Gibt es da Links?
Eine Google Suche nach WLAN panel 20dBi ergibt z.B: dies: http://www.wifi-highpower.co.u…wifi-24-ghz-n-female.html
Oder hier: https://www.wlan-shop24.de/24-ghz-richtantennen
Als ich vor einer Weile ein Panel in Erwägung gezogen habe, fand ich auch diverse Angebote auf Ebay
73 de Jens, HB9EKO.
Hallo Andreas,
einige OMs haben gute Erfahrungen mit WLAN Panel Antennen gemacht. Die gibt es mit Gewinnen um die 20 dBi, allerdings ist die Polarisation linear, so dass hier im Vergleich zu zirkularer Polarisation 3 dB Verlust entsteht. So ein Panel ist mit Sicherheit unauffälliger als eine Schüssel oder eine Helix.
Ich habe übrigens an meinem QTH dasselbe Problem. Gelöst habe ich es mit einer semi-portablen Installation auf dem Balkon. die Schüssel ist etwas versteckt hinter dem Balkongeländer, nur wenn ich Betrieb mache schiebe ich sie hoch über das Geländer. Ich habe einen Balkonständer, darüber ein verschiebbares Rohrstück mit Schrauben zur Fixierung, daran ist ein Ausleger für die Schüssel befestigt, den ich brauche um die Schüssel im Betrieb etwas neben ein Hindernis im HF-Pfad zu setzen.
73 de Jens, HB9EKO
A cheap Newgen.RTL.2832SDR and the way more expensive SDRplay RSPdx are showing no difference in SNR on the NB&WB.
Checked that some weeks ago.
Thanks a lot, that's what I was interested in.
With regards to the SNR. the crucial factor is the size of the dish and - to a smaller amount - the noisefigure of the LNB. The output of the LNB is way above the reception threshold of all SDRs. Goonhilly WebSDR runs a 1.3m dish.
Thanks Jean, that makes the audible difference plausible. Looks like an increase of dish size is the best option, if feasible.
by the way SDRconsole is a fantastic sortware and the audio is better compared with the classic receiver-converter approach.
Hi Alex, thanks for the info. I am running GQRX native on Linux, and SDRconsole in a Windows VM. I have not encountered major difference in audio quality between the two programmes. (maybe I should try to play with filter settings). So it looks like it's not worth investing in a downconverter. I was considering a conversion to 28 or 50 MHz in order to make use of the DSP filtering capabilities of my FT-891, but rather stick to what I've got.
Thanks for all the info, and hope to talk to you on the sat soon.
73 Jens, HB9EKO
Hi there,
I have optimised my QO-100 setup to a degree where I am happy with it for the time being. My signal with 2W into a 70cm dish is about 6dB below beacon level and fine fo QSOs in CW and SSB.
While I'm enjoying QSOs with that setup, I'm already thinking ahead for the next possible improvements: The S/N of my setup with a cheap Chinese RTL-SDR stick is obviously not as good as the various WEB SDRs, i.e. signals which are barely audible in my setup are better on the WEB SDRs. While my possibilities to increase the dish size are a bit limited, I wonder whether there are other possible improvements.
In order to get a feeling if it's worth investing in that part of the RX chain: Has anybody made a performance comparison between different SDR receivers? Is it worth investing in a more sophisticated SDR RX, to have a better reception than the Chinese RTL-SDR clone? Are there other SDR X with a significantly better performance? How does the RTL-SDR perform in comparison with a downconverter and a conventional HF or VHF RX?
73 Jens HB9EKO
Hi Luc,
the cable will always be a compromise between attenuation and minimum bending radius of the cable, i.e. the cable type depends on your possible mechanical setup.
I use Aircell 5 which has a minimum bending radius of 25 mm (for bending once, i.e. a fixed dinstallation) but an attenuation of 0.5 dB/m ( less than 3dB for your setup).
If you can manage to install a cable with a bending radius of 40mm, then Ecoflex10 would have approx. half the attenuation of Aircell 5.
If you go for a even thicker cable, let's say Ecoflex15, you could get the attenuation down to 0.16 dB/m, but the minimum bending radius is 70mm, which is pretty unhandy.
What s your exact setup? Do you really need to have that length of cable between PA and POTY, or could you place the PA closer to the antenna and run a longer cable between the PA and the TRX/Transverter? If the output of the TRX/transverter exceeds the minimum required input power of the PA, it might be better to put the cable loss in your link budget there.
I have connected my feed to a transverter with 0.5m of Aircell 5, and then run 5m RG58 from my 70cm TRX to the transverter. Thus I have most of the output power at the antenna, RF cable diameter is 5mm everywhere, the cables are cheap and flexible for my semi-permanent setup.
73 Jens HB9EKO
It should be OK, even though it is quite an old CPU from around 2012, without hyper-threading but with 4 cores. Had it been an early i3 with dual cores and limited performance it may have struggled. Especially if you had been looking in a wide bandwidth (some MHz) with a high res screen to update. There should be a CPU and GPU load indication at the bottom of the screen, as long as it's well below 100% you are not limited by CPU.
Pluto bandwidth rates with USB are not great and console does tend to crash if the connection to the SDR fails on it. USB lead, USB power, all things to check. If its more stable at 900kHz try 750kHz, 550kHz etc. That will help work out what is causing the crashes. There is also a logfile under tools. Another thing that causes crashes is where the Pluto reboots because it detects incorrectly that the power to it has changed. This is very common if you have an external antenna connected which is grounded. There is a mod to fix this.
Mike
Hi Mike,
as I mentioned, I use a mobile i3 CPU even a generation earlier, and it's definitely not the limiting factor.
I can confirm that the USB connection does cause crashes of SDR console. My Chinese RTL-SDR stick is a bit wobbly in the USB port in the laptop, and I have to be careful not to touch it accidentally. It helped to use a short USB extension cable to get the SDR stock out of the way.
73 Jens, HB9EKO
On an old laptop (i3 2310m, 8GB RAM), I have approx. 40% CPU load. (BW 1 MHz) when running SDR console without anything else.
73 Jens HB9EKO
Update:
This weekend, i had a close look at my setup again, and checked the signal path from the focal point to QO-100 +/- 10°. I then figured that there is not only the steel structure but also the balcony railing in the way. 
I replaced the attenuator-style jumper from the transverter to the feed with a piece of Aircell 5. Then I started looking for a "sweet spot", shifted the dish around on the balcony with an eye on the signal strength of my own TX signal via the transponder, and found around 5-6dB. 
CW QSOs are not a problem at all anymore. I even made a few successful SSB QSOs, QSO partners confirmed that my signal was weak but clearly audible. The beamwidth is now probably limited by the balcony railing on the bottom, and the upper balcony on the top. The steel pole is about 1.5m in front of the focal point. During a QSO with someone with the same TX power and dish size, I noticed around 4 dB difference in signal strength. That's apparently what disappears in the steel pillar, which is now 11-12 wavelengths from the focal point in TX direction.
Thanks for all the hints, now I can experiment with improvements to my setup for better SSB QSOs rather than struggling to communicate at all. Lessons learnt: an obstacle in the signal path does not neccessarily make QO100 operation impossible.
Vy 73 de Jens, HB9EKO.
Hello,
G0MJW DD4YR the picture doesn't clearly show the real direction of the antenna. When I started experimenting. I considered the visibility of the satellite already (see the thread DRO LNB for testing RX signal levels? )
I have LOS and a reasonable RX quality (maybe not the last possible dB), that's why I got optimistic and started investing into equipment.
I was aware from the beginning that the Fresnel zone is not clear, but there's nothing I can do about the position of the satellite, my balcony and the fact that I have to stay as stealth as possible. So now that I did my initial investment, I will just investigate further until it works. That's what ham radio is all about, isn't it?
DH2VA Looking at the setup now, I think it will be easiest to remove the concrete plate fom the bottom of the dish stand, put a box inthe corner of the balcony and move the dish temporarlily across the balcony railing. Then I have numbers in dB regarding the steel pole, and know where I am. I also hope that the situation at the borders normalize again, then it will be easier to buy components just for experimenting.
I was hoping that someone else in the Forum might have experience with similar issues already, but it looks like I'm the first one, so I'll keep on experimenting. The results will hopefully support other OMs in similar situations.
73 de Jens, HB9EKO
Thanks for the hint. Unfortunately I can't use the "Contact seller" function on Ebay, the button simply doesn't work. Checking in the web shop, the shipping cost to HB9 makes it pretty pretty unatttactive. I'll rather wait a bit.
DD0KP For that price I agree. Here they cost much more. I found the antenna on Ebay. The seller doesn't ship to Switzerland, and he can't be contacted with the "Contact Seller" function on Ebay. Looks like I have to put that on hold until I can get across the border to my parcel handling service . I don't want to spend half the price of let's say the SG Lab PA more for try and error.
73 Jens HB9EKO
I8LYL former I0LYL Yes, I see the option of either mounting a separate antenna, or increasing the output power. I have to be a bit careful, though: Our rental contract says I am not allowed to MOUNT/ATTACH anything to the building, which is why the setup has to be some kind of semi-portable. I already had discussions with a previous landlord somewhere else because of a Sat dish mounted visble to the bacony railing and I prefer to avoid that experience here.
The dish is currently on a stand inside the balcony, with limited visibility from outside, and I'd prefer it to stay that way. Maybe I could make a temporary antenna mount look like a flag pole, that seems to be generally accepted here in HB9 :-). Or hide a panel behind a Swiss flag or so.
DD0KP I thought about something like that already, I even found a similar panel with 1 dB more: http://www.wifi-highpower.de/1…24-ghz-wifi-n-buchse.html
Has anybody tried such a panel antenna with 2W already?
Just in Theory: The panel antenna has a linear polarisation, i.e. I lose 3 dB. Assuming that my dish has 22dBi, (taken from a table with dish size vs. gain and rounding down), the performance of such a panel compared to an unobstructed dish is -6 dB (3 dB difference between the antennas and 3 dB for polarisation).
The panel would then compensate a loss due to the steel structure of 6 dB. (22-19-3 dB) . So I get a better performance only if the attenuation of the steel structure is more than that. I'd like to have 6-10 dB more than my current signal for SSB. Is it a realistic that the steel structure attenuates my signal by 12-16 dB?
Not sure if adding a 20W SG lab PA to my setup would be the safer bet. If I have a barely audible SSB signal now, an extra 10dB should be fine for a basic signal in SSB, and good results in CW.
73 Jens, HB9EKO
Hello,
after being motivated by my first RX attempts (thanks to lots of support in this forum), I started getting my TX path together. I received all ordered components last week, put them together in an on the fly setup on the balcony yesterday, and started my first TX attempts
With a couple of successful CW QSOs, I managed to "limp" successfully over the NB transponder. Responding to a CQ call in SSB was unsuccessful, but at least the OM reported back that "the signal of the HB9 station" was barely readable. So I know at least that I am at the bottom end with my current setup.
The 72cm dish is set up for best RX signal. When I mount the Helix feed on the LNB, the RX signal goes down by approx. 2 dB. I can hear my own TX signal on the WebSDR in Goonhilly weak but clear. With my own RX setup, I can hear that there is something in the noise. (QSOs are possible without cheating by using the WebSDR for RX). There is certainly room for improvement, but the RX path is sufficient for QSOs and has no priority for the moment.
I use a SG-Lab transverter with 2W output. The short SMA to BNC jumper cable connected to the Feed with an BNC to N jumper probably attenuates an extra 2 dB (It's made in China, out of my "just in case" adapter box with adapters which I collected without any specific purpose) so with a proper low loss jumper and high quality connectors, I can probably recover 1-1.5 dB in the UL path.
My biggest worry is the TX antenna path: The dish is set up in a corner of the balcony. Approx. 1m in front of the dish, directly in the signal path, there is a vertical steel support of the balcony, which goes from the ground floor through the balcony of the upper floor.
I can "see" QO-100 just above the corner of the building. The options to move it are limited, just a bit to the back before the upper balcony obstructs the path to the satellite. Unfortunately, I have no option to mount the dish outside the balcony to avoid the steel structure. Putting a larger dish to the same place is not possible, either.
At the first look, a 20W PA would probably solve my problem, however with an unknown amount of RF being reflected randomly. Has anybody got any experience with obstacles in the TX path with an estimation, how many dB could get lost due to this steel structure?
Possible alternatives for a TX antenna would be a panel mounted to the steel structure itself, or a Helix pointed to the satellite close besides the steel structure. I am aware that both options have their issues. Any ideas if these alternatives would be a viable solution for 2W TX power?
73 de Jens, HB9EKO
hallo Hans,
davon ausgehend, dass die Leistung proportional zur Ausgangsleistung ist (0.0V = 0W, 3.5V=20W), findest Du die Formel, wie Du aus vorlaufender und reflektierter Leistung das SWR berechnest
https://de.wikipedia.org/wiki/Stehwellenverh%C3%A4ltnis
73 de Jens, HB9EKO
Hi Guys,
as promised, here is the result of my experiments: One of the 2 unknown LNBs received something. The best S/N I could get with the possible positioning of the dish was about 20dB. So as a proof of concept the DRO LNB was usable, although for following SSB QSO's, I had to be quick following the drift.....
--> Goal achieved, Proof of Concept done without major investment.
Thanks for all your support, now I have to get my equipment together step by step...
73 Jens, HB9EKO
Hi guys,
thank you very much for all the good hints. In the meantime, I downloaded a sat finder app on my phone and figured out that I can actually "see" the satellite. (Fingers crossed that reflections/multipath from the building don't mess up the RX path)
I'll be getting a dish this week, so during the Easter weekend I'll use my DRO LNBs and try to figure out a landlord/XYL compatible position for the dish on the balcony. Once I can hear something other than noise, I'll give a feedback about my results in the forum and start online shopping.
pe1hzg that was my first thought, too. However,after a web search for LNB models which have been successfully modified, I didn't find any in HB9 for less than the price of a modified LNB in the AMSAT-DL store. So I decided to first see what happens with what I've got, and then decide what hardware I need to order for the next steps.
73 de Jens, HB9EKO/DL9SBM
Hi there,
Looking for potential projects while being stuck at home, I started investigating if there is a way to get QRV on QO100 from my home QTH, since antenna options are quite limited here. However, I do not want to start with larger investmsnts only to find out that it doesn't work.
As a first step, I tried to point towards QO100 with a compass. I figured out that from my balcony, I should just about "see" it between the edge of the building and the roof of a neighouring house.
Next week, I'l probably get a hold of a 72 cm dish as a start. In my cellar, I found 2 old LNBs which most probably have a DRO. I also have a RTL-SDR.
The next step would be to check if I can receive any signals from QO100 preferrably with what I got at home, and start investing into more equipment once the Proof of Concept is done.
Is this possible with a DRO LNB at all? I don't expect to be able to monitor QSOs with that setup, but at least see something that confirms that I don't waste my time and money when I get a proper LNB and other stuff to set up a proper RX path as a next step. Any hints on how to do this test and what kind of RX signal I could see or hear with my RTL-SDR?
73 Jens, HB9EKO/DL9SBM
