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Forum Index : Electronics : Soldering Coax?
| Author | Message | ||||
| Phil23 Guru  Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Just grabbed some of Bunning's Quad core RG6 to make a Moebius Antenna. Dammed if I can get solder to take to the section of braid I've got twisted up. Presumed it would be just tinned copper, but can't get solder to take to it even after coating it with some rosin paste. Plenty of heat from a gas iron etc. Any suggestions, as it seems like something other than tinned copper. Thanks Phil. |
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BobD Guru Joined: 07/12/2011 Location: AustraliaPosts: 935 |
It could be aluminium. These days tinned steel is more likely than tinned copper. Have you noticed you can pick up a resistor using a magnet on the leads? |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Phill, if you can,t solder it try this ,it will be ok for an antenna feed . Get a couple of those double screw earth wire electrical connectors ,the little fellas that come in plastic boxes of 4 or so. get the big ones ,they,ll do the trick double screws, wrap the joint in self amalamating tape or a length of heat shrink -use a hairdryer for shrinking. all my antennas are done this way ,no problems Bruce Bushboy |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
A lot of cables these days are made for crimping or compression type fittings. And aluminium is cheaper than copper, so its becoming a lot more common. Cheers, Tony. |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
almost certainly aluminium, and will be impossible to solder And bruce, they are called BP connectors, or in the case of the double screw ones they are earth BP connectors  |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Thanks All, My mind was more on the design than the problems with it's execution. Light bulb did come on & I assumed it was Aluminium, like the foil after I'd resorted to Automotive crimp connectors. All finished now. Two Antennas, consisting of 4 Turns of RG6 Quad Core, in a 600mm diameter Moebius Loop. Feeding a Blitzortung Lightning Detector. Also has a 150mm Vertical Probe (2nd Pic). It's currently picking up strikes in the Tasman Sea between Bass Straight & New Zealand, so the design must be working.   |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
Nice- what kind of range are you getting? |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
It told me the Maximum it had read was 10,448km; not sure how true that is, being 1/4 the worlds circumference away. The stuff it received in the Tasman Sea would be around 2000km at a guess. It's gotta be sited properly yet in a more permanent location. Better view & less noise. Phil. |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
jeez, I was expecting a hundred km or so!!!! I did a lot of rf finding years ago when cb's were big, playing fox hunting, and I had a similar setup for hunting on 27mhz with twin alcock loops, I certainly wasnt expecting that kind of range |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
You can see the Station info & diagnostics here . It doesn't mean a lot to me yet. Seems like I've got a bit to learn. Phil. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Have an Issue that may be better asked here than the weather forums. Suggestions there are Brand X or Y & available in Europe or the US. I have a bad noise source in the 30-40kHz range which turned out to be the old Motorola 5V plug pack I was using. (Power input is Mini USB). What would people suggest for a low noise power supply? Is just an unregulated transformer type plug pack with something like an LM7805 added likely to be the best choice for the 5V 1A supply. Or are there switch modes that are known to be fairly noise free. Phil. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
[quote]What would people suggest for a low noise power supply? Is just an unregulated transformer type plug pack with something like an LM7805 added likely to be the best choice for the 5V 1A supply.[/quote] Yes, try and find one of the old (large warm running) dc transformer plug packs. These have now been outlawed and you cannot now buy them anywhere. All the new switch mode supplies are electrically noisy garbage and must be avoided like the plague for any sensitive radio receiver application. Eventually the old extinct transformer plug packs will become more difficult to find, but you can still buy the 24v ac plug packs. These 24v ac plug packs are still very common, and are used for garden irrigation systems and aquarium blubbers and heaters. The voltage is a bit high, but its still the most practical last resort. A big resistor and a shunt regulator may be your best bet. Cheers, Tony. |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
Transformers are still widely available from electronics suppliers such as Jaycar, Element 14 etc as are AC plugpacks (ie transformer in a plugpack with no rectification) so if you need a 'old fashioned' DC plugpack ie not a switchmode with its noisy output - you can still easily 'make your own' even if they arent available off the shelf any more in some countries These are given simply as an indication of what is required, any electronics supplier will have equivalents Using the circuit below, you can make your own 'old fashioned transformer driven' 5vDC supply either using a transformer if you are confident of your ability to solder and handle mains voltages, or if you are squeamish about touching anything to do with the mains, use a 9VAC 2A plugpack (wallwart) and put the rest in a box on the end of its lead eg of a 9VAC 2A transformer suitable for 5vdc supply (Note needs to be mounted in a box with suitable fixings and quality workmanship) 9VAC 2A transformer or toroid 9-0-9VAC 2.22A transformer (same goes, must be in box, proper mains construction techniques required) 9-0-9VAC 2.22A for those not happy with playing with mains, use something like this- note this one only has a 1A supply, so will result in reduced output, any 9VAC plugpack with 2A or higher output will give full output from circuit below 9VAC 1A plugpack Of course those in 110VAC countries would have to use 110VAC 9VAC transformer or 'wallwarts' rather than our 230VAC 9VAC transformer or plugpacks lol Circuit to build to give 5VDC, no switchmode noise and very little supply noise at all- can be built on perf board, tag strip or even point to point wiring and mounted in a small plastic box  (note +5v is at the right top rail, 0v is at the right bottom rail) Personally I would use a small bridge rectifier rather than the 4x in4007 diodes as its easier to mount. This circuit with suitable transformer (2A) and a small flag style heatsink on the 7805 will give a 1.5A fully smoothed 5vDC supply, overload and overheat resistant (the 7805 will auto shutdown in either case) note with a 1A plugpack as shown above it will likely cause the plugpack to shutdown first as it overload before the regulator chip will, a 2A plugpack wont have this issue (I just didnt look for a 9VAC 2A plugpack as Jaycar are in my shortcuts and they didnt have one lol) edit to add quick sketch of how to wire up  note plugpack leads are on the left- doesnt matter which way around they go... output is on the right, suggest using short length of red and black fig8 cable if you do use point to point or birdsnest wiring, I suggest so they cant move around or short out using hot melt glue or 2 part epoxy to glue each component down, another suggestion is use small heatshrink to cover all exposed metal leads and solder joints or use perf board or matrix experimenters board to make up a 'pcb' |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Thanks for that. Was a bit rusty on the correct values for the circuit etc. I do have a couple of drawers full of varying plug packs; Switch mode drawer & one each for AC & DC transformer based. From memory there are some from old cordless phones that are 7.5 & 9VAC. They might suit well & if I'm luck I might be able to fit it all in the original casing of the appropriate one. No issues with the construction; it's just the tiny SMD stuff that test me.... Phil. Edit: Aside from 7805's, I probably have some LDO regs on hand, not sure which without a look, but are LDO regs equally suitable? |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
dont see why not, most are fairly low current outputs tho, so depending on how much current you are pulling might be too much for them |
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