<div dir="ltr">On the balloon we currently have a 1/4 wave monopole with ground radials.<div><br></div><div>On the ground (At least on matt's car) there is a crossed-dipole, mainly for the hemispherical radiation pattern (no null directly overhead), but the circular polarisation can help when the payload is tumbling (reduces the depth of the nulls)</div><div><br></div><div>- Mark VK5QI</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, May 30, 2016 at 11:46 AM, Norm McMillan <span dir="ltr"><<a href="mailto:vk3xci@gmail.com" target="_blank">vk3xci@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><h3><span name="Mark Jessop"><span style="font-weight:normal">Mark Jessop said</span></span></h3><span class=""><p>><b><i> "Linear at one end and circular at the other is exactly how we do it right now."</i></b></p><p></p></span><p>I'm missing something here, maybe 'cause I've been on holiday and "lost the thread" hihi. <br></p><p>What is the actual antenna on the balloon?</p><p>What do you use for a receive antenna?</p><p>Is there a HAB website?</p><p><br></p><p>norm</p><p>vk3xci<br></p></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Mon, May 30, 2016 at 12:09 PM, Mark Jessop <span dir="ltr"><<a href="mailto:lenniethelemming@gmail.com" target="_blank">lenniethelemming@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><p dir="ltr">Linear at one end and circular at the other is exactly how we do it right now. :-)</p>
<p dir="ltr">- Mark VK5QI</p><div><div>
<div class="gmail_quote">On May 30, 2016 11:16 AM, "Norm McMillan" <<a href="mailto:vk3xci@gmail.com" target="_blank">vk3xci@gmail.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div><div><div>Mathew VK5ZM said <br>>" No circular polarised antennas are not the solution"<br></div>Boy, there's a can of worms right there, just waiting to be opened. Sherman, crank up the Way Back Machine!<br><br>In the days of AO-10, 13 etc a LOT of work went into circular, v oblique v linear poz. Seems for satellite work, when the squint angle was constantly shifting, matched sense circular poz at each end provided the best compromise, about 3db loss max from true circular to oblique to linear.. Trouble is, the sense reversed as the bird went overhead, so switching poz sense was required at the ground station.<br><br></div>Next best, circular to linear, 3db again and no need to switch sense. Unfortunately, the incoming sig was not always true circ. poz., often oblique, so 6db is a closer figure.<br><br></div>Worst... linear to linear cross poz, around 20 to 30 db loss, and circular to circular crossed sense, 30 to 60 db loss.These are pretty much real world empirical figures... like I said... a LOT of work.<br><br></div><div>Seems to me the best compromise would be linear at one end (balloon) and circular at the other. On the other hand if it aint broke, don't fix it :-)<br></div><div><br></div><div>Radiation pattern is a different story. <br><br></div><div>Maybe we need a new thread?<br><br><br></div><div>norm<br></div><div>vk3xci<br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sun, May 29, 2016 at 11:27 PM, Matthew Cook <span dir="ltr"><<a href="mailto:vk5zm@bistre.net" target="_blank">vk5zm@bistre.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">I'd suggest you research polarisation of antennae a little more and then think about that some more. No circular polarised antennas are not the solution.<br><div><br></div><div>73</div><div><br></div><div>Matthew</div><div>VK5ZM</div></div><div><div><div class="gmail_extra"><br><div class="gmail_quote">On 29 May 2016 at 05:59, Andrew Rich <span dir="ltr"><<a href="mailto:vk4tec@tech-software.net" target="_blank">vk4tec@tech-software.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="auto"><div>Hang a yagi looking back at earth<span><br><br><div>-----------------------------</div>Sent from my iPhone<div>Andrew Rich</div><div><a href="mailto:vk4tec@tech-software.net" target="_blank">vk4tec@tech-software.net</a></div><div><a href="http://www.tech-software.net" target="_blank">www.tech-software.net</a></div><div>0419 738 223</div></span></div><span><div><br>On 26 May 2016, at 11:08, Matthew Cook <<a href="mailto:vk5zm@bistre.net" target="_blank">vk5zm@bistre.net</a>> wrote:<br><br></div></span><div><div><blockquote type="cite"><div><div dir="ltr">Hi Norm,<div><br></div><div>That sounds about right with respect to range, height is might !</div><div><br></div><div>Also don't forget that if you've got local traffic on a digi that this will tromp on a balloon payload even at altitude. It all comes down to sneaking through the gaps. Even with altitude you still have free space path loss and the capture effect to contend with a the digi receiver. It is always sensible to run open squelch with software DCD if your packet engine supports it. That means weak signals don't have to crack the mute of the radio first or get truncated if it drops too low.</div><div><br></div><div>Another quirk with balloons is the antenna pattern at altitiude can have severe nulls in it, so being directly under a balloon can make it very difficult to decode (from bitter experience) when people 50km or more can copy it fine. YMMV.</div><div><br></div><div>73</div><div><br></div><div>Matthew</div><div>VK5ZM</div><div><br></div><div><br></div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On 25 May 2016 at 17:44, Norm McMillan <span dir="ltr"><<a href="mailto:vk3xci@gmail.com" target="_blank">vk3xci@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div><div><div><div>Thank you Mathew,<br><br></div>100,000 feet is 30480meters, range 625km.<br></div> VK3RBT to VK2HAB 510 km.<br><br></div>Seems odd that VK3RBT picked it up but not VK3RBX, which is closer. Better check the squelch/sensitivity on RBX I guess<br><br></div>norm<br></div>vk3xci<br></div><div><div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, May 25, 2016 at 4:55 PM, Matthew Cook <span dir="ltr"><<a href="mailto:vk5zm@bistre.net" target="_blank">vk5zm@bistre.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Norm,<div><br></div><div>Yes 100,000ft for a HAB is not uncommon. See if you can find an online radio horizon calculator and punch in 100,000ft. Take the position of the balloon when you received the posit and draw a circle around it from the horizon calculator. I'm fairly certain you'll find Bambil tanks is within this circle.</div><div><br></div><div>We regularly have VK3 stations receive our HAB telemetry with the balloon 25kms or more in to the stratosphere. Height is might !</div><div><br></div><div>73</div><div><br></div><div>Matthew</div><div>VK5ZM</div><div>AREG/Project Horus</div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div>On 25 May 2016 at 16:12, Norm McMillan <span dir="ltr"><<a href="mailto:vk3xci@gmail.com" target="_blank">vk3xci@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div><div dir="ltr"><div><div>Copied a few (20 or so) packets from this event. the path is interesting to say the least. Is there a digi not correctly identifying or did VK3RBT at Bambil Tank REALLY receive the balloon direct. <br><br><br>0:TNC-> VK2HAB-11>APT314,VK3RBT-1,VK2RBX-1,WIDE2*:!3349.O1S/14701.26E0161/003/A=100594/UpLift Balloon Flights|$"!!!!|<br><br></div>And did it really make it to 100594 feet?<br></div>And what does the |$"!!!!| at the end mean. I noticed the first two characters change as the flight progressed<br><div><div><br></div><div>Due to my inexperience with xastir I didn't log it, but I have a screen shot!<br><br><br></div><div>norm<br></div><div>vk3xci<br></div></div></div>
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