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> The Ad9850, Is it a VFO?
MacFromOK
Posted: January 17, 2017 11:48 pm
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QUOTE (kellys_eye @ January 17, 2017 12:56 pm)
I haven't reached the dizzy heights of 60

Me neither (though I'm within a couple months), but yeah...

I've had a hand-held magnifying glass (with a small "super magnifying" spot), as well as a hands-free one with soldering clamps, for probably 10 years or more. And I've actually used a conventional microscope to check component ID numbers a time or two... biggrin.gif


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cgriggs
Posted: January 23, 2017 04:31 pm
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(Taken from eHam Forum smile.gif
DDS graphical vfo controling a 40 meter rig
on: October 04, 2016, 11:49:57 PM

I found this project, and looks interesting. Does any one know where to find a nice graphical dds vfo like that one?
This project is all home brew I guess. Its hard to find other information on it. There is a link to the transmitter its self with
parts list and layout pdf for etching.
http://www.tb5x.com/2015/01/10/dds-kontrol...ranli-40-m-qrp/

Mac and Kelly,
I love the way this guy did it! Beautiful job! I hope my finished product looks even half as good.
Also, I see now that the Rotary Controller controls the VFO frequency as I suspected. I may have to figure out getting the bandspread of 7.0 to 7.3 though.
This high tech is a never ending learning process! LOL
Charlie

This post has been edited by cgriggs on January 23, 2017 09:41 pm
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kellys_eye
Posted: January 23, 2017 09:39 pm
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There are many, many different DDS controlled homebrew radios out there if you look. Here's a good one with a colour graphical display - I built this one late last year from the design published by G0ETP (Tim) who designed the zero-IF front end board and who offers this as a (partial) kit of parts. Total build cost runs to some $120 but can be built for less if you (like me) have a decent 'scraps' box....

Beware that the board is ENTIRELY surface-mount and wasn't easy for me to construct from the supplied kit although the finished version is very reliable.

http://www.themadhowes.org.uk/g0etp/sdr_rx/

Controlling the DDS board you've ordered Charlie isn't as difficult as imagined (says he who hasn't done what he's about to propose!) but modifying the code for individuality seems to be the in thing!




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cgriggs
Posted: January 23, 2017 11:17 pm
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My knee bows to your expertise! Judas Priest! My finest home-brewing day has been trashed in my eyes. I have never seen such beautiful work. Kudos! I would swear that it was off the production line. WOW!
"Sulking and mumbling in a dark corner" Charlie
On Edit: Just so you know I'm familiar with precision and close work, I worked 33 1/2 years as a tool and die maker at Talon, Inc. here in Meadville, Pa. I recognize and appreciate good work!


This post has been edited by cgriggs on January 28, 2017 02:50 am
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cgriggs
Posted: January 31, 2017 10:19 pm
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Kelly, the Dupont "jumpers' came today and fit beautifully! Now, if only the Rotary Encoders (I had to buy a 3 pack!) came, I'd be ready to find out "the rest of the story". (Paul Harvey's program of the 90's, I think) LOL
I have the schematic of the power hookup here somewhere that I believe you suggested.
Charlie
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cgriggs
Posted: February 01, 2017 03:43 am
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Kelly,
I have 3 pages of "instructions" that I'd like to get to you, but don't know how to do it. (3 pages!) That's a lot of space. How can I do it, have you copy it and then delete it, saving that space for others to use?
To you the instructions will make sense, but to me it's taking for granted that I'm familiar with the terminology, which I am not. (Not yet, at least.) Judas Priest! I feel like a novice wannabee talking to me in the 60's.) How disgusting! LOL
Charlie
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kellys_eye
Posted: February 01, 2017 05:15 pm
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Charlie - I'll send a PM (and email since you have your email link on your profile) with my direct email address so if you can photograph or scan the document I will do what I can to decipher and assist!


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cgriggs
Posted: February 01, 2017 07:40 pm
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Quoting from an old black and white cowboy movie:
"Bless you , my child!"
A franciscan monk, I believe.

Do I have to explain, "Old black and white cowboy movie"??? LOL
<hidden text> Kids! It's gotta be in color for them!! Sheesh!!<End Hidden Text>
LOL

I'll check my email.

Charlie
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cgriggs
Posted: February 03, 2017 02:53 am
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I put together an adjustable power supply for the DDS with an Lm317. (9 volts) Now if I can sit on my hands until the encoders get here??? LOL
Charlie
And I was one that went nuts in the Army with their daily, "hurry up and wait!" moments!! Some things never change!
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cgriggs
Posted: February 04, 2017 10:28 pm
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Dave, The encoders came, I wired one up and now I'm going back to my kitchen painting.
I know! I know! So I'm chicken! Maybe this evening I'll get your directions out again and give a try at deciphering them into common sense. ... whew!! ...
I visualize a puff of smoke, followed by a Celiac release moment and a very hasty flight from the odiferous stench, never to darken the attic again. LOL
Charlie unsure.gif
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kellys_eye
Posted: February 04, 2017 10:56 pm
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The modern stuff rarely goes up in a spectacular fashion these days - if it fails it'll do it surreptitiously and make you spend a week wondering why it's stopped working!


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cgriggs
Posted: February 04, 2017 11:09 pm
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OK. The pins were a lil bit smaller than the Dumont plugs and kept sliding off, but I was able to solder the wires onto the encoder without the plugs. (Easier than I thought. I think I'm getting the hang of soldering back. lol) I didn't get a power lead, but that was no problem.
Onward to the attic to power it up. Back later with results/questions/etc.
Charlie
After power up:
CNS 4.01
R Ub AM
7.000000 Mhz

Does that mean I'm at 7.0 Mcs on AM???
Could the Ub mean Upper Sideband?

WOW! I love it! I played with it and find it will make a great VFO! All I need is to get it into CW mode. (I think!) I had my 40 mtr rig on while sweeping the freq. Nice clean sound!
I went down your list of instructions. What intrigues me is how I can move up or down the frequency with the encoder without hitting a "stop." It just keeps going. (The Everready Bunny???)
Lots to learn! Lots to learn!
"In Seventh Heaven" Charlie
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kellys_eye
Posted: February 05, 2017 02:44 pm
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Not sure what the Ub means but the AM will signify that the 'AM' pin on the board is 'high' to allow you to use the signal to switch in the appropriate filter.

Whilst on AM there is no 'offset' (unlike USB with 2.4kHz or whatever) so the output frequency will be as the display shows and you can safely ignore the symbology.

You can also check for a logic high on the appropriate band pin and use that for filter selection too if needed. Sweep to another band (or even just move outside the current band) to see the logic level change and prove that the control pin changes state in/out of the relevant bands.

Although you can add the extra keys/buttons to make changes to mode, swap between two VFO outputs (both capable of being set independently etc) your current needs don't require this and the adage 'if it ain't broke, don't fix it' applies.

If/when you find yourself keen to explore the added facilities we can make the required changes but tbh I'd tell you to get ANOTHER device and use that for playing with rather than risk upsetting what seems to be the ideal solution to your current needs.

All that worry for nothing eh Charlie laugh.gif

PS - have you figured out moving the cursor to change the relevant digits as per my email advice?



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cgriggs
Posted: February 05, 2017 06:37 pm
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Yes, I've figured out about moving the curser and getting the different "scanning" rates. From mighty slow to zip. LOL

Will I be able to use it on CW the way it's set up now? (The AM, I mean. I can't find CW, LSB or USB.)

I want to take advantage of the two VFO's feature, although, I see the logic of leaving well enough alone for now.
The DC 40 transceiver rx is already tunable and I'll just be using the DDS for the transmitter section in place of the crystal.
I do see another DDS in my future!!!

One of the last projects I did before "closing shop" in the early 90's was building an adjustable voltage regulator. I liked it so much that I put together half a dozen of them. I found the coffee can the other day in my old junk drawer and am using one of them for this DDS. (I think I tend to go overboard at times. LOL)

One question though, how/where do I get the RF output?

Charlie
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kellys_eye
Posted: February 05, 2017 09:50 pm
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The RF output is the tiny socket on the board. It's unlikely that you'll have the appropriate plug/lead to fit (ain't modern stuff just wunnerful laugh.gif ) so maybe just soldering some RG-mini to it and hard wiring the output to a 'proper' plug is the way to go? laugh.gif

I'd need to see a close-up of the pcb wiring to figure out how they allocate the pins for the additional buttons so you can access the various modes and A-B VFO selection.

Can you email me a hi-res image of it? Scanner image or digital camera?

Ta


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cgriggs
Posted: February 05, 2017 11:01 pm
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I see what I believe you're talking about as far as the RF output goes, and, yes, it's going to be a problem. We have a ham club meeting coming up, I'll see what they say. (I'm thinking no builders, though. We're a dying breed.) I'll also check ebay for "connectors" and see if something looks like it.
My camera is having trouble getting pics into the computer. Maybe I can keep trying and, if successful, will email them. Thanks for your patience!!!
Charlie
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kellys_eye
Posted: February 06, 2017 01:38 am
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The connector is called an 'SMA' connector - you can purchase the usual adapters (SMA-BNC etc) but the small pcb size often precludes using such adapters as they weigh the board down too much.

Best bet is to obtain a short length of RG316 with SMA one end and BNC t'other. Again eBay is your friend and many versions in many lengths exist. If there are other hams at your club that use relatively modern kit then I'm sure one of them will at least know of the connector type if not actually use them.

But if you go for boxing in the circuit board then hard wiring it is the best route anyway. A nice stand-alone boxed DDS device can be dual purposed as an RF signal generator as well as a VFO.

I reckon your associates at the club will be well impressed with it.


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cgriggs
Posted: February 06, 2017 03:47 am
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Details about:
8" SMA Male to BNC Female Bulkhead RG316 Cable Pigtail; US Stock

Just ordered it. Should come in next Saturday. I'm working on the faceplate now.

Oh brother!! Do I miss being able to do this stuff on the milling machines at Talon! (Vertical and horizontal!) I even made my own chassis from scraps from the sheet metal shop.

If I'd ask, they'd form them for me in their spare time. Of course, a favor received is a favor owed, so it worked out ok. LOL

"Waiting again" Charlie
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cgriggs
Posted: February 07, 2017 03:48 am
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Dave, I'm thinking you might have a point in making it a stand-alone VFO. So I stripped down a 6n2 VFO (for parts only, much missing, so no loss) and plotted out a new faceplate.

I called a sheet metal place and asked the price for a 1/16 X 4 5/8 X 5 1/2 piece of aluminum sheet. He laughed and said come on down and get it, no charge.

Since I'm not that good looking and I'm surely not a rich widower looking for companionship, I figured I'd go. LOL

He gave me 2 of them, (cut to size), and 2 pieces about 9 x 12. "Just pieces of scrap I'd toss any way!"

I said I'd like to give him something for it all and he laughed and said, "Dude! I own the place! No charge!"

Judas Priest! Nice guy! (Have you priced aluminum stock lately??) Hmmmm. I wonder how good he is at bending chassis??? LOL

I didn't like how the power wires slipped off their pins so tried soldering them in place. So far, so good. Maybe I'll get up the courage to do the same with the encoder wires to the DDS. Maybe not.

Charlie
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kellys_eye
Posted: February 07, 2017 10:11 am
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It's always heartening to find people of such stock - that offer what is essentially scrap, for free - as far too many businesses these days will try to sell you every single particle of stuff at exorbitant prices, and usually shrink-wrapped at that!

If you go the stand alone VFO route might I suggest that you keep a look out for a quality encoder. It's not an essential item right now but the difference one can make to these DDS units by the use of one is remarkable - more so if you fix a weight to the shaft to give it some 'feel'.

My own SDR receiver (standalone) has such an encoder with 256 steps/rotation (those mechanical versions ex-china have only 16 or 32) and are good for 10^6 rotations+. The higher the pulse count the smaller you can set the tuning step and the smoother the result.

Only thing about quality encoders is, as you might guess, the price. The one(s) I have are all ex-equipment from stripped down surplus junk but the encoders are priced today (since they're still current stock items) at nearly $100 a pop!

Those with the right skills and patience can manufacture one from old (quality) potentiometer mechanisms fitted with slotted (or printed) disks and opto-couplers. You can achieve 180 steps/rev quite easily by this method but lacking a lathe and some keen mechanical construction skills this might not suit everyone as a solution.

You should still send me a decent picture of the board (such that all the tracks, both sides) are visible so I can plot out the rest of the keypad connections as your VFO would certainly be more useful with access to the A-B, mode, CAL and memory functions etc, if not by front panel push buttons then at least by rear panel ones.

Consider this BEFORE drilling what you think are all the holes you require!





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cgriggs
Posted: February 07, 2017 11:25 am
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I'm so pleased with what I have with this and the results I'm getting from it that I just want to leave it as is. (For the time being.)

I would love having a vertical mill to do my drilling and cutting instead of drilling a series of holes and filing out to a straight line. Being a t&d spoiled me for the perfection you're able to get with the proper machinery. sigh LOL

I find that I can "course tune" to the area and then "fine tune" to the target. That works for me. I'm reminded of when I started hamming in the early 60's, I purchased an ARC 5 transmitter from a WW2 surplus dealer and, from a book "Understanding Amateur Radio" (lovingly referred to as "UAR" by U.S. novices,) adding a BFO, converting filaments to 12 volt, etc. I was on the road called "home-brewing!"

I'm having a bit of a problem transferring pics to the computer. but as soon as I get it solved, I'll send you one or two.

Charlie
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kellys_eye
Posted: February 07, 2017 04:26 pm
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Some clarification for you Charlie:

the 'Ua' or 'Ub' (is actually 'V' not 'U') shows which of the VFO's are in operation ([A] or [B]) and you can switch between the two, independently settable.

There is a 'split' function that switches between Va and Vb as you press/release your PTT button available.

'R' designates whether the RIT function is active which, when it is, shows as frequency display at the top-right of the main display. The RIT function operates to +/- 3kHz only. The RIT function only operates when you press the appropriate button and the display reverts to the normal 'vfo adjust' function after 1 second of non-use of the RIT mode.

CNS 4.01 is just the software version.

AM is the mode (or USB, LSB or CW) and the appropriate offset is applied and is changed through the 'mode' button (when fitted). Offsets can be set through the CAL procedure.

You can also fit a full numeric keypad and 'type' the required frequency in - very useful if you do a lot of band hopping.

There are 19 preset memories you can access via push button.

One function you DO need is access to CAL as this allows you to accurately set the output frequency.

Yes, the device is crystal-controlled but the accuracy of the displayed output is only as per the accuracy of the crystal - but through the CAL button you can make the DDS display 10MHz and then spin the rotary encoder (whilst monitoring the output) to EXACTLY 10MHz and eliminate any errors whatsoever. Right out of the box it is probably accurate to 10Hz or better anyway - YMMV.

As previously mentioned, many of the facilities on offer are probably not required if you're just aiming to have a basic VFO but since they are there you should take this into account and maybe at least consider some that could prove useful and ensure the VFO is constructed to make them available.

I intend to knock up a simple NE612-based, 4.9152MHz IF multi-band receiver using one of these AD9850/1 devices as the VFO but I will be using the band and mode indicator outputs to switch filters and panel LEDs accordingly.

If time ever permits rolleyes.gif I'd like to roll my own software driver/display to take advantage of the many cheap full-colour LCDs that are around nowadays but that's a long way in the future if m current schedule is anything to go by laugh.gif

Equally, I want to build my 4-tube (6U8) CW receiver too! Burning both ends of the technological scale is me laugh.gif but I can't find any 454/457kHz crystals sad.gif anywhere I've tried doh.gif

You have your 'hi-tech' problems Charlie, I have my 'low-tech' problems laugh.gif


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cgriggs
Posted: February 07, 2017 05:11 pm
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The 'split' function is operable when you use the PTT and can therefor be used with the 'transmit' switch?? (The DC40 doesn't use that switch, but I can add it.)
Looking at the display I can see now that it is a 'U', not a 'V'.

I would like it set up for CW though.

I'd like to know as much as possible about the DDS, but will just play with it the way it is.

I'll get busy trying to figure out why the computer won't accept the latest pics I've taken. I use Photoshop Elements 8.

Charlie
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kellys_eye
Posted: February 07, 2017 07:40 pm
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If your camera plugs into the PC via a USB lead then you should be able to 'see' the camera as a storage device and locate the pictures in a folder of the memory card in the camera itself.

Just copy the file and attach to an email (doesn't matter what size it is) and I should be able to receive it.

With the DDS VFO set to CW mode the DISPLAYED frequency will be 'as is' but the actual output frequency will be offset by the amount programmed via the CAL function (IIRC the default for CW is 800Hz) so the VFO, if set for 7.0000MHz, will actually output 7.0008MHz.

Similarly if you set it to USB or LSB the output frequency would differ from the displayed frequency by +/-2700Hz (assuming that was what was set via the CAL function).

So the CAL button is an essential facility that you must have connected or your TX frequency will be wrong when set to CW (as it is).

Without actually entering the CAL function I can't say FOR SURE that the 800Hz shift is being implemented but if you have an accurate DFM you could make a quick check of output versus displayed frequency.

<edit> just noticed that your DDS is set for 'AM' in which case, if you're ok with the display saying 'AM' instead of CW then the output frequency will be correct (calibration notwithstanding).


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cgriggs
Posted: February 07, 2017 08:15 pm
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< just noticed that your DDS is set for 'AM' in which case, if you're ok with the display saying 'AM' instead of CW then the output frequency will be correct (calibration notwithstanding). >

My DC-40, with digital readout, was on while I was checking out the VFO and I received a very nice 'zeroing in' when I swept the received frequency. Looked to be accurate.

Charlie
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