Smallest EMWIN antenna

[GOES 12 GVAR user]

Also to let everyone that reads this know....EMWIN get it's satellite images of EAST and WEST form the GEO. satellite server the NOAA has. The server is at least 1 hour behind in updating compounded with the delay of EMWIN priority of products they are hardly even close to accurate. Only in a general term.

Timothy KC0HWG

 

[outatyme]

cool beans - It will be interesting to see the result.
For right now I am waiting on doubleoh to make some more recordings - the ones he has made so far seem 'off'. like there is something amiss with the SDR settings or the recording settings.

 

[GOES 12 GVAR user]

I have got two TL-ANT2424B Grid Parabolic Antennas coming. I have an idea that may solve Trip, doubleohwhatever and anybody's problem with low gain with these. I will not go into detail here yet until I test the idea. Meanwhile I will continue to build this 1.2M antenna and share the results. Thanks to Trip showing me what is under that feed cover with those and what to do to.

Timothy KC0HWG

 

[outatyme]

you got pics of what is under the feed? Now you got me curious

 

[GOES 12 GVAR user]

Trip has pics, post 119 page 6. Shows the antenna details just what I was looking for.

 

[outatyme]

Ah yeah, I see where he lengthened the dipole. I'm sure that helps with gain.

 

[GOES 12 GVAR user]

That's makes the antenna resonant at or near 1.6 GHz. But that alone will not provide more gain. Gain is a function of the reflector size and antenna element together at an reasonable efficiency. They should be here in a week.

 

[doubleohwhatever]

Well, here's the update for today. The tp-link antenna arrived (photos attached). There are two obvious differences between the tp-link antenna and the other antenna. The tp-link antenna has better quality coax and the dish is almost twice as heavy. A minor but interesting difference is that the tp-link antenna has a MUCH better paint job. The odd thing is that these two antennas are otherwise identical. They're obviously made in the same factory somewhere in Asia. The tp-link antenna just has a slightly better build quality. So for this reason, I swapped out my old antenna for the tp-link antenna. I'm just going to chunk the old one because the dish really is quite flimsy in comparison.

My sdrplay also arrived today and with it I have now discovered problem #99... The machine I had running sdr-console with the airspy on out in the garage isn't powerful enough to run sdr-console with the sdrplay. I sort of figured I'd run into this problem at some point. I had originally planned to run airstreamer on the little machine I've been using and run the decoder in a VM on my xen cluster. Unfortunately, sdr-console is much more CPU intensive with the SDRPlay. So now I have one of these arriving thursday:
www.amazon.com/Gigabyte-i7-6500U-Compact-Barebone-GB-BSi7H-6500/dp/B0195XYOV8

 

[outatyme]

Woah! Major difference in the coax there. - keep the old dish for wifi or something

 

[doubleohwhatever]

I boxed the old dish up in the tp-link box and tossed it in the attic. Might come in handy some day.

I forgot to mention that I also ordered the dish I linked to on ebay. This one: http://goo.gl/308XWR

While I feel like I could most likely get the grid dish to work (and will keep working with it for now), I think a larger dish is a better long-term solution. I was watching the signal the other night when we had a thunderstorm roll through and the signal virtually disappeared. I know that particular dish is pricey but it's new (no dents to deal with) and it'll be easy to mount to a concrete slab I already have in place.

Btw, does anyone have a link to a DIY l-band feed tutorial?

 

[GOES 12 GVAR user]

Keep the old dish it may yet be of use for this project. That coax is LMR 400 type. It work well for jumping between blocks but it does have a weakness. If it is the solid center conductor type the center conductor can break if bent repeatedly. See my picture of the L band feed for what it's best for (Pg. 12).

 

[GOES 12 GVAR user]

I can tell you how to make an L band feed like the one that's in my picture. I have dimensions for the design. All that is needed is an N or SMA connector whatever is preferred. It's said that you can use the coffee can but I don't like them as they rust.

 

[doubleohwhatever]

If it is the solid center conductor type the center conductor can break if bent repeatedly

Definitely not solid. I have some LMR400 that's solid and it's much stiffer.

I can tell you how to make an L band feed like the one that's in my picture

That would be great. What diameter does the can need to be? Would something like this work?: http://goo.gl/ybgdv9
I have a kit of those in the attic. They're horrible at being a storage containers but I figured they might come in use someday. If you remove the ring holding the top on you're left with a can. This photo gives a good view: http://goo.gl/hiIvsR

 

[GOES 12 GVAR user]

Still here just drawing up the diagram for you, with a picture.

 

[doubleohwhatever]

Much appreciated but definitely no rush! I've discovered this project is a massive exercise in patience!

Btw, I discovered something interesting. sdr-console freezes the moment I start running it with the sdrplay. However, I noticed some UDP traffic still coming from the machine. So I started the decoder and it actually seems to be getting better data with the sdrplay. Apparently it's just the sdr-console interface that freezes. The background process still runs. Once I get the more powerful machine and can actually run sdr-console and tweak things, I may actually get somewhere with this.

 

[GOES 12 GVAR user]

Forgot to mention use connectors with PTFE dielectric, Nylon at Min NO plastic.

Probe detail, just used copper flashing bent at a 90 to give rigidness.

 

[doubleohwhatever]

Awesome! Thanks for this!

I just dug through my parts drawer and found one of these:
http://www.alliedelec.com/amphenol-rf-172119/70031804/

Any reason that wouldn't work?

Also, is the length or diameter more important? I have a 5' x 7.5" canister and a 5.5" x 14" canister I could cut down.

 

[GOES 12 GVAR user]

That'll work. Keep your hole size just bigger that the lip so the connector sets down on the surface. Use 4 bolts no screws to bolt er on. Use round head bolts (machine bolts) with the head on the inside on the horn thread nuts from the top. Put some sort of sealer around connector body where it meets the horn body after it's installed so water will not enter horn. BYW keep bolts as short as possible so that they don't interfere with connector mating.

 

[doubleohwhatever]

Actually, since my LNA has SMA connectors, I imagine it would be better to just use an SMA panel mount and ditch the N to SMA adapter. I'm gonna grab these:
www.amazon.com/CablesOnline-Bulkhead-Connector-Adapter-RF-M901-2/dp/B00KOVOTSE/

I have a high quality SMA jumper I can use between one of those and the LNA.

Again, thanks a ton of the help! I'm calling it a night

 

[GOES 12 GVAR user]

Dish is about done. I'm out be back soon.