If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
Zaon MRX causing radio interference 2
This afternoon I found when I connected my brand new Zaon to ship's
power that I had Zaon squelch disease. I ran the factory supplied Zaon power lead through a 1" long by 1/2" diameter non-split ferrite three times right next to the power plug, then connected to power and ground behind the instrument panel. For what it's worth, I hear noise on 123.00 but not on 123.30, while on the ground. In flight all frequencies were quiet when I was using the internal Zaon batteries. Tomorrow I'll buy another power tip, and connect it to a shielded two conductor cable temporarily running directly to the ship's battery. If that doesn't work, I'll try a 25 V polarized 0.01 uF capacitor in parallel with a ceramic 0.001 uF capacitor near the power tip, if Radio Shack has them in stock. If I can find another ferrite I'll put one on power and one on ground, too. Wierd - my old Zaon (bought August 2006) never exhibited this problem in my ASW-19, and it was wired exactly as I wired the new Zaon in my LS8 today. Similar age Becker AR4201 radios in both the -19 and the LS8, but maybe there's a different squelch level adjustment and/or changes to the new Zaon board. I'll report on the results of my experiments - there may be a delay, as the temps tomorrow are going to be God awful... -John |
#12
|
|||
|
|||
Zaon MRX causing radio interference 2
Can someone post a link to the original thread on this topic? Google
Groups has "improved" their search engine, and I cannot locate the original thread and/or related threads. I also tried Glider Pilot Network, but there's no search available on that site. -John |
#13
|
|||
|
|||
Zaon MRX causing radio interference 2
On Jul 22, 1:32*pm, Eric Greenwell wrote:
Itsaplane wrote: * As such, they don't have any real solutions for running with external power. * He did suggest either a) trying more ferrite cores on the Zaon power lead (!), b) trying a ferrite core on the negative (?) side of the radio's power lead, or for the sure fix c) running the Zaon off its internal battery or a *separate* external battery other than the one driving the radio. 1) Does the static problem go away when you use it's internal battery? If it doesn't, your problem isn't the power lead and could be a radio wiring problem, or maybe an MRX defect. 2) Have you tried another MRX to see if it has the same problem? Try to borrow the newest one you can find, as the older ones did not have as much "rf emission control". 3) Run a new power lead to the MRX directly from the battery terminals, using shielded, twisted pair cable. Connect the shield to the negative (-) terminal on the battery, along with the negative lead. Don't connect the shield to anything at the MRX end. I believe this cable from Radio Shack will work: $9.89 50-Ft. Audio Cable - RadioShack.com * * * * * * * * 50-Ft. Audio Cable Model: CL2 UL Approved *| *Catalog #: 278-513 Do the simplest - but still safe - installation to test the idea. You can do permanent installation it works, including fusing the lead at the battery. -- Eric Greenwell - Washington State, USA * Change "netto" to "net" to email me directly * "Transponders in Sailplanes"http://tinyurl.com/y739x4 * * * Sections on Mode S, TPAS, ADS-B, Flarm, more * "A Guide to Self-launching Sailplane Operation" atwww.motorglider.org I can confirm that the problem goes away when the Zaon is run on its internal batteries (but I had to replace batteries twice in two 6+ hour flights). So the problem is with running the Zaon on external power. My next moves will be to follow suggetions I've received in this discussion: 1) change the squelch setting on the radio (adustable if I pull out this Dittel radio, I presume); if that doesn't work: 2) look for a non half-shell ferrite core; and if that doesn't work 3) replace the power cord with a shielded, twisted pair. Oh, and is it fair to say that this is a KNOWN and WIDE-SPREAD problem, at least for us poor glider pilot customers -- so it sure would be nice if Zaon got its engineering team cracking on this problem! Eric |
#14
|
|||
|
|||
Zaon MRX causing radio interference 2
I did a set of noise experiments using my Zaon MRX and my Icon A6.
The setup for the Zaon was (1) Flight Mode = On, (2) Brt down until just disappears, (3) Antenna pointed vertically, (4) Power – internal, external, external w/ 0.01uF ceramic and 0.1uF metal film caps in parallel across power leads at tip going into Zaon (I couldn’t fit my 1” long by 1/2" diameter non-split ferrite into the test rig). The setup for the Icom was (1) Frequencies 123.300, 123.075, 122.800, (2) Internal batteries, (3) Antenna pointed vertically (4) unit on opposite site of power input to Zaon and external battery. The testing procedure was (1) Place antennas 3 inches apart, (2) Reduce squelch from highest value until sound appears, note number, increase squelch, reduce squelch, note number, repeat until lowest consistent squelch number is obtained. Test 1 – Zaon on internal batteries, Test 2 – Zaon on external battery, no caps, and Test 3 – Zaon on external battery, caps used. Results: Test 1 Test 2 Test 3 Internal External Ext w/ caps 123.300 5 18 14 123.075 5 24 21 123.800 5 24 16 It’s clear that the Zaon radiates noise when running on an external battery. It’s also clear that the 0.01uF ceramic and 0.1uF metal film caps in parallel across the Zaon power leads reduce the noise the Zaon is radiating, but they are nowhere near as effective as running the Zaon on internal batteries. Any electrical engineers out there who'd like to make some suggestions for further tests to help me try and get the Zaon noise down? -John |
#15
|
|||
|
|||
Zaon MRX causing radio interference 2
Just a suggestion:
Get 4 good Nimh rechageable AA batteries and a good charger. Keep one pair in the charger and other in the MRX. Switch after every flight - or day, if several short flights. Advantages: No radio noise, no extra wires, can use your MRX in other gliders/towplanes. Disadvantages: If you do a long out and back, may need to have some backup AAs in your landout kit. Have to remember to charge and switch batteries. Works for me - the rechargeable batteries last long enough for a long XC, and I like having my MRX in all the club gliders and towplanes I often fly in. Kirk LS6 "66" |
#16
|
|||
|
|||
Zaon MRX causing radio interference 2
Hi, Kirk,
That's a very sensible suggestion, but for various reasons too long to go into now I want to put the MRX into my panel. So I must figure out how to kill the radio noise caused by the Zaon when it's running on an external battery. -John On Jul 29, 3:14 pm, " wrote: Just a suggestion: Get 4 good Nimh rechageable AA batteries and a good charger. Keep one pair in the charger and other in the MRX. Switch after every flight - or day, if several short flights. Advantages: No radio noise, no extra wires, can use your MRX in other gliders/towplanes. Disadvantages: If you do a long out and back, may need to have some backup AAs in your landout kit. Have to remember to charge and switch batteries. Works for me - the rechargeable batteries last long enough for a long XC, and I like having my MRX in all the club gliders and towplanes I often fly in. Kirk LS6 "66" |
#17
|
|||
|
|||
Zaon MRX causing radio interference 2
"jcarlyle" wrote in message ... I did a set of noise experiments using my Zaon MRX and my Icon A6. The setup for the Zaon was (1) Flight Mode = On, (2) Brt down until just disappears, (3) Antenna pointed vertically, (4) Power – internal, external, external w/ 0.01uF ceramic and 0.1uF metal film caps in parallel across power leads at tip going into Zaon (I couldn’t fit my 1” long by 1/2" diameter non-split ferrite into the test rig). The setup for the Icom was (1) Frequencies 123.300, 123.075, 122.800, (2) Internal batteries, (3) Antenna pointed vertically (4) unit on opposite site of power input to Zaon and external battery. The testing procedure was (1) Place antennas 3 inches apart, (2) Reduce squelch from highest value until sound appears, note number, increase squelch, reduce squelch, note number, repeat until lowest consistent squelch number is obtained. Test 1 – Zaon on internal batteries, Test 2 – Zaon on external battery, no caps, and Test 3 – Zaon on external battery, caps used. Results: Test 1 Test 2 Test 3 Internal External Ext w/ caps 123.300 5 18 14 123.075 5 24 21 123.800 5 24 16 It’s clear that the Zaon radiates noise when running on an external battery. It’s also clear that the 0.01uF ceramic and 0.1uF metal film caps in parallel across the Zaon power leads reduce the noise the Zaon is radiating, but they are nowhere near as effective as running the Zaon on internal batteries. Any electrical engineers out there who'd like to make some suggestions for further tests to help me try and get the Zaon noise down? -John Not an EE, but it might be interesting to see how a the length of the llne to the battery affects things. I have a suspicion that the radiating element is the power lead, rather than the antenna. They could be using a switching regulator for external power (not unreasonable if you want a wide input range and decent efficiency). See if, with the Zaon antenna and power cord at right angles, rotating the receiver antenna from parallel to the Zaon antenna to parallel to the power cord makes the problem worse. Sometimes it's useful to find how to make things worse, and that gives you a clue as to how to make things better. A different approach might be to supply your own regulator as a "battery eliminator" that goes in place of the battery, supplying a filtered nominal battery voltage. But if a little is good, a lot may be better. Try paralleling a 10 uF cap with what you have. Keep increasing the capacitance until it doesn't help or gets worse. Some linear regulators will oscillate with too little capacitance on the input, but I would think Zaon would catch that. Also, is the power cord through the ferrite as many times as it will fit? The inductance is non-linear, it's proportional to the number of turns squared. So managing another turn or two through the toroid may help. Gosh, it's easy to come up with work I don't have to do myself. Tim Ward |
#18
|
|||
|
|||
Zaon MRX causing radio interference 2
Hi, Tim,
Thanks for your thoughts. While at the glider port yesterday I talked with club member who’s a EE, and he seconds your suspicion that Zaon is using a switcher. From their specs, it’s pretty inefficient (as well as being noisy)! Your idea of replacing the batteries with an efficient, RF quiet, 12VDC to 3VDC supply might be a good way to go (although I don’t have the resources to do it). I did a quick experiment and found that the RF noise is indeed coming from the power lead, and it's polarized. The noise is less when the VHF antenna is vertical when the power lead is in the horizontal plane. I found the original thread on this subject. In it, Henryk Birecki posted a Zaon noise filter, made up of 4 Miller & Bourns FB20010-3B-RC coils and 1 ceramic 0.47 uF capacitor. See http://groups.google.com/group/rec.a...eafbb2ca4182c? I found a 0.1 uF cap and some torroidal coils, Radio Shack 273-0108, and built something similar to Henryk’s filter. It worked much better than the 0.01uF ceramic and 0.1uF metal film caps I reported on befo Test 1 Test 2 Test 3 Test 4 Int Bat Ext 12V Ext w/ caps Ext w/ coils 123.300 5 18 14 11 123.075 5 24 21 12 122.800 5 24 16 10 Hopefully this week Zaon’s technical people will come back from Oshkosh, and they'll have ideas to tackle this problem at the source. -John On Jul 30, 10:43 pm, "Tim Ward" wrote: Not an EE, but it might be interesting to see how a the length of the llne to the battery affects things. I have a suspicion that the radiating element is the power lead, rather than the antenna. They could be using a switching regulator for external power (not unreasonable if you want a wide input range and decent efficiency). See if, with the Zaon antenna and power cord at right angles, rotating the receiver antenna from parallel to the Zaon antenna to parallel to the power cord makes the problem worse. Sometimes it's useful to find how to make things worse, and that gives you a clue as to how to make things better. A different approach might be to supply your own regulator as a "battery eliminator" that goes in place of the battery, supplying a filtered nominal battery voltage. But if a little is good, a lot may be better. Try paralleling a 10 uF cap with what you have. Keep increasing the capacitance until it doesn't help or gets worse. Some linear regulators will oscillate with too little capacitance on the input, but I would think Zaon would catch that. Also, is the power cord through the ferrite as many times as it will fit? The inductance is non-linear, it's proportional to the number of turns squared. So managing another turn or two through the toroid may help. Gosh, it's easy to come up with work I don't have to do myself. Tim Ward |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Zaon MRX causing radio interference | [email protected] | Soaring | 16 | March 26th 09 06:49 PM |
FM radio interference from planes | rb | Piloting | 34 | July 19th 06 05:53 PM |
GPS / radio interference | Cub Driver | Piloting | 2 | October 31st 04 10:57 PM |
radio / vario interference - HELP! | Chris Davison | Soaring | 13 | November 3rd 03 06:09 AM |
Radio Interference Information | Ross Richardson | Piloting | 0 | October 17th 03 02:06 PM |