Recap of EOSS-132

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Recap

by Mike Manes, W5VSI

EOSS-132 for the Boy Scouts out of Crow Valley is over and can be chalked up as the typical mixture of successes and failures, but a good flight overall.

Highlights:

The Honda EU1000 ran the full duration, with plenty of gas left in its tank when we left for home. This included powering 400 W and 75W lamps during setup from about 0545 until sunrise at 0700.

The HF G5RV was erected w/o help along the 3rd base fence line and did a great job with the pactor link to K0TER in COS on 3590 kHz. Both the FAA and APRS predict files moved in just a few minutes with Mike's S9+40 signal. This proves that we can get those predicts in the absence of internet at any site we launch from.

There were plenty of Scouts and leaders on hand during the launch and early flight, and about 6 of 'em chatted with Mark on the crossband repeater.

We got a great VHS recording of the burst, even though the Scouts had already moved on to their next event at that time.

Many thanks to Bill K0UT (ed note: Bill reports Dave Galpin KB0LP and others were pitching in on the setup) for setting up the ground station gear at my position while I was occupied getting the HF station running, to Don KD4SDW (?) for helping get the payload string configured, and to Russ and Don for erecting the az-el mount. Apologies if I got Don's callsign wrong. (ed note: Don, send along your callsign and I'll correct it)

The LiftWin gas fill and burst altitude estimates were pretty accurate.

The new Li-ion battery packs on AE0SS-11 and the de-spun ATV held up quite nicely during the 3+ hours of operation from power-up to shutdown. AE0SS-11 still had about 80% of life left, and ATV had over 50% left. So the Li-ion conversions of these 2 modules are now flight qualified.

For Glenn WB0DKT: The parachute as delivered after recovery was in FB shape. Thanks! But it carries easier if it's rolled up in the bundled shroud lines.

Lowlights:

Murphy's first shot was failure of the ATV module to deliver video. Thanks to Dave KBOLP's diagnosis of carrier and no video - this wasn't apparent from the ground station which was just showing a "blue screen" from the VCR. And to Don KD4SDW for his invaluable assistance while I did surgery inside the module with a butane soldering iron to restore video. That effort resulted in accidentally creating a solder bridge, shorting out the ATV CW ID signal.

Despite that effort, the down look view was obscured by a fogged-up acrylic dome. Amazingly, that dome got fogged up while it was waiting for the launch team to arrive!

Although I got the APRS predict file easily on 80m pactor, my attempt to post it on the AE0SS-11 BBS, BALBOX, failed, since the VHF-side PTT keying signal from the KAM+ that I thought had been fixed returned.

The crossband repeater 2m downlink signal was QRP to the extent that the Scouts had a hard time hearing Mark KC0D.

Despite the great signal on 80m from K0TER, the noise level on 3810 KHz at my site wiped out the SSB signal from Marty WA0GEH. At first, I thought this was computer noise from the ground station gear, but prior to tearing down, it was traced (maybe) to inverter noise from the Honda generator.

Postmortem:

The intermittent loss of the ATV video was caused by my incomplete insertion of pins in the Molex Micro-Fit 3.0 connector added to the B-LAN interface. I guess the jiggling while trying to fix a suspect bad solder joint on the ATV xmtr got the loose pins to mate for the duration of the flight.

A cracked-out piece of the ATV down look dome broke free from the solvent bond used to fix it after a prior hard landing. This probably contributed to the fogging problem. We will have to replace that dome if the broken piece doesn't show up on disassembly.

The loose Molex connector pins have been fixed, and the solder bridge that killed the ATV CW ID has been removed. ATV runs FB now from the partially discharged Li-ion pack.

Somewhere during the flight, the B-LAN GPS apparently lost lock, since the lat/lon reports were unchanging and the "Alt:" field was blank. Suspect this happened during descent. I'll bring the B-LAN and VHS tape to the October meeting in Longmont for Steve 'SCC to figure out.

The weak crossband 2m downlink signal was caused by an "air gap" between the coax center conductor and the ground plane radiating element. That junction is embedded in epoxy pot, and is on the bench as we speak. Orthopedic meatball surgery may be required.

Repair of the KAM+ VHF PTT problem is next on the list. Suspect a bad bond wire in the TO92 keying transistor. Got a replacement on hand.

So once again, our quest for the flawless flight remains just a bit beyond our reach - but that's why we keep doing it, eh?

Others may have differing evaluations and reports. Let's hear 'em!

ed note: After looking over the payloads Mike submitted this email for our consideration.

Here's the final postmortem of the failures observed during the flight. Ironically or whatever, three of 'em turned out to be "air gaps" (open circuits), with 2 inside connectors. I guess Murphy was on an air gap jag last weekend!

Postmortem:

The intermittent loss of the ATV video was caused by my incomplete insertion of pins in the Molex Micro-Fit 3.0 connector added to the B-LAN interface. I guess the jiggling while trying to fix a suspect bad solder joint on the ATV xmtr got the loose pins to mate for the duration of the flight. The loose Molex connector pins have been fixed, and the solder bridge that killed the ATV CW ID has been removed. ATV runs FB now from the partially discharged Li-ion pack.

A cracked-out piece of the ATV down look dome broke free from the solvent bond used to fix it after a prior hard landing. This probably contributed to the fogging problem. We will have to replace that dome if the broken piece doesn't show up on disassembly. Update: I've found a source for optical domes on the web: http://www.cleardomes.com/domes.htm which lists an 8" acrylic dome at $39 and in Lexan (polycarbonate) for $78. Much cheaper than reseller Edmund Optics acrylic. Lexan will withstand a lot more abuse than acrylic.

Somewhere during the flight, the B-LAN GPS apparently lost lock, since the lat/lon reports were unchanging and the "Alt:" field was blank. Suspect this happened during descent. I'll bring the B-LAN and VHS tape to the October meeting in Longmont for Steve 'SCC to figure out. Update: Just ran the ATV and B-LAN to verify that my video gain and pedestal adjustments were correct, and discovered the 4x AA NiMH pack was totally discharged - unloaded output was just 2.5Vdc. The power switch was OFF when returned from the field.

The weak crossband 2m downlink signal was caused by an "air gap" between the coax center conductor and the ground plane radiating element. That junction is embedded in epoxy pot, and is on the bench as we speak. Orthopedic meatball surgery may be required. Update: This "air gap" was in the RG-142 center conductor midway between the ends - right where bend radius maxes out. This was discovered only after performing a root canal on the epoxy pot that mounts the radiator. It's now repaired, although coax is about 2.5" shorter than before.

Repair of the KAM+ VHF PTT problem is next on the list. Suspect a bad bond wire in the TO92 keying transistor. Got a replacement on hand. Update: The PTT keying was OK, but there was yet another "air gap" in the xmit AF coax center conductor inside the DB-9 connector. Now fixed and tests OK on air.