- AMSAT-BB - mailman.amsat.org

Re: Leo Pack issue
by Jim_WØNBC 27 Dec '22

27 Dec '22

A friend had an issue also and he said the phasing cable were marked wrong. Not sure if that is your issue. Jim, W0NBC. Sent from Yahoo Mail for iPhone On Tuesday, December 27, 2022, 10:59 AM, markemorris via AMSAT-BB <amsat-bb(a)amsat.org> wrote: Hello All, I recently assembled and mounted M2 LEO-Pack antenna system. Problem: The 2 meter SWR was impacted significantly "after" the antenna was mounted to the boom and phasing lines, coax, and peripheral wiring was secured. (The 70 centimeter side was not impacted.) I'm confident that adjustments to the shorting bars will bring the antenna back into resonance. Question: What's the best way to make the adjustments and perform the tests? Obviously I have both horizontal and vertical entities to adjust. Is there a sequence that I should follow? Any input is greatly appreciated. Warm wishes for a safe and healthy holiday season. Kind Regards best 73sMark Morris N3NJ ----------------------------------------------------------- Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/ View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org

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Leo Pack issue
by markemorris 27 Dec '22

27 Dec '22

Hello All,I recently assembled and mounted M2 LEO-Pack antenna system. Problem: The 2 meter SWR was impacted significantly "after" the antenna was mounted to the boom and phasing lines, coax, and peripheral wiring was secured. (The 70 centimeter side was not impacted.)I'm confident that adjustments to the shorting bars will bring the antenna back into resonance. Question: What's the best way to make the adjustments and perform the tests? Obviously I have both horizontal and vertical entities to adjust. Is there a sequence that I should follow? Any input is greatly appreciated. Warm wishes for a safe and healthy holiday season. Kind Regards best 73sMark Morris N3NJ

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Upcoming ARISS Contact Schedule as of 2022-12-27 16:30 UTC
by aj9n＠aol.com 27 Dec '22

27 Dec '22

Upcoming ARISS Contact Schedule as of 2022-12-27 16:30 UTC Quick list of scheduled contacts and events: TBD The crossband repeater continues to be active. If any crewmember is so inclined, all they have to do is pick up the microphone, raise the volume up, and talk on the crossband repeater. So give a listen, you just never know. ####################################################################################################################################### Comments on making general contacts I have been seeing a lot of traffic on Facebook and I suspect on other social media sites with people asking why they are not hearing the crew make general contacts. First off the crew is very busy on the ISS and they simply may not have the time to just pick up the microphone and talk. Also, one needs to be aware of their normal daily schedule. I have listed below the constraints that we at ARISS have to follow in order to schedule the school contacts. Hopefully this will help you better schedule your opportunities. Typical daily schedule Wakeup to Workday start= 1.5 hours Workday start to Workday end=12 hours Workday end to Sleep= 2 hours Sleep to wakeup= 8.5 hours The crew's usual waking period is 0730 - 1930 UTC. The most common times to find a crew member making casual periods are about one hour after waking and before sleeping, when they have personal time. They're usually free most of the weekend, as well. SSTV events are not that often. So please check out https://www.ariss.org/ for the latest information or watch for the ARISS announcements. And don’t forget that the packet system is active. As always, if there is an EVA, a docking, or an undocking; the ARISS radios are turned off as part of the safety protocol. The latest information on the operation mode can be found at https://www.ariss.org/current-status-of-iss-stations.html The latest list of frequencies in use can be found at https://www.ariss.org/contact-the-iss.html ######################################################################################################################################## A multi-point telebridge contact means that each student will be on the telebridge from their own home. **************************************************************************************************************************************** ARISS is very aware of the impact that COVID-19 is having on schools and the public in general. As such, we may have last minute cancellations or postponements of school contacts. As always, I will try to provide everyone with near-real-time updates. Watch for future COVID-19 related announcements at https://www.ariss.org/ The following schools have now been postponed or cancelled due to COVID-19: Postponed: No new schools Cancelled: No new schools **************************************************************************************************************************************** Note, all times are approximate. It is recommended that you do your own orbital prediction or start listening about 10 minutes before the listed time. All dates and times listed follow International Standard ISO 8601 date and time format YYYY-MM-DD HH:MM:SS The complete schedule page has been updated as of 2022-12-27 16:30 UTC. (***) Here you will find a listing of all scheduled school contacts, and questions, other ISS related websites, IRLP and Echolink websites, and instructions for any contact that may be streamed live. https://www.amsat.org/amsat/ariss/news/arissnews.rtf https://www.amsat.org/amsat/ariss/news/arissnews.txt The successful school list has been updated as of 2022-12-17 02:00 UTC. https://www.amsat.org/amsat/ariss/news/Successful_ARISS_schools.rtf The ARISS webpage is at https://www.ariss.org/ Note that there are links to other ARISS websites from this site. The main page for Applying to Host a Scheduled Contact may be found at https://www.ariss.org/apply-to-host-an-ariss-contact.html +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ARISS Contact Applications (United States) Call for Proposals The proposal window for US schools and educational organizations to host an Amateur Radio contact with a crew member on board the ISS for contacts to be scheduled for July 1, 2023 – December 31, 2023 has closed. Watch for the next opportunity for proposals for the first half of 2024 sometime in the springtime period of 2023. (***) Please direct any questions to ariss.us.education(a)gmail.com. For future proposal information and more details such as expectations, proposal guidelines and proposal form, and dates and times of Information Webinars, go to www.ariss.org. About ARISS: Amateur Radio on the International Space Station (ARISS) is a cooperative venture of international amateur radio societies and the space agencies that support the International Space Station (ISS). In the United States, sponsors are the Radio Amateur Satellite Corporation (AMSAT), the American Radio Relay League (ARRL), the ISS National Lab and National Aeronautics and Space Administration (NASA). The primary goal of ARISS is to promote exploration of science, technology, engineering, and mathematics (STEAM) topics by organizing scheduled contacts via amateur radio between crew members aboard the ISS and students in classrooms or public forms. Before and during these radio contacts, students, educators, parents, and communities learn about space, space technologies, and amateur radio. For more information, see www.ariss.org. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ARISS Contact Applications (Europe, Africa and the Middle East) Schools and Youth organizations in Europe, Africa and the Middle East interested in setting up an ARISS radio contact with an astronaut on board the International Space Station are invited to submit an application from September to October and from February to April. Please refer to details and the application form at www.ariss-eu.org/school-contacts. Applications should be addressed by email to: school.selection.manager(a)ariss-eu.org ARISS Contact Applications (Canada, Central and South America, Asia and Australia and Russia) +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Organizations outside the United States can apply for an ARISS contact by filling out an application. Please direct questions to the appropriate regional representative listed below. If your country is not specifically listed, send your questions to the nearest ARISS Region listed. If you are unsure which address to use, please send your question to the ARISS-Canada representative; they will forward your question to the appropriate coordinator. For the application, go to: https://www.ariss.org/ariss-application.html. ARISS-Canada and the Americas, except USA: Steve McFarlane, VE3TBD email to: ve3tbd(a)gmail.com ARISS-Japan, Asia, Pacific and Australia: Satoshi Yasuda, 7M3TJZ email to: ariss(a)iaru-r3.org, Japan Amateur Radio League (JARL) https://www.jarl.org/ ARISS-Russia: Soyuz Radioljubitelei Rossii (SRR) https://srr.ru/ +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ARISS is always glad to receive listener reports for the above contacts. ARISS thanks everyone in advance for their assistance. Feel free to send your reports to aj9n(a)amsat.org or aj9n(a)aol.com. Listen for the ISS on the downlink of 145.8Ø MHz unless otherwise noted. ******************************************************************************* All ARISS contacts are made via the Kenwood radio unless otherwise noted. ******************************************************************************* Several of you have sent me emails asking about the RAC ARISS website and not being able to get in. That has now been changed to https://www.ariss.org/ Note that there are links to other ARISS websites from this site. **************************************************************************** Looking for something new to do? How about receiving DATV from the ISS? Please note that the HamTV system has been brought back to earth for troubleshooting. Please monitor ARISS-EU or ARISS-ON for the very latest news on the troubleshooting efforts. If interested, then please go to the ARISS-EU website for complete details. Look for the buttons indicating Ham Video. http://www.ariss-eu.org/ If you need some assistance, ARISS mentor Kerry N6IZW, might be able to provide some insight. Contact Kerry at kbanke(a)sbcglobal.net The HamTV webpage: https://www.amsat-on.be/hamtv-summary/ **************************************************************************** ARISS congratulates the following mentors who have now mentored over 100 schools: Sergey RV3DR with 193 Francesco IKØWGF with 149 Satoshi 7M3TJZ with 148 Gaston ON4WF with 124 Peter IN3GHZ with 115 Steve VE3TBD with 103 **************************************************************************** The webpages listed below were all reviewed for accuracy. Out of date webpages were removed, and new ones have been added. If there are additional ARISS websites I need to know about, please let me know. Total number of ARISS ISS to earth school events is 1596. Each school counts as 1 event. Total number of ARISS ISS to earth school contacts is 1505. Each contact may have multiple schools sharing the same time slot. Total number of ARISS supported terrestrial contacts is 48. Please feel free to contact me if more detailed statistics are needed. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ The following US states and entities have never had an ARISS contact: South Dakota, American Samoa, Guam, Northern Marianas Islands, and the Virgin Islands. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ QSL information may be found at: https://www.ariss.org/qsl-cards.html ISS callsigns: DPØISS, FXØISS, GB1SS, IRØISS, NA1SS, OR4ISS, RSØISS **************************************************************************** Frequency chart for packet, voice, and crossband repeater modes showing Doppler correction as of 2005-07-29 04:00 UTC https://www.amsat.org/amsat/ariss/news/ISS_frequencies_and_Doppler_correcti… Check out the Zoho reports of the ARISS contacts https://reports.zoho.com/ZDBDataSheetView.cc?DBID=412218000000020415 **************************************************************************** Exp. 68 on orbit Sergey Prokopyev Francisco Rubio Dimitri Petelin SpaceX Crew-5 on orbit Josh Cassada KI5CRH Nicole Mann Anna Kikina Koichi Wakata KI5TMN **************************************************************************** 73, Charlie Sufana AJ9N One of the ARISS operation team mentors

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ANS-361 AMSAT News Service Special Bulletin - W2RS Memorial AMSAT CW Activity Day to be Held January 1st
by Paul Stoetzer 27 Dec '22

27 Dec '22

AMSAT NEWS SERVICE SPECIAL BULLETIN ANS-361 The AMSAT News Service bulletins are a free, weekly news and information service of AMSAT, The Radio Amateur Satellite Corporation. ANS publishes news related to Amateur Radio in Space including reports on the activities of a worldwide group of Amateur Radio operators who share an active interest in designing, building, launching and communicating through analog and digital Amateur Radio satellites. The news feed on http://www.amsat.org publishes news of Amateur Radio in Space as soon as our volunteers can post it. Please send any amateur satellite news or reports to: ans-editor at amsat.org. You can sign up for free e-mail delivery of the AMSAT News Service Bulletins via the ANS List; to join this list see: https://mailman.amsat.org/postorius/lists/ans.amsat.org/ In this edition: * W2RS Memorial AMSAT CW Activity Day to be Held January 1st SB SAT @ AMSAT $ANS-361.01 ANS-361 AMSAT News Service Special Bulletin AMSAT News Service Bulletin 348.01 From AMSAT HQ WASHINGTON, DC DATE December 27, 2022 To All RADIO AMATEURS BID: $ANS-361.01 W2RS Memorial AMSAT CW Activity Day to be Held January 1st In March 2022, the AMSAT community lost one of our pioneers when Ray Soifer, W2RS, became a silent key. In addition to his numerous contributions to AMSAT and the worldwide amateur satellite community, Ray was also the long time organizer of AMSAT's CW Activity Day - previously AMSAT Straight Key Night - held in conjunction with the ARRL's event on New Year's Day. In recognition of Ray's long time service to AMSAT and his keen interest in CW operating via satellite, AMSAT is pleased to announce that AMSAT's CW Activity Day will now be known as the W2RS Memorial AMSAT CW Activity Day in Ray's honor. The rules are simple - operate CW through any amateur satellite between 0000 UTC and 2359 UTC on January 1, 2023. Straight keys and bugs are encouraged, but not required. Logs are not required, but operators are encouraged to submit a report of their activity to the AMSAT-BB. Photos and video clips of activity are also encouraged - post them on Twitter and tag @AMSAT. Remember to use the minimum power required for communication as constant carrier modes, including CW, can disrupt transponder operation for other users. [ANS thanks AMSAT for the above information] /EX In addition to regular membership, AMSAT offers membership in the President's Club. Members of the President's Club, as sustaining donors to AMSAT Project Funds, will be eligible to receive additional benefits. President's Club donations may be made at https://tinyurl.com/ANS-PresClub. Primary and secondary school students are eligible for membership at one-half the standard yearly rate. Post-secondary school students enrolled in at least half time status shall be eligible for the student rate for a maximum of 6 post-secondary years in this status. Join AMSAT today at https://launch.amsat.org/ 73 and remember to help Keep Amateur Radio in Space, This week's ANS Contributing Editor, Paul Stoetzer, N8HM n8hm at amsat dot org

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Re: UHF preamps
by crohtun＠aol.com 27 Dec '22

27 Dec '22

I have two of the SSB preamps — one at home and one strapped to the portable tripod and they’re really solid. Using an IC 9700, they can be turned on and off from the radio. When on, they tx/rx switch just fine and they can handle anything the 9700 might throw at them on tx. Ray KN2K Sent from the all new AOL app for iOS On Tuesday, December 27, 2022, 8:51 AM, Don Solberg via AMSAT-BB <amsat-bb(a)amsat.org> wrote: Another really good preamp is made by SSB Electronics and sold by HRO https://www.hamradio.com/detail.cfm?pid=H0-016832 I have used this one for well over a year. 73, Don K9AQ On Tue, Dec 27, 2022 at 4:28 AM J. Hunt via AMSAT-BB <amsat-bb(a)amsat.org> wrote: Hi Tom, Beko Elektronik, represented by Island Amplifiers has your answer(s) with a complete remote 440mhz preamp with internal T/R by-pass relay. https://islandamplifier.com/ https://www.beko-elektronik.de Another source is Down East Microwave https://www.downeastmicrowave.com/ Best of knowledge, neither had a 1296 (23cm) complete remote pre-amp with internal T/R by-pass relay.With my engineering background, I made a 600 watt model. Works great on the weak signal / tropo scatter. Thanks n 73,JamesKI5DQ On Monday, December 26, 2022 at 11:04:54 PM CST, Zach Metzinger via AMSAT-BB <amsat-bb(a)amsat.org> wrote: On 12/26/22 22:31, tjschuessler--- via AMSAT-BB wrote: > I do have a question for Yaesu FT847 users. With that radio, you can > power a Preamp via the built in Bia- T power inserter, And assume > that when this mode is turned on, it cuts the inserted DC to the > preamp as the tranciever goes into transmit. Does this work fast > enough to protect, even RF switched preamps? That might be a good > safety measure as I have traditionally used external DC to power my > preamps. I have a homebrew UHF LNA that initially suffered the same fate as yours before it was modified with protective PIN diodes on the output. I am powering the relays which switch from "inline" (during RX) to "bypass" (during TX) with the FT-847's bias-tee function. I found that the relays might not be quite fast enough to avoid getting a significant RF pulse back into the LNA output. This was most pronounced with CW, while SSB was tolerated better -- probably because I waited a moment to speak after pressing the PTT. In a previous posting, I wrote: > http://www.n0zgo.net/lna/70cm/max2640/70cm_lna_max2640_annotated.jpg > > (The BAR64 PIN diodes were added to protect the MAR3-SM+ output gain > block when transmitting. Without those, the MAR3 was dead within a > few minutes of use at >10W TX.) You might try putting some of those PIN diodes into your unit. It might just keep it from going up in smoke. --- Zach N0ZGO ----------------------------------------------------------- Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/ View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org ----------------------------------------------------------- Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/ View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org ----------------------------------------------------------- Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/ View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org

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Re: UHF preamps
by Don Solberg 27 Dec '22

27 Dec '22

Another really good preamp is made by SSB Electronics and sold by HRO https://www.hamradio.com/detail.cfm?pid=H0-016832 I have used this one for well over a year. 73, Don K9AQ On Tue, Dec 27, 2022 at 4:28 AM J. Hunt via AMSAT-BB <amsat-bb(a)amsat.org> wrote: > > Hi Tom, > > Beko Elektronik, represented by Island Amplifiers has your answer(s) with > a complete remote 440mhz preamp with internal T/R by-pass relay. > https://islandamplifier.com/ > > https://www.beko-elektronik.de > > > Another source is Down East Microwave > https://www.downeastmicrowave.com/ > > Best of knowledge, neither had a 1296 (23cm) complete remote pre-amp with > internal T/R by-pass relay. > With my engineering background, I made a 600 watt model. Works great on > the weak signal / tropo scatter. > > Thanks n 73, > James > KI5DQ > On Monday, December 26, 2022 at 11:04:54 PM CST, Zach Metzinger via > AMSAT-BB <amsat-bb(a)amsat.org> wrote: > > > On 12/26/22 22:31, tjschuessler--- via AMSAT-BB wrote: > > > I do have a question for Yaesu FT847 users. With that radio, you can > > power a Preamp via the built in Bia- T power inserter, And assume > > that when this mode is turned on, it cuts the inserted DC to the > > preamp as the tranciever goes into transmit. Does this work fast > > enough to protect, even RF switched preamps? That might be a good > > safety measure as I have traditionally used external DC to power my > > preamps. > > I have a homebrew UHF LNA that initially suffered the same fate as yours > before it was modified with protective PIN diodes on the output. > > I am powering the relays which switch from "inline" (during RX) to > "bypass" (during TX) with the FT-847's bias-tee function. I found that > the relays might not be quite fast enough to avoid getting a significant > RF pulse back into the LNA output. This was most pronounced with CW, > while SSB was tolerated better -- probably because I waited a moment to > speak after pressing the PTT. > > In a previous posting, I wrote: > > > http://www.n0zgo.net/lna/70cm/max2640/70cm_lna_max2640_annotated.jpg > > > > (The BAR64 PIN diodes were added to protect the MAR3-SM+ output gain > > block when transmitting. Without those, the MAR3 was dead within a > > few minutes of use at >10W TX.) > > You might try putting some of those PIN diodes into your unit. It might > just keep it from going up in smoke. > > --- Zach > N0ZGO > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available > to all interested persons worldwide without requiring membership. Opinions > expressed > are solely those of the author, and do not reflect the official views of > AMSAT-NA. > Acceptable Use and Privacy Policies available at > https://www.amsat.org/about-amsat/ > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/[email protected] > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org > > ----------------------------------------------------------- > > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available > to all interested persons worldwide without requiring membership. Opinions > expressed > are solely those of the author, and do not reflect the official views of > AMSAT-NA. > Acceptable Use and Privacy Policies available at > https://www.amsat.org/about-amsat/ > > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/[email protected] > To unsubscribe send an email to amsat-bb-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org

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Re: UHF preamps
by J. Hunt 27 Dec '22

27 Dec '22

Hi Tom, Beko Elektronik, represented by Island Amplifiers has your answer(s) with a complete remote 440mhz preamp with internal T/R by-pass relay. https://islandamplifier.com/ https://www.beko-elektronik.de Another source is Down East Microwave https://www.downeastmicrowave.com/ Best of knowledge, neither had a 1296 (23cm) complete remote pre-amp with internal T/R by-pass relay.With my engineering background, I made a 600 watt model. Works great on the weak signal / tropo scatter. Thanks n 73,JamesKI5DQ On Monday, December 26, 2022 at 11:04:54 PM CST, Zach Metzinger via AMSAT-BB <amsat-bb(a)amsat.org> wrote: On 12/26/22 22:31, tjschuessler--- via AMSAT-BB wrote: > I do have a question for Yaesu FT847 users. With that radio, you can > power a Preamp via the built in Bia- T power inserter, And assume > that when this mode is turned on, it cuts the inserted DC to the > preamp as the tranciever goes into transmit. Does this work fast > enough to protect, even RF switched preamps? That might be a good > safety measure as I have traditionally used external DC to power my > preamps. I have a homebrew UHF LNA that initially suffered the same fate as yours before it was modified with protective PIN diodes on the output. I am powering the relays which switch from "inline" (during RX) to "bypass" (during TX) with the FT-847's bias-tee function. I found that the relays might not be quite fast enough to avoid getting a significant RF pulse back into the LNA output. This was most pronounced with CW, while SSB was tolerated better -- probably because I waited a moment to speak after pressing the PTT. In a previous posting, I wrote: > http://www.n0zgo.net/lna/70cm/max2640/70cm_lna_max2640_annotated.jpg > > (The BAR64 PIN diodes were added to protect the MAR3-SM+ output gain > block when transmitting. Without those, the MAR3 was dead within a > few minutes of use at >10W TX.) You might try putting some of those PIN diodes into your unit. It might just keep it from going up in smoke. --- Zach N0ZGO ----------------------------------------------------------- Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/ View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org

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Re: UHF preamps
by Zach Metzinger 27 Dec '22

27 Dec '22

On 12/26/22 22:31, tjschuessler--- via AMSAT-BB wrote: > I do have a question for Yaesu FT847 users. With that radio, you can > power a Preamp via the built in Bia- T power inserter, And assume > that when this mode is turned on, it cuts the inserted DC to the > preamp as the tranciever goes into transmit. Does this work fast > enough to protect, even RF switched preamps? That might be a good > safety measure as I have traditionally used external DC to power my > preamps. I have a homebrew UHF LNA that initially suffered the same fate as yours before it was modified with protective PIN diodes on the output. I am powering the relays which switch from "inline" (during RX) to "bypass" (during TX) with the FT-847's bias-tee function. I found that the relays might not be quite fast enough to avoid getting a significant RF pulse back into the LNA output. This was most pronounced with CW, while SSB was tolerated better -- probably because I waited a moment to speak after pressing the PTT. In a previous posting, I wrote: > http://www.n0zgo.net/lna/70cm/max2640/70cm_lna_max2640_annotated.jpg > > (The BAR64 PIN diodes were added to protect the MAR3-SM+ output gain > block when transmitting. Without those, the MAR3 was dead within a > few minutes of use at >10W TX.) You might try putting some of those PIN diodes into your unit. It might just keep it from going up in smoke. --- Zach N0ZGO

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UHF preamps
by tjschuessler＠verizon.net 27 Dec '22

27 Dec '22

For my portable/temporary satellite antenna rig, I have need of using a UHF preamp, which I have strapped to the tripod that holds and aims my Arrow antenna. I find that my FT847 is just not as sensitive on 70 CM as it is on 2M. I have been using an ARR (Advanced Receiver Research ) SP432VDG which is supposed to have a maximum power pass through imitation of 25watts. I try to be pretty careful as to how much output I run through the thing, maybe limiting to 15 watts or so. Unfortunately, I have blown the preamp out several times, even with being conscious of the RF level. I sent the pre to them, they repaired and sent back. I recently discovered that I had blown my unit again. Symptom is that it adds noise to the output, but does not amplify any signals coming into it from the antenna. I have sent the unit in to ARR in the past for repair. This time I am contemplating replacing this one with a more robust device that might be able to handle more RF running through it (RF sensing means you will still hit the device with an instantaneous burst of RF before the internal relays kick in. A friend has confided that he has the higher power version of the ARR Preamps, but has had similar problems with killing the things. Thus I am in the market for maybe another option. While I oft times, will stroll over to the antenna tripod, and barrel off the cables going to and from the preamp to bypass completely from the transmit chain, this is kind of a pain, even in a portable situation. I looked at M2s web site and can find a 2 Meter amp, but no 70CM (Might be missing something. I have heard a lot of good things on the SSB preamps, but the only pace I can see them being sold, is Dolstra in Europe. Don't see a US vendor. Looking for suggestions. I would be interested in buying pre-owned, if someone had a Preamp that would like a new home. I do have a question for Yaesu FT847 users. With that radio, you can power a Preamp via the built in Bia- T power inserter, And assume that when this mode is turned on, it cuts the inserted DC to the preamp as the tranciever goes into transmit. Does this work fast enough to protect, even RF switched preamps? That might be a good safety measure as I have traditionally used external DC to power my preamps. Wisdom from the cloud here would be much appreciated. . Tom Schuessler, N5HYP

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IO-117 added to LoTW
by David G0MRF 26 Dec '22

26 Dec '22

Hooray and Merry Christmas. IO-117 Added on 21st Dec. - Sorry if I missed it. David G0MRF

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