 or 2.8 kHz filter is required in the main K3. It is used as the transmit filter for CW, Data and SSB modes. Even if you're a 100% CW operator, you'll need one of these two filters, 2.7 or 2.8 kHz, on the K3 main RF board. If you're uncertain, the smallest initial investment would be to order the "default" 2.7 kHz 5-pole filters for both main and sub. If you plan to use diversity, investing in a matched pair would be a good idea. Some users feel that starting with two 2.8 kHz 8-pole filters is a better investment than the matching fee. Others are quite happy with the 2.7 kHz 5-pole filters. I chose 2.8 kHz 8-pole filters as my initial filters in main and sub. If you're primarily a CW operator, you should also consider a narrow filter, somewhere around 400-500 Hz. There are several to choose from; Elecraft offers a 400 Hz 8-pole filter and a 500 Hz 5-pole filter, and I think Inrad may offer a 500 Hz 8-pole filter. You don't have to get this right on day one. You can start with what you know you need and add filters later. 73 de Dick, K6KR -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of callen1155 Sent: Wednesday, February 24, 2010 2:30 PM To: [email protected] Subject: [Elecraft] Determining best roofing filter with DSP?? Hello guys. Sorry about all the questions but I think this is the last one before I press the "buy" button for a K3. Once again a question about cw roofing filters. I am initially ordering the K3 without the 2nd receiver but do plan on getting one within a year. That said, and knowing it's best to have 'matching roofing filters' for both receivers, even after all the reading I still have no idea what would be the best roofing filter to get. It seems to be such an individual choice. Ideally, I'd prefer to purchase only one filter (or one for each receiver) and want to make the best filter choice for my operating. So if I order the K3 with no roofing filters, can I determine from operating with just the DSP which cw roofing filter would be the optimal one for me. Or is the above an exercise in futility and I just need to order say a 400 and see how that does before I'll know? But then again I guess it wouldn't be 'matched'' when I get one for the second receiver. Too many decisions! thanks again. chuck af4xk ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
