Parachute Mobile... AM?

[af6im]

Posted this on qrz.com: (check out the video)

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A group of SF Bay area hams are having a lot of fun with parachute mobile operations. See K6MFW's video shot on March 20 2010 documenting jumps made in conjunction with RadioFest 2010 held in Seaside CA. During this operation AF6IM and KF6WRW made jumps from as high as 18,000 feet and worked as many as 30 stations during their descent. The jumpers' position, altitude, heart rate and blood oxygen levels were sent via APRS to mission control. Future jumps will explore altitudes in the 20,000 ft and above range with the jumpers carrying oxygen gear. We will also be using PSK 31 beaconing on 20M and checking reception on pskreporter.com in preparation for future HF SSB QSOs.

Video: http://www.youtube.com/watch?v=dWimbrpGF14

Website www.parachutemobile.org

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I am Jumper 1 (AF6IM) and I love AM. I'd like to do an AM Parachute Mobile jump but the gear has to be small and light. A CB radio tweaked to 10M with a trailing wire antenna might work. Will be jumping in Byron CA (near Tracy) thoughout the sunny season. Any SF Bay Area hams up for some AM Parachute Mobile QSOs? From 14,000 feet I should be able to work many local stations line of sight. Any gear suggestions?

BTW, check this out, it had to be AM and it was done in 1937!: https://parachutemobile.org/forums/viewtopic.php?f=3&t=28
Double click your mouse on the image to expamd it.

73
AF6IM
ART 13 being worked on, ARR 15 up and running incl autotune. And no, I am not jumping with them.

[WB2EMS]

I am Jumper 1 (AF6IM) and I love AM. I'd like to do an AM Parachute Mobile jump but the gear has to be small and light. A CB radio tweaked to 10M with a trailing wire antenna might work. Will be jumping in Byron CA (near Tracy) thoughout the sunny season. Any SF Bay Area hams up for some AM Parachute Mobile QSOs? From 14,000 feet I should be able to work many local stations line of sight. Any gear suggestions?

Mark Great video! I've had a computer problem and been off for a week, so my reply is delayed.

I used to fly sky divers at our local drop zone here in the finger lakes. One of my friends used to operate his Icom IC2AT after opening. I would operate my HT in the plane  while spiraling out of the sky back down after dropping the jumpers. These days I routinely operate 2 meter and 70cm FM from my ELSA aircraft, a CGS hawk. I operate voice and also APRS, SSTV, and on occasion ATV (double sideband AM!). In the pick, a Kenwood D7 on the left is doing APRS with the GPS above it, and can be slaved to the VC-H1 and the nose cam for SSTV. On the right is an FT-51 doing 2 and 70cm FM, and backup Airband receive. The center radio is the Icom Airband unit. PTT is the square red button on the top of the stick, and PTT/Mic select is the buzzardly pointy knob under the airspeed indicator right of center. Left is airband and both headphones get only airband audio. Right is ham, and the left headphone stays on airband and the right headphone gets the audio from the FT51.

For operating AM, or even FM, my gear recommendation would be get a hold of an FT-817. 160m-70cm, all modes, 5 watts and a compact package with batteries inside. I've made AM contacts with it even with pretty poor antennas.  I think you could even wear it on a harness inside your coverall with just the mic arrangements similar to what you use now on a fixed frequency. If you could find a safe way to stow the wire antenna until after a good opening, you could carry a 1/4 wave end fed wire and just pull it clear and drop it to deploy on whatever band you desire.

Consider maybe 8-66 feet of snag free wire on a spool or bundle in a smooth fitting pouch on your leg with good velcro closures so it would stay safely stowed until after you were under canopy, then open the bag and drop the wire down below you. Cut it for a 1/4 wave on the band you want to work. I'll bet on 40 meters or 20 meters you could make some pretty good dx contacts from 15,000 ft, and I'd bet that a 75 meter qso would be pretty sought after.

I've run my FT817 on the hawk, but the ignition noise is something I need to cure. You won't have *that* problem. 

Keep us posted on your future exploits in the area. I would love to work you on 20 meters from the east coast from my air mobile while you were parachute mobile!

[af6im]

Great response Kevin, thank you. That Hawk looks like real fun. I have about 12 hours solo in ultralights, Eipper MXs and Lazers, long ago. That panel and ham gear install looks great.

I have the use of an Icom 703 QRP HF rig which might do the job and it has an AM mode. It's slightly larger than the Yaesu FT 718 and doesnt have an internal batt, but I think I could safely jump with it. It has a built in antenna tuner.

My teammates think I am nuts to try HF phone, much less AM, but I am going to try it. I'll keep you posted.

If I hear ignition noise under canopy at high altitudes I am probably seconds away from being hit.  
I read that the USAF used special rcvrs in low flying SP2H aircraft to listen for ignition noise at night along the Ho Chi Minh trail. The North Vietnamese trucks had poorly shielded ignition systems. Don't know how well it worked.

A trailing wire antenna sounds good, just have to be sure to jettison it or roll it up. Wouldn't want to drag that underneath me as I cross power lines.

I wonder what the chances of a jump coinciding with good proapgation would be? These days many DZs are tandem mills and we have to wait for empty slots on loads since we pay about 10% of what the tandems pay per jump.

I am glad you replied. I was starting to think AMers might have no interest in paracute mobile. Any further ideas you might have or responses from others would be gratefully recieved.

73
AF6IM

[K6IC]

Hi Mark,

Great Topic,

I worked one of you guys last year on 2M Simplex.  The jump ended near Tracy, CA ... perhaps it was KF6WRW,  I do not recall,  but great sing from under canopy.

Could easily do Rice Box 10 M AM from the remote QTH,  SE of Livermore about 15 air miles.

Sorry for my delay,  the other QTH has no internet.  72  please keep us posted,  Have Fun,    Vic

[af6im]

Hi Vic,

We will definitely try an HF AM QSO this summer while jumping at Byron (near Tracy CA). Jumps are really cheap there, $17 to 14,000 feet and views are nice too from higher altitudes. You can see the bay, the delta and the ocean and if WX is clear, the Sierras.

We will be jumping at Byron during Pacificon in Oct. Maybe we can get some interest stirred up and get more folks wanting to work parachute mobile AM during the event. The venue might  be line of sight during the higher portions of the jumps.

Do you remember if you were talking with Jumper 1 or Jumper 2? We were making some jumps together at Byron in October 09 and using diff 2M freqs. We gave our callsigns but only every ten min. We used Jumper 1 & 2 calls to keep it short.

73,
Mark
AF6IM

[K6IC]

Hey Mark,

Well it was an event where there was a Net Control -- K6OJ (with KI6BEN),  and some clown was on the rag about weather EVERYONE had a real Hammie license.

I do not really remember the Jumper #,  I did log the Q,  but that paper log is @ the other QTH.   If any of that rings a bell.  I do not even remember the FM Simplex freq ...

Nice to see you here,  and will stay tuned.  Good luck,  and sounds like a real kick for the jumpers,  'twas a kick for me to make the QSO.

72  Have  Fun,     Vic

[WB2EMS]

Mark,

Yeah, sorry for the delay. I had a hard drive failure (solid state hard drive - just turned to molasses, and while I could read from another machine, I didn't have my password so I couldn't log in to reply!

The 703 is a nice rig too, though maybe a little large for comfort. I use an 817 on my recumbent bike in a pouch hung from my neck and laying on my chest with a lead off the BNC back to an antenna on the rear of the bike and it would be easy to just slide it under a jumpsuit. The 703 could probably be done that way too, but you'll also need a battery. But hey, if you have it, 'run what you brung'!

I didn't think about a hanging wire hitting a power line, that would be no fun at all. Maybe something cheap you can cut loose as you get down near the ground, or something easy to retract back up into a pocket or something. If you can pick the wire length, you don't really need the tuner. If you did need a tuner with the 817, I'd recommend the elecraft T1. Tiny and good.

One advantage of the 817 is you could pre-program a bunch of different channels on it, some on HF, some on 2 meters or 70cm. Put a whip on the BNC on the front and route the wire antenna to the so239 on the back and you can go from vhf to hf with just a channel change.

A quarter wave worked against just your body as ground would probably work, but you might have a more effective antenna if you used a whole half wave, and end fed it. Google End Fed Half Wave (EFHW) antennas in connection with HF packing. N0LX and AA5TB have written some very good articles on making a simple tuner (parallel LC) in a plastic box to end feed a half wave or a shortened half wave with loading coils and they work quite well. I use one on 20 meters on my HF packing backpack with a shortened antenna on a crappie (a type of fish) pole like Jake N0LX came up with, with good results.

http://pages.suddenlink.net/wa5bdu/efhw.htm - this one describes how they work pretty well
http://n0lx.com/  - check out jakes EFHW antennas

a fix tuned little box with the correct length of wire would be a very effective antenna at 15K.

The Hawk is a good bird. Mine is a two seater, was a trainer until the F'nAA changed all the rules and put most of us out of business. Got converted to an ELSA in the window of opportunity to do that. PITA! 65 hp rotax twin, 900 fpm climb solo. Once I tame the ignition noise, I will be looking into installing some sort of trailing wire antenna. I figure a 66' wire worked against the 36 foot wingspan as a counterpoise will do pretty well.

Your drop zone sounds beautiful, I'd love that view. Ours was in the middle of the finger lakes region of Central NY (Ovid). From 10,500 I could see about half the finger lakes, Syracuse 70 miles away, Lake Ontario to the north, and down into PA and lots and lots of farm land. Beautiful on a clear day or night.

I love mixing ham radio and aviation. My first airborne QSO was on a 2 meter HT on the flight back from my PPL check ride!  One of the most interesting aviation contacts I made was from a C-172 to a replica viking longboat making it's way down the Erie Canal enroute to the Atlantic for a crossing attempt. Wish I'd gotten the QSL for that.