Re: [RCSE] Altimeters
The range equation composed of the following. 0) Range 1) Tx output conducted power 2) Rx input conducted power 3) Tx antenna gain 4) Rx antenna gain 5) operating frequency Tx power is much easier to appreciate for significance regarding range perception. However, Rx sensitivity is another parameter critical in long range RF link. Not all Rx design for Vario and the like kind of application have equal sensitivity or any close to same found in communication equipment. So a Rx has 10X more sensitive can make up for 10X lower power from its corresponding Tx. YK - Original Message - From: Jimmy D. Andrews [EMAIL PROTECTED] To: Howard Rudy [EMAIL PROTECTED] Cc: RCSE [EMAIL PROTECTED] Sent: Sunday, January 07, 2001 9:05 PM Subject: Re: [RCSE] Altimeters Howard Rudy wrote: ... The Vario is low power (~100mw), but this is enough to Tx 10-15mi line of sight. Hi Howard, The rated output of my Skymelody is 10mw, and it appears that my Telario has about the same power output. Respectfully, Jimmy Andrews RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: Re: [RCSE] Altimeters
That's why I asked about that Vario's legality at 433Mhz. Getting a Ham license is not that big of a deal since they "dumbed it down", but my concern would be use on that band. If it's OK today at one site, there is no telling what the situation would be in the future or at other sites. Too expensive to risk not being able to use it. Working at 27 Mhz might be a better option. --Bill On Sat, 06 Jan 2001 02:34:02 -0700 Howard Rudy [EMAIL PROTECTED] wrote: Hi In part 15 it tell you that you can't cause interference with other licensed use of the freq. band. The 433Mhz is in the 70cm Ham band. And the freq. that the vario is using has been set a side for Auxiliary/repeater link control by the ARRL band plan. The Vario is low power (~100mw), but this is enough to Tx 10-15mi line of sight. So in your TD ship 500-2000 ft up in the air. The Vario signal could cause interference over a large area. Like there add said, it's legal license free in Germany, you have to make sure that it is legal in other countries. You will use it on your own risk. If you are not a Ham, don't know what the control freq. are in the area you use it. You could face a fine of $10,000 per use in causing interference to the control of a repeater. And people have had to pay this much for causing interference. So get your Ham license check with the local ARRL band freq. coordinator. That way you will be legal not cause interference to the control/link freq.. You don't have to know any code. Just get a study guide for no-code Tech license read through it 3 or 4 times. Take the test (it's very easy to pass W/O the code) get your license. Then you can use 6 meter (50 Mhz) R/C Radios too. Howard Rudy KA7YWO SLC, UT. "Jimmy D. Andrews" wrote: Is it possible that it would be legal to use under FCC part 15? The transmitting power is within the limits described in part 15: http://www.arrl.org/tis/info/part15.html Jimmy RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: Re: [RCSE] Altimeters
I'm tempted to buy a Telario some day, but is the 433 MHz-Band USA-legal? I seem to recall that it might not be. The only other r/c vario that I know of currently is the Multiplex Helios, which operates on the CB band (27 mhz). I'd like to borrow an old ACE Thermal Sniffler and reverse-engineer one for personal use. --Bill On Thu, 04 Jan 2001 13:11:46 -0600 "James V. Bacus" [EMAIL PROTECTED] wrote: At 01:59 AM 1/4/2001, YK Chan wrote: Actually, I think a altimeter watch that can talk would be nice. Just hook up a voice down-link in the plane and monitor it with a scaner. YK, that is exactly what I do, and that is exactly what the Telario Talk offers... http://www.thommys.com/html/picolario_english.htm Jim Downers Grove, IL Member of Chicago SOAR club ICQ 6997780R/C Soaring Page at http://www.mcs.net/~bacuslab/soaring.html RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] Altimeters
Bill Harris wrote: I'd like to borrow an old ACE Thermal Sniffler and reverse-engineer one for personal use. I've seen a few different implementations of varios ... Use heated wires in a bridge, with half of the bridge inside the flask. The resistence of the heating wires change with temperature, and unbalance the bridge, causing a measurable output. Similar to above, but use warmed thermisistors. I think this is what the sniffler used, and the flask was only plastic. [Been ages since I looked at a sniffler.] Use a solid-state differential pressure transducer to measure the flow in and out of the flask. Very little power required (no heating). This is the simplest to design a vario around. Use a solid-state absolute pressure transducer to measure the rate of change of pressure. Doesn't require a flask, but needs additional smarts to output the rate of change. -- Andrew E. Mileski RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] Altimeters
"Andrew E. Mileski" wrote: I've seen a few different implementations of varios ... Use heated wires in a bridge, with half of the bridge inside the flask. The resistence of the heating wires change with temperature, and unbalance the bridge, causing a measurable output. Similar to above, but use warmed thermisistors. I think this is what the sniffler used, and the flask was only plastic. [Been ages since I looked at a sniffler.] Sorry for the double post, but I remember more now. The bridge is located outside the flask. One side of the bridge is next to an air vent that lets outside air flow in/out of the vario. The other side of the bridge is next to an air vent that lets air flow in/out of the pressure flask. Air flowing into the vario and into the flask cools the sensor next to the outside air vent more. The resistance changes more on the outside air vent side, unbalancing the bridge. This indicates you are descending. Air flowing out of the flask and out of the vario cools the sensor next to the flask air vent more. The resistance changes more on the flask air vent side, unbalancing the bridge in the opposite direction. This indicates you are ascending. Use a solid-state differential pressure transducer to measure the flow in and out of the flask. Very little power required (no heating). This is the simplest to design a vario around. Use a solid-state absolute pressure transducer to measure the rate of change of pressure. Doesn't require a flask, but needs additional smarts to output the rate of change. Measuring absolute pressure gives you slow response. A differential method is better. -- Andrew E. Mileski RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] Altimeters
Jim, I know exactly what you mean. Do you think it priced exactly unpopular. g YK - Original Message - From: James V. Bacus [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 04, 2001 11:11 AM Subject: Re: [RCSE] Altimeters At 01:59 AM 1/4/2001, YK Chan wrote: Actually, I think a altimeter watch that can talk would be nice. Just hook up a voice down-link in the plane and monitor it with a scaner. YK, that is exactly what I do, and that is exactly what the Telario Talk offers... http://www.thommys.com/html/picolario_english.htm Jim Downers Grove, IL Member of Chicago SOAR club ICQ 6997780R/C Soaring Page at http://www.mcs.net/~bacuslab/soaring.html RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] Altimeters
Hi I have been repairing the Ace Sniffler for sometime now. The Tx case is sealed air tight is used as an air chamber. There is one screw with a pin-hole drill through its lenght in the side of the Tx case. This is an orifice that meters the air flow in out of the Tx case. In the Tx case their is a short piece of tubing that goes over the end of the screw on the side of the case the other end goes over a smaller case (air flow meter) that has two bead thermisistors (about .015" OD each bead). The two thermisitors sit side by side in line with a hole (about .062" ID) through their case. The air flows through this air flow meter, in out of the bigger Tx case. The thermisistors (1K to2K) are in a bridge circuit. When the Tx goes up higher in the air, air flows out of the Tx case cools just the one thermisistor in line with the air flow through the air flow meter . The air flow over the first therm blocks the the flow over the second therm., so it is not cooled as much. Then when the Tx case comes down lower, the air flows into the Tx case cooling the other therm. So you get a a tone change, higher when air flows out of the Tx case lower when air flows into the Tx case. The Picolario Talk is on 433 Mhz is in the Ham Bands this freq falls in the use fro Auxiliary/repeater link control. So you would have to be a Ham, then is some parts of the USA you could interfere with these link/control freq. Howard Rudy KA7YWO SLC, Ut. RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
