Australian Ham Radio Discussion Forum ( AHRDF )
What's on your workbench? - Printable Version

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What's on your workbench? - VK3ALB - 13-09-2016

With due consideration to the forum currently being hosted over ADSL I won't post an image but I'm building a Cumbria Design DSP audio filter.

I know I could buy a BHI speaker which does a similar thing but I think this works out cheaper and I get to build it myself.

Re: What's on your workbench? - VK3PP - 13-09-2016

On my workbench is a home brew transverter board i made still a work in progress still waiting on parts to populate the rest of the Board.

also on the go is one of these cheap ebay pll boards utilizing an ADF 4351 PLL chip and it will be controlled by an Arduino UNO with a simple voltage divider to match the levels between the boards ebay.com.au

(Unfortunately i cant attach files more to come..)

Re: What's on your workbench? - VK2JDS - 16-10-2016

i'm experimenting with an at.tiny85 pcb and a AD9833 pll pcb. connecting these 2 tiny pcbs together and flashing some code into the atTiny85 and it can generate any frequency from a few hertz to 12 MHz ! triangle, sinewave or squarewave.
the current application is to replicate a 1.647MHz crystal in the Codan 8528 transciever to add lower sideband, and it works !
so, instead of $70 from HYQ its just 10 bucks from ebay.
instant crystal!

73 Dave

I must add, dont trust the onboard 5 volt regulator on the atTiny85 pcb, the version with the micro usb socket on it for programming, as it shoves 7 volts into the PLL when connected up to 12 volts.... found out the hard way.

Re: What's on your workbench? - admin - 16-10-2016

VK3ALB Wrote:With due consideration to the forum currently being hosted over ADSL I won't post an image but I'm building a Cumbria Design DSP audio filter.

I know I could buy a BHI speaker which does a similar thing but I think this works out cheaper and I get to build it myself.

You must have missed the earlier Forum Setup Issues posting in the System Notices area (October 11), this forum is now hosted on an Australian web server - as of last weekend - and the maximum image file size was been raised to 100KB so that higher resolution images can be utilised. This file size will be reviewed again (upwards) once the storage area growth is assessed as new postings appear.

http://www.ozlogger.net/forum/viewtopic.php?f=3&t=3&start=20#p249 refers.

Admin

Re: What's on your workbench? - VK3ALB - 16-10-2016

ADMIN Wrote:You must have missed the earlier Forum Setup Issues posting in the System Notices area (October 11),

I didn't miss the post on October 11th but my message you quoted was from September 13th.

Re: What's on your workbench? - admin - 17-10-2016

VK3ALB Wrote:
ADMIN Wrote:You must have missed the earlier Forum Setup Issues posting in the System Notices area (October 11),

I didn't miss the post on October 11th but my message you quoted was from September 13th.

Apologies Lou, my error in not crosschecking your post date.

Regardless, the image size limit is currently 100KB.

Admin

Re: What's on your workbench? - VK2JDS - 17-10-2016

Thanks for the clarification Admin, I will upload some pics and a file.

These photos show how to make the programmable crystal using the 2 ebay pcbs soldered together. Note the atTiny85 already comes with a a microusb socket, so programming is a snack. Just plug your mobile phone microusb to usb cable into the atTiny85 when the programmers says to.


.zip   AD9833_sinewave.zip (Size: 3.46 KB / Downloads: 502) [attachment=1]

the code:
to load the code you use the arduino programming tool, its free. quick install and plug and go operation, except you have to load up the libraries for this atTiny85 pcb. i just googled the way to do it and there are several tutorials.
the file is zipped to get around the rules for posting files here, its only 4kb, so unzip it.
Lindsay vk2amv who wrote this code has documented it thoroughly.
73 Dave vk2jds

Re: What's on your workbench? - VK2ZIP - 10-03-2017

Hi Dave,
Thanks very much for this post.
I have bought the boards, but I haven't downloaded the Arduino IDE yet.
I have a question: Do you need to program the ATTiny85 before connecting it to the DDS, or can you do real in-circuit programming?
Best wishes,
Lew.

Re: What's on your workbench? - VK2JDS - 14-03-2017

Hi Lew,
you can program them assembled.
however they can be done before you assemble them just to get the hang of experimenting.
its just plug in the usb cable to your laptop and the microusb end of the cable into the pcb and write. easy. no extra power cables or anything else.
get the hang of flashing code into them and you might get the bug and do more with them.
from power-on they take less than 5 seconds to boot up and produce the programmed frequency.
mine runs every day in the ute and its been very reliable.

there are 2 ports on them, so there are mentions of not using the port you program it with to program the port on the pll synthesiser pcb. once you have the assembly looking just like what I did it works fine.
73 Dave

Elcom Synthesizer Mod - VK5ZD - 14-03-2017

Modified a LCDFSL-1201MS with an internal Picaxe chip to program the PLL.
A pin on the external connector allows me to select one of two programmed frequencies.
It also programs the AD5200 (smaller IC to the right of the PLL) to match what the Elcom micro did.

Mine is programmed to produce either 11,736.00MHz or 11,735.75MHz.
These go to a x4 to give LO frequencies for 144MHz or 145MHz I.F. on 47GHz.

   

Re: AD9833 DDS and ATtiny85 - VK2ZIP - 16-04-2017

Hi Dave,

Thanks for the additional information about programming the ATtiny85 (your post of 14 March). That is very helpful. I have bought a couple of DDS boards and a few ATtiny85 boards. One of each appears to be identical to the boards shown in your photos, so that will give me a great place to start. I will try programming both ways.

Initially, I just want to synthesise a crystal, for which your approach using the ATtiny85 seems perfect. I note that there was also a very helpful article on getting started with this board in Silicon Chip, in March 2017.

Meanwhile, I am also interested in controlling the AD933 using a Micromite computer. First I found an article by Dan Amos on the Micromite Backshed forum ( thebackshed.com/forum ), and then I noticed that it had been described in Silicon Chip Circuit Notes in June 2016. This article described using a Micomite "Backpack", which is a 4.3" colour touchscreen, to turn the AD9833 into a signal generator. Then in Silicon Chip this month (April 2017), there is a full article on doing the same thing in a different way, and an article about the AD9833, including control using both Arduine and Micromite, in the series entitled "El Cheapo Modules", by Jim Rowe.

It was your original post that got me started on all this.

Thank you,

Lew.

RE: What's on your workbench? - VK3ALB - 29-12-2017

A high current dummy load for testing power supplies. No circuit diagram required it's that simple.  I used four halogen globes that I can switch individually which means I can increase the current in 9 amp steps. A cheap eBay volt/amp meter with current shunt and a couple of cooling fans all built into a old PC power supply. You don't often need to do this to a power supply, but when you do, a load like this makes it easy.

These Manson clones just keep on going. Who has ever seen their power supply do that for a prolonged period of time?


           

RE: What's on your workbench? - VK2ZIW - 30-12-2017

My MMDVM project: Banana Pi & SSD and STM32 Nucleo-64

RE: What's on your workbench? - VK3ALB - 14-04-2018

1296 in a biscuit tin.

       

A fun project for playing radio in the hills. These SG transverters gave a good account of themselves at the recent VK3 activity day.

RE: What's on your workbench? - VK3ALB - 14-04-2018

2.4GHz on a small grid pack. The aim is to have something small enough to throw in the back seat of a sedan but minimise carrying a mecano set.

   

RE: What's on your workbench? - VK2ZRH - 15-04-2018

Great stuff, Lou.

Pardon me a few minutes while I rush out the back to the recycling bin and rescue those biscuit tins I threw out earlier this morning . . . . Sad

Back indoors. Smile

Phew.

Keep up the good work.

RE: What's on your workbench? - VK3ALB - 15-04-2018

Imagining Roger on a future field day . . . 

"Crumbs I took the wrong tin"!   Rolleyes

RE: What's on your workbench? - VK3ALB - 15-04-2018

Then you stack them all together on the Aldi bike stand. Mounts with a single U bolt.

Each transverter mounts to the cross arm with wing nuts for quick disassembly in case the whole lot won't go in the car as is.

I standardise on a few different thread sizes and keep a bag of nuts/bolts/wing nuts in the go kit.

   

RE: What's on your workbench? - VK2ZRH - 15-04-2018

Bloody ingenious!

What shall we call it? The Geelong Geronimo ! :D

RE: What's on your workbench? - VK3ALB - 15-04-2018

Thanks Roger,

Just looking for a better (easier) mousetrap.