Smallest EMWIN antenna

[GOES 12 GVAR user]

doubleohwhatever
Agree with outatyme need antenna size type, downconver type, amp type, coax.
From what I see you have a decent signal there , but there is a lot of other stuff (odd signals) that shouldn't be there. If you got EMWIN this is what you should be able to see.

HDSDR EMWIN Same view.jpg - Same view as doubleohwhatever's, Note there isn't any other signals than the one that your after. LRIT (left) DCPR (right).

Desktop\HDSDR EMWIN.jpg - Zoomed into the spectrum and the waterfall dispaly shows what you'll be looking for. See the horizontal lines that look like little boxes, these are EMWIN's file headers. if your seeing these your seeing EMWIN. They really show up in the readout below the spectrum display.

Timothy KC0HWG

 

[outatyme]

One thing i notice from your screenshots is that you appear to be running a sample rate of 625Khz in sdr-console. From what I understand this needs to be 500khz. Under the tools menu you should have UDP broadcast enabled and configured to output data on localhost on port 60002 with packet size of 1024.
Also, it will be difficult but you need to center up the emwin signal somewhere around + or - 50000hz off center so that the decoder will see it. Look at the main white decoder console window and the second set of data the one with +220hz in your screenshot is the tuning offset that the demodulator is currently looking for signal at. Ideally you want this to be as close to 0hz as possible.

 

[doubleohwhatever]

Agree with outatyme need antenna size type, downconver type, amp type, coax.

The dish is nearly identical to the one outatyme has. I listed the parts I'm using a couple of posts up.

From what I see you have a decent signal there , but there is a lot of other stuff (odd signals) that shouldn't be there.

I have absolutely no clue where those signals are coming from. I get them even if I attach the SDR directly to the dish. I'm wondering if it's just the airplay causing the issue with the odd signals. I have a SDRPlay arriving this week for a comparison.

One thing i notice from your screenshots is that you appear to be running a sample rate of 625Khz in sdr-console. From what I understand this needs to be 500khz

Yeah, I've been a bit stumped on that one. I've attached a screenshot with the options SDR-Console offers.

Btw, I'm thinking about grabbing something like this and making my own l-band feed: http://goo.gl/Acqa8E

Any reason that dish wouldn't work?

I really appreciate you guys helping me get this sorted.

 

[GOES 12 GVAR user]

Ya I see, you listed the parts already Thanks. What is the amp, It links to minicircuits but doesn't show anything. The downconverter is good, looks like you got the proper connectors from the list. I will have to do some research on that antenna, I did see you posted that a few pages ago sorry.

Timothy KC0HWG

 

[doubleohwhatever]

Sorry about that. Here's the direct link to the LNA datasheet: http://www.minicircuits.com/pdfs/ZRL-2400LN+.pdf

 

[outatyme]

Here are some screenshots of my working settings.
The Airspy config may be slightly different.

 

[GOES 12 GVAR user]

That dish should work that you linked to on ebay, but you would have to design a new feed support for the L band and make shure that you have the feed at the focus of the dish. Offset feeds can be complex but at least it comes with a feed support so you would have pretty good idea of where it needed to be. Again let me do some research on that other antenna before you put out for another.

Timothy KC0HWG

 

[GOES 12 GVAR user]

Seems like a nice amp and a decent price. It will work fine.

Timothy KC0HWG

 

[outatyme]

Those signals (lines in the waterfall) are probably broadband noise.

They can emanate from several different sources including:

1). Poor RF shielding on the SDR.

(wrapping with aluminum foil and tape usually solves this)
Verify the noise is coming from the radio or computer by unhooking the antenna connection from the receiver.
If the noise is still there with no antenna connected, The noise is coming from the PC, USB cable or inadequate shielding of the SDR receiver.​

2). Cable ingress / leakage

Cabling between the SDR and antenna has poor shielding or poor termination that is allowing the noise in.​

3). Poor RF shielding on the LNA or downconverter which should be located on the dish antenna after the feed.

Same as above, Try to put the LNA or downconverter in a metal enclosure or wrap it with aluminum or copper foil.​

4). Broadband noise being picked up from the environment and coming though the antenna and receive system.

Noise from power lines, nearby radio transmitters, street lights, airport radars that is received by the antenna.

This is the issue that I faced and am still fighting. In my case, I suspect power lines or a nearby streetlight.
I still have a periodic loss of sync (LOS) issue that I cannot solve so far.

How I determined my noise was from the outside environment and coming through the antenna was by sweeping the dish left or right and watching the SDR# waterfall.
I noticed my noise spikes would change as I turned my dish. I also noticed I could put my hand infront of an area of the dish and block out some of the noise.​

 

[outatyme]

If your noise is still there when hooked directly to the dish with nothing between (no LNA, no downconverter) then the noise is likely coming from the radio itself or PC or coming through the receive setup (through the antenna from some outside source).

The Noise spikes shouldn't matter so much as long as the noise spikes are not within the Emwin signal itself when looked at on the waterfall.

ANY noise spikes within the 25 - 30 Khz wide Emwin signal 'hump' WILL cause issues.

Noise spikes outside the 25-30 Khz wide Emwin signal theoretically should not matter so much
(unless they cause the demodulator to loose lock - but I haven't tested or confirmed that).


A band pass filter should really help with noise in some instances.

Because you can also get RF frontend overload and intermodulation from strong signals outside the frequency range that you are tuned to - A band pass filter would 'reject' those strong signals.

(if you've ever seen Broadcast FM stations up at 300mhz on your SDR before, you know what I am describing here - A signal at say 95.7 Mhz (WBFM radio station overloading the RF frontend and being mirrored up at 300Mhz.)

(Tuned to 300Mhz and seeing an FM radio station that shouldn't be there in this example).

Also, you do not need that downconverter within the receive system.
You're just eating up your SNR (Signal to noise margin) and maybe adding noise and extra cabling.

Just setup your system like so:
Antenna Feed -> LNA ->SDR -> PC.

 

[GOES 12 GVAR user]

outatyme makes a great point, Trying to get the SDR away from the computer can help alot on that noise. From the pictures above my SDR was on the floor about 5' away from my computer (used an USB extension cable). Computers are noisy in the RF world. Though I would think that downconverter and amp are shielded pretty well.
Try to keep the computer away from the downconverter and amp/antenna well.

Timothy KC0HWG

 

[GOES 12 GVAR user]

Looking at the specs on that antenna it's not built for 1.6 Ghz.
1.7-2.1 GHz is it's working range, this could be a major problem as that antenna is resonant at a frequency above the GOES spectrum. As I said before you're working with signals at the edge of their working limit, parts not made to work within the 1.6 Ghz band will affect signal quality. You can keep trying with this antenna, but it may not work from what I am reading.

Timothy KC0HWG

 

[outatyme]

My antenna was built for 2.4-2.5 GHz band but it works well for EMWIN.
The feed matters more than the Dish in my opinion.

(Although with a grid parabolic (non-solid) dish reflector, the size of the holes / grooves DOES matter and play a role.)

 

[doubleohwhatever]

Here are some screenshots of my working settings

Thanks for these. I spotted a couple of things I was doing wrong. Unfortunately the AirSpy just doesn't offer the required sample rate. I have a SDRPlay coming this week.

Broadband noise being picked up from the environment and coming though the antenna and receive system

I actually just discovered there is a cell tower about an 1/8 of a mile from here. I'm wondering if that might be contributing to noise. I'm also going to try a USB extension cable and see where that gets me.

A band pass filter should really help with noise in some instances.

I have one coming tomorrow. Hopefully that will help.

Trying to get the SDR away from the computer can help alot on that noise

I'm going to place it in a metal box as far from the computer as my usb extension will left me.

Looking at the specs on that antenna it's not built for 1.6 Ghz.

I was hoping it would work since 1692 is so close to 1700. Unfortunately I've been unable to find an antenna designed specifically for 1.7Ghz

My antenna was built for 2.4-2.5 GHz band but it works well for EMWIN.

I'm going to grab one of those TP link antennas. At least I'll be able to rule out the antenna since I know that model works for you.

 

[outatyme]

Here's you a youtube video from a few years ago talking about noise interfering with emwin.


Go to youtube and read the video description

 

[outatyme]

I wouldn't be so fast to write off the airspy or the antenna yet. - it might too be that you aren't peaked properly.

Joe Steinmetz (USA-SATCOM Author of the demodulator) is using an airspy in his setup. Perhaps he will post his settings.

 

[GOES 12 GVAR user]

outatyme your right about the feed and reflector. That antenna has some kind of feed because it has coax coming from it. So it has some sort of built in feed that doesn't work with 1.6 Ghz (not well at least).
doubleohwhatever 1.7 Ghz is the lowest frequency that was made for, It's supposed to work for 1.9 Ghz. As for antennas, any C abnd dish will work. If you know anybody that has an old unused C Band dish (old TVRO) dish above 4' dia. then that will work. Solid or mesh as long as the hols in the mesh are not a 1/2" and it's not all beat to death it will work. All my antennas are C band dishes. That would be alot cheaper than buying one off ebay. You might try to modify that antenna but I don't know how easy that would be. I can tell you the the antenna (element it's self) is too short in my opinion). Making a feed for a C band dish is easy and not to expensive.

Timothy KC0HWG

 

[doubleohwhatever]

Joe Steinmetz (USA-SATCOM Author of the demodulator) is using an airspy in his setup

I've been hesitant to bug him. He seems to be super busy at the moment. He's usually posting to twitter a lot but has been fairly quiet lately.

If you know anybody that has an old unused C Band

Unfortunately C Band and HOA are two things that do not play nicely together. A 4' dish is about the largest I can reasonably hide in the backyard. I would really like to go with a 39" dish but I'm unsure if that size would be worth trying.

 

[GOES 12 GVAR user]

If you can get a 39" then that what you can try. I mention 4' because it a standard size.
If you can get a 48" dish then go with that. That would put you right at 1.2M min. size recommend for GOES. You can continue to try as outatyme said with the current antenna. In MY own opinion I would be looking for something else but not pay an arm or leg to get it and ya HOA's = BUMMER.

Timothy KC0HWG

 

[outatyme]

My dish measures 40'' from end to end horizontally.
Here's another link of someone doing something interesting.
http://wxmesg.blogspot.com/2010/04/converting-werner-labs-3-foot-dish-to-6.html