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Re: BITX40 goes Digital this Xmas!
Ron, This documents what you must do to the boards that are shipping from now on. The new boards do not have the L4 soldered in.? Can you spot me in the picture?? - f On Fri, Dec 23, 2016 at 1:57 PM, ron van doremalen ronvandoremalen@... [BITX20] <BITX20@...> wrote:
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Re: BITX40 goes Digital this Xmas!
¿ªÔÆÌåÓýAshhar, ? Not sure, but the tuning pot and the regular vco in combination with the DDS signal. Isn¡¯t that interfering. ? Our DDS supports full coverage of the band, where I read there is now only 50Khz band. ? Ron ¨C PA3FAT ? ? Van: BITX20@... [mailto:BITX20@...]
Verzonden: 23 December, 2016 09:21 Aan: BITX20@... Onderwerp: RE: [BITX20] Re: BITX40 goes Digital this Xmas! ? ? thanks, fixing it. anything else that slipped past? - f ? On 23-Dec-2016 1:46 pm, "ron van doremalen ronvandoremalen@... [BITX20]" <BITX20@...> wrote:
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Re: BITX40 goes Digital this Xmas!
Great work Farhan! Looking forward to paying radio with it!
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At 23-12-2016, you wrote: ? |
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Re: BITX40 goes Digital this Xmas!
thanks, fixing it. anything else that slipped past? - f On 23-Dec-2016 1:46 pm, "ron van doremalen ronvandoremalen@... [BITX20]" <BITX20@...> wrote:
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Re: BITX40 goes Digital this Xmas!
¿ªÔÆÌåÓýHi Ashhar, ? In the calibration section, last line: Short the brown wire of the 8-pin Raduino to the ground Isn¡¯t this again putting the Raduino into Calibration as the next lines states you should prevent this wire from being grounded. ? Ron ¨C PA3FAT ? Van: BITX20@... [mailto:BITX20@...]
Verzonden: 23 December, 2016 08:56 Aan: BITX20@... Onderwerp: Re: [BITX20] Re: BITX40 goes Digital this Xmas! ? ? Jerry, hfsignals@.... This is only available to people who have already bought a BITX40. As you can imagine, 14 dollars doesn't cover the full cost. However, this offer is worked out to keep the early adopters on par with the new BITXers. ? - f ? On Fri, Dec 23, 2016 at 1:20 PM, ohwenzelph@... [BITX20] <BITX20@...> wrote:
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Re: BITX40 goes Digital this Xmas!
Jerry, hfsignals@.... This is only available to people who have already bought a BITX40. As you can imagine, 14 dollars doesn't cover the full cost. However, this offer is worked out to keep the early adopters on par with the new BITXers. - f On Fri, Dec 23, 2016 at 1:20 PM, ohwenzelph@... [BITX20] <BITX20@...> wrote:
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BITX40 goes Digital this Xmas!
Comrades, The upgraded BITX40 has been released. Check , you may have to refresh the page with a Ctrl-R or something. RADUINO! The new BITX sports the Raduino, a tiny board that carries a full Arduino Nano, a 16x LCD display and an Si5351a. The Raduino is fully open sourced and it will be available on github by the weekend. With this, the BITX40 is now capable of sporting dual VFOs, RIT, keyer, SWR meter, etc. No, these are not built-in. Instead, these are things that can be made with a few resistors and capacitors and some clever software added around the Raduino. I will document it fully in a few days. I am very excited with the possibilities of the Raduino.? As you can imagine, the Raduino adds to the cost of the BITX40. Hence, the price has been upped by 14 dollars to 59 dollars. I hope people find it worth the additional cost. For those who prefer the old analog radios, you could toss the Raduino into the junk box and solder the VFO inductor to work your old analog radio. For those of you who have already purchased the BITX40 and want to 'upgrade' with the Raduino, drop a line to hfsignals@..., they will upgrade you for the same 14 USD (including the postage). Let's keep this list for technical stuff, for any queries related to shipping, payments etc. You should just write to hfsignals@... - f |
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Re: BITX 40v3 no xmit - suggestions?
here is some brief stuff you can try, 1. I hope you have connected the PA power line. When you speak, does the current change?? 2. Set the bias again. Insert an amp meter in the power line. Start with the bias pot fully clock-wise position. Keep the PTT pressed. Now inch it back, counter-clockwise. Around 9 o'clock position the current should start climbing up, set it to 100 ma over and above that you saw with the bias in fully clockwise position. Try transmitting now. 3. Fashion an RF probe. Measure the RF at the predriver's collector when you go 'HAAALLLOOW'. It should do one volt or thereabouts. If it doesn't carefully separate out the turns of the T5 with a tooth pick. 4. Measure the RF on the gate of the IRF510. The HALLLLOW should bring it up to 4-5 volts. Try looking for a short on the T6. Use the toothpick to move the wires of the T6 away from each other. 5. Measure the RF on the drain of the IRF510. The HALLOW should now bring up 10-12 volts. Use the toothpick similarly. Almost always, the trouble is with transformer windings' tinned ends touching each other. Unless you have blown the IRF510. But that would show up in the static current drain. On Fri, Dec 23, 2016 at 4:01 AM, iam74@... [BITX20] <BITX20@...> wrote:
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Re: Bitx 40 board.
Bravo, Ken. You have taken on a huge chunk of RF Engineering, to say the least.
john AD5YE ---In BITX20@..., <chase8043@...> wrote : Hi John Tonight I gave a small presentation on side band inversion to the homebrew group I belong to. A couple were aware of the?'phenomenon', but most found it very interesting. I used this to help in explaining. Thanks again for your help, very much appreciated. 73 Ken VA3ABN |
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Re: BITX 40v3 no xmit - suggestions?
One of the things that happens with crystals is aging. They will shift their frequency output over time. I always keep my crystals oscillating for at least a day, and then measure them again. They are always shifted. In circuit, usually, this will affect both receive and transmit, but not always; sometimes one is effected and the other is not.
Another thing to consider is: has your BFO shifted somewhat out of the passband of the filter? Remember that both the filter passband and the BFO can shift somewhat in frequency. It may be that you are not getting enough signal through to properly drive the mixer output. Maybe not, but it is something to consider... Another thing to think about is a failure of some active device. Perhaps it is that one of the IF or RF transistors has failed or weakened in some way. Measure all the voltages against what is expected for clues. In the IF, the receive and transmit sides are about equal. Also in the RF. Is the current draw what it was in the beginning?? What, you didn't record that information! Hmmm... Another thing to consider is the result of a faulty assembly. There may be a cold solder joint (the most common problem) which is now making it's appearance. It has happened before...and will happen again, especially around the transformers. Also, does any one part get got on transmit? It may be suspect. Unbalance your BFO mixer a bit to allow some carrier down on PTT. It is normal for everything to heat up a bit (as compared to SSB), but one part may get some runaway thermal effect. And don't forget impedance mismatch between the main circuit board and your PA. That is a big item. In fact, it can destroy some devices with reflected bad SWR. john AD5YE ---In BITX20@..., <jeffamextra@...> wrote : I have the same problem. Receive ok but absolutely no power down the line on transmit. I was getting about 100mW out when I first hooked things up but now after a couple of weeks no transmission goes out at all. Disappointed.? |
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Re: BITX 40v3 no xmit - suggestions?
I have the same problem. Receive ok but absolutely no power down the line on transmit. I was getting about 100mW out when I first hooked things up but now after a couple of weeks no transmission goes out at all. Disappointed.?
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On Monday, December 19, 2016, 6:46 PM, nobody.really@... [BITX20] wrote:
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Re: Yeah! No!
Arv.
Well, your writings cover the RX, but not the PA transformers T5, T6 and T7? in And it does not matter if I use a BITX20 v.3 PA PCB or a breadboard or whatever - the whole point is that I cut and add traces / jumpers in order to replicate the PA circuit in . But the schematic as it is now is useless because one has to guess that T5, T6 and T7 are transmission line transformers 10 turns bifilar on FT37-43 or FT50-43? And the predriver and driver could be 28AWG wire, but the output transformer should maybe use a thicker wire. But I am now out of here. I have wasted enough time. IMO - the ONLY solution is that ALL INDUCTORS AND TRANSFORMERS are specified IN THE SCHEMATIC. Schematics that can not be built without guessing are not for me. Just my opinion and choice - of course. Others may be fine guessing and experimenting. Thanks again Arv for your kind help. Roy |
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Re: Yeah! No!
Thank you Arv.
Your point illustrates mine perfectly: Inductor and transformer information MUST be in a small list in the schematic. If not, the result will be endless frustration and waste of time. And of course I am talking about It shows trifilar symbols all round - a leftover from the first BITX TV baluns 10 or more years ago. Can it be so difficult to write that T5, T6 and T7 are bifilar x turns on Y core ... Roy |
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Re: Yeah! No!
The L1, L2 and L3 have 40 turns on T30-6, yellow core. - f On 22-Dec-2016 9:05 pm, "Kent Vanderploeg kvanderploeg@... [BITX20]" <BITX20@...> wrote:
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Re: Yeah! No!
Roy? AG7CK There are many versions of BITX now available, some by Farhan, and some by others.? Each design has its own set of inductors that are mostly specific to that particular design. This makes it a bit complicated to provide a list of inductor specifications for "all" BITX designs. For those BITX schematics that do show the inductance value you can go to then select your core type and enter the desired uh value.? This will give you the number of turns and the length of wire required.? If unsure of the inductance value you can use or other similar circuit simulator to emulate the circuit segment and adjust the inductor until it provides the correct operation. Circuit simulators allow you to play with LC values to determine the best component match for specific frequency performance. Having said all that...if the question is specific to Farhan's recent BITX-40v3 design, the inductance value is shown on the schematic.? The HF coils are wound on T37-6 cores and mixers are wound on FT37-43 cores.? T37-6 cores have one side painted yellow and the other side is black.? FT37-43 cores are all black.? Mixer transformers are 10 turns trifilar (3 wires twisted together) on the FT37-43 cores.? You can use smaller T37-2 cores for the HF inductors but turns for 6 uh will be 39 instead of the 45 turns required for a T37-6 core. Core size affects power handling capability in case you want to upscale a circuit segment for more power. is a good place to purchase T37-6 or FT37-43 cores.? They also have magnet wire. An unexpected source of magnet wire is also your local arts-and-crafts store.? In the section for "beading supplies" you should find coils and spools of PVC coated copper wire in various diameters.? For toroidal cores the wire size is not particularly critical, as long as it is not so large to not allow the required number of turns through the toroid core. NOTE:? If you are changing the band on a BITX design (or on design of any similar equipment), you can use the site to determine LC impedance at operating frequency for the original design, and then use that impedance to find the L and C values for the new frequency of operation.? Arv? K7HKL _._ On Thu, Dec 22, 2016 at 11:25 AM, r j rjinspace@... [BITX20] <BITX20@...> wrote:
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Re: Yeah! No!
According to one needs 44.7 i.e. 45 turns to get 6uH (as stated earlier in the thread). As Arv is a BITX resource person mentioned by Farhan himself on the hfsigs-page, may be Arv could ask Farhan how on earth? anyone can publish a schematic that is: [quote] HackableThe BITX40 will inspire you to experiment. Modify it, mount it, tweak it, change it. [end of quote] that does not contain inductor information? A small list of inductor / transformer core material and turns below the schematic is all that is needed. Roy AG7CK |
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Re: Yeah! No!
I see in the schematic for the BPF that L2 is 6uH. Since it is a tuned circuit one can guess that it is type 6 material and calculate turns. Thank you.This is IMO more difficult for the 37(?) material transformers. Could Farhan please add toroid types and turns for transformers to the schematic. |
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