[RTTY] External DSP devices

[Robert Chudek]

Well, there you have it... more sage advice! I'm not sure there's anymore secrets left to share!

I agree with Don regarding the Icom IC-756 Pro III... I have one in the box waiting for my new ham shack to be finished... the only issue with this radio is the price tag... for a ham on a tight budget this transceiver might be out of financial reach... but it is a great radio. It is so great that I'm switching from Ford to Chevy... errr I mean from Kwd to IC.

Also, I would heed Don's advice regarding the TS-570D... if it didn't play well for him, then you really don't want it for RTTY operation. I checked eBay for TS-850SAT's and see a couple of them have sold for less than $800 recently. (I thought they were more expensive than this!) I used this radio on Field Day (CW) and it definately is much more radio than my TS-690SAT.

So let's see, we've got used $500 radios covered, used $900 radios covered, and new $3,000 radios covered. What's the opinion on used radios in the $1500 ~ $2000 area? I would suggest a TS-950SDX loaded up with filters. I've owned 3 of those in the past 15 years. But that's my personal bias.

Oh... yes... all this chatter reminds me... I guess there is one more secret I have used that I will share...

You can try this trick on almost any radio... If your transceiver has an RF gain control and you can shut off the AGC, experiment with the following combination... turn off the AGC and back the RF gain way down... in many cases a weak station can then be decoded even though a strong station is nearby.

Which reminds me... when I do have the AGC turned on, I have it set to the "Fast" position, especially when working DX signals that have a lot of QSB or flutter. This technique helps provide a more consistent volume of audio to your decoder.

Well now I've gone and done it... sold rope to the hangman... loaned bullets to the gunman... given away the keys to the castle... So I want all you guys to give me a 2-hour head start in the next contest!  :-)

73 de Bob - K0RC



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Message: 8
Date: Mon, 30 Jan 2006 16:34:23 -0600
From: "Don Hill AA5AU" <aa5au at bellsouth.net>
Subject: Re: [RTTY] External DSP devices
To: "'Robert Chudek'" <k0rc at pclink.com>, <rtty at contesting.com>
Cc: k8jwt at adelphia.net
Message-ID: <20060130223345.SLIZ28960.ibm61aec.bellsouth.net at AA5AU>
Content-Type: text/plain; charset="us-ascii"

Bob is correct on this one.  An external DSP audio filter is not going to help
you.  I use the JPS NIR-12 (no longer available) on both radios and the only
thing it does is make the audio sound nice to my ears (and maybe the sound
card).  I would probably decode just as well without them.

I did want to make one comment on the Kenwood TS-570.  I used one as a second
radio in a CQWW RTTY contest a few years ago and the 250 hz filter did not work
well at all.  Nearby stations killed the AGC and made it nearly impossible to
copy weak signals.  The Kenwood TS-870 does not have this problem and has
excellent filters.

But nothing I've used so far compares to the Icom IC-756PRO III.  This appears
to be the ultimate, affordable, RTTY radio with it's Twin Passband Filter.

I hope to put all three of my TS-870 radios up for sale in the foreseeable
future so I can purchase a second (and possible 3rd) PRO III.  I still love the
'870 and it is my main radio on 10, 20 and 80 meters in RTTY contests, but I
really want a band scope on both radios.

73, Don AA5AU