ID: hamfest find DDS-DRIVEN SYNTHESIZER 10 MHz - Page 1
Forum section: electronics / testgear

author: wd5jfr
author_rank: Regular Contributor
timestamp: October 09, 2023, 04:57:34 pm
content: I can't find anything about it Googlng description or photos of it or the pcb. It powers up and the displayed frequency can be changed but no output. Really not sure what this unit was designed to do.Any info appreciated.ThanksHank

author: bingo600
author_rank: Super Contributor
timestamp: October 10, 2023, 04:57:25 am
content: The interesting part would be the SMD Chip , but we can't see the "ID"To me it seems like there is an unpopulated component near A1 / C12 , that could have been an Oscillator.Any chance that the Coax connected there , is connected to the REF BNC ??If yes , then i'd try to inject some 10MHz to the REF BNC/Bingo

author: ebastler
author_rank: Super Contributor
timestamp: October 10, 2023, 05:44:21 am
content: Any hints on the backside of the PCB?

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 10, 2023, 09:54:55 am
content: The SMD chip looks like a AD9850 or family member, the ref clock input is indeed at pin 9 and it goes to the coax near the A1 designator. A basic AD9850 uses a 125MHz reference so maybe it needs something higher than 10MHz to output the correct frequency.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 10, 2023, 10:43:08 am
content: yeah same here, 9850 or 9851 controlled by a PICthe problem would be to find the non compiled code ...... must came from many projects found on the webyou seem to have an transistor going into the filter line to smooth out the output frequencies, but we dont see the other side of the pcb for this sectionjust find theses dds ic's datasheet and follow the signal lines, maybe there is a selection to enable or disable the dds output

author: wd5jfr
author_rank: Regular Contributor
timestamp: October 10, 2023, 08:57:35 pm
content: Just took a few more pics. Googled S&S & part number but nothing found. Connected 10MHz to the REF and got output frequency which jumped around from KHz to MHz when the encoder know was changed a few Hertz. LOCK light is not installed. Will have to find instructions on what this unit was designed an instructions on toggle switches SET1 & SET2 as well as recessed push buttons PROG and SET do. Also Lock lamp wring.ThanksHank

author: coromonadalix
author_rank: Super Contributor
timestamp: October 11, 2023, 11:30:48 am
content: not being rude, i haven't found nothing,if you do not have a source code you'll never know all the functions implemented in it, nor communication software who can control it or make it work ..you'll have to fiddle the integrated functions to see how it work .....search for any pic implemented dds controller / code etc .... and try to reverse engineer it ?and we did not saw the possible dds ic markings ... or is it buffered ?

author: wd5jfr
author_rank: Regular Contributor
timestamp: October 11, 2023, 02:50:21 pm
content: Here's a pic of the DDS chip, nothing visible. Since S&S is gone my only hope is that some who has one stumbles across this post and responds. At 82 I'm not worth a shit in trying to figure it out.Hank

author: Dazed_N_Confused
author_rank: Contributor
timestamp: October 11, 2023, 03:05:56 pm
content: It may be worth a shot to browse through some of the QRP email archives of different list to find some intel. QRPers have always worked with the DDS's from the beginning

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 11, 2023, 07:36:43 pm
content: So this is a kit sold by S&S Engineering, they did QRP transceiver kits too:https://www.eham.net/reviews/view-product?id=593Since these kits already have a built-in synthesizer I guess this standalone DDS is even older, so pre year 2000. I tried to find some information but have not been able to locate anything in an hour. Maybe I'll do some more searching later but maybe it was pre-internet?

author: wd5jfr
author_rank: Regular Contributor
timestamp: October 12, 2023, 02:37:47 am
content: On one data sheet the PIC was introduced in 1998. I've searched QST, QEX, Nuts & Volts for the PIC and S&S Engineering and no luck. QRP search next. Thanks for everyones efforts and responses.

author: wd5jfr
author_rank: Regular Contributor
timestamp: October 14, 2023, 10:40:08 pm
content: Not much luck in finding anything on QRP sites except on eham.net reviews of 2 QRP rig made by S&S Engineering about yr 2000. I've tried many different REF frequencies from 500 KHz to 500 MHz and I get outputs from low KHz to about 100MHz but there is no linear response to tuning as frequency output jumps in large steps showing up to 9 digits. I'm unsure of what its' application is I but I assume it's a VFO that requires a REF standard frequency. There are 2 recessed push buttons PRG & SET that change what's displayed but I can't make sense of any programming sequence. Toggle SET 1 seems to be active but toggle SET 2 is inactive. I'm guessing that the REF input must correct and I've had no luck with shot gunning. Here's as list of different SET displays.TUNE UP (FORWRD)TUNE DN (BAKWRD)O/S NBR X. X can be from 0 to 9. changed by FREQ SET knob??.? ? ? ? ? ? DIALFR??.? ? ? ? ? ? VFO FR+100 PPM CAL ADJ controlled by FREQ SET knob from + or - 999I'm coming to the conclusion that unless I find some documentation I've wasted a bunch of time and at 82 I don't have good trial & error luck.

author: tautech
author_rank: Super Contributor
timestamp: October 15, 2023, 12:20:35 am
content: Quote from: wd5jfr on October 14, 2023, 11:42:09 pmSpace them so to not be auto converted to the Huh? emoji.