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Long leads a problem?
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Reading the "Wire Up" manual, it says to Keep all the leads short. I am wondering if anyone has had any problems having the leads as long as they come.? I am planning on only keeping the leads long of the raduino because I will have a enclosure that has front panel with hinges. Everything else will be kept relatively short. |
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Simon Thompson
I am curious about this, as well. On Fri, Mar 24, 2017 at 9:31 AM Daniel Acevedo <dan.ace86@...> wrote:
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As a general rule, with unshielded wires, twist them. In particular, the RF leads on the back, and do keep those short. Dress leads close to the chassis if possible, and use small zip ties to tie things. down. As for unused wire, just use a small sharp object and release the pin in the plug. Save them for later modifications.
73 /paul W3FIS |
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Will probably work ok with longer leads, but with increasing issues such as birdies due to vfo harmonics mixing with the bfo, perhaps rf getting into the volume pot leads causing speaker noises when you transmit, perhaps clicks as you change frequency. ?Maybe even a 50hz jump in frequency when you press the PTT key. ?Hard to predict. The wire pair from Raduino to DDS connector on the Bitx40 would be my first concern. ?At least twist them together, better would be to replace that wire pair with some skinny flexible coax (50 or 75 ohms). ?Also twist or use coax for the antenna connector. ?Other connectors (two power connectors, speaker, ptt, mike, volume control center pin to ground) might want 0.01uF (or 0.1uF?) RF bypass caps. ?If you try any of this stuff and find it helps, do report back. ?The WireUp section recommends adding that 0.1uF cap across the tuning pot from center to ground, I'd recommend another such cap at the far end of those two tuning cap wires soldered directly to the Raduino pins. ? I've kept my leads fairly short, twisted the antenna and DDS wire pairs, added a tuning pot cap at the Raduino. ?Good enough for me. Jerry, KE7ER On Fri, Mar 24, 2017 at 09:31 am, Daniel Acevedo wrote:
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College Professor Simon Thompson
¿ªÔÆÌåÓýI will definitely use coax for the antenna connector and the DDS pair.
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I plan on keeping the speaker, power, antenna (will use rg-174), and tuning wires as short as I can. The longest part I suppose would be the volume and DDS connector because those would be on the lid of my enclosure. When I fully open the lid where my raduino is, it would obviously have to have leads long enough to open.
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RG174 for the DDS too.? And use an old audio shielded cable from a PC CD drive for audio runs. The only unshielded wiring in mine is power.? Those are twisted.? Removing the excess unneeded wiring made a nice improvement for me.? I have mine in a plastic project box with an aluminum top, the radio plus raduino, a tight but usable fit.? And I removed the backlight display, replaced with non- saving 70 mA. Larry KB3CUF On Fri, Mar 24, 2017 at 2:43 PM, Daniel Acevedo <dan.ace86@...> wrote: I plan on keeping the speaker, power, antenna (will use rg-174), and tuning wires as short as I can. The longest part I suppose would be the volume and DDS connector because those would be on the lid of my enclosure. When I fully open the lid where my raduino is, it would obviously have to have leads long enough to open. |
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In what way did it improve? On Fri, Mar 24, 2017 at 11:53 am, Larry Acklin wrote:
Removing the excess unneeded wiring made a nice improvement for me.? ? |
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On Fri, Mar 24, 2017 at 12:43 pm, Michael Davis wrote:
I get a birdie when receiving exactly on 7200. What might this be from? ? |
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I had a reduction in minor birdies and overall switching noises from the Raduino.? I get the same birdie from a completely different VFO also based on an Arduino chip, and SI 5351. And another receiver board not even close in design- ?I think the 7.2 bird is from the Arduino/SI5351 combo.? On Fri, Mar 24, 2017 at 4:04 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
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