Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
- BITX20
- Messages
Search
|
uBitx Go Box 3d print
My newly created uBitx Go-Box - 3D printed and inserted into flight case. If you want more information and pictures head over to https://www.thingiverse.com/thing:3239609
Working to install a Raspberry pi now.
73's Daimon. G4USI. This is a re-work of DU2RK and AngelDMercedes work, also on Thingiverse and linked from my entry.
|
|
Re: To shield or not to shield, that is the question.
Carlos E. Wenzel
My bitx40 is on the original plastic box... Because it's not really end it. I'm planning to update to a metalica one.? My ubitx has a aluminum container. Shielded and hard protected.? Carlos 73's IK1YRA KD2QKE LU4AE? Il sab 24 nov 2018, 19:09 Lee <mr.olson@...> ha scritto: Some have built in metal boxes, some use plastic boxes, and some put metal shielding inside the plastic boxes.? Is it a ,should do, must do, or doesn't really matter at these low power levels.?? Can you also explain why you made your choice?? Thinking about options for for my JackAl add-on new radio build. |
|
Re: RF power chain mods and improvements..
Andy,
I've always used 450degF with my smd stuff and have never had a problem soldering anything. I don't use a pointed tip but one with a small flat on the end, a *very* small flat. Don't remember where I got it but it works. The only problem with it is that when it gets hot it bends easily so you have to be careful about the pressure you put on it. tim ab0wr On Sun, 25 Nov 2018 14:51:03 -0800 "AndyH" <ahecker@...> wrote: I understand that heat's bad.? I'll have to try different tips as I |
|
Re: Power supply
I'm using one of the 12V outputs from an ATX power supply that literally came from the dump.? I was dropping off the garbage and noticed an old PC lying on the ground.? The power supply and CPU heatsink came off without any tools, so they came home to my junkbox.
Just to be sure about the noise, I hooked up an 11.7V Li ion battery (from a model plane) and it made no difference noise-wise. It was an expensive-looking PC, so? maybe it had a better-than-average power supply.? The usual audio in PC's is 16 bits, which is ~85 dB dynamic range, so a premium PC that's going to get hooked up to a good stereo is going to want a pretty quiet power supply. |
|
Re: STREAM of solar wind is approaching Earth and experts fear it could hit us as early as November 26
Joe Puma
¿ªÔÆÌåÓýPerfect time to get that Nickel spray and spray it around the shack so the solar winds don¡¯t fry the front end of our xbitx¡¯s.?Joe On Nov 25, 2018, at 4:12 PM, ajparent1/KB1GMX <kb1gmx@...> wrote:
|
|
Re: RF power chain mods and improvements..
I understand that heat's bad.? I'll have to try different tips as I usually use a fine tip.? I usually dial back to about 600 ¡ãF when soldering SMD.? I have a couple of recent successes hand-soldering SI5351s.? The thing about this was that it had me doubting everything except the real problem.? I was going nuts looking for cold joints, broken end caps, copper foil glitches, and all the other usual stuff like whiskers from RG173 but didn't even think to question that a 2.2 Ohm resistor that looked fine and tested fine could fail before a transistor did.? But hey - I'm doing this to learn new things and I can confirm that that's happening!
I've been desoldering 1205 and 0805 parts using the 'solder blob' method.? I wonder if there's any benefit to the 'pronged' tips that can reach around to both ends.? (That being said, I'd much rather not have to remove parts.) ?One thing is not ripping everything up that?can be left alone.That reminds me of this: I can confirm that I'm not there yet.? hi hi Thanks again for your help.? The radio seems to be capable of more power on 40 and 20 after the re-work than right after I did the initial mod.? I guess I'll keep it.? hi hi Andy On Sun, Nov 25, 2018 at 02:54 PM, ajparent1/KB1GMX wrote: Andyh, |
|
Re: Bitx40 Power Supply - stackeing 4 2032 Lithium coin batterieis?
Hi Allison,
toggle quoted message
Show quoted text
In other words we really can't put 10 pounds of balogna in a one pound sack. 73, Bill KU8H On 11/25/18 4:02 PM, ajparent1/KB1GMX wrote:
Seriously poor choice for battery. --
bark less - wag more |
|
Re: RF power chain mods and improvements..
Vince Vielhaber
I had to read that twice. The first time I read it I thought you said your PES51 had a tip bent on a 90 degree angle!
toggle quoted message
Show quoted text
Vince - K8ZW. On 11/25/2018 03:54 PM, ajparent1/KB1GMX wrote:
Andyh, --
K8ZW |
|
Re: STREAM of solar wind is approaching Earth and experts fear it could hit us as early as November 26
I have to ask what does that have to do with a metal or plastic cased radio?
We have been going though varying streams of solar wind for a long time and at most we get geomagnetic storms and the bands get better or go quiet. Note, its not a CME a very different thing. Allison |
|
Re: To shield or not to shield, that is the question.
On Sat, Nov 24, 2018 at 11:08 AM, Gwen Patton wrote:
This is the spray I used:? Yes MG chemical super shield (spray nickel flake).? I've used it for making plastic cases RF tight and turning plastic shapes and surfaces conductive enough to use as antennas. When dry it runs about 1ohm per square inch which is fairly good conductance as well as magnetic. I'd not advise spraying it on clothes and using a respirator if one is nickle metal sensitive. FYI definitely spray it outdoors.? Be careful as some plastics can be attached by the solvent in the spray. Allison |
|
Re: Bitx40 Power Supply - stackeing 4 2032 Lithium coin batterieis?
Seriously poor choice for battery.
It will be a short and very unhappy life for those cells.?? I'd consider 8 AA cells undersized!? On RX its around 150ma and TX??over 450ma and peaks to 2.5A (some higher or lower) for the uBitx.? Most used a 7-9Ah gell 12V battery or 4ah (4000mah) or more LiFePo battery if weight is an issue. The Bitx 40 will be better but still assume 80ma RX (analog version) and more for the Raduino equipped on RX and TX at full power maybe 2A. Allison |
|
Re: RF power chain mods and improvements..
Andyh,
The most common problem is a very hot iron and a pointy sharp tip. The very small tip often means running higher heat so it can heat larger joints but one hot they maybe too hot.? Also the excess?heat often causes the materialization at the end of the devices to disintegrate if not outright cracking the part. If people saw what I use they would likely faint.? My PES51 I usually have a .90" tip in it, sometime the .125 wide and the second iron a older Wtcp-60 a larger .250 tip, and its a 60W temp controlled iron!? Its handy as it makes heating both ends of a 1206 easy.? Doesn't hurt I have a massive number of years experience with PACE, HAKKO, and Weller servicing and building.? One thing is not ripping everything up that can be left alone. Allison |
|
Re: RF power chain mods and improvements..
No doubt that there are plenty of failure modes.? What threw me here is that I don't re-work or re-use SMD - the parts go away.? As I've broken end caps from resistors and caps, I probe the board/solder interface and not on the chips.? At least one .01 uF cap was shorted and at least four resistors tested in spec but weren't working right.? Since I don't know what happened, I can't make a change that keeps it from happening again.? That's less than optimal.? I'll leave the surface mount parts to you, Jerry - I prefer to work with parts that don't need a scanning electron microscope to find fractures...if the fracture.? hi hi?
toggle quoted message
Show quoted text
On Sun, Nov 25, 2018 at 02:33 PM, Jerry Gaffke wrote:
Those surface mount caps and resistors are easy to mechanically fracture. |
|
Re: RF power chain mods and improvements..
Mark McNabb
For sure,
SMD parts are not tolerant of PCB flexing.? Be sure when handling, mounting, placing in a vise, etc. that you you do not bow or twist the board in any way.? It should always be kept flat.? When in a vise, be especially careful of clamping hard end-to-end, as the board is being put under pressure to bow.? And when mounting in a box, make sure the case is flat and the stand-offs are all the same height.? Then be careful of plugging and unplugging connectors.? This is the one disadvantage of plastic housings -- some won't provide good support for the board. The advantage of SMD parts is compact size and short leads so there is little parasitic capacitance or inductance, but on the other hand one needs to be careful with the board.? It's vice-versa with leaded parts and boards! 73, Mark. |
|
Re: RF power chain mods and improvements..
Those surface mount caps and resistors are easy to mechanically fracture.
toggle quoted message
Show quoted text
Flexing the board or excessive thermal gradients could do it. Pressing at it with meter probes can momentarily fix the fracture. Problems like this can often be found pushing at parts with a probe or maybe applying heat to specific parts, see if the problem comes and goes. I've had bypass 1206 caps short hard enough to burn a hole in the board at a nearby feedthrough.? No obvious damage looking at the cap under a microscope, but the manufacturer verified it was indeed an internal fracture.? Bleeding edge high capacity high voltage surface mount caps are especially delicate, maybe 47uF at 25v stuffed into a 1206. And their capacitance can be reduced to less than half the face value as the applied DC voltage rises from zero to the rated voltage. ?? ? Often, some rough rework with a soldering iron dislodges those metal caps on the ends from the stuff inside the ceramic, and the metal caps are hanging on by force of habit and a little bit of friction.?? This can also be very difficult to see by inspection. If I do rework and the surface mount parts looks the worse for wear, they get replaced. ? We've all dealt with cold solder joints. But with today's small parts and tight pin spacing, thin filaments of solder can also be an issue. They can be thinner than a human hair and maybe a millimeter long,? will give a dead short but are impossible to see without magnification. I've had this happen with good quality 63/47 tin/lead solder. None of this happens very often, in part because I am aware of the potential trouble and work to avoid it.? I find surface mount parts generally easier to work with than the through hole?equivalents. Assuming they are larger than 0402's, and pin pitch is better than 0.5mm. Jerry, KE7ER ? On Sun, Nov 25, 2018 at 10:47 AM, AndyH wrote:
Thanks for the confirmation, Allison. |
Vic WA4THR
to navigate to use esc to dismiss