Hi Guys,
Really appreciate all your comments / feedback here, just one additional question from me, In real world / every day use - what difference does using X-Pol (Cross Polarized) antennas versus a straight beam mounted vertically ? - How much of a difference does it make to the received signals ?
Thanks again for your thoughts..
Cheers
RH
G0TKZ
On 14/10/2015 03:47, Lou Michaels wrote:
Hey Rupert
Here's the list I am working with on my ground tests, which have been going well:
|Yaesu G5500 Az.El Rotor Fox Delta SatTracker 2 RS232 Interface Arrow II dual band yagi Arrow II Mast Mount Comet CF416 Duplexer 3 Foot Tripod (Radio Shaft) 2 x 5 foot mast (Radio Shaft) Andrew Heliax FSJ2-50 Yaesu 8800 for FM birds (complete station will use Icom 9100) 2 x 60ft Rotor Control Cable (DX Engineering) |
The above is basically the portable setup. I could take it anywhere to work an FM bird. I thought of trying some EME with JT65. Buddy of mine has the rig, amp, and Cushcraft yagi that would get the job done.
I'm waiting for the two antennas to be delivered. My ground tests should be done by the time they arrive, so I'll do one or two more ground tests with them, then put everything on the roof.
The antennas I'm going with are available in a package, but are under production (m2 doesn't keep stock apparently) - M2 LEO Pack:
|M2 2MCP8A 4x4 Circularly Polarized 2m Yagi M2 436CP16 8x8 Circularly Polarized 70cm Yagi |
And in the future I'll be adding preamps, but sitting on them for now. For some weak birds, preamps would be very helpful.
As far as software used in the sat shack:
|SATPC32 - Tracks birds and controls VFO Orbitron - Alternative Sat tracking - much better interface UISS - Used for ISS APRS SoundModem - Software TNC for APRS VSPE - needed for COM port sharing / routing (a real bitch) ICOM Keyer - app to key radio for APRS Ham Radio Deluxe - Digital Modes & Basic Sat Tracking |
And as far as online resources:
|Online tracking
www.heavens-above.com http://www.heavens-above.com www.N2Yo.com http://www.N2Yo.com http://www.amsat.org/amsat-new/tools/predict/index.php
Find Modes & Frequencies
http://www.ne.jp/asahi/hamradio/je9pel/satslisf.htm%7C%7C ||Hope this gives you some insight :)|
On Tue, Oct 13, 2015 at 5:16 PM, Rupert Hamblin <rupert.hamblin@gmail.com mailto:rupert.hamblin@gmail.com> wrote:
Hi AMSAT, I am looking for some guidance regards antenna setup for a fixed installation to work both FM sats & linear transponder satellites. My initial thought was: AZ / EL Rotator 2M xpol beam 5 ele ? 70cm xpol beam 9 ele ? LNA for both 2M & 70cm receive feeds ...plus some spare space on the boom, perhaps for 3 ele for LEO wx sats..? I appreciate this will probably cost a few $$ - but hopefully worth it....obviously won't build all this in one go..! Appreciate your thoughts / comments here..? Regards RH G0TKZ _______________________________________________ Sent via AMSAT-BB@amsat.org <mailto: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
ll your comments / feedback here, just one additional question from me, In real world / every day use - what difference does using X-Pol (Cross Polarized) antennas versus a straight beam mounted vertically ? - How much of a difference does it make to the received signals ?
This is the best site I have seen with good explanations:
http://sv1bsx.50webs.com/antenna-pol/polarization.html
Many/most satellites are not true polarised sources, rather just omni antennas on one side. Often they are not controlled so they spin and twist. As a result they can appear to change from vertical to horizontal to LHCP to RHCP.
If you have circular, and the satellite is linear, the worst case (according to the chart) is 3dB. while if you are vertical at the satellite appears horizontal the worst case it 30dB. So in normal use, you can change from 30dB fading to 3dB fading.
Some polarisation switches have the option to remotely change from RHCP to LHCP to vertical and horizontal. Thus you can compare them all such as wimos unit: http://www.wimo.com/download/1808xx.pdf
Sometimes even true circular polarised sources, can reflect off something, (e.g. the solar panels on the ISS) and suddenly a RHCP can become LHCP.
So I think the answer is if you see sudden fading in the middle of a pass, it may be due to difference of polarisation, but sometimes it is dues to the antenna pattern of the transmit antenna being away from the Earth side of the satellite. The only way to know for sure is to switch polarisations quickly and compare.
I would consider it if buying a new beam and if you have elevation control. Circular is also useful for ground contacts as DX stations tend to use Horizontal Beams, and mobile and base tend to be vertical omni. With RHCP you only have a 3dB loss to either user at the other end.
participants (2)
-
Daniel Cussen -
Rupert Hamblin