MENU item 19 and TS950 SDX

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JJ2013
Voodoo Audiophile
Posts: 141
Joined: Sat Apr 27, 2013 9:16 pm

MENU item 19 and TS950 SDX

Post by JJ2013 » Mon Aug 11, 2014 2:58 pm

Hi y'all Audioheads, Audiophiles and VooDoo Gurus!

I am curious, MENU item 19 is used to "set the cut-off frequency of the DSP BPF and LPF during receiving" but it also says that this MENU item works in FSK mode only. Now, I also tried in when in the SSB mode and switching to different high cuts made a difference to perceived audio on SSB. At the same time the low-cut is really high at 400 Hz so I guess I should leave this item alone as the manual says? You can change the high-cut, but the low-cut is even higher than 400 Hz for the other high-cuts so I don't like it! However, it does impact audio quality on receive and this MENU item is perhaps something that CAN actually improve the RX pass-band for a VMSDX??

Based on what the Manual says this MENU item shouldn't have any impact or more precisely the Manual says that this item 19 works in FSK only..... :roll:

OK, don't be too tough with your come-back :wink:

Cheers!

JJ

BillPaul
Digital Voodoo Guru
Posts: 66
Joined: Wed Jan 19, 2011 11:52 am

Post by BillPaul » Mon Aug 11, 2014 4:30 pm

Menu 19 does in fact work in SSB mode, including the BPF settings. It may also work in CW mode, though I don't remember off the top of my head, and I'm not in front of my radio right now so I can't test it. I know it does not work in AM mode. This is because the DSP unit is not used for AM receive filtering: the radio uses the analog filters for AM RX selectivity instead. (As a side node, menu 21 only has two working settings in AM: 3100 and off. You can select a setting lower than 3100 in AM mode, but it doesn't actually have any effect. The computer "knows" that anything narrower than 3.1KHz doesn't make sense for AM so it overrides any smaller setting internally.)

The manual may be trying to say that the BPF1/2/3 settings are only useful for FSK mode, but you can engage them in SSB mode.

For whatever the reason, Kenwood didn't make the DSP unit as configurable in RX mode as they could have. The DSP-100 unit which you can us with the TS-850 allows you to configure the low and high cut settings independently with two knobs. In the TS-950SDX you can only scroll through the selections in menu option 19.

In general, you can use both the menu 19 DSP setting and the analog filter settings to complement each other and improve the receiver selectivity even more compared to just having the analog filters alone.

-Bill, N1GPT

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