Re: [amsat-bb] Falconsat-3 Test 2 (turnstyles and amps)
LNA Preamps by all means are required.
But I am curious. It would seem that the turnstyle cannot have any more gain than a simple dipole (2.3 dBi) circular, but broadside to each dipole, it should have a net -0.7 dbi since one dipole is contributing nothing and power is split - 3dB between them.
Yes, it gives 2.3 dbi circular polarization gain overhead which reduces fading, but has little gain in the quadrant directions. An infinite reflector can gain another 3 dB but this is not achieved with a simple reflector element.
On the other hand, a vertical 1/4 wave doesn't do any better. But if the vertical is made 3/4 waves long, (about 20" tall for UHF) and is placed over a good sized ground plane, then the gain is over 7 dBi above about 30 degrees.
That's the good news, but the bad news is that Sateliltes only spend about 30% of their total time in view above about 22 degrees as shown on this page: http://aprs.org/LEO-tracking.html
But the high elevation gain of the simple 3/4 wave vertical above 30 degrees is shown about 80% down this very long page: http://aprs.org/astars.html
As an old fud, I hold to this firmly held belief about the same as other old fud's cling to theirs, so I hope someday to actually make some real comparisions instead of just talking about it.
But here is my bottom line, Turnstyles and egg beaters (in my opinion) are excellent omni directional cross polarized antennas for satellite work... but equally poor in all directions. In other words, they sacrifice gain when the satellite is higher and much close, for gain at the horizon where they can never possibly hear a weak satellite anway.
So I like the reverse. Sacrificing gain at the horizon, where I can't hear them anyway, for higher gain higher up when they are closer and give a 5 dB stronger signal.
So for a simple quick test, put up a 19" quarter wave whip over a ground plane and it will give you 5 dBi gain on VHF above about 15 degrees and 7 dBi gain on UHF above about 20 degrees.
Your mileage may vary. Bob, WB4APR
-----Original Message----- From: AMSAT-BB [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Andrew Rich Sent: Thursday, October 12, 2017 7:08 AM To: Dave Webb KB1PVH Cc: AMSAT -BB Subject: Re: [amsat-bb] [OZAPRS] Falconsat-3 Test 2 - Signalink USB Sound Card 9k6
Roger that
Turnstiles and amps underway
Could not find anyone willing to send me 9k6 locally I would have seen that
A
Sent from my iPhone
On 12 Oct 2017, at 8:46 pm, Dave Webb KB1PVH kb1pvh@gmail.com wrote:
Andrew,
You need a pretty decent signal with 9600 to be able to decode and your X300 vertical isn't going to cut it for satellite work.
Dave-KB1PVH
Sent from my Galaxy S7
On Oct 12, 2017 6:40 AM, "Andrew Rich" vk4tec@tech-software.net
wrote:
Rick
What antenna preamp are you using
And what signal strength do you get
Andrew
Sent from my iPhone
On 12 Oct 2017, at 4:54 pm, Rick Kowalewski rick@vk6xlr.net wrote:
Sure it can:
Here's copied data from a few days ago: 1:Fm PFS3-1 To TLMC-1 <UI R Pid=F0 Len=4> [20:56:49R] [AA] [+--++--]CL:0 1:Fm PFS3-1 To LSTAT <UI R Pid=F0 Len=46> [20:56:49R] [AA] [---+---]I
P:0x13A8 o:0 l:26062 f:26092, d:1 st:6 e:cb
1:Fm PFS3-1 To TIME-1 <UI R Pid=F0 Len=64> [20:56:58R] [AN]
[-------]PHT: uptime is 707/07:49:24. Time is Fri Oct 06 12:57:53 2017
1:Fm PFS3-11 To PBLIST <UI R Pid=F0 Len=11> [20:59:01R] [NN]
[+--+---]PB: Empty.
On 12/10/2017 14:29, Andrew Rich wrote: ICOM 910H
9k6 ON
Signalink with UZ7HO sound modem FSM G3RUH 9600 baud
Elevation 89.4 degrees
MacDoppler correction 435.112 MHz to 435.xxx MHz
No Packets copied
435.112 MHz Start heard a change in static
I am not convinced the SignalLink can do it
I am going to move across to a my FunCube Dongle and use Software
Defined Radio to try and snag it
Will report back
I can certainly hear the 9k6 rush from the bird
Diamond X300 BS antenna LDF4-50
Andrew VK4TEC
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_______________________________________________ Sent via AMSAT-BB@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. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
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Robert Bruninga