> On 20 Mar 2017, at 02:56, W9HGO <[email protected]> wrote: > > Hello, > > Will a Timewave DSP-9 will be of any help with jt65 signals for my FT-871 ?
That filter will be detrimental if you turn it on as far as I know. Those filters, described in a very simplified way, are a sort of "spectral squelch". Frequency bands that fall below certain threshold are attenuated. They help to clean up a voice transmission, but can be a disaster for JT which often relies on signal below the noise level. I left it turned on by accident on my IC-7200 and it was a complete disaster ;) > Does the CW filter help as much as the TCXO does for JT6 ? A narrower filter won't be very useful, because on these narrow modes you operate much better if you can see 2 KHz or, even better, 4 KHz of spectrum. Seeing 2.2 KHz of spectrum lets you see all of the JT65 or JT9 activity on the band you are operating. However, the optional Collins SSB filter can be a great improvement. The stock filter in the FT-817 has a so-so response, with some attenuation near the edges. However, the Collins mechanical filter has a much straighter response, which means that you won´t see much attenuation on the band pass edges. It's really noticeable in voice transmissions. The Collins filter sounds much crisper. This web page shows the difference between the stock ceramic filter and a mechanical one. http://www.w4rt.com/FT-817-Accessories/One-Plug-Filter-SSB.htm And, I forgot, a TCXO is always great for these digital modes. Anyway, try without it before pulling the trigger. But I think that the SSB filter will really help. Borja - EA2EKH ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ wsjt-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/wsjt-devel
