Email Detail
Show an email
GET /hyperkitty/api/list/[email protected]/email/6UKNNLFO5AC3ZZXKXSZXVDHVK2EELI6G/
{ "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/6UKNNLFO5AC3ZZXKXSZXVDHVK2EELI6G/", "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/", "message_id": "[email protected]", "message_id_hash": "6UKNNLFO5AC3ZZXKXSZXVDHVK2EELI6G", "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/5333LNAR3CJJ6GFQCTXJS4X4RRNB2BLK/", "sender": { "address": "rnutter (a) networkref.com", "mailman_id": "9d4409219c4248a6be735e65e52a44fc", "emails": "https://mailman.amsat.org/hyperkitty/api/sender/9d4409219c4248a6be735e65e52a44fc/emails/" }, "sender_name": "Ronald Nutter", "subject": "[amsat-bb] Re: Feedback on downlink on VO-52", "date": "2008-04-02T15:45:17Z", "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/5333LNAR3CJJ6GFQCTXJS4X4RRNB2BLK/", "children": [], "votes": { "likes": 0, "dislikes": 0, "status": "neutral" }, "content": "Desense may not be the correct word but I am hearing a distorted/fuzzy \nversion of my voice regardless of where I tune. I have tried one thing \n- the coax I am using on the VHF antenna may not have been the best. It \nwas some old coax I had with BNC connectors on it (It was used on \nnetwork cards when thin-net was the way to go). I have found a heavier \npiece of coax and have changed out the respective section. Will see how \nthat works.\n\nRon\n\nJohn Kopala wrote:\n> Ron,\n> \n> I have to throw in my 2 cents.\n> \n> I'm not sure why you would be getting any desense. I have virtually the \n> same setup.\n> I have not had any indications of desense with my installation.\n> I'm using an IC-910H, separate feedlines, mast mounted preamps, and yagi \n> antennas.\n> Feedlines are 9913F7 ultraflex and are about 60' long plus connections from \n> the preamps to the antennas.\n> I have a 2 meter CP KLM (oldie), a 1.2 GHz looper, and a 435 KLM.\n> Separation between the 2 meter and the 70 cm antennas is about 8 feet.\n> I do use an elevation rotor and so the antennas can be aimed quite \n> precisely.\n> Normal power output is usually about 5 watts unless the satellites have a \n> very low pass.\n> Using more than 25 watts would be pretty unusual with most satellites.\n> I live in Phoenix, AZ, and am surround by mountains, some within walking \n> distance,\n> so in most directions I have an elevated, rugged horizon.\n> \n> The first question that I would ask is how much power are you running on the \n> uplink?\n> And then, how far apart are the antennas?\n> \n> I use the CI-V interface with SATPC32 to control the doppler. It works \n> great.\n> You just have to make sure the address in the radio matches what you have \n> set in the software configuration files.\n> For SSB I have the frequency updated whenever it gets off by 20 or more Hz. \n> For FM I'm using 300 Hz.\n> Maybe overkill on SSB, but it's better than having the tone jumping up and \n> down all the time.\n> As George said, do the CAT interface first, expecially if you plan to be \n> doing SSB or CW.\n> Once you have that set up, you can tweek your downlink on the CAT display \n> when you first transmit.\n> After that, your uplink and downlink should pretty well track with each \n> other.\n> The fun comes when you have to follow someone who has no doppler control.\n> \n> I don't think you are going to find any easy way to interface the Channel \n> Master rotor to a computer interface.\n> Generally the interfaces expect a voltage between 0 and 5 volts representing \n> the azimuth of the antenna.\n> A higher indicator voltage can be scaled down to the 0 to 5 range if you can \n> find something suitable.\n> Most ham rotors have separate wiring for the indicator potentiometer in the \n> rotor and that can be easily scaled\n> and used with computer interfaces.\n> \n> Hope this helps. I can set a picture of my antenna installation if that \n> would help.\n> \n> John\n> N7JK\n> \n> Message: 13\n> Date: Tue, 01 Apr 2008 10:12:03 -0500\n> From: Ronald Nutter <[email protected]>\n> Subject: [amsat-bb] Re: Feedback on downlink on VO-52\n> To: George Henry <[email protected]>, \"[email protected] >>\n> AMSAT-BB\" <[email protected]>\n> Message-ID: <[email protected]>\n> Content-Type: text/plain; charset=UTF-8; format=flowed\n> \n> I am using seperate antennas and feedlines. For the time being, I am\n> using a Channel Master antenna to turn the antennas. I have a pvc pipe\n> rig setup with the antennas at an angle of 25 degrees due to the clutter\n> in the neighborhood I have to clear to see the sats. I hope to have a\n> tower in the future but with being laid off from my job, cant really\n> have any expenditures right now.\n> \n> I have the cat interface for the IC910H but havent looked into how to\n> set it up yet.\n> \n> Ron\n> KA4KYI\n> \n> George Henry wrote:\n>> -----Original Message-----\n>>> From: Ronald Nutter <[email protected]>\n>>> Sent: Mar 31, 2008 10:40 PM\n>>> To: AMSAT-BB <[email protected]>\n>>> Subject: [amsat-bb] Feedback on downlink on VO-52\n>>>\n>>> Thanks to the help of several on this listserv, I was able to get a\n>>> contact on VO-52 until I lost coordination on keeping the rotor turned\n>>> and the IC910H tweaked the right way on the VFO's. I had problems\n>>> finding my downlink because of what I think is desensing on the 2M \n>>> downlink.\n>>>\n>>> Can I resolve this by putting a filter on the 2M receive to stop the\n>>> desensing like I would on the UHF receive on the FM birds ? If not, is\n>>> there another way to fix the problem ?\n>>>\n>>> Thanks to W0EOZ for putting up with me while I was trying to figure\n>>> things out. Hopefully my next contacts will last a bit longer <G>.\n>>>\n>>> Ron\n>>> KA4KYI\n>> Are you using separate 2 meter and 70 cm antennas with separate feedlines, \n>> or diplexing onto a single feedline to a single antenna? First thing to \n>> do is reduce your uplink power as much as possible while still being \n>> heard. If you are diplexing to a single feedline, you only have about \n>> 60dB or so of isolation, so too much uplink power can exceed that. You \n>> should be able to work VO-52 with 25 watts or less...\n>>\n>> I have never experienced desense on 2 meters from my 70 cm uplink... only \n>> the reverse, which can be cured with separate feedlines and antennas, \n>> ample separation between the antennas, and the diplexer-as-filter trick \n>> found at <http://www.amsat.org/amsat-new/articles/Mode-J/>\n>>\n>> And I strongly recommend buying or building a CAT interface and letting \n>> your tracking program take care of tuning the radio (and turning the \n>> rotors, if you buy or build a rotor interface as well). The demo version \n>> of SatPC32 is fully functional except for saving your station parameters, \n>> and can be downloaded from <www.dk1tb.de/indexeng.htm>.\n>> If you like it, register it: all proceeds go directly to AMSAT. A CAT \n>> interface PC board with the harder-to-find chips included is available \n>> from <www.farcircuits.net> and only costs about $20 to build. The \n>> FOD-Track rotor control PC board is also available from Far Circuits, and \n>> will cost $45 - $50 to build. The LVB Tracker is available thru the AMSAT \n>> store, and has the advantage of being able to operate without a computer \n>> attached... nice for mobile ops!\n>>\n>> Go for the radio control first: that'll free you up to deal with the \n>> rotors manually, and they demand far less attention than tuning does.\n>>\n>> 73,\n>> George, KA3HSW\n>>\n>>\n>>\n>>\n> \n> \n> \n> _______________________________________________\n> Sent via [email protected]. Opinions expressed are those of the author.\n> Not an AMSAT-NA member? Join now to support the amateur satellite program!\n> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb\n> \n", "attachments": [] }