开云体育

My son suggests "Try running Linux as a guest OS in VirtualBox (hosted on the Mac). I can’t make any promises, however.” 73 John F5VLF

Try changing R32 and R33 to 10k instead. You can leave C23 and C24 off for testing. By doubling the feedback resistors you are halving any OpAmp noise that loops back into V-. If this doesn't help

Without looking at the circuit, I would *guess* that the resistors were placed there to suppress any spurious oscillations. It's also a place to measure current flow in some circuits by measuring the

Well that was disappointing....... Instead of paralleling a second 10 ohm resister across each of R30 and R31, I went for broke and simply bridged them out of the circuit. As nearly as I could tell it

Here is the image I forgot to post.

Not having power issues any more. Waveform issues happen in HDSDR and other SDR programs when I try to view the Waterfall image. I receive the attached image constantly, no matter what frequency I

Sent: Wednesday, April 23, 2014 9:22 AM To: softrock40@... Subject: Re: [softrock40] Re: softrock40 Original Message ----- Subject: Re: [softrock40] Re: softrock40 John, Ah! I was thinking

What did you do that made things better? What do you mean by 'waveform issues'? Are you using an oscilloscope to observe a waveform? If you are using a line powered scope, make sure that it is plugged

I agree with you Alan. If I were changing anything I would do the op amp input resistors rather than the ones feeding the mixer. If I am reading the schematic correctly both are involved in setting

Original Message ----- Subject: Re: [softrock40] Re: softrock40 John, Ah! I was thinking of the other 10 ohm resistors in the op-amp inputs. But will the reasons for and effects of these resistors be

Here are some tests done by DG8SAQ with and without those resistors at the input to the mixer. http://dg8saq.darc.de/switchimpedance/index.shtml This from the above link: “Apparently, by bridging

Original Message ----- Subject: Re: [softrock40] Re: softrock40 The 10 ohm resistors have been discussed before. From memory I think you have covered all points:- 1) Prime purpose to swamp switch

Roger I replied to Milt before I read you post. Please take the measurement after pulling the USB plug to the receiver. This effectively removes the mixer and anything behind it from contributing to

Milt You may well be correct. And I think it is pretty simple to verify it. In a real use case, if the noise floor rises when the antenna is connected, then nothing in the receive chain is limiting

Warren & Milt, re. noise limit. I measured, with an oscilloscope, the noise level of my Ensemble II op amp output (with no antenna connected) as 0.4 mV peak to peak (with a 4.5 kHz passive audio LP

Milt, thank you for the info on the I/Q balance issue. I had not thought of that. When I said, rather hastily, that I thought the 10 ohm resistors were non-essential, I was thinking from the point of

On 4/22/2014 8:22 PM, tharlam@... wrote: > > > Hi Warren, > > Interesting re. changing gain of the op amps. If the Rx II MDS is limited by the noise floor of the op amps, then it is not clear to

VERY interesting observations Roger. I like your style! My tests so far do not indicate to me that the op amp noise is the limiting factor. I have found I hit the noise floor of the sound card first

Hi Warren, Interesting re. changing gain of the op amps. If the Rx II MDS is limited by the noise floor of the op amps, then it is not clear to me that changing the gain will affect this in a

Thanks for the confirmation Roger and for the research. It is comforting to know that my measurements are not off in left field as they sometimes are. The RXII with good software should not be