radio aerial modification

[Stumpyone]

Hi guys,

I'm thinking about getting more range out of my bike to bike radio. The radio (with its integral aerial) is under the pillion seat but I was wondering if i could change to using the bikes radio aerial for my PMR radio. I know i need to change the cables and connectors to do this but would that work?

Anyone got a technical opinion? (don't need opinions on having bike to bike comms of this kind thanks - I know bluetooth headsets are easier but the group I ride with are radio fitted)

cheers guys

Stumpy

[john348]

I would think there would be quite a mismatch in aerials for PMR and receive only broadcast radio.  I would think it would not harm it as the power is so low BUT with a mismatch you would be getting a lot of reflected power back into the PMR.  You really need a proper matched aerial to get any decent transmit.  I am a Ham but not an RF designer though!

[Stumpyone]

Thanks John.. good point. I need to look into this a bit deeper.. Perhaps find a way to fit a more appropriate aerial in the radio aerial housing.

food for thought

[john348]

I have not managed to unscrew mine but other have easily?  But unscrew it and put an appropriate aerial on.  I am sure it will still pick up some broadcast radio.  Wet string sometimes works???  You would then have to put a correct connector on the end to fit radio probably an Sam?  Check the radio.  Actually if the radio aerial comes off it might just fit the mount. 

Putting a correct connector on the coax connector is probably the most difficult part.  Not easy?

[john348]

If you were closer I could fit it for you (or actually get it fitted)  I own a electronics design and manufacturing company.

[Coconut]

Hi Stumpy,

I'm currently working on a little project to update the Trophy Radio system
( not ready to release details yet - waiting on external Company
to complete some testing and configuration ),
but while doing so I looked into the existing Radio Aerial connections,
and have a few thoughts to share with you that may be useful :

The aerial fitted to the front of the Trophy has a fly lead that runs across behind the Instrument panel,
where there is a centrally located standard DIN connector, the Fly-Lead has a male Plug that
connects into the Female socket of the Audio Harness - the connection is clipped into place
at the back of the Instrument Panel - quite easy to locate once you have removed the Instrument Pack
fascia panels ( See davybull's HOW TO: Topic on fitting the Triumph Sat Nav mount ).

That connection may provide an opportunity for you to make your Bike to Bike connection.
possibly by splicing into the connector using some sort of "Splitter" cable ?
( The Image below shows an SMB Connector -
you'd need to get one with a connector for your specific Bike to Bike aerial ).


 
NOTE : I have NO idea how transmitting a signal on that connection might affect the Trophy Audio Unit
if it also remains connected - it's a VERY expensive radio to replace if it goes "POP" !

The other end of the Audio Harness Aerial Cable runs to the Audio Unit,
which is directly under the stowage box, under the Riders Seat - just 4 Torx screws to remove
and the stowage box lifts out to reveal the Audio Unit.





That may also provide an opportunity to connect to the existing Trophy aerial 

You can probably feed a new cable into the Audio housing through the large rubber grommet
located on the left side of the bike.

Inside the Audio Unit Housing you should also see another cable with a yellow plug,
( "FAKRA" Type connector ? ) - which is not connected to anything. 
This is used on the US / Canadian export models for the additional XM Satellite Radio antenna. 
The other end of it is behind the left mirror pod clipped to the framework.
( You can see some Photo's of it in this Topic : What's this connector ? )

You might be able to utilise that cable to fit an additional matched aerial for your Bike to Bike Comms
on the front left of the Trophy ( perhaps mirroring the original aerial on the front right ),
if you can find a suitable aerial mount ?

Cheers 

[Stumpyone]

thanks Coconut,

yeah am familiar with the cockpit removal. I fitted my satnav mount. Great feedback. I dont really use the radio on the bike so i dont mind losing the aerial to that if it could work with the PMR radio or even to use the mount for the PMR aerial.

I'll have a look at things... and let you know how things progress.

cheers

Stumpy

[AZBob]

IIRC, the only things that matter with RF antennas are length and placement. More length isn't better, it just depends on the frequency of the signals involved. If you do splice into the existing antenna, you should be able to fit an appropriately sized diode to the existing wire that goes back to the stock radio head to stop any feedback into the stock radio.