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Re: The BITeensio board is here.
#ubitx
I bought a pair similar to those.? Could only use one eye at a time and my nose was about 2 inches from the board.? After trying several things, I finally spent $ 200 for a good stereo microscope.? I had spent about 1/3 of that trying several cheep things. de ku4pt On Sat, Jun 16, 2018 at 7:51 PM, Roy Appleton <twelveoclockhigh@...> wrote:
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Re: Alternate pop fix...
What's not seen and didn't make a difference to pop/thump was I removed k3 from the audio path
(K3 contacts 1,3,5) so I could use them to ground the RX path during TX and use K1 to switch the antenna and Q90 to the output/input of the 30mhz low pass filter.? This relieves the filter and receiver of Q90 base resistor (100 ohms) from the path on RX and helps improve sensitivity. There are many mods most will not do or feel are not needed for them.? Most of what I am doing are to suit my wishes eclectic as they may be. Allison |
Re: Alternate pop fix...
¿ªÔÆÌåÓýYes it is the timing Allison I set mine to about 1.5 ms (I¡¯d have to check my notes) and that solved both thump and pop. I played with the values too before settling on what I ended up with, using parts on hand.?Skip Davis, NC9O On Jun 16, 2018, at 19:25, ajparent1/KB1GMX <kb1gmx@...> wrote:
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Re: The BITeensio board is here.
#ubitx
I tried those 2 inch focal length goggles but I kept burning my nose on the soldering iron.? 8-) _._ On Sat, Jun 16, 2018 at 5:52 PM Roy Appleton <twelveoclockhigh@...> wrote:
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Re: The BITeensio board is here.
#ubitx
No way I could use those "goggles" with a focus length of 2" (50mm)! Roy WA0YMH On Sat, Jun 16, 2018, 5:40 PM Lawrence Macionski via Groups.Io <am_fm_radio=[email protected]> wrote: Jim- |
Re: PA transistor uBITX
On Sat, Jun 16, 2018 at 02:19 pm, Joel Caulkins wrote:
MTP3055VWill work fine for the lower bands.? I've used them for 40M and they work ok, shame they are obsolete.? Some one got them thinking they were 2n3055 by error bought them and could not find a use for them.? They found their way to me. Input C is 410PF (nominal) and only 50V.? At 12V it should be OK but power on 20 and up will be lower as the drivers have to work harder.?? It would be like using IRF520. Allison |
Re: Alternate pop fix...
Hi Skip,
Also just having the Resistor and diode on the Radiuno was less effective as you get the return to RX thump when DC is applied to Q70.? It only got the POP. I wanted the TX release thump to go away. This approach using the Raduino kills the RX audio before the relay actually moves so the key down pop when power is applied to Q6 disappears completely.? The TX power resistor and diode hold the audio off until after Q70 has power by a few milliseconds (1k*.1uf=about 1ms) and that kills the return to RX thump.? FYI the cap needs about 3-4 RC time to release the mosfet as the gate threshold us under 4V and we charge the cap to 12V. Its a timing issue.? Relays are slow and there are enough capacitors in the switched lines that nothing stops working immediately so we get RX/TX overlap.?? Muting this way is very clean and the audio comes back smoothly.? That and its well tested. I finally got to writing it up. Allison |
Re: The BITeensio board is here.
#ubitx
Lawrence Macionski
Jim-
Thank you for showing me the BITeensio Board at the swap-n-shop today!!.. Guys- ??????? I had the board in my hands and I have 40 years in IT/Heavy Military and NASA. It is Total 1st class quality.. Yes, I know there is a hundred ways to go to make your uBITX your's .. But seriously consider Jim's value added features and such to see if they are right for you.? Especially the 4 line display ability offers so much more than just 2. Not that is is a negative but both Jim and I agree- Assembly requires patience, a very good soldering station, and soldering tools.. Plus if you are like us..You need? Geezer goggles!!!? (https://www.banggood.com/DANIU-White-10X-15X-20X-25X-Spectacles-Glasses-LED-Lamp-Magnifier-Loupe-Maintain-Tool-p-1067682.html?rmmds=detail-top-buytogether-auto__2&stayold=1&cur_warehouse=CN) de Larry W8LM ARRL Life Member - Licensed? 368 DOG Years.. |
Re: Went Dead
Thank you very much for the information! Roy WA0YMH On Sat, Jun 16, 2018, 1:21 PM Ralph Mowery <rmowery42@...> wrote:
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Re: Alternate pop fix...
¿ªÔÆÌåÓýAlso move the parallel resistor/diode to the Raduino T/R and you won¡¯t need the other diode you added.Skip Davis, NC9O? On Jun 16, 2018, at 18:06, Skip Davis via Groups.Io <skipnc9o@...> wrote:
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Re: Alternate pop fix...
¿ªÔÆÌåÓýAllison try moving the FET to the M1/C51 side and mute the audio preamp directly that is where I have it and I¡¯m not experiencing any detectable pop in my headphones. Having said that, your results may very.?Skip Davis, NC9O? On Jun 16, 2018, at 16:28, ajparent1/KB1GMX <kb1gmx@...> wrote:
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Re: Ubitx and Sherwood rx tests
Sherwood only tests receivers so the only must have mod is the RX AGC ND6T flavor.
All the hot receivers are SDR and direct digital sample (flex, and Anan) thought the 7300 (also a SDR) is up there. Of the radios using more conventional analog techniques two of mine the Atlas? and the TT 340 are fair comparisons for single conversion.? The Tentec is the only low IF with selectable filters at 9mhz to digital IF unlike those with VHF first IFs.??Of those three the? listed radios Tentec Eagle, Atlas 215X, Tentec 340/Triton? on the list in that order from best to worst.? This radio without AGC is not likely to be above any of them.? Also the Atlas 215X a 1976ish design is a diode mixer front end like the uBitx with?and AGC in the IF and a diode mixer for product detector so it would compare closest to the uBitx.?? Note: In dollars none of those radios even as used/broken approach 100$ and new were much more expensive by many times. Comparable transceivers in the power class is FT817, IC703 and Tentec Argonaut QRP series such as the used Argonaut model 505 that I use very regular for the 5W QRP level. Reasons that is likely: RX overload point, the limit here being the diode mixer.? Filters First (45mhz) is wide and the second is fixed at SSB bandwidth. close in and wide overload Phase noise from the LO systems (LO1, LO2, BFO). Sensitivity is never an issue.?? Allison |
Re: Exciting times in the uBITx world
Lots of fun using the nextion displays and more users are jumping in by the day
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Show quoted text
Definitely my favourite display! Using 3.2 Enhanced Joe Ve1bwv On Sat, Jun 16, 2018, 3:22 PM William Cullison <wa8vih@...> wrote:
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Alternate pop fix...
While working with the uBitx V3 I finally got annoyed enough by the pop to fix it.
Basically copied from uBITX V4 but it still popped some.. Parts count 4: 2 1n4148/914 diodes. 1 10K resistor (any value from 10 to 100K really) 1 2n7000 mosfet Why the second diode?? The TX line is relay switched 12V and relays are not instant they take milliseconds to physically move contacts.? So the second diode to the T/R line form the Raduino its the fast acting audio kill as that the command to the relay.? The second diode resistor is the hold until the relay returns to RX position. TX muting with no pop, no thump.?? Allison schematic enclosed. |
Re: Ubitx and Sherwood rx tests
One without mods, the latest version. Btw most of the mods regard the TX, I have not seen so many mods at the RX. Il 16/giu/2018 13:32, "Dennis Zabawa" <kg4rul@...> ha scritto: Which variation?? Everyone builds theirs differently. |
Re: Went Dead
The V4 board is the latest ubitx circuit board.? It has several modifications to it from the original ubitx circuit board.? One of the main ones is the audio IC was replaced by several transistors as there seems to be a real quality control problem with the original IC.?? Mr. Farhan is looking at all the mods that have been made by others and using some of the best of them in the V4 boards. While the original works very well for the price there have been lots of modifications to it and the software.? I think he did a great job of making the original by keeping the price very low.? While I can not do much with the engineering of the electronics, I have enjoyed making some of the modifications to the ubitx.? I look at this as the way I am at chess.? I know how each piece moves, but when playing with a real chess player I get beat in about 3 moves because I don't know how to hook it all together. The IRF510 can be mounted by using the insulators.? I don't know much about the IRF510 but the RD16HHF is a 'real' RF device and the specs say it will withstand a SWR of about 20 :1 .? However it is about $ 10 per pair instead of the $ 1 a pair for the IRDF510s. de ku4pt On Sat, Jun 16, 2018 at 3:09 PM, Bill Watkins <kf7yxs@...> wrote:
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