Dave, You wondered if I¨d share with the other satellite enthusiasts a few words about my equipment.
John,
Having read your prior e-mail "AO-7 report" and the warnings about running too much uplink power .... and using better receive, I wonder if you would share with the readers what antennas, power at antenna, resulting EIRP, and receive antenna and preamp you are using on AO-7.
Maybe your example will help folks figure out what they need to do. You probably remember that I have hammered on about using a preamp (at the antenna) for years on this reflector.
Certainly Dave, happy to oblige.
First it must be noted, as I've been waffling on about for donkey's! years (Manchester slang = a long! time) that you *DO NOT* have to affluent to have a fully automated satellite station ... (nor does one need to be fully automated) ... that's just a "convenience".
Let me also say, that if I could afford one of the "all singing, all dancing fully automated rigs with a CAT interface, I'd buy one, it's just that I've never been able to afford !!! one. My QRP power levels are not *ONLY* due to my being "sensible" ... (note the parentheses) ... the main reason has always been lack of availabler funds for satellite gear. One of my first "OBSERVATIONS" was entitled "Oscar 13 on a Shoestring" ... I digress.
The radios are the FT-290/790 pair, now well over 20 years old but still providing adequate service. For AO-7's uplink the FT-790 feeds a modified Norwegian Telenor mobile base station amplifier that originally operated on 460Mhz. I hack-sawed off the first two stages, added a 6dB pad, "tweaked" the filter and fed it with 200mW from the 790 to produce 8 watts. I have 6dB of loss at 70cm with the RG-214 coax ... (scrounged from the oil industry installation here) ... so I have an EIRP of about 20 watts from the elliptically polarised home brew 2 x 6el beam. I have never found an elevation rotor to be a necessity.
The 290 for AO-7's downlink is preceeded by a home brew BF981 preamp mounted at the aerial. At 2m an ultra-low noise gaAsFET preamp in my opinion is not necessary ... due to the inherant sky noise of approximately 2dB at 145Mhz *IN CERTAIN PORTIONS OF THE SKY* ... though at microwave and above, where the sky is quieter, they are a must.
For LEO's, more important than a preamp IMHO is a polarity switcher.
The debate of circular polarisation vis-a-vis ellipticasl can be found on the website ...
The aerials at ...
http://www.observations.biz/Observations_from_Norway/Observations_15_04_2007.htm
... at the bottom of the page.
For AO-7 at 1400-1600Km above the earth you don't need to bother too much about doppler correction but for LEO's like VO-52 that literally streak across the sky some sort of auto-doppler tuning is recommended.
Even newcomers will be aware of the "One True Rule" ... (doppler tuning). This is all very well if you do! have the latest all singing/all dancing rice-box but what do you do if you operate with 20 year old rice boxes that don't have !!! CAT tuning?.
You use a program called InstantTUNE together with InstantTRACK which allows automated doppler tuning using mic pushbutton rigs. Instantune only allows tuning EITHER the uplink or the downlink so if you want to be FULLY automated, you'll need a pair of old 386 IBM's (or equivalent) and a pair of monitorsd from the nearest computer company/school skip.
Everything else I can think of is home brewed and is to be found on the OBSERVATIONS page mentioned earlier.
A couple of useful links are ...
http://www.observations.biz/Observations_from_Norway/how_much_power_is_enough_pt2.htm
... which illustrates what can be done with QRP and a shoestring buget.
http://www.observations.biz/Observations_from_Norway/howmuchpowerisenough.htm
Self explanitory.
http://www.planetemily.com/ao7/ao7log.php
... everything you ever wanted to know about AO-7 is on this site ... I know, cos' I maintain it. If it's not there, ask me, it'll be in my archives.
You'll find a lot of useful information here ...
http://groups.yahoo.com/group/eu-amsat/?yguid=188558692
... and it's all free.
I hope this mail illustrates thast it is possible to operate amateur radio satellites on a shoestring buget. Remember, a *BIG* signal is not necessary a good signal.
Have a nice day, all.
73 John. la2qaa@amsat.org
At 02:18 PM 10/19/2007, John Hackett wrote:
... You use a program called InstantTUNE together with InstantTRACK which allows automated doppler tuning using mic pushbutton rigs. Instantune only allows tuning EITHER the uplink or the downlink so if you want to be FULLY automated, you'll need a pair of old 386 IBM's (or equivalent) and a pair of monitorsd from the nearest computer company/school skip.
Everything else I can think of is home brewed and is to be found on the OBSERVATIONS page mentioned earlier.
Hi John and AMSAT Friends,
I am thrilled to hear you are using InstantTune for doppler control it is still my favorite program :) However,...
I would just like to point out that InstantTune + InstantTrack provides full Doppler tuning for BOTH the up and down links even with mic-button radios. Just connect radio 1 to parallel port 1 and radio 2 to parallel port 2.
I apologize if the manual is confusing on this point What it is supposed to say is that it will only tune one link PER RADIO for mic-button radios but it can actually tune up to 3 separate mic-button radios simultaneously (1 up and 2 down. Will anyone ever bring back mode K/T?)
I have personally used an FT-290 (with mic-button tuning) along with a 432 to 28 MHz converter into an HF rig to make tons of satellite contacts on the old FO-12 and FO-20 birds.
So, to be clear, you do not need more than 1 PC, and it can even be a really old 20MHz '386, for full doppler tuning, you just need 2 parallel ports to interface to the 2 mic-button radios.
If anyone needs help getting this working, please email me.
73, Tony AA2TX
Hi John and AMSAT Friends,
I am thrilled to hear you are using InstantTune for doppler control it is still my favorite program :) However,...
I would just like to point out that InstantTune + InstantTrack provides full Doppler tuning for BOTH the up and down links even with mic-button radios. Just connect radio 1 to parallel port 1 and radio 2 to parallel port 2.
..very interesting that dr Tony !!!
Well, probably you remember me, I had several questions about ITUNE in order to do it workable with my vintage V-U, but finally worked just perfect.
After your Email I wonder about "ITUNE.cfg", as I can't see any line about LPT's ports, just for COM-ports (=serial ports).
Are you using LPTs? If yes, how's that?
Are you changing the values of COMs with new for LPTs ? ( ie LPT1 #378 IRQ=7 & LPT2 #278 IRQ=xx ???)
I would like to have your "ITUNE.cfg" for example !
73, Mak SV1BSX
If anyone needs help getting this working, please email me.
73, Tony AA2TX
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At 07:07 PM 10/19/2007, SV1BSX wrote:
..very interesting that dr Tony !!!
Well, probably you remember me, I had several questions about ITUNE in order to do it workable with my vintage V-U, but finally worked just perfect.
After your Email I wonder about "ITUNE.cfg", as I can't see any line about LPT's ports, just for COM-ports (=serial ports).
Are you using LPTs? If yes, how's that?
...
Hi Mak,
Sure I remember, it was about a year ago I recall.
There are no commands for the LPT ports because there is nothing to configure, you just put the LPT port number in the radio command. Here is an example. Lets say you have a 2-meter FT-290 on LPT1 and a 70cm FT-790 on LPT2 and you want work AO-07 on mode B. The complete config would be as follows:
---
satellite AO-07 B ; for mode B transponder 578.1 invert beacon 145.975 cw rx micbutton 1 145.975 100 ; FT-290 on LPT1, 100 Hz step size tx micbutton 2 432.125 100 ; FT-790 on LPT2, 100 Hz step size
---
This will start tuning at the beacon. If you prefer to start in the middle of the passband, just change the frequencies like this:
satellite AO-07 B ; for mode B transponder 578.1 invert beacon 145.950 cw ; really the middle of the passband rx micbutton 1 145.950 100 tx micbutton 2 432.150 100
note that these are the nominal frequencies. My FT-290 was off by 300 Hz so you may have to play with them a little for your radios.
73, Tony AA2TX
Hello Tony, "Takk for siste" (thanks for the last time, as the NOG's say).
Great !! re: Itune being able to tune 2 x rigs using 2 x parallel ports.
Being as *THICK* as 2 short planks I never even considered putting both parallel ports into one PC. GM1SXX is ther "brains" of the team, I'm just the one with the "mouth" who takes the credit.
Actually, two old 386's help warm up the shack in the winter but it *WILL* be nice to cut out at least one of the noisy fans ... sounds a bit like a southbound from Charring Cross on the underground.
Thanks Tony.
73 John. la2qaa@amsat.org ...................................................................................
Date: Fri, 19 Oct 2007 17:14:01 -0400 To: la2qaa@amsat.org; amsat-bb@amsat.org From: aa2tx@comcast.net Subject: Re: [amsat-bb] Equipment. CC: eu-amsat@yahoogroups.com; aa2tx@amsat.org
At 02:18 PM 10/19/2007, John Hackett wrote:
... You use a program called InstantTUNE together with InstantTRACK which allows automated doppler tuning using mic pushbutton rigs. Instantune only allows tuning EITHER the uplink or the downlink so if you want to be FULLY automated, you'll need a pair of old 386 IBM's (or equivalent) and a pair of monitorsd from the nearest computer company/school skip.
Everything else I can think of is home brewed and is to be found on the OBSERVATIONS page mentioned earlier.
Hi John and AMSAT Friends,
I am thrilled to hear you are using InstantTune for doppler control it is still my favorite program :) However,...
I would just like to point out that InstantTune + InstantTrack provides full Doppler tuning for BOTH the up and down links even with mic-button radios. Just connect radio 1 to parallel port 1 and radio 2 to parallel port 2.
I apologize if the manual is confusing on this point What it is supposed to say is that it will only tune one link PER RADIO for mic-button radios but it can actually tune up to 3 separate mic-button radios simultaneously (1 up and 2 down. Will anyone ever bring back mode K/T?)
I have personally used an FT-290 (with mic-button tuning) along with a 432 to 28 MHz converter into an HF rig to make tons of satellite contacts on the old FO-12 and FO-20 birds.
So, to be clear, you do not need more than 1 PC, and it can even be a really old 20MHz '386, for full doppler tuning, you just need 2 parallel ports to interface to the 2 mic-button radios.
If anyone needs help getting this working, please email me.
73, Tony AA2TX
participants (3)
-
Anthony Monteiro -
John Hackett -
SV1BSX