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Re: Mic doesn't work in bitx40
#bitx40
The mic may be bad or connected reverse polarity.. pay attention to that!
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At 17-05-18, you wrote:
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Re: Mic doesn't work in bitx40
#bitx40
Are you using an electret condenser mic ?
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If you connect a dynamic mic then what you describe is correct. The design is for electrets. Raj At 17-05-18, you wrote:
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Re: Core for Output Transformer
¿ªÔÆÌåÓýBill, are you still using the IRF510¡¯s and if so how many turns for the primary and secondary windings? While experimenting last night I noticed that T11 was heating up and power out would drop somewhat.?Skip Davis, NC9O On May 16, 2018, at 22:03, K9HZ <bill@...> wrote:
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Re: share your BITX success stories
Daniel Conklin
I agree too!? I have been making contacts with special events stations and DX on 40 meters SSB.? My first contact was the Marconi Birthday Memorial station in Cape Cod, then the Indy Speedway F1 race day station.? Since I sole my FT=817 two years ago I've only been using CW with home built QRP transmitters, so it's a real treat to be able to make some voice contacts with a radio that I may not have designed and built, but at least I assembled it.??
- Dan , W2DLC |
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Re: Mic doesn't work in bitx40
#bitx40
¿ªÔÆÌåÓýAre you using the mic element that came with the UBITX? If you are did you wire it up correctly, there is a positive/audio pin and a negative/ground pin connected to the case of the element. You can see the case/pin connection with a magnifying glass on some elements it is only a small trace that can be measured with your ohm meter.?Skip Davis, NC9O On May 17, 2018, at 05:46, qonita.salimah@... wrote:
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Re: uBitx
Nice info, but i fear same device if bought from ebay could well be a fake "wx" device (tda2822) Regards MVS Sarma ? On Thu, May 17, 2018 at 4:57 PM, alans77 via Groups.Io <alans77@...> wrote: An unexpected bonus from using the NJM2037 is a significant reduction in receive audio distortion. Highly recommended.? |
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Re: share your BITX success stories
I am having a ball with mine, I get around 10 watts on 80 and 40 meters. I am making contacts up to around 700 miles from a fan dipole at 35 feet (10 meters or so). I am putting the finishing touches on my enclosure, a re-purposed Cobra 148 CB case, and am enjoying the whole experience. I am going to attempt to do Howard's mods for leveling out the power on the upper bands and add the necessary cabling for digital.
I have also uploaded the KD8CEC firmware, and must say it is a pleasure to use. Thanks to Ian for his hard work! 73 de WS4JM |
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Re: Using IRF530 outputs and 2N3553 drivers in ubitx
They come up as obsolete On Wed, May 16, 2018 at 07:54 pm, Rahul Srivastava wrote:
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Mic doesn't work in bitx40
#bitx40
Hello everyone.. I have some problem with my mic pre-amp.. The voltage from 4.7KOhm resistor suddenly drop to 0.130-0.132Volt after I connect it to the mic electret..? Is this normal? I've put my oscilloscope on the 1uF capacitor to observe the change of the frequency, but it doesn't even display any change when I said or scream in front of the mic. What could be the problem? Need help here.. |
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Re: Core for Output Transformer
ps I didn't fit the MPSH10's in this test.
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vk3pe On Wed, May 16, 2018 at 11:51 pm, Glenn wrote: Hi Nick, yes close to AUD$11 here plus postage. |
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Re: Core for Output Transformer
Hi Nick, yes close to AUD$11 here plus postage.
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I did a few tests on my uBITX today. It started off totally stock. I measured the power out (CW mode) and then added the 220pF caps and some other changes as below. Max. output on 10M band was 6W. The R97,98 mods were part of Ashhars mods. Since I had already fitted the 220pF at that stage, I didn't remove the 220pF caps and do all his mods. Glenn On Wed, May 16, 2018 at 10:43 pm, Nick VK4PLN wrote: Only problem is the 002 is 10x the price of the 202.... |
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Re: #ubitx #ubitx-help
#ubitx-help
#ubitx
If you build per the plans and don't happen to have a fuse on the power supply, there is no reverse polarity protection. Search for "reverse polarity" in this forum to see the various threads. Here's one:? ?/g/BITX20/message/35353 Once you pop the diode, you have the full reversed supply to the board. The only way to be lucky here would be if you had a really wimpy supply that was unable to blow the diode open, or you happened to have an appropriate fuse on the 12v line from the power supply of 2 or 3 Amps. If you had the Raduino plugged in when you powered the board up, that will be the major hit. The LM7805 does not offer any reverse supply protection, so if the Raduino saw reverse 12v, that would almost certainly blow the Nano, and probably the display and si5351 as well. Could have been avoided by having a diode where 12v goes into the LM7805, we can afford to lose a little voltage there. Try plugging just the Raduino into a host computer (no connection to the uBitx) via the mini-USB connector, see if it comes to life. If you have a very new board from hfsignals, than the TDA2822 is likely socketed and easy to replace. Most likely blown if it saw a reversed 12v. The 78L05 at U2 may have blown. The remainder of the radio is suspect, but may well have survived. Jerry On Wed, May 16, 2018 at 08:36 pm, R. E. Klaus wrote:
If you built it per the plans with the diode across the power jack, you may be lucky and just shorted the diode.? I've replaced hundreds of protect diodes in various mobile equipment with no further issues. If you didn't then it's time to break out the multimeter and start checking for shorted semiconductors and ICs. |
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Re: #ubitx #ubitx-help
#ubitx-help
#ubitx
R. E. Klaus
If you built it per the plans with the diode across the power jack, you may be lucky and just shorted the diode.? I've replaced hundreds of protect diodes in various mobile equipment with no further issues. If you didn't then it's time to break out the multimeter and start checking for shorted semiconductors and ICs.
Roxie -- K1AUS |
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Re: Core for Output Transformer
Bill
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do you mean you fitted it for the power feed to the finals instead of the Chokes? glenn On Wed, May 16, 2018 at 07:34 pm, K9HZ wrote:
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