What's on your Workbench?

VK5TX · Post by **VK5TX** » Mon Jun 23, 2014 8:02 am

Do you have any internal photos Ian?

VK2OMD · Post by **VK2OMD** » Sat Jun 28, 2014 9:47 am

I received a V2 Agile PLL from Graham today.

It is not committed to a particular application, but rather an experimental device with some initial projects lined up. For that reason, I will use a different controller and provide facility to update firmware and configuration from outside the box. I intend trying Graham's amplitude keying solution, and also the Si4133's capacity to turn an oscillator on and off, and of course FSK... but frequency shift is not very flexible for this type of PLL.

One experiment may be a 20W GPS locked beacon on 2m using QRSS3 keying. The real maybe about this is that experience shows that QRSS does not attract observer reports.

I am now waiting on some parts on a slow boat from China (eg some SMA/RG316 tails to plumb the outputs to the back of the diecast box).

A WIP.

Owen

VK2OMD · Post by **VK2OMD** » Sun Jun 29, 2014 2:39 pm

The VK3XDK Agile PLL pumping out 50.41MHz. Though it is outside of specified range, the inductor supplied for the IF oscillator sets the osillator at 360-490MHz and so division to 6m is a possibility.

Owen

VK1JA · Post by **VK1JA** » Sun Jun 29, 2014 3:17 pm

I'm working on putting a 23cm transverter/amp into a 19 inch 2U rack case. Along with the sequencer and switching relays, 28v SMPS, bi-directional coupler and the 28v to 12v converter (not shown in pic) it's going to be a bit tight. Figuring out the most efficient layout is interesting! It looks relatively bare at the moment, but it'll be very different once I start laying the semi rigid coax and wiring up the sequencer.

Does anyone have a contact that does etching/drilling of front panels?

VK2GOM · Post by **VK2GOM** » Sun Jun 29, 2014 3:46 pm

There's these people - you download their CAD program, design your panel, then the software will quote for it and you can submit the order and get it cut in whatever colours or finish you fancy. Not cheap though!

http://www.frontpanelexpress.com/

73 - Rob VK2GOM / GW0MOH

VK2JDS · Post by **VK2JDS** » Sun Jun 29, 2014 6:50 pm

I just finished building up a vfo kit based on the si570 chip.
It is a standalone device (no usb or pc reqd) and operates in 1Hz steps from 3.45MHz to 940MHz (or higher depending on what flavour of si570 your have)
I already had a si570 so i bought the "PA0KLT Kit D Low Noise Synthesized VFO Kit - Si570 Chip NOT supplied" for 22 pounds plus about 5 pounds postage.
Its a absolute bargain and works as well as they claim. It took me today (raining/sleet etc) to assemble, test and fit-out the device into a box with a couple of 18650 lithiums in a holder inside.
I calibrated it (chip cal is built into the software) against WWV for zero beat and its very stable.
Now I can dial up a frequency and use this as a sig-gen, weak signal source or a LO and the harmonics will be useful up into the microwave regions.
If you have an old transciever with a drifting analogue vfo then this unit is a drop-in vfo replacement and its got RIT, 32 memories, 2 vfo's, programmable IF offset to suit any radio, offsets for each mode CW,LSB,USB etc etc and simple to build!

Have a look at it here : http://sdr-kits.net/PA0KLT_Description.html

I built mine into a 4 inch by 4 inch by 2 inch high electrical IP56 box so its rugged and battery powered, with a bnc socket so it can take a whip antenna etc (was going to use sma but no single-hole ones in the junque box). It just needs some stick-on labels for the pressbuttons and its finished.
73 Dave vk2jds

VK3ALB · Post by **VK3ALB** » Sun Jun 29, 2014 7:38 pm

Must have been the day to stay inside and solder?

Here's a portable 10MHz reference based on the G3RUH design. It uses a Jupiter T GPS engine that has a 10kHz output as well as the 1PPS. The 10MHz is divided down to 10KHz and compared against the GPS signal. The error voltage is used to control the OCXO. The 10MHz output looks roughly sinusoidal but it's rich in harmonics so best to use some kind of filter at the output. The Demi 4 way 10MHz splitter cleans it right up.

It takes just over 10 minutes to stabilize. The case is 170x120x60mm. It works out about half the cost of a Trimble Thunderbolt.

: Simple 10MHz reference

Details as requested. http://www.jrmiller.demon.co.uk/project ... rqstd0.htm

VK2ZRH · Post by **VK2ZRH** » Sun Jun 29, 2014 8:49 pm

A very neat solution, Lou. And cost-effective to boot!

VK5TX · Post by **VK5TX** » Mon Jun 30, 2014 11:54 am

Started building a DSB rig for 40m

VK2OMD · Post by **VK2OMD** » Mon Jun 30, 2014 3:11 pm

A little test of VK3XDK's Agile PLL V2 in A1 CW using a keyer to key one address line to select between normal programming of the IF VCO and VCO OFF.

Note, this is not the MOSFET keyer of the MMICs on board... in fact this board doesn't (yet) have MMICs on it.

Negligible clicks, this would be suitable to put to air (keying wise).

Note, this is not the original controller chip.

Owen

VK2OMD · Post by **VK2OMD** » Mon Jun 30, 2014 5:35 pm

VK2OMD wrote:...
Note, this is not the original controller chip.

Above is the burst of clock pulses during 4 x 3 byte transfers to the Si4133 for ordering up the carrier. The OFF set is shorter (just one register). At just over 100µs, it sustains keying at beacon speeds just fine.

The PLL itself in stunningly fast, faster than I write the data to it, it actually relocks between the write of the R divider register and the N divider register.

Owen

Edit: The original controller takes around 700ms for a data transfer, so it is unsuited to normal CW speed keying.

VK3BQ · Post by **VK3BQ** » Thu Jul 03, 2014 9:18 am

While I don't have the construction skills (yet) of a lot of you. I've been increasing my building of small items to help solve that. This is a band pass filter for 10mhz to turn my raspberry pi into a wspr beacon.

VK3ALB · Post by **VK3ALB** » Thu Jul 03, 2014 11:47 am

VK3BQ wrote:While I don't have the construction skills (yet) of a lot of you. I've been increasing my building of small items to help solve that.

Since you didn't ask

, I would spend a bit more time getting the insulation off those wires and some of that tinning looks like the iron may have been used to paint the solder on. If there's enough heat on a clean wire the solder should flow really nicely and the result will be clean and bright. It's a real bugger getting the insulation off if it doesn't burn away with the application of heat. I like using the blade of a hobby knife to scrape away the insulation. The toughest part is that the wires are so small and you have to work in close. I think Adam posted some info regarding holding cores in a soft jaw vice.

Posted in the spirit of sharing and assistance.

VK3HZ · Post by **VK3HZ** » Thu Jul 03, 2014 12:11 pm

VK2OMD wrote:A little test of VK3XDK's Agile PLL V2 in A1 CW using a keyer to key one address line to select between normal programming of the IF VCO and VCO OFF.
Note, this is not the MOSFET keyer of the MMICs on board... in fact this board doesn't (yet) have MMICs on it.
Negligible clicks, this would be suitable to put to air (keying wise).
Owen

Hi Owen,

You'll find that on some frequencies, the VCO comes on very rapidly and clicks badly - been there, done that, hence the addition of the external MOSFET switching for the MMICs.

BTW, if anyone wants to use the PLL board as a locked beacon source, there is already beacon code available for the original PICAXE controller.

Regards,
Dave
VK3HZ

VK2OMD · Post by **VK2OMD** » Thu Jul 03, 2014 12:29 pm

VK3HZ wrote:...
You'll find that on some frequencies, the VCO comes on very rapidly and clicks badly - been there, done that, hence the addition of the external MOSFET switching for the MMICs.

Thanks David, I will keep that in mind. The project is awaiting some bits from China to finish boxing it up, and when I have done that I will try CW on 70cm.

Owen

VK5TX · Post by **VK5TX** » Thu Jul 03, 2014 12:48 pm

A solder pot is the best thing i ever brought for tinning wires. $15 from eBay. The solder I put in in costed more.

VK3BQ · Post by **VK3BQ** » Thu Jul 03, 2014 1:46 pm

They are installed now. I had another go at the legs after that photo. They seemed to have a pretty good cover. I spent some time with the side cutters scrapping. The wire is 3 layers of epoxy. A pain to get rid of. But thanks again for the pointers. Learning. Ps. I used the instructions from the supplier website. http://www.kitsandparts.com/univbpfilter.php. And made sure I cleaned it as best I could.

VK2OMD · Post by **VK2OMD** » Thu Jul 03, 2014 1:57 pm

VK3BQ wrote:They are installed now. I had another go at the legs after that photo. They seemed to have a pretty good cover. I spent some time with the side cutters scrapping. The wire is 3 layers of epoxy. A pain to get rid of. But thanks again for the pointers. Learning.

For next time...

Enamels fall into two broad classes, those that 'melt' when heated to soldering temperatures and those that don't.

In the first case, you try to tin them with solder and a very hot iron, and the enamel will bubble up and the wires tin. (Don't try this now that it is in the PCB, you will probably damage the PCB.

In the last case, you must clean the enamel off with a blade, sandpaper etc prior to soldering... it is very difficult to fix them after you have applied solder. You can try degrading the enamel with a cigarette lighter, but you will still have to scrape some residue off to get clean copper which will accept solder.

Owen

VK2GOM · Post by **VK2GOM** » Thu Jul 03, 2014 4:36 pm

You can check your coils have good continuity by checking with a multimeter from pad to pad on the PCB - not lead to lead. You must test pad to pad to determine continuity to test the integrity of the solder to enamelled wire joint. Of course assuming no solder bridges

And then the fun will begin with a spectrum analyser with a tracking generator to get the thing into bandpass spec. It should be possible to design and build a BPF these days with decent quality spec fixed value components and not have to resort to supplying variable trimmer caps!

73 - Rob VK2GOM / GW0MOH

VK5TM · Post by **VK5TM** » Thu Jul 03, 2014 4:49 pm

It should be possible to design and build a BPF these days with decent quality spec fixed value components and not have to resort to supplying variable trimmer caps!

But..but..but......

That doesn't leave anything for the fiddlers to twiddle.

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