What's on your Workbench?

VK4KL · Post by **VK4KL** » Tue Jul 22, 2014 4:43 pm

Latest project is Arduino based 24 hour clock.
Still a work in progress but getting there.

Adrian

VK2OMD · Post by **VK2OMD** » Wed Jul 23, 2014 8:07 pm

A headless APRS Digi and Igate, javAPRSSrvr running on a RPi with KISS TNC.

Owen

VK7JG · Post by **VK7JG** » Fri Jul 25, 2014 3:56 pm

6M GPS locked VK7RAE Beacon using a modified Unilab KL70 and XDK exciter

VK2BLS · Post by **VK2BLS** » Fri Jul 25, 2014 7:41 pm

23CM 60W PA with 28db Preamp to compliment SGL Labs Transverter.

Set up my FT290R as IF, for SGL Labs Transverter as carry round pack for portable or mobile use and FT100D at base.
Decided to make a PA for Base. Found a sizeable old heat sink and aluminium plate in junk box, just enough to box around heat sink.
Gradually collected a 23cm 28db Preamp, minikits relays, 60 Watt PA module, K6VHF sequencer, 2.2ghz power relays, 12 to 28V inverter and various Ebay bits.
Up and running using a 'Directive Systems' 24 element 18dbi loop antenna that went together like Lego.
Gee it's quiet on 23cm..... Sydney beacon good S1 copy and vk1kw on A/E so far. Looking for more contacts now incuding JT65c & wspr.

73 Darrell

VK7DB · Post by **VK7DB** » Sat Jul 26, 2014 9:25 am

VK7JG wrote:
6M Beacon.jpg
6M GPS locked VK7RAE Beacon using a modified Unilab KL70 and XDK exciter

I think I worked out that you can replace the 12MHz TCXO with 10MHz GPS and manually program the EPROM for the new 625KHz reference with a 1KHz channel step and it should run on 50.057MHz.. You've done this now, so I wont worry about testing that idea.. My idea would need the RX or something to replace the divider though..

VK3BQ · Post by **VK3BQ** » Sun Aug 03, 2014 8:49 am

A crane!! Emdrc swapped the Hf yagi yesterday. New coax. New a4s antenna. New lower band wire dipoles. It should mean we have a working club station again, though no horizontal VHF/UHF antennas.

The dish / yagi is for the ATV transmitter.

VK5TX · Post by **VK5TX** » Sun Aug 03, 2014 3:12 pm

Work on my back pack 23cm transverter.

Ben

VK3BQ · Post by **VK3BQ** » Thu Aug 07, 2014 11:15 pm

The raspberry pi is TXing ~10mw 30m wspr finally. No decodes yet!! But it's going! (And I can decode it locally!) uses this source code https://github.com/JamesP6000/WsprryPi

And it works. Amazing

VK2CMP · Post by **VK2CMP** » Sat Aug 09, 2014 11:36 pm

A IC910 with a new Xref-VS and IF tap - sooner or later it just had to happen;-)

VK2GOM · Post by **VK2GOM** » Sun Aug 10, 2014 7:55 am

Get that Rigol scope modified Mick! We tested mine yesterday against some high end HP gear and it's performing well. 50MHz extra bandwidth for free

73 - Rob VK2GOM / GW0MOH

VK2CMP · Post by **VK2CMP** » Sun Aug 10, 2014 8:59 pm

I was waiting for your test drive Rob!

VK2OMD · Post by **VK2OMD** » Tue Aug 12, 2014 5:30 pm

VK2OMD · Post by **VK2OMD** » Sat Aug 16, 2014 6:37 am

My OSDCD prototype under test in a MFJ-1270B:

The TNC normally derives Data Carrier Detect (DCD) from its modem chip, usually a broadband energy detector is used. DCD is usend to enable decoding of incoming Receive Data (RD), and to block transmission whilst the channel is busy.

There are two problems that the OSDCD addresses:

- squelch may be slow to open on some receivers, preventing decoding of some packets with short preamble; and
- if squelch opens because of interference or non-packet signals, the transmitter is blocked.

The OSDCD monitors the RD pin of the modem chip, and tries to recognise transitions characteristic of 1200Bd data transmission. The name derives from the fact that the receiver can be operated with squelch open as the OSDCD differentiates between 1200Bd data and other audio.

VK1JA · Post by **VK1JA** » Tue Aug 19, 2014 5:26 pm

23cm transverter/amp project is about 95% done.

Transverter/psu/amp/switching all mounted into a 2RU rack case.

I had to modify the minikits sequencer a little as I wanted the antenna relay (I'll be running separate rx/tx lines) to engage into the rx position with power. So if it fails (coil fails) it'll fail in the tx position and save the pre amp !!

I also (at the last minute) had to add a small relay circuit to the PTT line, as the TS2000's PTT line didn't pull low enough for the sequencer to start off.

I've still got to run another coax up the pole for the dedicated rx line, so at this stage I'm not running the pre amp or the power amp, just the 2-3w out of the transverter. Oh, I still need to make up labels for the front and rear panels too

VK6OX · Post by **VK6OX** » Sat Sep 06, 2014 2:30 pm

Another 23cm PA project in progress!

VK6XLR · Post by **VK6XLR** » Sat Sep 06, 2014 6:49 pm

VK6OX wrote:Another 23cm PA project in progress!

Nice one Andy!
What SMPS are you using and what's the smaller module next to it?

73,

VK6OX · Post by **VK6OX** » Sat Sep 06, 2014 7:33 pm

Hi Rick, thanks!

It's been a "rainy day" project in the main (today I got quite a lot done!

) so I now have just a bit of DC wiring to complete, and make up the two RG402 semi-rigids between the PA module and the xfer relay. Then it's "power up" time!

The main SMPS is a MeanWell SE-450-24 which can readily be adjusted to 28V. It's required to power the PE1RKI 150W PA module and was an eBay purchase. It will easily provide the grunt that the PA requires (~11A@28V).

The smaller unit is a 5V supply, another eBay buy. It also has a pot to adjust the O/P voltage, which in my case I've set to around 6.2V which is the max. I can get out of it. The O/P is "floating" so I've tied the +ve rail to gnd. This gives me -6.2V which I will use as ALC control for the TS-2000X in an additional attempt to minimise too much RF going places it shouldn't during the TX sequencing phase.

For 12VDC, there is a small LM2596 28V-12V step-down module (again from eBay) which powers the VK5EME sequencer and the various relays. These things are rated to ~3A so should do the job OK.

If you want to know more, lemme know and I'll drop you an email Rick.

73

VK4CZ · Post by **VK4CZ** » Sun Sep 07, 2014 5:58 am

Another 23cm PA project in progress!

Well done Andy... making great progress.

VK6OX · Post by **VK6OX** » Mon Sep 08, 2014 7:46 pm

Thanks Scott!

Another crappy wx day today has enabled me to complete all the DC wiring, and the RG402 interconnections. It remains to wire up and calibrate the power meter, and to assist in that I purchased a little variable SMPS from Altronics ( http://www.altronics.com.au/p/m8303-pow ... er-supply/ ) which will double as a general purpose bench p/s.

Once that is done, a full DC and RF test will be undertaken.

VK4CZ · Post by **VK4CZ** » Mon Sep 08, 2014 9:53 pm

Andy

Belatedly here's my 1296MHz 150w PE1RKI amp finished a few months back.

(Yes... In the true spirit of amateur radio, Andy and I collaborated across the continent on the design.)

Which will now been teamed up with a MiniKits 1296MHz LNA constructed on the weekend, but yet to be tested!

Scott
VK4CZ

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