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Re: Desoldering tool suggestion
I have never used a solder sucker on surface mount parts.
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I don't think I would find much use for that particular tool, even on through hole parts. You do want a soldering iron with a very small tip. Should have thermostatic control of heat, preferably with a knob to set the temperature. Removing a surface mount resistor or cap, I use two small irons, one on each end With a wider tip that can touch both ends you could get by with one iron, but I find two easier. For something like a 3 pin transistor in a SOT-23 package, I first wick excess solder away with copper braid and some flux.? Then heat and lift the lone pin on one side. Then heat the other two pins using two irons. For parts with more pins than 3, I cover nearby parts with tinfoil and hit the part to be removed with a hot air gun.? An embossing gun (under $20) is sufficient. Gently lift while heating using tweezers or Xacto knife, but don't tug too hard or you will lift?pads and traces right off the board. When the board is hot, the glues holding down the copper are not very strong. Removing parts can be made much easier with a low temperature solder such as Chip Quik. First remove as much of the old solder as possible using solder braid and flux. Then apply a little bit of the low temperature solder to each pin using a soldering iron. It now takes very little heat from a heat gun to remove that part. Jerry On Thu, Dec 6, 2018 at 04:30 AM, d balfour wrote:
I have soldered for 55 years Have used the bulb style with the teflon tips. It has only been recently that I have tried working on sm parts All my equipment has been too big. |
Re: LSB signal looking more like AM
Gordon Gibby
Good advice Bill Cromwell!
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And maybe he can find some ham somewhere he still knows some things and can listen to him. Or use some waterfall and a CW Carrier somewhere to allow him to plot his own response ¡ª there will probably be a lot of fun learning involved, and that¡¯s very very valuable Cheers! Gordon On Dec 6, 2018, at 06:55, Bill Cromwell <wrcromwell@...> wrote: |
Re: LSB signal looking more like AM
Hi,
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JoshuaClough4 starts his post with his SDR. I have been playing with SDR a little and with "legacy" radios for a long time. That SDR can be and probably is being pushed *hard* by rf being generated right next to it - in the same room, in the same house, on the same estate. Not in the next state. There are so many ways with that kind of proximity to overload the receiver. Inside the transmitter the carrier and the opposite sideband are fully present. The signal is processed to remove the carrier and the opposite sideband and then send it to the antenna. But due to varying amounts of leakage they are always present on the same estate, in the same house, and even down to a couple of inches away from the transmitter. A new ham who would just casually tweak those pots while watching the SDR may be one of the new hams who denies that a shielded box is needed for the receiver AND for the transmitter. Just as a suggestion..reset those pots following the directions for the radio. And then leave them alone until *after* you have installed replacement transistors. Then lookup a WebSDR station within range of your transmitter but still hundreds of miles away (well beyond your local leakage). Examine your signal as seen from afar without having to enlist some other ham to look at it from afar on one of those dreadful "legacy" ham stations :) Back in antiquity we relied on distant friends to examine our signals from those distances. Now we can do it ourselves via WebSDR so the receiver is beyond the "local leakage". I mentioned newbie mistakes and misunderstandings. Somebody is going to be offended. There are hundreds of us here. A few have thin skins. It's really hard trying to 'elmer' new hams via email and mail lists even if everybody uses the same language. We don't. I'm trying to help and nothing is off limits. Real questions here or in private are welcome. Flames will get you membership in my bit bucket. 73, Bill KU8H On 12/6/18 3:14 AM, iz oos wrote:
I don't have a bitx40, but seems you should set BFO further in a way you have only the 500-2500hz bandpass. --
bark less - wag more |
Re: LSB signal looking more like AM
I don't have a bitx40, but seems you should set BFO further in a way you have only the 500-2500hz bandpass. Il 06/dic/2018 01:50, <joshuaclough4@...> ha scritto: My SDR shows my BITX40 signal looking more like AM. Has the carrier and USB when it should not. The USB does look weaker than the LSB that's actually supposed to be there, but still way too strong. |
Re: Ashhar Farhan
#ubitx
I don't see a post yet that clearly spells out how to take care of the spurs.
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This should include pointers to specific parts, show how they get mounted to the board, include fixes for both the 45mhz-DialFreq and the 12mhz spurs. And not be spread across dozens of different posts over the past couple months. There are still questions about the 12mhz spur fix, do Farhan's notes really result in something that resonates at 12mhz?? Is there a way to avoid knocking out 30m? It's easy enough for some of us to get there with the information provided. But I'd say it's not yet clear enough for the majority of uBitx owners. I'm not finding time to do much other than pontificate here myself. And I suppose that means I'm fair game for criticism, so have at it. But creating easy to follow instructions to cure harmonics and spurs is critical here, and I intend to push the issue now and then if it does not get resolved. Once we have complete instructions down that have been properly vetted, it should be possible for everyone to confidently mod their rig for spurs and harmonics. Till then, it will take a spectrum analyzer to verify the fix is correct. Or a day with a step attenuator and a general coverage receiver Looks like HFSignals is still shipping boards with no mods to address harmonics or spurs. ? ??/g/BITX20/message/62307 In message 62308, Raj does say the Axiom relays do address the harmonics if not socketed. He also states:? "The 45MHz filter fix of mine and the LP filter of Farhans does the same thing." I vote for the LP filter, as the extra 45mhz crystal filter is much tougher to obtain than coils and caps, Note that the new crystal filter would have to match the center frequency of the filter at Y1, these filters are often sold in pairs to ensure a match. Jerry, KE7ER . ? On Wed, Dec 5, 2018 at 07:37 PM, AndyH wrote:
Respectfully, the point of being a ham is to learn about electronics and RF.? The point of the BITX radios is that we have a base radio to mod and explore and learn from/with.? Toroids are really easy to wind - and Farhan's latest mod was developed specifically because there's nothing critical.? It's easy to build, easy to install, and doesn't require a spectrum analyzer to align. |
Re: Ashhar Farhan
#ubitx
Respectfully, the point of being a ham is to learn about electronics and RF.? The point of the BITX radios is that we have a base radio to mod and explore and learn from/with.? Toroids are really easy to wind - and Farhan's latest mod was developed specifically because there's nothing critical.? It's easy to build, easy to install, and doesn't require a spectrum analyzer to align.
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As for the relays:? I'm guessing anyone that can read in any language can pattern match 'Virtual' and "Axicom" and understand that if their radio doesn't have Virtual relays that it's been upgraded.? We've been photographing the boards, comparing schematics, and noting differences since the BITX40s started to ship - we'll know when it's updated (and Farhan's already stated that the relays have been updated). Questions from folks are good - we should be encouraging them!? Answers from folks that grok more fully is called leadership.? Calling new hams 'clueless' is not useful. 73, Andy, KG5RKP On Tue, Dec 4, 2018 at 02:39 PM, Jerry Gaffke wrote:
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Re: Is push pull hf amp has higher spectral purity
I think there was brief mention by somebody in early 2017 about that spur getting transmitted
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now that Brian has jogged my memory.? But mentioned only once more or less in passing, and then it was dropped.?? I think. But I don't think anybody ever got around to measuring the spur, Maybe Brian knows more about this. Possible that the spur strength varies from rig to rig.? Whatever might effect the strength of the VFO's 4'th harmonic. I personally don't think it's a significant issue. And if it were, going to Allard's v2 firmware and mods is a very easy fix. Jerry On Wed, Dec 5, 2018 at 05:36 PM, Guy WB7SZI wrote:
Have you seen QST¡¯s review of the BitX40? Seemed to pass their analysis.? |
Re: LSB signal looking more like AM
Mindlessly twiddling RV1 on the Bitx40 (or RV2 and RV3 on the uBitx) will blow the IRF510's.
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I assume you were watching IRF510 drain current when you did the adjustment.. If not: Power down, turn that pots full clockwise (it's backwards) for minimum drain current. (it's backwards) and minimum drain current. Carefully adjust that pot for 100ma of quiescent current through the IRF510 as instructed on the HFSignals tuneup page. Will be nothing at all for about half a revolution, then the adjustment gets kind of touchy. On Wed, Dec 5, 2018 at 04:50 PM, <joshuaclough4@...> wrote:
I've tried adjusting the two pots thinking that something was overdriving the signal to create this, but those in any combination don't seem to change the sideband supression (or lack there of). |
Re: Fw: [BITX20] UbitX audio hiss but no rx
Sean
do check to make sure you don't have a short on the antenna connection.? tuning around one or more bands - do you find evidence of signals that you can tune in?? this would be a BFO that is very far off.? note the frequency dial should show a frequency change with tuning - otherwise you have a misconnection between raduino and main board.? do rule out simple issues.? Curt |
LSB signal looking more like AM
My SDR shows my BITX40 signal looking more like AM. Has the carrier and USB when it should not. The USB does look weaker than the LSB that's actually supposed to be there, but still way too strong.
I've tried adjusting the two pots thinking that something was overdriving the signal to create this, but those in any combination don't seem to change the sideband supression (or lack there of). I even tried changing the raduino sketch (which being evidently a clone was fun in itself) without any change. I've previously tested a lot of stuff already on the board because It stopped transmitting before and stuff tested fine, which drove me nuts. Eventually figured out it was the incompatible microphone type I had hooked up. Had simultaneously changed the power supply and thought that had damaged something and never thought about the mic. |
Re: Is push pull hf amp has higher spectral purity
Jerry,
I agree with what you have written and detailed. The transmit spur varies with frequency. Away from 7.2MHz it is outside of the band. Feeding the Raduino into the disabled vfo is not optimal as regards signal purity. The start of this thread was a suggestion that the Bitx40 might be easier to get fcc compliant. Being single band that might be true but it is not without its own problems. There has been little reported on the Bitx40 since the uBitx was released. Brian VK4BAP |
Re: FS: SotaBeams Laserbeam DSP Variable Filter
No apology necessary, David. I just need to use my eyes the way they
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were meant to be used. Link showed up fine. - Rich On 12/4/18, N8DAH <Dherron@...> wrote:
Sorry gents should have made the link more obvious. I sold it this afternoon |
Re: Desoldering tool suggestion
¿ªÔÆÌåÓýJust took my relays off in 20 minutes using a?ECG J-045-DS Electric Corded De-Soldering Iron, 420 Degree C Tip Temperature, 45W From Amazon. Didn¡¯t even need to clean the holes 73 Art On Dec 5, 2018, at 3:18 PM, bill@... wrote:
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Re: Ashhar Farhan
#ubitx
Using a toothpick to open the holes is a great idea.?
-- Lee - N9LO? "I Void Warranties" ? |
Re: Ashhar Farhan
#ubitx
Link? On Wed, Dec 5, 2018 at 6:42 PM Rob Bleumer <Bleumer@...> wrote: It was a? very easy swap with the relays. They came to me im Europe from Alibaba in 3 weeks 18$ for 10. 5 for my friend. Taking the old ones out with normal solder pump. Just one of the old relays lost a leg. With wooden toothpiks and soldering iron I opend the holes. |
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