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Re: ??IF Stage doubts??


 

Hello friend Arora here Carlos PT9EB I wish you well with your family. I don't know if you managed to solve E-BITX IF as you reported. I've been looking at your comments and it looks like you've made changes to the transistors and I hope it worked because the transistors listed in the project are perfect for the radio to work properly. BF494 I want you to leave it on the PCB, it has greater efficiency as a whole. Step 5 place the xtal carcass for gnd. In Step 6, check the voltages of the transistors in TX and RX, but remember that the VFO / BFO must be connected to the board and other accessories of the TX / RX volume led set with a clamp or a touch tip on the C30- on Base Q5) You will hear a noise in the AF indicating that the previous steps are ok. In the following steps you need to be very careful with the windings of the toroids in relation to the spacing between the turns and tightening so that it is as fixed as possible on the toroid that after inspecting the turns externally and internally so that the spacing is perfect then you can use a plastic product to fix the loops as well as I used and you can see in the video that indicates the supplier. In this step 7 you use the 1N4148 diode, it is easier to measure it yourself if you use the BAT54S, but use the 1n. Making sure everything is fine in Step 8 after mounting and checking the voltages, do a test on the Base of the (Q7) BF494 then you will hear the noise of the ok strip. And follow your assembly according to the instructions of each stage. In BPF you have to be very careful with the winding because there is a beginning and an end of each inductor and not all are the same. If you need some support, even with engineering training, we always have the opportunity to learn from friends with bench experience. I have more training and radio work. I'm about 30 years old on the radio, but I'm always learning from former teachers. and amateur radio friends. If you need better information my phone and whatzapp is: +55 64999629242

Em qua., 19 de mai. de 2021 ¨¤s 12:23, <arorasimran@...> escreveu:

Hi, it is with the STOCK firmware that BFO and VFO are not independent of each other.
With Raduino V2, I have done necessary modifications to
1) Hold the PTT low so the Dial lock goes away
2)VFO pot is smooth
3)Did the necessary changes to have it oscillate to 14Mhz.

I have been provided with the original sketch that Sunil Has. If you guys want it either let him post, or I can do the need ful if no body minds( technically it is open source, right?)

Measurement Apparatus is CADDO 35MHz CRO which is soon going to be upgraded with a MSO or DSO by month end which has 100MHz Bandwidth.
Technique to measure:-

I am not counting the numbers or using ms/div scale to calculate the frequency.
It is common sense that the sinusoidal graph should etiher compress or expand (VOLTAGE TIME) for either BFO or VFO depending on which one is selected.

I tried it with load (ie EBITX CONNECTED TO DDS) and without load (JUST DDS)

If i change bfo, vfo changes too and vice a versa.

Shall post raduinov2 sketch on GIT for E.Bitx.....do let me know what more can be done :)






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Atenciosamente.
Carlos Fraga



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