ARCHIVE: Australian Ham Radio Discussion Forum ( AHRDF )

Someone suggested "three on the tree".

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So the system is now ready to go. Not exactly how I wanted it but I'm running out of time to finish some of the bits so I used a really big Anderson distribution board and a large multi-pole relay box I built a few years ago. Whilst convenient in terms of the available time they are pretty clunky and annoying when it comes to set up and tear down.

The tree bit fits in the back seat of the car as a single assembly and the bike stand and battery fits nice in the foot well. One thing that is really worth doing is getting a bit of Loctite into all the screws that hold the legs together on the bike stand. Doesn't matter how tight you make them they always rattle loose during transport.

FT817 is held in place with an artistically contorted coat hanger. Easy to install and the radio is always looking right at you.

Setup time from stepping out of the car is 15 minutes while tear down and packing the car is around 5 minutes. The price I pay for this convenience is the weight of the bike stand and the tree assembly. I also use one of my standard battery boxes containing 2 x 18Ah SLA which is well over kill but worth the peace of mind. This arrangement is not SOTA friendly unless you go to a drive-up summit.

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Well done, Lou. I'm very impressed. Well thought-out.

I'll have to get to work on mine. First, decide on which vehicle I'm gonna get. Woops! Have to upgrade my Learner Driver Permit

Thanks Roger.

I'm in VK1 for two weeks and I've taken it all with me. Fingers crossed it all works out.

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Wednesday saw me on top of Mt Stromlo for and afternoon activation with the VK1 crew. Great signals all around but I learned that even such a simple setup as this has its problems. Dues to the weight and size of the system I had to make two trips from the carpark to the summit. In this case it wasn't so bad but I can imagine that leaving half my gear unattended in a more populous place may be problematic. It was a case of leaving the bike stand and transverters out of sight on the peak while I went back to the car to collect the batteries and radio.

Still, a good time was had by all and for less than half the cost of an IC7300 you too could be active on 23cm and 13cm with a pair of SG Labs transverters. You WILL make good solid contacts around town with these units with just a little elevation and a clear view.

Beacons for the Barossa valley area, to be honest they have taken root on my bench and I seem unable to get them off..

Synth boards for 144, 432 and 1296 (new 50MHz beacon not shown in these photos)

Controller and Programmable Oscillators by ZL2BKC (Wayne) see here for details on his web site: https://zl2bkc.com/projects/multi-beacon-controller/

(28-04-2018, 09:02 PM)VK5PJ Wrote: [ -> ]Beacons for the Barossa valley area, to be honest they have taken root on my bench and I seem unable to get them off..

Synth boards for 144, 432 and 1296 (new 50MHz beacon not shown in these photos)

Controller and Programmable Oscillators by ZL2BKC (Wayne) see here for details on his web site: https://zl2bkc.com/projects/multi-beacon-controller/

Nice one Pedro

I have the same arriving soon for the WA VHF Group.  4 bands as well.

I see you just paralleled the 10MHz reference.  That working ok?  Interested to find out as we've opted for a 4 O/P distribution amp.

Are those PA modules from Wayne as well?

The whole duplexer is built now. Four of these below for BpBr style and two cans just BandPass. Ask me about the coil design

I had the need to switch my radio to three different transverters and I didn't want to swap cables. In my junk box was a pair of SPDT BNC relays with 28V coils.

What a frustration! I wanted these relays for portable operation and that limited me to a nominal 12V supply. I could have used one of those $2 SMPS PCB's ubiquitous on eBay but they do make a bit of noise in the VHF/UHF range so I ruled them out. 

Then I found an article by KO4BB. This was the answer I was looking for. The circuit is quick to lash up on vero board and in my case it worked as advertised. To conserve current drain the circuit is arranged so there is only ever one relay on at a time. As it turns out these relays only pull 50mA so unlikely to cause any problem. As a bonus the circuit works reliably to below 11 volts.

I wanted to see how fast I could switch a relay on and off with this arrangement and it was pretty good. If I switched really fast there was not enough time for the capacitor to fully charge and the relay would not pull in. However, it is unlikely that you could key your PTT that fast on a regular basis so I think you could quite safely use this circuit to drive the main change over relay in a transverter.

Here's a look at my test setup.

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Retuning a 5 pole 2.7GHz filter salvaged from some old OB gear.

My aim was for minimum loss at 2403MHz and maximum rejection of the 2m IF product.

Result is insertion loss is less than 1dB at 2403MHz and better than 15dB at the point that a 145MHz IF may appear. Obviously a 70cm IF would make things easier.

The test gizmo is a TPI-Link 1001B and has changed the way I do things in the shack.

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Following on from my previous effort I am working on a much simpler  transverter controller/switcher

This uses an Arduino NANO and speaks to VKCL and FT817.  It switches the rig to one of six transverters, sets the rig to the matching IF for each transverter and tells VKCL what band is selected.

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Sorting through my junkbox today and what did I find?

Here's an example of a homebrew 23cm and 13cm transverter from the 1980's. This was based on a design by YU3UMV published in VHF-Communications 1986. The boards are fiberglass drawn freehand with a Dalo pen then etched. I count 23 x BFG96 transistors and a TP3020A in the 23cm PA.

There are two crystal oscillators (one for each band) running 30MHz and 32MHz crystal multiplied to 540MHz & 576MHz. Separate TX & RX converters take the appropriate LO and multiply for 144MHz in/out.

Oscillator and TX/RX switching is done with PIN diodes and is controlled by RF sense from what the author called a VOX board, not sequencer as we do today.

This builder removed some of the PIN diode switching and replaced it with a To Tsu (Tohtsu) relay. Next to the relay is a dual band stripline RF detector for reading TX power.

Just consider the effort and commitment both in time and dollars this fellow went to get on these bands. It's a lot different today.

I've posted this in several places basically for the sake of posterity because it will soon disappear from FB.

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A Yaesu FT- 60R. Trying to revive its battery pack.

73,

Nandu.

(18-01-2019, 03:15 PM)VU2NAN Wrote: [ -> ]A Yaesu FT- 60R. Trying to revive its battery pack.

73,

Nandu.

Nandu

The batteries are most likely not really recoverable - my FT50R cells were not. The FT60R is old (circa 2004/2005) and those batteries only have a finite lifespan, even if really cared for. 

You may be better off carefully splitting the battery pack open (or taking it to a battery re-packer just to do that task), physically measuring the physical battery cell sizes and finding the same size, or slightly smaller, cells to replace the originals. Try to get the same chemistry if you can but maybe a newer style might be even better. 

The newer-style cells are likely to have even larger capacity values for the same physical size than the original giving you a longer run-time.

Hi OM Doug,

Your'e right, I'll have to open the pack!

A couple of years ago, when the pack did not accept charge, I could revive it by momentarily applying 12V DC directly across its terminals using a 1A regulated power supply.

No luck this time, so I thought I'd open the pack and 'shock' the cells individually.

Before that, a voltage check on individual cells would perhaps reveal the defective ones.

I suppose I'll end up replacing the lot with the new 2100 mAH NiMH type. However I am wary of soldering the jumpers, lest the cells be damaged due to heat.

Many thanks for your tips.

73,

Nandu.

If all else fails, then there are any number of retailers on aliexpress and fleabay who sell after market battery packs.

Yes, I should consider that too, OM Colin.

Many thanks.

73,

Nandu.