I wish someone would post a PIC of this mod.. Even a hand drawn schematic
with a parts list would be great... Or, maybe that was done before, and I
am just too new to the list... Hmmmm
I am not so worried about the noise as I am the small traces... But if I am
in there to relieve that problem, might as well go all out...
Back out on 10m, Tokyo is busting into north Texas right now...
Any VY2 calls out here on the list? I would LOVE to work P.E.I. sometime on
10m...
At 12:37 PM 3/2/00 , Warren J. Walsh wrote:
>I have had several people ask about the actual modifications I performed
>on my OMNI-VI+ (Option 3 Upgrade). I really did not do anything
>extraordinary. I basically followed the suggestions listed by Piotr
>Tomczak in his posts about the OMNI synthesizer noise. This board lacks
>sufficient de-coupling caps, and the POWER (+5V) and GROUND connections to
>the IC's are made with SIGNAL size traces are what I consider to be a
>problem. The second part of the last sentence is what I feel causes the
>~5 Ohm resistance between pin 26 and pin 57 of the DSP chip. I added
>de-coupling caps between the POWER (+5V) and GROUND pins on all the
>digital IC's. The value of these caps is NOT critical you can use .1uF,
>.01uF or .001uF 50V CERAMIC caps. I did not have enough of any one value,
>so I used some of each of the previous values. I also soldered a piece of
>24ga. Teflon wire between pin 26 and pin 57 of the DSP, this eliminated
>the ~5 Ohm resistance. I did NOT add any ferrite beads to any of the
>interconnecting cables other then the incoming +12V line, for that I used
>a small snap on ferrite I had handy wrapping the +12V wire twice through
>this ferrite. As I said in my previous post, I CANNOT say for sure which
>mod made the difference, but I have a SIGNIFICANT reduction in birdies
>across the bands
>
>73
>Warren Walsh - K2BM
>
>==================================================================
>Warren J. Walsh (warrenw@pentek.com) Pentek, Inc.
>Design Engineer One Park Way
>Phone: (201) 818-5900 x 251 Upper Saddle River, NJ 07458
>Fax: (201) 818-5941 http://www.pentek.com/
>==================================================================
>
>
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+-------------------------------------------------------+
| 73's KA5PPX/Robert McAdams/TechPlus/ARRL/10-10 #70957
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| Lat: 33° 26' 50"n Lon: 97° 2' 43"w
| 10-10 club ID# 70957
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| Lat: 33.45074 Lon:97.044392
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