Re: [altusmetrum] Antenna in a small AV bay?
Casey Barker writes: > Hey Winton, this was also my first question to the altusmetrum list, about > 2 years ago. :) > > Don't curve it around or dangle it outside. Just drill a hole in the > bulkhead and run it up next to the chute, then use some RTV or glue to seal > the bulkhead hole and prevent residue from getting into the bay. I've glued a piece of acrylic tubing to a hole in the bulkhead for one airframe; the antenna wire slips up inside that nicely and the chute packs around it without too much trouble. It's survived probably a dozen flights with the BP charge going off right next to the tubing. Useful if you need to pull that bulkhead off the ebay. I've also gone 'naked' without the tubing and I've found the wire tangled up after flight most of the time; not sure what I'm doing wrong, but clearly it's not working for me like it does for others. -keith pgpFTSEubGR0G.pgp Description: PGP signature ___ altusmetrum mailing list altusmetrum@lists.gag.com http://lists.gag.com/mailman/listinfo/altusmetrum
Re: [altusmetrum] Antenna in a small AV bay?
Winton Davies writes: > Ah, sorry - I just noticed Casey suggesting sealing it -- thats the bit I > dont understand - the bulk head has to be removable? or is it glued to the > sled, in which case the antenna doesn't need to "separate" Depends a lot on how you put things together. May electronics bays are designed with a "sled" that's more or less attached to one bulkhead, often by being attached to threaded rods that are attached to the bulkhead. Using a suitable connector to make the other bulkhead detachable allows you to pull the bay apart to get to the contents... but you have have the altimeter hard-mounted to a sled with the wire going through the semi-permanently attached bulkhead. Bdale pgpAcCDNWNX3I.pgp Description: PGP signature ___ altusmetrum mailing list altusmetrum@lists.gag.com http://lists.gag.com/mailman/listinfo/altusmetrum
Re: [altusmetrum] Antenna in a small AV bay?
Winton Davies writes: > So no glue needed? I thought one needed to seal the tube against the > gases? I've been known to drill a hole small enough to be an "interference fit" for the antenna wire, at which point there isn't much left to seal. But a dab of modeling clay or RTV works fine too. Bdale pgp1tpQYEIxXR.pgp Description: PGP signature ___ altusmetrum mailing list altusmetrum@lists.gag.com http://lists.gag.com/mailman/listinfo/altusmetrum
Re: [altusmetrum] Antenna in a small AV bay?
Ah, sorry - I just noticed Casey suggesting sealing it -- thats the bit I dont understand - the bulk head has to be removable? or is it glued to the sled, in which case the antenna doesn't need to "separate" W On Thu, Apr 11, 2013 at 9:19 PM, Winton Davies wrote: > Thanks! > > So no glue needed? I thought one needed to seal the tube against the > gases? > > W > > > On Thu, Apr 11, 2013 at 9:12 PM, Bdale Garbee wrote: > >> Winton Davies writes: >> >> > I was hoping to get the TM into a 2.6" diam x 5" long AV bay (the Madcow >> > one) - however my forward and rear payloads are already pretty crowded >> with >> > linen, and I'd rather not have a dangling wire in there that could be >> > ripped off. >> >> Running the antenna wire through a small hole in the bulkhead and just >> letting it lay against the side of the bay works pretty well in >> practice. A useful trick is to use a drinking straw to hold the antenna >> wire straight while you stuff in the laundry, then pull the straw out. >> >> > So - How much signal loss if that wire is just curved to fit the AV >> > bay ? >> >> It's not great. You can easily ground test this, though, since altosui >> will show you the received signal strength for each packet received. >> >> Bdale >> > > ___ altusmetrum mailing list altusmetrum@lists.gag.com http://lists.gag.com/mailman/listinfo/altusmetrum
Re: [altusmetrum] Antenna in a small AV bay?
Thanks! So no glue needed? I thought one needed to seal the tube against the gases? W On Thu, Apr 11, 2013 at 9:12 PM, Bdale Garbee wrote: > Winton Davies writes: > > > I was hoping to get the TM into a 2.6" diam x 5" long AV bay (the Madcow > > one) - however my forward and rear payloads are already pretty crowded > with > > linen, and I'd rather not have a dangling wire in there that could be > > ripped off. > > Running the antenna wire through a small hole in the bulkhead and just > letting it lay against the side of the bay works pretty well in > practice. A useful trick is to use a drinking straw to hold the antenna > wire straight while you stuff in the laundry, then pull the straw out. > > > So - How much signal loss if that wire is just curved to fit the AV > > bay ? > > It's not great. You can easily ground test this, though, since altosui > will show you the received signal strength for each packet received. > > Bdale > ___ altusmetrum mailing list altusmetrum@lists.gag.com http://lists.gag.com/mailman/listinfo/altusmetrum
Re: [altusmetrum] Antenna in a small AV bay?
Winton Davies writes: > I was hoping to get the TM into a 2.6" diam x 5" long AV bay (the Madcow > one) - however my forward and rear payloads are already pretty crowded with > linen, and I'd rather not have a dangling wire in there that could be > ripped off. Running the antenna wire through a small hole in the bulkhead and just letting it lay against the side of the bay works pretty well in practice. A useful trick is to use a drinking straw to hold the antenna wire straight while you stuff in the laundry, then pull the straw out. > So - How much signal loss if that wire is just curved to fit the AV > bay ? It's not great. You can easily ground test this, though, since altosui will show you the received signal strength for each packet received. Bdale pgpLtT11Pxejz.pgp Description: PGP signature ___ altusmetrum mailing list altusmetrum@lists.gag.com http://lists.gag.com/mailman/listinfo/altusmetrum
Re: [altusmetrum] Antenna in a small AV bay?
Hey Winton, this was also my first question to the altusmetrum list, about 2 years ago. :) Don't curve it around or dangle it outside. Just drill a hole in the bulkhead and run it up next to the chute, then use some RTV or glue to seal the bulkhead hole and prevent residue from getting into the bay. It's easy to solder a new piece of wire if you damage it, or get the SMA version to make it replaceable. You could use a piece of straw to protect it, but to be honest, I don't see much damage even when it's right next to a 2g BP charge. Casey On Thu, Apr 11, 2013 at 6:01 PM, Winton Davies wrote: > Hi, > > I was hoping to get the TM into a 2.6" diam x 5" long AV bay (the Madcow > one) - however my forward and rear payloads are already pretty crowded with > linen, and I'd rather not have a dangling wire in there that could be > ripped off. > > So - How much signal loss if that wire is just curved to fit the AV bay ? > It'll be inside 2 layers of fibreglass, (not CF) obviously? > > Has anyone flown with it dangling outside through a static pressure port? > > Should I consider some kind of compromise - like 2" of the 7" whip antenna > outside, epoxied in place to the bulkhead, with the bulk of it inside the > bay, connected by an SMA-SMA coax? > > Has anyone gotten a good solution for this? > > Cheers, > Winton > > > ___ > altusmetrum mailing list > altusmetrum@lists.gag.com > http://lists.gag.com/mailman/listinfo/altusmetrum > > ___ altusmetrum mailing list altusmetrum@lists.gag.com http://lists.gag.com/mailman/listinfo/altusmetrum
[altusmetrum] Antenna in a small AV bay?
Hi, I was hoping to get the TM into a 2.6" diam x 5" long AV bay (the Madcow one) - however my forward and rear payloads are already pretty crowded with linen, and I'd rather not have a dangling wire in there that could be ripped off. So - How much signal loss if that wire is just curved to fit the AV bay ? It'll be inside 2 layers of fibreglass, (not CF) obviously? Has anyone flown with it dangling outside through a static pressure port? Should I consider some kind of compromise - like 2" of the 7" whip antenna outside, epoxied in place to the bulkhead, with the bulk of it inside the bay, connected by an SMA-SMA coax? Has anyone gotten a good solution for this? Cheers, Winton ___ altusmetrum mailing list altusmetrum@lists.gag.com http://lists.gag.com/mailman/listinfo/altusmetrum
