Flex 6300 Line input level in sufficient with Timewave Navigator

Mark Erbaugh

I hooked up my Flex 6300 to a Timewave Navigator soundcard interface. I ran pin 1 of the Flex to pin 25 of the Navigator for Tx audio and pin 6 of the Flex to pin 13 of the Navigator for analog ground. With the Navigator at max output (20 dB pad is disabled), I can only get about -10dB of drive which isn't enough to get full output from the Flex. Question: are all the grounds on the 15 pin header common, or are some for audio signals and some for digital/control?

According to the Flex specs, that aux input is -10dBV. According to the Navigator spec, the output is 410 mV into 4.7 kOhms. I did a website conversion calculation and 410mV rms should be about -7dBV so I would thing I should be able to get more than full output (the Navigator has a **** for adjusting the output level so it can easily be backed off).

I can get full output from the Flex when using DAX.

I'm running SSDR 1.3.8.

Thanks, 73,
Mark

Ken - NM9P

I remember the one on the 1500 had separate mike + and - that were not linked to the "chassis" ground.  

But after looking at the hardware manual for the 6000 Series, it doesn't appear that there is a separate ground for the TX audio input at the "line level" ACCY connector.

Perhaps you need to turn on the +20 dB button in the Phone setup tab?

Ken - NM9P

Mark Erbaugh

I tried the +20 dB button and it didn't seem to make a difference.

np2g

Doesn't,t the 6300 have DAX. It can work better than the navigator.

KY6LA_Howard

Based on some relatively unscientific tests, we got 7dB better decodes with DAX than with any of the Sound Card based Interfaces such as the Timewave.   DAX is digital throughout its entire path while the sound card based systems convert from Digital to Analog and back to Digital.   Each conversion step introduces distortion which accounts for the much better decodes using DAX which does not suffer from those distortion products.

So unless you are trying to use some special feature of the Timewave..
Why would you not just use DAX?

np2g

I mostly run psk. DAX. Superior. Sold my navigator

Tim - W4TME

Mark - we have been looking into this and it looks like the ACC input may be down in input gain.  This fix is something that may make it into the next release of SmartSDR.  Just depends on how testing goes.

Mark Erbaugh

Tim - thanks for letting me know.

David Decoons, wo2x

Mark,

Have you used the RTTY filter on the Navigator? how does it compare to using DAX on weak signal RTTY decode? Overall have you compared decode on various modes to using DAX?

I submitted a feature request to Flex for a DSP RTTY peak filter for the standard mark and space tones. Not sure if/when it will make it into SmartSDR. The Kenwood TS-990 incorporates a RTTY peak filter and it really makes a difference with weak signal detection.

Thanks
Dave, wo2x

Mark Erbaugh

I found my original thread on low input levels with ACC port line in. Tim confirmed the problem in SSDR, with a possible fix in later versions. It looks like the problem is still present in at least SSDR 2.4.9, some 5 years later. Will it ever be fixed?