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n6gn

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n6gn
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  • That's why I chose APRS as the data channel. It stays up when the Kiwi system is down, has built-in worldwide distribution and can be done with cheap hardware within amateur radio. With the Arduino as controller a whole host of sensors are similarly…
  • The family of lines in 6.5-7 MHz you suggest seem to me to be power line related, though this is true of many SMPS noise sources. When I detect in 10 kHz AM and analyze with Audacity I see astrong 50 Hz family/component http://forum.kiwisdr.com/uplo…
  • I designed and built an APRS/solar_charger for monitoring the PS at a remote KiWi site. It's not quite what you are asking for but since the Kiwi data is IP over microwave, the use of out-of-band monitoring means I can see the power situation and te…
  • In spite of the low end roll-off, I do see lines in MW that might be explained by an SMPS at ~20 kHz (bipolar transistors?) with rather wide spectral lines. By 1.6 MHz these lines are all merged and the coherence isn't as obvious but if one listens…
  • I just run multiple tabs in a single browser, one tab/kiwi-receiver. That allows separate audio, squelch ... for each of the receivers. It's sometimes useful to do this on kiwis that differently located and experience varying and different propaga…
  • Presuming I have the correct K7GFH-associated Kiwi, at 1450 UTC you really aren't doing too badly. While I do hear a mains-related family of QRN from LF half way into HF, the levels aren't that terrible. Using the 10 kHz AM detector to allow heari…
  • I think a more accurate UI could improve performance too. As an example, the last time my remote KiwiSDR returned to the site, antenna parameters were adjusted based on the OV indication with 1 event per 64K samples selected. This resulted in fair…
  • @jks I think we're dealing with it by using the 2x.5A available from the (dual output) TPS2051 sourcing the USB-A connector. Rob has built a Y cable so he could get data from the microUSB-client connector but power from the USB-A. It may be that th…
    in usbnet Comment by n6gn December 2020
  • Rob,AI6VN, and I have looked at using Kiwi/BB in a "power-over-USB" manner in order to hopefully reduce ground loops and noise with a single OpenWRT WiFi router. While Rob has been using it with the KiWi/BB as client, using the microUSB …
    in usbnet Comment by n6gn December 2020
  • When chasing low impedances or shorts on a board like this, before the most drastic steps I often use a current-limited supply set to something reasonable such as perhaps only a few hundred mA, and then use a millivoltmeter across PC traces to follo…
  • I gathered remote off-Internet data again today and this time remembered to try out the Kiwi's WSPR extension with the new GPS additions. It appears to work correctly in the absence of any (functioning) RTC. Only a GPS antenna is required to pro…
  • Last night I took my portable wpsrdaemon/RPI3/Kiwi system with v1.412 out to a semi-remote site and collected WSPR and noise data. Previously (without GPS) it had been necessary to set the Kiwi clock so that WSPR spots would be nearly the correct f…
  • Thanks John. I like the aperture mode selection and the ability to better use the spectrum to convey larger dynamic range. I think it can do everything I want. Colormap Designer, on the other hand, does more than I'm capable of easily handling!…
  • From your description, it sounds to me like the SDR PCB has a very low resistance path to ground and is pulling too much current such that the BBG sourcing it goes into current-limit. When the SDR is unplugged from the BBG what resistance do you me…
  • @la6lu that made me smile... I too had problems with the factory fan and replaced several with Clint's suggestion https://www.alltronics.com//cgi-bin/item/28F082/search/Sunon-5V-Fan-Size--30mm-x-30mm-x-6mm- I've now replaced four fans with this a…
  • I think it might be very profitable to investigate for the presence of common mode noise current from the new router, over the LAN cable, through the Kiwi and out the "other side" where "other side" is the SMA connector to antenn…
  • I concur with @njc. It turns out to be pretty difficult to get high coupling between two antennas. period. In the near-field not all the energy is available. In the far-field, apertures don't permit high transfer. I once tried (at low microwave) t…
  • Be careful that their "Advanced Security" (https://internet.xfinity.com/connect) is not enabled. It ends up blacklisting multiple sites that are necessary! Everything quit for me when I enabled it and it took a while to figure out how &quo…
  • I think your ceiling/floor slider could go a long way to adjusting a WF the way I typically do. I almost automatically hit 'shift W' about 6 times every time I auto scale. Sometimes I also bring the maximum down 10-30 dB as well but it's the dark b…
  • I think you were interested in the time constant. Here's what I measure for a falling/rising edge of a longish, very square S9 pulse in AM, 10 kHz bw, X axis is seconds (Image) It looks like things are tailing for a few ten's of ms, not certain th…
    in AGC control Comment by n6gn August 2020
  • fbx wrote "Doing so, the min would become closer to the noise floor, and would not require manual tweaking with the slider, and the max would always fit the spectrum view." Should this not be "... farther from the noise floor...&quo…
  • risking some thread drift, I might add that it can be very revealing to process a sample of wideband AM or IQ from a section of spectrum that appears to be 'white' noise, yet elevated above ITU values - which is the case for many if not the vast maj…
  • wsprdaemon is a nice way to get this same information over an entire day. It also plots noise by band which gives even more insight into noise time and other characteristics. Because there are two algorithms, even more information is possible than …
  • I was suggesting a terminated noise test, apart from external antenna or CM on the transmission line. Stock Kiwis tend to have a mid-HF bump while I didn't see that on the BBAI. I slightly suspect it will be pretty good and certainly not an issue i…
  • Thanks for posting. It does make one wonder how it might work were the intervening sheet Copper and perhaps thicker and even lower thermal resistance. Also what would happen if thermal padding were placed between the components or ground plane on e…
  • I agree it's probably not casual listening to USAF Global Comms, I had someone with an IP address associated with St. Petersburg on my Kiwi for some time, repeatedly relogging on when booted. I like Clint's idea...
  • Here's a plot of the two 21m steps in Latitude with the Kalman filter turned off midway between the moves.(Image)
  • Inexpensive GPS receivers do work fine and would perhaps be better for small-area surveying. However I'm now thinking that using a geostationary satellite to provide location data across a typical residence-sized yard is probably not the best way to…
  • Since reporting my experience with administrative GPS access which John kindly added to the kiwiSDR's capabilities, I feel I need to provide an update based on further investigation. With help from G3ZIL it is now clear that the apparent high preci…