[hpsdr] Hpsdr Digest, Vol 160, Issue 5

[pa5bw]

Hi Scott,You correctly state that the ionosphere plus the earth's magnetic field split any wave enterig the ionsphere in a left-hand and a right-hand circularly polarized component. The advantage of a circularly pola about, but the fading reduction, especially in NVIS propagation.There most of the fading is caused by interference of the left-hand and right-hand circularly polarized waves, with minima of -35 dB. They will virually disappear when using circular polarization.You can find several scientific publication on this subject on my ResearchGate website (Ben Witvliet). 73, Ben PE5BSent from my Samsung Galaxy smartphone.
-------- Original message --------From: hpsdr-request at lists.openhpsdr.org Date: 14/06/2019  22:36  (GMT+01:00) To: hpsdr at lists.openhpsdr.org Subject: Hpsdr Digest, Vol 160, Issue 5 Send Hpsdr mailing list submissions to	hpsdr at lists.openhpsdr.orgTo subscribe or unsubscribe via the World Wide Web, visit	http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.orgor, via email, send a message with subject or body 'help' to	hpsdr-request at lists.openhpsdr.orgYou can reach the person managing the list at	hpsdr-owner at lists.openhpsdr.orgWhen replying, please edit your Subject line so it is more specificthan "Re: Contents of Hpsdr digest..."PLEASE change your subject line in any replies to this digest to reflect the actual subject!!!  Also please trim quotes of previous messages to a minimum necessary to maintain context. Remember: if you post using fancy rtf or html, it will not be read by Digest recipients without a big effort. We all thank you for this thoughtfullness.Today's Topics:   1. Scientific publication using HPSDR published (Erik van Maanen)   2. Re: Scientific publication using HPSDR published (Scott Traurig)----------------------------------------------------------------------Message: 1Date: Fri, 14 Jun 2019 13:36:39 +0200From: Erik van Maanen <pa3des at xs4all.nl>To: hpsdr at lists.openhpsdr.orgSubject: [hpsdr] Scientific publication using HPSDR publishedMessage-ID: <240e86e1-1d94-4584-26ae-b70d06c25f94 at xs4all.nl>Content-Type: text/plain; charset=utf-8; format=flowedDear all,Our scientific publication on NVIS research is just published in MDPI Sensors journal.We used a measurement system based on the ANAN200D and powersdr as well as a large amount of self developed hard and software.We specially like to thank Joe K5SO and Doug W5WC for their support and modifications of powersdr.(These modifications are now part of the normal powersdr release.)The publication is Open Source, freely downloadable for anyone, and can be found on:https://www.mdpi.com/1424-8220/19/11/2616Besides good reading material for the weekend we also hope it can be used as another example of the value of ham radio.73' Erik PA3DES and Ben PA5B------------------------------Message: 2Date: Fri, 14 Jun 2019 16:29:11 -0400From: Scott Traurig <scott.traurig at gmail.com>To: hpsdr <hpsdr at lists.openhpsdr.org>Subject: Re: [hpsdr] Scientific publication using HPSDR publishedMessage-ID:	<CAGK9zXpZQFvtH97ioTC53_XMWK6GeAVDOBnQ2vDx=OeB+pDNpw at mail.gmail.com>Content-Type: text/plain; charset="utf-8"It's probably worth mentioning that if you build an HF turnstile antenna(two crossed dipoles or inverted V's) there are no modifications requiredto PowerSDR or Thetis to use them as a circularly polarized array onreceive. Just feed each dipole to RX1 (ADC0) and RX2 (ADC1) with equallength coaxial cable of the same type. Then use the "Diversity" function toinvoke a positive or negative 90 degree phase difference with unity gain.You'll get either left or right hand circular polarization. I've alwayswanted to try this, but I do not have a way to put up the required antennas.Of course you'll have to choose one antenna or the other for transmit. Oryou could build a 90 degree phasing harness and do it the old school waybut the phasing harness will only be correct at a single frequency.This applies to more than just NVIS. All signals reflected off of theionosphere become circularly polarized. If you can match your polarizationyou can avoid the polarization loss from circular to linear. However atworst that is only 3dB in theory.73,ScottOn Fri, Jun 14, 2019 at 7:36 AM Erik van Maanen <pa3des at xs4all.nl> wrote:> Our scientific publication on NVIS research is just published in MDPI> Sensors journal.> We used a measurement system based on the ANAN200D and powersdr as well> as a large amount of self developed hard and software.> We specially like to thank Joe K5SO and Doug W5WC for their support and> modifications of powersdr.> (These modifications are now part of the normal powersdr release.)>> The publication is Open Source, freely downloadable for anyone, and can> be found on:> https://www.mdpi.com/1424-8220/19/11/2616> Besides good reading material for the weekend we also hope it can be> used as another example of the value of ham radio.>> 73' Erik PA3DES and Ben PA5B>>-------------- next part --------------An HTML attachment was scrubbed...URL: <http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/attachments/20190614/7809a2e1/attachment-0001.html>------------------------------Subject: Digest Footer_______________________________________________HPSDR Discussion ListTo post msg: hpsdr at openhpsdr.orgSubscription help: http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.orgHPSDR web page: http://openhpsdr.orgArchives: http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/------------------------------End of Hpsdr Digest, Vol 160, Issue 5*************************************
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