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QDX-M for 630M?
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I know that Hans has many things going.? My QDX-M just arrived.? Having been in this Ham stuff for 60+ years, I have a well-supplied back room and fading experience in building.
Looking at the schematic and thinking 630M, I wonder if simply changing the frequency selective components to fit what I have: T2 to Mini-Circuits Labs T-626-KK81+ and T1 to BN-73-202 with 22 turns to get about the same Z as the BN43-202 has on 20M along with filter changes to L12 and the LPF to 630M will that be enough is there something else lurking? That said, I'll try it anyway! Thanks, N0UU Why does the input turn on T2 go to the Center tap of T2 instead of to ground?? Suspect was left over from the previous models. |
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On 26/01/2023 17:07, Steve Z wrote:
I'm not sure why one input side of T2 goes to the output center tap, but that node goes to ground through a 2.2 microFarad cap. The impedance of this cap is 0.01 ohms at 7 Mhz, so it is essentially RF ground.Steve It looks better to me:-) But the centre tap is the RF grounded point of the phase-splitting transformer. Putting the primary's ground there looks more balanced although practically it may make little difference. 73 Alan G4ZFQ |
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Hello Muhsin Abi I think we would also have to consider the possibility of operator error (inflicting configuration error)....? ;-) 73 Hans G0UPL http://qrp-labs.com https://www.buymeacoffee.com/g0upl -------- Original message -------- From: Muhsin TA1MHS <muhsin.dogrular@...> Date: Fri, Jan 27, 2023, 2:40 PM To: [email protected] Subject: Re: [QRPLabs] QDX-M for 630M?
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Hello Hans Abi It was very late and I didn't push to solve it. tomorrow I'm returning to Istanbul, there I will give another try 73 muhsin TA1MHS note: mixture of heisenberg uncertainty principle and?schrodinger's cat?situation ? |
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Hello Muhsin Abi, and anyone else who is experimenting with their own off-piste band configurations for QDX: At the moment, the way the firmware works (since the beginning) is that if the default start-up frequency on the Configuration page is not inside a valid band (as defined on the Band Configuration page) then transmit will be disabled. The way out of this is to amend the default start-up frequency to be within the defined limits of one of the bands in the Band Configuration screen. Then cycle the power to the QDX. It's a little ugly because if the operating frequency is subsequently moved into a band, it still doesn't allow transmit. In other words once transmit is disabled by this out-of-band situation, it stays disabled until you cycle the power. It's not necessary, it's just the way the code was written - I should fix this in the next firmware version. 73 Hans G0UPL On Fri, Jan 27, 2023 at 7:30 PM Muhsin TA1MHS <muhsin.dogrular@...> wrote:
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