Free Supplies for Cone Extension Experiment


#21

Tyler, your paper cup assembly should work fine too as you’ve found out.

Yes I did add a short ribbon cable with a male connector at one end, and a female at the other. As you guessed, the display should have been mounted elsewhere on my travel case so I could read the display in bright sun. That’s usually the direction my LNB is pointing when I site it. Ken


#22

I guess I have a questioning mind. There is no longer any discussion on signal strength, cone’s, antenna mounts.

Did the format/mode changes back in September really solve the snr issues ? Or was there an increase in satellite xmit power ? What do we need to expect if/when the next geographic area gets satellite coverage ? What parameters changed to allow the signals to be easier to receive / decode ?


#23

The other question I have is - - what was the the effect of the recent MODEM replacement at the MD earth station have. SNR increased about 8 dB here (however Rssi remained the same).

Perhaps some of us who installed cones and wave guides should temporarily remove them and report results. Ken


#24

@ac8dg We are currently designing a flat panel antenna that is a bit higher gain than the Maverick. Designing patch arrays is tricky business so it is taking some time and there is sometimes two steps forward and one step back. The problems at the teleport had nothing to do with SNR; it was a hardware issue.

We need to finalize the front end before we can expand to Europe and Africa. I’m hoping the antenna design will finish by the end of this month. A higher gain antenna does allow for better reception quality. Of course, higher gain also means smaller beam width, which makes it harder to point. It’s a bit of a trade.

@kenbarbi We ended up not needing to replace the modem. It was another hardware issue. I’m not sure how SNR increased by 8 dB for you. We saw maybe a 2dB improvement.


#25

Thanks for the update, just for info,
I have a signal of +5 snr, yes that is right a positive value.


#26

What is your antenna for +5? I have about the same gain using DirecTV dish and Maverick LNB.


#27

Hmm @Syed are there any plans on like a golf ball attenna style so even if it high gain we could get higher data transfer then what it has now with a some what of a Omi directional attenna?


#28

No plans on a golf ball antenna.


#29

Trust me - - my Dreamcatcher 500 ft away from my Ku-band FTA offset dish/LNB did increase and is still running hi. I think other will confirm higher SNRs.

I took my portable terminal outside just now to compare with my observations. With a bare LNB, I immediately found the satellite by aiming ruffly at the sky receiving a signal with an SNR of -7.25dB and Rssi of -77 dBm. When I pulled up my expandable cup cone, my SNR jumped to -3.75 dB with an Rssi still at -77 dBm.

You’ve done something :rofl: Ken


#30

PS

I think it will be worth your while finding out what else got tweaked. 8 dB is nothing to sneeze at. Ken


#31

@donde my antenna is similar , the 18" dishtv but with a non-maverick lnbf, I found on ebay a linear v/h with a rectangular insert that fit the original boom mount. The ‘stock’ dishtv lnbf was circular and the wrong frequency range.


#32

The key is more diameter. I still commend the Team wanting to pursue a much smaller design.


#33

Diameter/aperture is the key to increased gain and better SNR, but that needs to be balanced with the design of a simple, easy-to-install product. We could always get our ideal gain by using a large dish, but if we did that why bother with the inefficient bandwidth utilization of a spread spectrum carrier. We could (and previously did) use operate our data broadcast over DVB-S. But the consistent feedback we received was the need for a smaller device that did not need large cable runs. Sure, we could just use a small dish–a 4-inch reflector has the second aperture as a 4-inch cone and 4-inch array. But an LNB and dish (even small one) is still pretty messy.

What we are shooting for is something the size of a DVD; antenna on one side and digital components on the other. And less than 8 ounces so it ships cheaply.


#34

Please don’t forget to address this. Ken


#35

We haven’t seen the same 8dB bump you are seeing anywhere. There is a few more dB coming down, but not that much.


#36

I like this plan, particularly if it easy to point. Reminds me of how easy it was to setup the L-band antenna. Just pointed it in the general direction with no trees. It even worked sitting indoors pointed out the window.


#37

Higher gain means smaller beam width. There is no way around that, sadly. The L-band antennas had a beam width around 60-degrees. I think the gain was around 7.5 dBi?

We are targeting 20 dBi of gain, which requires an aperture of about 4-inches (a DVD has a 4.7-inch diameter). The theoretical beam width of the antenna would be 20-degrees, assuming there are crazy side lobes which pull down the peak gain and also decrease beam width.

As reference, a typical Ku satellite dish has a beam width of 2-degrees.