---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 10/28/19: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:38 AM - Re: Headset to hand-held and panel radio at same time? (Robert L. Nuckolls, III) 2. 06:50 AM - Re: Headset to hand-held and panel radio at same time? (Alec Myers) 3. 08:49 AM - Re: EAA award and banquet (Robert L. Nuckolls, III) 4. 08:49 AM - Fw: Help with panel design? (Peter Feneht) 5. 08:52 AM - Glastar Dipole comm antennae behind doors (Robert L. Nuckolls, III) 6. 10:52 AM - Re: Re: EAA award and banquet (rd2) 7. 04:50 PM - Re: EAA award and banquet (johGrey) ________________________________ Message 1 _____________________________________ Time: 05:38:37 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Headset to hand-held and panel radio at same time? At 04:57 PM 10/27/2019, you wrote: > >Is is possible to utilize a Y cable to connect a headset to a >hand-held and panel radio at the same time? The situation would be >no intercom panel, Garmin GTR200, Yaesu FTA-550, and twin plugs on >the panel for a headset. This topic link indicates OK >http://forum.matronics.com/viewtopic.php?t=37809 but it refers to an >intercom panel. However, the Audio Systems chapter seems to >indicate that either radio would not sense an resistance in the >other so the headset would not receive much useful output. My >thought is the handheld could function as a back up to the GTR200 >and or second frequency monitor if the volume was turned up with out >the need to change the headset plugs from one to the other. You can try it . . . there's no risk of damage . . . it simply would not work as you expect. Adding multiple audio sources together is normally done with an audio isolation amplifier as described in the chapter. As to microphones, the mic in your headset can be connected to only ONE transmitter at a time. You would need a XMTR1/XMTR2 microphone transfer switch. So if you're only needing the HT for backup, you might as well transfer the headphones audio with the same switch. Bob . . . ________________________________ Message 2 _____________________________________ Time: 06:50:24 AM PST US From: Alec Myers Subject: Re: AeroElectric-List: Headset to hand-held and panel radio at same time? If it doesnt work, you can build a two input audio amplifier for about $3. But youd have to wire it in to 12v power. On Oct 27, 2019, at 9:41 PM, Robert L. Nuckolls, III wrote: At 04:57 PM 10/27/2019, you wrote: > > Is is possible to utilize a Y cable to connect a headset to a hand-held and panel radio at the same time? The situation would be no intercom panel, Garmin GTR200, Yaesu FTA-550, and twin plugs on the panel for a headset. This topic link indicates OK http://forum.matronics.com/viewtopic.php?t=37809 but it refers to an intercom panel. However, the Audio Systems chapter seems to indicate that either radio would not sense an resistance in the other so the headset would not receive much useful output. My thought is the handheld could function as a back up to the GTR200 and or second frequency monitor if the volume was turned up with out the need to change the headset plugs from one to the other. You can try it . . . there's no risk of damage . . . it simply would not work as you expect. Adding multiple audio sources together is normally done with an audio isolation amplifier as described in the chapter. As to microphones, the mic in your headset can be connected to only ONE transmitter at a time. You would need a XMTR1/XMTR2 microphone transfer switch. So if you're only needing the HT for backup, you might as well transfer the headphones audio with the same switch. Bob . . . ________________________________ Message 3 _____________________________________ Time: 08:49:48 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: EAA award and banquet At 09:53 AM 10/28/2019, you wrote: >Hi Bob, > >congratulation as well on your EAA award very well deserved. > >Cheers Werner Thank you sir! BTW, I'm told that there are 8 chairs at 'my' banquet table. At the moment, there are 4 chairs unclaimed. If any Listers are so motivated/able, I'd be pleased to have them join us. It's the evening of Nov 7th in OSH. Bob . . . ________________________________ Message 4 _____________________________________ Time: 08:49:59 AM PST US From: Peter Feneht Subject: AeroElectric-List: Fwd: Help with panel design? P.S. A change I made since the photos were taken, was that I reduced the breakers from 3 down to 2. One for now will be 20 amps and the other 5 amps. They will be the two next to the starter button. In the area of the previously anticipated 3rd breaker, I will have one of the panel attachment bolts. ---------- Forwarded message --------- From: Peter Feneht Subject: Help with panel design? Cc: Peter Feneht Apparently I suffer from lack of knowledge, lack of experience changed with being tempted by perfectionism. That is a miserable, stuck situation so I am hoping you Or others in the group can help me. I have decades of hang gliding experience and now I want to build a Xenos motor glider. Some of the factors for locating the instrument panel items included the size of the device behind the panel. For example a bulky item could not be located too low because of the angle of the support structure at the bottom edge. That=99s why smaller switches are on the bottom edge but not th e breakers. Also my plan is to install all instruments switches and devices on a flat sheet of aluminum the exact size of the panel that attaches to the aircraft. I will use a number of bolts to attach the flat, instrument-laden sheet to the attachment points for the instrument panel frame that will be riveted to the Aircraft frame. That way I can just loosen several bolts and remove the whole instrument panel for ease of access for future maintenance repairs or troubleshooting. Perhaps as a result of knowing my inexperience while trying to design something that I will be happy with for a long time after I get more experience, I asked The opinion and advice of many willing pilots in our local chapter, Sonex and at EAA. I think those many opinions have contributed to my confusion and hesitation. So at the risk of getting even more confused, I humbly ask for more advice from you and your group. I hope that the large volume of advice will settle into some kind of consensus with which I will be comfortable in the short and long term. Bob, I did this from my phone so I=99m not sure it will go to the gro up. If it doesn=99t go to your group can you kindly forward it? Thanks! Peter Sent from my iPhone ________________________________ Message 5 _____________________________________ Time: 08:52:34 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Glastar Dipole comm antennae behind doors >I=99ve got dipoles in the tail, one close behind >bulkhead A, and one in the vertical tail. This >was what was being done in TWTT back in 2006. > >I measured the fraction of reflected energy >(measured in terms of what=99s called =9CSWR=9D) >and the impedance of both antennas a few years >ago. The ideal impedance is 50 ohms (to match >the coax). The ideal SWR is unity. For an >antenna in a free-field (like on a pole), one >would hope for an SWR less than 1.5 over the >full VHF aviation band. For less than ideal >circumstances, < 2.0 or even 3.0 might be considered tolerable. Actually, if one can get 3:1 or less over the entire spectrum of interest, then performance for aviation purposes will be adequate . . . ASSUMING that locality conditions don't add factors un-related to SWR. Emacs! >As you can see in the attached graphs, impedance >is all over the map, and rarely near 50 ohms. >The SWR seems to indicate that the front antenna >is barely tolerable up to 127 MHz, above which >it gets pretty bad. Conversely, the tail antenna >is pretty crappy until 116 MHz, then tolerable right up to 135 MHz. The aft antenna (vertical fin?) does show a smooth curve with pronounced dip at 130MHz. This suggest the antenna is doing a reasonable job of accepting energy from the feedline over the range of interest. Further, it's under 3:1 SWR . . . I'd call it good. The front antenna plot suggests complete lack of resonance at any point in the explored spectrum. I'm assuming this antenna is wrapped around the inside surface of the composite shell with a predominantly vertical polarization. If the SWR scan had been taken lower frequency, I suspect that a pronounced dip in SWR would be discovered . . . the trend of the plot as it approaches 113Mhz suggests this. It makes sense. Close proximity of either/both CONDUCTIVE or DIELECTRIC features tend to lower the resonant frequency of a radiator. Pasting the antenna to the inside surface of the fuselage will lower it's resonant frequency measurably . . . proximity to steel structure inside the fuselage will lower it more . . . perhaps MUCH more. Suggest the ends of the forward antenna be shortened a bit and new scan taken . . . start at some much lower frequency to see if there's a real resonance artifact down there.I suspect that the interaction with conductive structure, such as the cage in front and the tail spar in the rear have more to do with the anomalies than the modest curvature. Not only that, the coax is connected to both antennas directly. Since the coax is an unbalanced=9D conductor, and a dipole antenna is balanced=9D, there is supposed to be something called a balun=9D between them. I don't know if it was ignorance, cheapness, or weight-consciousness behind the absence of a balun, but no doubt that=99s also part of the problem. A BALUN can improve on energy transfer between feedline and antenna but the thing needs to be RESONANT in the range of interest first. I'm fiddling with an dual-band (121.5/406) ELT antenna intended for installation on the inside surface of an RF friendly composite fuselage. Looking at the value of some BALUN options. Discoveries would applied to the VHF comm antenna being discussed here. Get the SWR down and 'centered up' first. Bob . . . ________________________________ Message 6 _____________________________________ Time: 10:52:28 AM PST US From: rd2 Subject: Re: AeroElectric-List: Re: EAA award and banquet I'd love to....but am too far away and have a conflicting schedule. Bob and the table - enjoy; well deserved!Rumen ----- Original Message ----- From: Robert L. Nuckolls, III Sent: Mon, 28 Oct 2019 11:48:35 -0400 (EDT) Subject: AeroElectric-List: Re: EAA award and banquet At 09:53 AM 10/28/2019, you wrote: Hi Bob, congratulation as well on your EAA award very well deserved. Cheers Werner Thank you sir! BTW, I'm told that there are 8 chairs at 'my' banquet table. At the moment, there are 4 chairs unclaimed. If any Listers are so motivated/able, I'd be pleased to have them join us. It's the evening of Nov 7th in OSH. Bob . . . ________________________________ Message 7 _____________________________________ Time: 04:50:53 PM PST US Subject: AeroElectric-List: Re: EAA award and banquet From: "johGrey" Sounds a great night, not available here as well. Enjoy Read this topic online here: http://forums.matronics.com/viewtopic.php?p=492024#492024 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.