Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Signal splitter

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

Speedy11(at)aol.com
Guest

Posted: Wed Aug 31, 2011 7:15 am Post subject: Signal splitter

Listers,

 I want to split a VHF comm signal to use two radios with one  antenna.  I know two radios cannot use the same antenna at the same time  because one radio will be damaged.  But, like the VHF nav signal splitter,  I wonder if there is a splitter available that will allow only one radio to use  the single antenna at a time.  Can an audio panel accomplish the  task?

 I have a comm "splitter" that when a handheld radio cable is inserted  it bypasses or disables the coax to the primary aircraft radio.  I'd  like something similar except that is switchable between two aircraft  radios.

 Thanks,

 Stan Sutterfield

 [quote][b]

Neal.George(at)hurlburt.a
Guest

Posted: Wed Aug 31, 2011 7:53 am Post subject: Signal splitter

Stan - 



It depends on your goals.  



If you only want to use one radio at a time, a physical, mechanical coax

switch will do the job easily and inexpensively.  Amateur radio

operators commonly use coax switches to switch one radio among multiple

antennas - works just as well the other way around.  



But you if you mount a coax switch, the other radio is completely out of

the circuit - you can't talk on one and monitor the other.  



I have seen adaptations of transmit/receive relays that would allow

attaching two radios to one antenna.  In effect, when the operator keys

radio A, the T/R relay disconnects radio B, preventing back-feed damage.

This type of arrangement would allow you to use one radio and monitor

the other.  These critters are scarce, and since it's an active device,

they tend to be expensive and temperamental.



neal  



--

kesleyelectric(at)iowatel
Guest

Posted: Wed Aug 31, 2011 8:23 am Post subject: Signal splitter

Stan,  

   

The comm splitter that you have is exactly what I am looking for.  In case of primary radio failure, I would like to be able to disconnect the primary radio and connect the handheld into the external antenna.  Do you have any information to pass along about this device.  

   

One issue that I need to address is making sure not to activate the stick mounted PTT switch with the antenna disconnect from the primary radio.  The Garmin folks say there is a high probability of damage.  The simple answer would be to remember to turn the primary radio OFF if it is malfunctioning.  Any and all thoughts on this matter welcome.  

     

Tom Barter  

Kesley, IA  

Avid Magnum-wiring  

        

  

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Speedy11(at)aol.com

 Sent: Wednesday, August 31, 2011 10:12 AM

 To: aeroelectric-list(at)matronics.com

 Subject: Signal splitter  

  

     

Listers,  

    

I want to split a VHF comm signal to use two radios with one antenna.  I know two radios cannot use the same antenna at the same time because one radio will be damaged.  But, like the VHF nav signal splitter, I wonder if there is a splitter available that will allow only one radio to use the single antenna at a time.  Can an audio panel accomplish the task?  

    

I have a comm "splitter" that when a handheld radio cable is inserted it bypasses or disables the coax to the primary aircraft radio.  I'd like something similar except that is switchable between two aircraft radios.  

    

Thanks,  

    

Stan Sutterfield  

   	  Quote: 	
		    http://www.matronics.com/Navigator?AeroElectric-List 	
0 	  Quote: 	
		   	
1 	  Quote: 	
		   	
2 	  Quote: 	
		   	
3 	  Quote: 	
		   	
4 	  Quote: 	
		   	
5 	  Quote: 	
		   	
6 	  Quote: 	
		   	
7 	  Quote: 	
		   	
8 	  Quote: 	
		   	
9

       [quote][b]

ftyoder(at)yoderbuilt.com
Guest

Posted: Wed Aug 31, 2011 1:07 pm Post subject: Signal splitter

What plane are you flying? If it is composite the  handheld should work fine; anyway, mine does.

 [quote]   ---

kesleyelectric(at)iowatel
Guest

Posted: Wed Aug 31, 2011 2:42 pm Post subject: Signal splitter

The Magnum is a rag and tube taildragger with dimensions similar to a Super Cub.  Others in similar planes have told me that their hand helds with just the rubber duckie antenna work to varying degrees, depending on range and altitude.  I seem to recall a posting by Bob some time ago regarding how much improved hand held performance would be if connect to the comm antenna.  If there is a simple way to accomplish this while isolating the panel mounted main radio, I would like to do it.  

   

A few years ago at Oshkosh I listened to a NTSB investigator describe an incident with the chain of events leading to a crash with fatalities.  A electrical failure on a night cross country in west Texas prevented the pilot of a 152 from turning on the lights at the last airport available before running out of fuel.  (Remember, chain of events.) Had they been carrying a hand held radio, (or wired with Z13-, the outcome may have been different.   

   

Some time ago Jim Weir published an article in Kitplanes magazine about using a mini plug and receptacle to do this, but I think there ended up being some problems with it.  

     

Tom Barter  

    

   

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of F. Tim Yoder

 Sent: Wednesday, August 31, 2011 4:04 PM

 To: aeroelectric-list(at)matronics.com

 Subject: Re: AeroElectric-List: Signal splitter  

  

     

What plane are you flying? If it is composite the handheld should work fine; anyway, mine does.  

  [quote]    

---

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Aug 31, 2011 9:00 pm Post subject: Signal splitter

At 10:11 AM 8/31/2011, you wrote:

  	  Quote: 	
		   Listers,

 I want to split a VHF comm signal to use two radios with one antenna.  I know two radios cannot use the same antenna at the same time because one radio will be damaged.  But, like the VHF nav signal splitter, I wonder if there is a splitter available that will allow only one radio to use the single antenna at a time.  Can an audio panel accomplish the task?

 I have a comm "splitter" that when a handheld radio cable is inserted it bypasses or disables the coax to the primary aircraft radio.  I'd like something similar except that is switchable between two aircraft radios. 	


    There are things called 'diplexers' that will

    prevent two transmitters on the same antenna

    from destroying the opposite receiver but they're

    VERY expensive and I'm not sure they can be had

    for a broad frequency range like the VHF comm band.



    Years ago I built an adapter that might serve your

    purposes. It was a combination "splitter" in the

    common receive mode so both radios could listen

    simultaneously. When one of the transmitters was

    selected and then keyed to talk, a relay disconnected

    the opposite radio from the antenna system and made

    a hard connection to the comm antenna for the

    transmitter in use.



    That was about 30 yeara ago and hand wired. I could

    probably do a much more compact version on an

    etched circuit board with captive BNC connectors

    Should go together a lot quicker and be smaller

    too.



 

 

   Bob . . .    [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Aug 31, 2011 9:09 pm Post subject: Signal splitter

 	  Quote: 	
		    

 Some time ago Jim Weir published an article in Kitplanes magazine about using a mini plug and receptacle to do this, but I think there ended up being some problems with it.

  

 Tom Barter 	


   We had some discussion a about the Tap-Jack

   that would let a hand-held take ownership

   of the ship's external VHF comm antenna.



   I built one here . . .



  http://aeroelectric.com/Pictures/Antenna/CommTap-Jack.jpg



   . . . and bought an ICOM product to disassemble

   here . . . 



  http://aeroelectric.com/Pictures/Antenna/ICOM_Hand_Held_Adapter_1.jpg

 

   http://aeroelectric.com/Pictures/Antenna/ICOM_Hand_Held_Adapter_2.jpg 



   Two problems: (1) The ICOM product made not the slightest

   pretense for maintaining feed line integrity through

   the device. (2) The quality of miniature, closed circuit

   phone jacks generally suck for air. I just couldn't

   get excited about this gizmo as a product. I think my

   recommendations at the time called for having a cable-

   male to cable-female junction in the antenna feed line be

   accessible in flight. You could break into the coax using

   a short piece of coax off your hand-held fitted with the

   appropriate connectors.



 

   Bob . . .    [quote][b]

Speedy11(at)aol.com
Guest

Posted: Thu Sep 01, 2011 5:58 pm Post subject: Signal splitter

Tom,

 I used the Icom box that Bob mentioned.  But, after Bob's comments,  you may want to not consider the Icom product.  Anyway you can view my  photos of it at http://www.rv-8a.net/2008.htm and  scroll down to 7 Feb.  I have not given it a rigorous checkout, so take  Bob's comments as those of a professional.

 Here is the Aircraft Spruce link to see their ad - http://www.aircraftspruce.com/catalog/avpages/icomswitchbox.php

 Regards,

 Stan Sutterfield

  

  In a message dated 9/1/2011 3:04:16 A.M. Eastern Daylight Time,  aeroelectric-list(at)matronics.com writes:

  	  Quote: 	
		  The comm    splitter that you have is exactly what I am looking for.  In case

of    primary radio failure, I would like to be able to disconnect the    primary

radio and connect the handheld into the external antenna.  Do    you have any

information to pass along about this device.

One    issue that I need to address is making sure not to activate the    stick

mounted PTT switch with the antenna disconnect from the primary    radio.  The

Garmin folks say there is a high probability of    damage.  The simple answer

would be to remember to turn the primary    radio OFF if it is malfunctioning.

Any and all thoughts on this matter    welcome.

Tom Barter



Kesley, IA



Avid    Magnum-wiring



	


 [quote][b]

Speedy11(at)aol.com
Guest

Posted: Thu Sep 01, 2011 6:10 pm Post subject: Signal splitter

Thanks to all for your comments and suggestions.

 I'm flying a RV-8A and using one radio at a time would be fine - both  radios also have a second freq monitor capability.  I assumed there was  some type of coax manual switch available, but I was unsure where to  search.

 Has anyone heard of the Narco VP-16?  Another guy on the list has one  for sale but I have no experience with them.  Would it be suitable to  safely split the signal?  I'd hate to risk damaging two high dollar  radios.

 Thanks,

 Stan Sutterfield

  

  

  In a message dated 9/1/2011 3:04:16 A.M. Eastern Daylight Time,  aeroelectric-list(at)matronics.com writes:

  	  Quote: 	
		  It    depends on your goals.  



If you only want to use one radio at a    time, a physical, mechanical coax

switch will do the job easily and    inexpensively.  Amateur radio

operators commonly use coax switches to    switch one radio among multiple

antennas - works just as well the other way    around.  



But you if you mount a coax switch, the other radio is    completely out of

the circuit - you can't talk on one and monitor the    other.  



I have seen adaptations of transmit/receive relays that    would allow

attaching two radios to one antenna.  In effect, when the    operator keys

radio A, the T/R relay disconnects radio B, preventing    back-feed damage.

This type of arrangement would allow you to use one radio    and monitor

the other.  These critters are scarce, and since it's an    active device,

they tend to be expensive and    temperamental.



neal 	


 [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Sep 01, 2011 9:05 pm Post subject: Signal splitter

At 08:54 PM 9/1/2011, you wrote:

  	  Quote: 	
		   Tom,

 I used the Icom box that Bob mentioned.  But, after Bob's comments, you may want to not consider the Icom product.  Anyway you can view my photos of it at http://www.rv-8a.net/2008.htm and scroll down to 7 Feb.  I have not given it a rigorous checkout, so take Bob's comments as those of a professional.

 Here is the Aircraft Spruce link to see their ad -  http://www.aircraftspruce.com/catalog/avpages/icomswitchbox.php 	


     Those miniature closed circuit jacks will probably

     work as advertised for several years. I'd go for

     a Switchcraft or similar product. Corrosion and

     loss of contact pressure over time puts the panel

     mounted radio at-risk for loss of connection to

     the antenna.



 

   Bob . . .    [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Sep 01, 2011 9:50 pm Post subject: Signal splitter

At 09:07 PM 9/1/2011, you wrote:

  	  Quote: 	
		   Thanks to all for your comments and suggestions.

 I'm flying a RV-8A and using one radio at a time would be fine - both radios also have a second freq monitor capability.  I assumed there was some type of coax manual switch available, but I was unsure where to search.

 Has anyone heard of the Narco VP-16?  Another guy on the list has one for sale but I have no experience with them.  Would it be suitable to safely split the signal?  I'd hate to risk damaging two high dollar radios. 	


   I've attached a sketch for a modern incarnation

   of the device I mentioned earlier today. It takes

   4, surface mounted dpdt relays. The relays are wired

   such that when neither PTT is active, the receivers

   are both connected to the antenna through a modern

   power splitter.



   Energize either PTT and the opposite receiver is

   disconnected, it's audio is quieted through a set

   of relay contacts and the splitter is isolated from

   the antenna.



   The whole assembly can be put on an etched circuit

   board about 2" x 2.5". Power, audio and PTT signals

   are brought off through a 9 pin d-sub. The relays

   are miniature DPDT devices mounted over a solid

   ground plane to minimize effects to feed-line

   integrity.



   It's configured such that +14v power has to be

   present on the board before EITHER radio can be

   keyed. This prevents loss of power from allowing

   a transmitter to be keyed without benefit of

   protection by transferring the proper contacts.



 

   Bob . . .

Auto_Antenna_Switch.pdf

Description:

Download

Filename:

Auto_Antenna_Switch.pdf

Filesize:

52.84 KB

Downloaded:

240 Time(s)

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum