Many of you have no idea what goes on when AO51 is in the S band downlink mode. Until this past week, I was in the dark as well. Who operates S band and what is it like compared to the more popular V/U mode? What kind of equipment does it take to get on S band. If you don't have S Band equipment, should you invest in some? Are you going to work anybody new or perhaps a new grid? After a week of making q's and listening to 29 passes of S band, there is some data and observations to share.
A lot of people are using the K5GNA setup. My setup was quite different. The antenna used was a Hyperlink Technologies (now L-Com in Florida) 18dbi Wifi Panel Antenna. It is well made and comes with stainless mounting hardware including a 2-1/2" U-bolt that will fit most any mast. It's about 2" thick and 14"x9" rectangular. Price is $50, not bad for a well made weatherproof outdoor antenna. The Down East Microwave preamp kit and outdoor housing for it is about $85. The outdoor box is as expensive as the preamp kit itself. It was mounted on the antenna with a 7' 9913 pigtail. The 45' of coax into the shack is 3/8" Andrew Heliax. In the shack is a Drake 2880 down converter with a new crystal from G0MRF to get the output on 145 MHz. Both the preamp and the downconverter are powered through the coax so you need two power inserters. I used a second radio for the IF so that there was no chance of transmitting into the downconverter. Doppler is about =/- 55 KHz from horizon to horizon. You can see what it looks like on the tower on my qrz.com page. Click the image to enlarge.
At first I was disappointed because I am used to hearing 435.300 down to the horizon in most directions. It didn't happen with S-band. But after listening to other stations, it was apparent that my setup was hearing better than most. There has been discussion about the slow roll of AO51 and that is certainly apparent, however, I could not hear much below 6 degrees, ever. Maybe a bigger antenna would help out, but those that were active didn't seem to have any better receive capabilities so it makes you wonder.
Now for the activity data. Below is each pass that I operated or listened to and the stations I worked (with an asterisk) or ones that I just heard (no asterisk).
8/16/2009 2245Z (first S-Band mode pass) KC9ELU* KJ4MC KD8CAO*
8/17/2009 0036Z KC9ELU* N6PAA W7LRD
8/17/2009 1053Z KC9ELU*
8/17/2009 1234Z VE2DWE* KC9ELU* KD8CAO* KB2M* W8KHP N5ZNL*
8/17/2009 2359Z W8KHP* N5ZNL* VE2DWE* W7JPI* K5WH* W7LRD* K9QHO*
8/18/2009 1151Z WB8OTH* W7JPI* N5ZNL* W8KHP*
8/18/2009 1331Z K9QHO* W7JPI*
8/18/2009 2128Z WB8OTH* KC9ELU* W8KHP
8/18/2009 2305Z W7JPI* KC9ELU N0JY* W8KHP* N5ZNL K9QHO KD6IRE? XE2BHL
8/19/2009 1116Z KC9ELU
8/19/2009 1252Z WB8OTH* XE2BHL* KC9ELU*
8/19/2009 2230Z W8KHP* VE2DWE*
8/20/2009 0006Z N5ZNL/P* N5UXT* N0JY* VE2DWE* W8KHP* WB8OTH W7LRD*
8/20/2009 1213Z KC9ELU* KB2M* W8KHP* N5UXT* N5ZNL
8/20/2009 1353Z AI7W* W7JPI* KC9ELU WB6QVU?
8/20/2009 2153Z NO STATIONS HEARD
8/20/2009 2326Z W7JPI W8KHP K9QHO W7LRD WHISTLER
8/21/2009 0111Z 2 DEGREE PASS, NOTHING HEARD
8/21/2009 1145Z N5ZNL* KB2M*
8/21/2009 1314Z KC9ELU* N5UXT* W7JPI*
8/21/2009 2246Z KG4ZLB* WB8OTH* N0JY* W8KHP* AK5V*
8/22/2009 0029Z AK5V* KB2M N0JY* W7LRD*
8/22/2009 1053Z KC9ELU* KB2M*
8/22/2009 1234Z KC9ELU* W7JPI* K8KHP*
8/22/2009 2207Z KC9ELU*
8/22/2009 2347Z WA5KBH* WD9EWK* N5ZNL* XE2BHL* KC9ELU*
8/23/2009 1156Z W2NBJ* KC9ELU* WA4SCA*
8/23/2009 1332Z KC9ELU* W7JPI* N5UXT* XE2BHL
8/23/2009 2127Z KC9ELU* N1RCN*
Mike, KC9ELU was on vacation this past week and was the most active station on S-Band. It was interesting to compare our reception and have airtime to discuss it.
The only new guys I'm aware of were myself and N1RCN who got things working on the very last S-Band pass. Drew, where were you?
Some have been asking for more S Band, but if you take a look at the activity, it pales in comparison to what we have in the V/U mode. The last AO51 V/U pass tonight (8/25/2009 0007Z max elevation 17 degrees to the west for me) had at least 23 stations on it. More were trying. It's a Monday night! I never heard more than 8 stations on any S-Band pass, and there were plenty with just one, two or three.
If you have AO40 equipment laying around, you might be a good candidate for S band. But unless you are prepared for a very high dollar investment/qso, you probably won't be buying S-Band equipment to work the few stations that get on that mode. If you want to do L/S, there will most likely be even less activity since making noise on 1.2GHz is even more expensive. (When L/S comes on, I'll have another report.) My antenna system could be improved but there's not much point in spending more effort and putting more windload on the az/el rotor to hear down to the horizon.
We need to balance the interests of everyone and that is understood. We need some V/S or L/S from time to time. I'm not sure, however, that an entire week should be devoted to it considering the usage. Maybe a few days at a time would make more sense. You work on your equipment and get ready for the three day period. If your setup doesn't work, you figure out why and get on the next time. Shorter sessions would focus the activity rather than spread it out over a week's time.
We should do things that will interest new people in working satellites. V/U is the entry level for newcomers and we should make that available as much as possible. There are other FM birds, but nothing compares to what AO-51 does to attract new hams to satellite technology. It's signal level, available time/pass and morning/evening pass schedule over the US are ideal.
There is a lot of debate over what we should be doing for the future. But it is as important to debate how we should use the resources we have available to us right now. My hope is that this post will inspire some constructive comments and discussion on this subject.
John K8YSE