Les,
According to the RFSM web page, you need at *least* 300 to 3000 Hz audio
response, and preferably 300 to 3400 Hz. Even an INRAD filter is not going to
completely meet the 3000 Hz high end requirement, much less a 3400 Hz
requirement. I think some other Yaesu rigs optionally support a 3300 Hz high
end with an optional Yaesu filter, but my point was that if your low end is
only 700 Hz, something is misaligned on your FT-857 to start with. You also
could wind up paying for an INRAD filter and still find the low end or high end
inadequate because the audio itself is rolled off too fast.
Anyway, it is probably better to use something other than the FT-857 for
digital modes as finding the ALC threshold is very critical for getting low
IMD, even on PSK31, and drift is a problem on 2 meters unless you have the TCXO
option, which my FT-857 does not.
73, Skip KH6TY
----- Original Message -----
From: Leskep
To: digitalradio@yahoogroups.com
Sent: Saturday, April 19, 2008 12:11 AM
Subject: Re: [digitalradio] RFSM8000 and Yaesu FT857
Hi Skip
The problem is that I need to pass around 2.4 khz of signal audio
and with the stock filter it will not do it - have to look at a wider filter
or
an IC7000 hihi
Regards
Les
From: kh6ty
Sent: Saturday, April 19, 2008 11:40 AM
To: digitalradio@yahoogroups.com
Subject: Re: [digitalradio] RFSM8000 and Yaesu FT857
Les,
Are you sure it is the IF passband? If your BFO injection frequency is set
correctly, you should be able to pass 300 to maybe 2200 Hz. Otherwise, SSB
phone will have no lows.
If you have audio transformers in a homebrew interface, make sure they have
the necessary frequency response. The best around here seem to be the little
green ones from Radio Shack.
73, Skip KH6TY
----- Original Message -----
From: Leskep
To: Digitalradio
Sent: Friday, April 18, 2008 9:08 PM
Subject: [digitalradio] RFSM8000 and Yaesu FT857
Greetings to all
Is anyone using the FT857 for RFSM8000
I have been trying mine out over the past two days after getting a
new Signalink USB interface
Big problem with the RX passband - it is not wide enough using
the standard filter supplied with the FT857 and consequently too
much of the signal is cut off on the low frequency end of the audio
Waterfall shows that there is no or very little audio up to about 700 hz
making it impossible so far to make a connect even though it will
spring up the called station every time
Any ideas? I am now looking at an INRAD filter either 2500 or 2900
that would allow the required passband audio
Any comments or feedback welcome
Regards
Les VK2DSG
----------------------------------------------------------------------------
No virus found in this incoming message.
Checked by AVG.
Version: 7.5.524 / Virus Database: 269.23.1/1385 - Release Date: 4/18/2008
9:30 AM
------------------------------------------------------------------------------
No virus found in this incoming message.
Checked by AVG.
Version: 7.5.524 / Virus Database: 269.23.1/1385 - Release Date: 4/18/2008
9:30 AM
