[amsat-bb] Re John Heath G7HIA, SK
I was very saddened to learn of John's passing. We had exchanged many e-mails during the last few years. I didn't know John very well, although we had met at the ASAT-UK Colloquium on several occasions. Topics we discussed by e-mail included processing Delphi 3C telemetry, OSCAR-11 spin rate, automatic Doppler tracking and ARISSat-1 decay. John was very active in using our satellites and promoting their use to others. For several years he was net controller of the Midlands two metre AMSAT net. He also wrote the Space column for RSGB's RadCom magazine for a number of years. He contributed many articles to OSCAR News, recently in the September 2012 issue about ARISSat-1 orbital decay. His last contribution to OSCAR News was a short item in the December issue, congratulating AMSAT-UK on their 200th issue of the magazine. He included a photograph of himself, Astronaut Ron Parise WA4SIR and Geoff Perry, founder of the Kettering Group of satellite observers. It was taken at the 1998 Colloquium. During the course of our discussions John mentioned that he was having some unpleasant hospital treatment. He also told me about his working career, which I thought may be of interest. As a teenager he was interested in organic chemistry and went to work in industry, eventually in the RD department at Bakelite in Tyseley, Birmingham. In the 1960's/70's he worked on the phenolic resins used to make copper clad PCB material, and did the first industrial synthesis on nonyl phenol by ion exchange. There were massive world stocks of Nonene at knock down prices so they were looking for a way to use it to make phenol/formaldehyde resins used in PCB manufacture. His YL Pam at that time worked in a small hairdressing supplies business and he sometimes worked with her when they needed extra staff to cover late night opening. After his marriage to Pam, her firm decided to open a branch in Leicester and they were offered the opportunity to re-locate and run the new operation. Together they built up the business, diversifying into related activities with a skin care manufacturing company (where his science background was invaluable), a beauty products wholesale business and a mail order operation. The business expanded from 6 people to a staff of nearly 200 on four sites. John said that Amateur radio helped to keep him sane by giving him a totally different set of things to think about and emptied his head of business concerns for a few hours each week! A few years ago Pam was diagnosed with a serious illness and confined to a wheel chair. This caused them to bring forward their retirement plans and they moved to Devon. My condolences to Pam, family friends. RIP John, we will miss you. Clive Wallis G3CWV ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] QFHA for SO-50... polarization issue ???
This weekend I tested a Quadrifiliar Helicoidal Antenna for 70cm (LHCP) I designed it by the online calculations of jcoppens on the internet... It is a 1/2 turn and 1 lambda, about 5 meters of elevation with ~25 cm of RG-58U (a section of it is coiled to form a balum) and then ~15 meters of A.H. LDF4-50A down to the shack directly to the radio, of course BNC to N adapter on the antenna and N to PL259 on the radio side... It's at mast top. Results are good... In passes of over 20 degrees (almost the real horizon here) I have a good copy, until... TCA, in which I lost the signal completely... TCA = Time of Closest Approach. In northbound passes (I've not tested it in southbound) it work as I just said... I have been reading and investigating this strange issue and I think it is due to polarization... I had read that SO-50 is linear polarized on 2m AND 70cm with aprox 45 degrees each other... Then Linear to LHCP in the worst case is 3dB loss (half power) but consistent over the entire pass... or have SO-50 some circular/elliptical component in it's signals that renders useless the antenna after TCA? spin maybe? There is any chapter of the book I missed or other variable(s) that I have not taking into account here? Any comment, link or other kinds of help are welcomed.. 73 de CO7WT. ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: QFHA for SO-50... polarization issue ???
Ing. Pavel, There are a whole series of QFH antennas. 1/4,turn, 1/4 wavelength through 1 turn 1 Wavelength. Gain at the horizon is determined by the ratio of the axial length in fractions of a wave length. The best performance I have obtained is a 1 wavelength per side, 1 turn, for good gain at the horizon with an axial length of .65 wavelengths. You need the least gain at the Zenith as the satellite is closest in range at that point. The best reference I found is Resonant Quadrifilar Helix Design by C.C. Kilgus, December 1970 Issue, of the Microwave Journal, Pgs 49-54. 73, Art KC6UQH -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Ing. Pavel Milanes Costa Sent: Saturday, February 16, 2013 8:22 PM To: amsat-bb@amsat.org Subject: [amsat-bb] QFHA for SO-50... polarization issue ??? This weekend I tested a Quadrifiliar Helicoidal Antenna for 70cm (LHCP) I designed it by the online calculations of jcoppens on the internet... It is a 1/2 turn and 1 lambda, about 5 meters of elevation with ~25 cm of RG-58U (a section of it is coiled to form a balum) and then ~15 meters of A.H. LDF4-50A down to the shack directly to the radio, of course BNC to N adapter on the antenna and N to PL259 on the radio side... It's at mast top. Results are good... In passes of over 20 degrees (almost the real horizon here) I have a good copy, until... TCA, in which I lost the signal completely... TCA = Time of Closest Approach. In northbound passes (I've not tested it in southbound) it work as I just said... I have been reading and investigating this strange issue and I think it is due to polarization... I had read that SO-50 is linear polarized on 2m AND 70cm with aprox 45 degrees each other... Then Linear to LHCP in the worst case is 3dB loss (half power) but consistent over the entire pass... or have SO-50 some circular/elliptical component in it's signals that renders useless the antenna after TCA? spin maybe? There is any chapter of the book I missed or other variable(s) that I have not taking into account here? Any comment, link or other kinds of help are welcomed.. 73 de CO7WT. ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: QFHA for SO-50... polarization issue ???
Hi Pavel, The issue may not be the antenna - but SO-50. The antennas are linear - but the received signal strength can vary a lot if you have just RHCP or LHCP. During passes here in Copenhagen, Denmark I experience large differences in signal strength which can be counteracted by changing polarity from RHCP to LHCP during the pass. With large changes I mean from nothing to 59 signals. Hope that helps. 73 de OZ1MY/Ib -Oprindelig meddelelse- Fra: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] På vegne af Ing. Pavel Milanes Costa Sendt: 17 February 2013 05:22 Til: amsat-bb@amsat.org Emne: [amsat-bb] QFHA for SO-50... polarization issue ??? This weekend I tested a Quadrifiliar Helicoidal Antenna for 70cm (LHCP) I designed it by the online calculations of jcoppens on the internet... It is a 1/2 turn and 1 lambda, about 5 meters of elevation with ~25 cm of RG-58U (a section of it is coiled to form a balum) and then ~15 meters of A.H. LDF4-50A down to the shack directly to the radio, of course BNC to N adapter on the antenna and N to PL259 on the radio side... It's at mast top. Results are good... In passes of over 20 degrees (almost the real horizon here) I have a good copy, until... TCA, in which I lost the signal completely... TCA = Time of Closest Approach. In northbound passes (I've not tested it in southbound) it work as I just said... I have been reading and investigating this strange issue and I think it is due to polarization... I had read that SO-50 is linear polarized on 2m AND 70cm with aprox 45 degrees each other... Then Linear to LHCP in the worst case is 3dB loss (half power) but consistent over the entire pass... or have SO-50 some circular/elliptical component in it's signals that renders useless the antenna after TCA? spin maybe? There is any chapter of the book I missed or other variable(s) that I have not taking into account here? Any comment, link or other kinds of help are welcomed.. 73 de CO7WT. ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: QFHA for SO-50... polarization issue ???
Thanks to all for the reply to this thread... Conclusion is that I need RHCP LHCP switchable antennas... And my antenna is working good... but I'm reading an article Art send me to improve my knowledge about QFHA... 73 and Thanks to all. El 16/02/13 23:21, Ing. Pavel Milanes Costa escribió: This weekend I tested a Quadrifiliar Helicoidal Antenna for 70cm (LHCP) I designed it by the online calculations of jcoppens on the internet... It is a 1/2 turn and 1 lambda, about 5 meters of elevation with ~25 cm of RG-58U (a section of it is coiled to form a balum) and then ~15 meters of A.H. LDF4-50A down to the shack directly to the radio, of course BNC to N adapter on the antenna and N to PL259 on the radio side... It's at mast top. Results are good... In passes of over 20 degrees (almost the real horizon here) I have a good copy, until... TCA, in which I lost the signal completely... TCA = Time of Closest Approach. In northbound passes (I've not tested it in southbound) it work as I just said... I have been reading and investigating this strange issue and I think it is due to polarization... I had read that SO-50 is linear polarized on 2m AND 70cm with aprox 45 degrees each other... Then Linear to LHCP in the worst case is 3dB loss (half power) but consistent over the entire pass... or have SO-50 some circular/elliptical component in it's signals that renders useless the antenna after TCA? spin maybe? There is any chapter of the book I missed or other variable(s) that I have not taking into account here? Any comment, link or other kinds of help are welcomed.. 73 de CO7WT. ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Congratulations to Jim Adams, K0BAM
Thank you! I sent that photo in on a dare, what a shock it was to see me in QST! Jim Adams - K0BAM ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Congratulations to Jim Adams, K0BAM
I saw it too and meant to mention it, got ties up with Hamfest preparations. Always nice to a face to the call sign. 73 Rick Tejera (K7TEJ) Sagauro Astronomy Club www.saguaroastro.org Thunderbird Amatuer Radio Club www.w7tbc.org 30 Meter Digital Group # 5794 Feld Hell Club #3994 OMISS #8629 -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Jim Adams Sent: Monday, 18 February, 2013 16:10 To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Congratulations to Jim Adams, K0BAM Thank you! I sent that photo in on a dare, what a shock it was to see me in QST! Jim Adams - K0BAM ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: QFHA for SO-50... polarization issue ???
- Original Message - From: Ing. Pavel Milanes Costa pa...@conas.cu To: amsat-bb@amsat.org Sent: Monday, February 18, 2013 9:29 PM Subject: [amsat-bb] Re: QFHA for SO-50... polarization issue ??? Thanks to all for the reply to this thread... Conclusion is that I need RHCP LHCP switchable antennas... 73 and Thanks to all. 73 de CO7WT. Hi Pavel, CO7WT The QFHA is not a switchable antenna from RHCP to LHCP because RHCP is wound with turns conterclockwise and LHCP is wounded with turns clockwise just the reverse of the classic W8JK helical antenna. If you like RHCP and LHCP polarizations you need two separate antennas swichable with a coax relay. In a separate email I have sent to you the best original article on helix antennas written by Walter Maxell W2DU. More information on QFH antennas from W2DU are available here: http://w2du.com/ 73 de i8CVS Domenico ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
