Oops, I send to the wrong?email addy. Sorry about that. this was meant for Bill. - f
On Wed, Jun 2, 2021 at 7:28 PM Ashhar Farhan via <farhanbox= [email protected]> wrote: Bill, The only time I used gilbert cell (NE602) was to build the 21 MHz to 29 MHz transponder. The nearest station would be at least 500 KM away and the Yagis of the bad boys would be pointing along the ground towards each other. Isn't it an active mixer? The KISS mixer is a passive mixer. The FETs are used as switches, not as amplifiers. The big deal is this: In a diode mixer, the diodes are turned on by the switching current that flows along with signal current through the same paths. In the FET switching mixer, there is no switching current, and the switch is turned on by driving the gate very hard and almost instantaneously - that makes it so resilient?to any reflected current coming back from the filter side.? SDR aside, the KISS mixer, theoretically consumes zero drive power. It just needs a square-wave voltage to switch. It makes for a great analog front-end. That's what I tried with the Minima, I should have used multiple band pass filters and added CW and AGC, it would have made a great radio. I might still do that! I just got a strip of 100 40 MHz, fundamental crystals. Let me see if I can hammer out a filter with them. If it works, then I can extend the sBITX to full 30 Mhz coverage. I must read up on the Gilbert cell, EMRFD has devoted quite a few pages to it. - f
On Wed, Jun 2, 2021 at 3:22 PM Rafael Diniz < rafael@...> wrote: One question: Which is the transmit and receive bandwidth of the sBITX?
How to buy or build one? (Without the Raspberry Pi, as the need for
processing I have is much higher of what the Raspberry can provide - I
need at least AVX2 4th gen Intel chip for ML purposes).
Thanks,
Rafael Diniz
On 6/2/21 12:04 PM, Rafael Diniz wrote:
> Thanks a lot!
>
> Reading the names of Farhan and Phil Karn makes me shiver! Wow!!
>
> You are the ones!!!
>
> Rafael
>
> On 6/2/21 11:32 AM, Shirley Dulcey KE1L wrote:
>> I should?add that it's a transceiver design, not just a receiver.
The
>> DSP is done by a Raspberry Pi 4. The talk first presents a
>> modification of the uBITX, then goes on to show a new design that
>> Farhan is working on.
>>
>> On Wed, Jun 2, 2021 at 4:30 AM Shirley Dulcey KE1L via
>> <> <mark=[email protected]
>> <mailto:[email protected]>> wrote:
>>
>>? ? ?The sBITX is a simple hybrid SDR; it uses a conversion to 27 MHz,
>>? ? ?a crystal filter there, and then downconversion to a near-zero IF
>>? ? ?where the signal goes into an audio ADC.
>>
>>? ? ?Here's a link to Farhan's talk about it at
>>? ? ?FDIM:?
>>? ? ?<>
>>
>>
>>? ? ?On Wed, Jun 2, 2021 at 2:07 AM Rafael Diniz
>>? ? ?<rafael@... <mailto:rafael@...>> wrote:
>>
>>? ? ? ? ?Hi everybody,
>>
>>? ? ? ? ?I'm sorry, but after many messages, I also wanna know what
>>? ? ? ? ?sBITX is.
>>? ? ? ? ?This link does not give any clue. Any link with the actual
>>? ? ? ? ?video of
>>? ? ? ? ?Farhan speech?
>>
>>? ? ? ? ?Thanks,
>>? ? ? ? ?Rafael
>>
>>? ? ? ? ?On 6/1/21 8:41 PM, Jerry Gaffke via
>>? ? ? ? ?<> wrote:
>>? ? ? ? ?> See? ?/g/BITX20/topic/82011726
>>? ? ? ? ?</g/BITX20/topic/82011726>
>>? ? ? ? ?> </g/BITX20/topic/82011726
>>? ? ? ? ?</g/BITX20/topic/82011726>>
>>? ? ? ? ?>
>>? ? ? ? ?> On Tue, Jun 1, 2021 at 08:42 AM, allen west wrote:
>>? ? ? ? ?>
>>? ? ? ? ?>? ? ?I guess I have not been following as closely as I
>>? ? ? ? ?should.? But
>>? ? ? ? ?>? ? ?what is this sBITX?? When I joined this group it was for
>>? ? ? ? ?the BITX
>>? ? ? ? ?>? ? ?20, 40 or the uBITX. ?
>>? ? ? ? ?>? ? ??
>>? ? ? ? ?>
>>? ? ? ? ?>
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