Display More"The reality is surely that over the time of a QSO we do not have to retune"
here an OM tested the D75F and i see a frequency drift about 100Hz in a few seconds:
http://www.dg0opk.darc.de/Octagon_LNB_mod_March2017.html
I wish fun turning the VFO
vy 73
DB8TF
Could you please specify which test you are referring to? Actually DG0OPK confirms the excellent behaviour of the D75F.
I cannot see them here.. try a check and see if the signals are gone if you put your hand in front of the LNB. Powerful test to see if signals come from a satellite or from your setup.
Does someone know what signals cause those "lines" every few khz in the spectrum as seen in DL3CWS second pic?
If you mean the lines at +- 15 Khz: that is the engineering telemetry. The carrier in the signal is the residual carrier, as the beacon is BPSK modulated .. maybe not with +-90 deg phase phift (as the carrier would be non existing then) but something like +- 60 deg.
I am not quite sure about your setup (maybe I misunderstood, my apologies!), but if you use the Andrew T2400 Reflector with a LHCP feed, you will still get a linear signal.
The reason is the large spacing of the reflector gaps in one direction. When used without mods, this reflector will only reflect one polarisation plane and be transparent for the other. If you want to use this reflector for circular polarisation, you have to line it with a mesh which has a mesh opening of < lambda/10 (so less than 1.3cm) (rule of thumb).
Maybe you mean Faraday rotation. A linear radio signal will rotate its plane when passing the ionosphere. However, if the receiving antenna is RHCP (as it is for Phase-4A), this has no influence on the overall radio link, even if the transmitter is using linear (you just lose 3dB). If you receive linear as well, then of course any linear mismatch will cause 'fading'..
Because 'horizontal' is referenced to the local system. Linear H in Europe and linear V in Brasil generate the same signal at the satellite. RHCP will always be RHCP when it reaches orbit, no matter where it originates.
For uplink we chose this as this is kind of S-Band standard and space rated antennas are easily available. The same is true when using linear on X-Band downlink (as you might see when checking your TV satellite programme settings). We need both polarisations to decouple the WB and the NB transponder and as the local definition of horizontal/vertical is depending on your location, you need to apply LNB skew, which can be calculated here:
Without knowing any details, it typically takes about one week to get into geostationary orbit (on a test position which is NOT the final one). Then the in-orbit testing starts.. and as said before, our transponder will likely be last. I personally do not expect any transponder opening in 2018. Please stay tuned, we will announce news as we have them.
Most important of all: do not transmit unless the transponder has been officially declared open! Doing so will only delay commissioning and the release date for all. Last but not least, any misbehaviour of users will not help our good relationship with Es'hailSat and we all want to keep it good, do we?
Maybe nothing except for the polarization mismatch loss. But as these antennas are not rated for high (>=10W?) TX levels, you might run into problems here. This needs to be carefully tested, best with a circulator to prevent bad things from firing back into your PA.
I also have some early ranging code (Sorry Achim, only carrier at present, Spread Spectrum will be have to wait), that I'm hoping to test to at least some degree with the same spacecraft assuming I can confirm a good uplink
Iain,
this sounds like an exciting start! I am sure once the transponder is up and running, things will develop very fast!
Dear friends,
without (!) having an official launch date one can certainly say: we are getting close now. On various places in the internet different launch dates are being listed and on this occasion I would like to communicate or clarify a few things on behalf of the Phase4-A team.
- There is NO official launch date yet. As of today (October 29th) there are only NET data (not earlier than), which are derived from different indications, which can be found from more or less official places in the internet.
- NET means: certainly not before. But also means: probably later, unless EVERYTHING goes smoothly.
- For various reasons (last but not least respect towards our 'hosts') AMSAT-DL will not participate in such speculations (and nothing less are NET data for us).
- SpaceX will (as usual) perform a static fire test about 5-7 days before the launch attempt without payload. The launcher is lifted on the pad and the engines are ignited for a few seconds. If this test does not reveal any problems, SpaceX will officially announce the date for the launch attempt shortly afterwards (a few hours).
- The rocket is then taken off the pad, the payload is mounted and back it goes. Of course delays can pop up at any time...
Personal note: I plan (with a few team members) to go to Florida to the launch. I haven't booked any flights or hotels yet, maybe this gives you a feeling how feel about the rumors right now.
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Spoiler alert: for the next AMSAT-DL Journal I am writing an article about how SpaceX gets a satellite (NOT Es'hail-2) from the pad into the transfer orbit and how it continues from there. This is based on existing data of an already launched payload. Also here: no info about Es'hail-2... because there are none.
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Let's all take a deep breath and enjoy the launch... SpaceX will offer as always a great webcast.
73s Achim, DH2VA
Yes.. and in HB9, the responsible federal department has banned the UV-5R altogether (no sales, no ads, no usage, not even giving away for free). Not to say that all UV-5Rs are bad, but apparently too many..
By definition Es'hail-2 will not be an OSCAR because it's not orbiting ; -)
Excuse me? Do you believe geostationary satellites are sitting somewhere on a shelf?
By definition, a satellite in geostationary orbit isorbiting. 
Ich fänd das auch nicht richtig unsere Satelliten OSKAR zu nennen..
"ist doch das gleiche" ... eben nicht
Eine korrekte Schreibweise ist für mich eine Frage des Respektes.
It's not only the required bandwidth for the beacon but also a guard band to prevent interference of other uplink signals with the beacon. And last but not least, the beacon should serve as a guide rail for the users to keep clear of the transponder limits.
Look at it as a guide rail on a highway: in theory you can drive really close to it but in practice it is recommended to have keep a certain distance.
Anyways: It is expected that the document will be updated regularly to take into account the operational experience.
Ich habe die 2m Eggbeater von Jerry K5OE nachgebaut und empfange damit zuverlässig die NOAA APT Satelliten auf 137 MHz:
Hi David,
good remark, thank you! I fell into the Fox trap (!) just recently.. I understand that Connor Winfield advertise their analogue TXCO circuitry. I have failed to find a cheaper alternative (well, I guess you get what you pay for)..
73s Achim
Small addendum: my proposed design only works for a 'normal' downconverter with LO of 9750 MHz. Peter's mentioned unit from DB6NT sounds more like a LO frequency of 9360 MHz which requires an SDR.
Try SG-Lab's 23cm transverter. It's LO can be programmed to 1122 MHz which gives you 1267 MHz with a 145 MHz LO. But best if you ask them first to be sure.
Hi Ross,
what satellites would that be, if I may ask? For hamradio, the frequencies you are referring to used to be Earth-to-space only.. so no telemetry.
73s Achim
