Cheers Boon, I'll keep an eye open for the Roxon on ebay and please do post pictures of the radios and antenna's when your done!Ahem ..well I was using a Hora C408 and a Yaesu VX-1r but I tracked down a rexon RL-402 on ebay for £27 and I had one in my 'collection' so I was gonna fit them to my GS and wifeys R850r for touring.......they can run straight off 12v.....have a bnc connector and if you know the correct button presses can be opened up to 446
I am currently using the cheap and cheerful bike to bike harnesses from maplin,OK up to 60mph but not great.......but it does plug straight in to the rexons 3.5/2.5 mm mic/ ear socket
downsides.........the radios have 3 power settings at mid and high you would almost certainly be exceeding the spec for pmr 446..........but they dont police it at all so ..............
Last year we never took the radios with us and missed them sorely........its amazing how convienient they are especially if you are in a group........someone stops for a 'comfort break' and everyone else dissapears..........
I will be fitting the antenna and radios to the bikes soon.....I will take some fotos and post them
linky for rl 402 http://www.rigpix.com/mischam/rexon_rl402.htm
minimag is like this but with a small 4 inch straight whip:http://www.qsradio.com/MM-270X.JPG
found it .watson wsm-138 :http://www.wsplc.com/acatalog/Watson_Mobile_Antennas.html
Aerials Again
- Thread starter Fudpucker
- Start date
Boon
Registered user
length of exposed whip section ,watson,is 122mm,length of complete antenna with screw in bottom section is 143mm 1/4 wave at 446mhz
length of exposed stainless whip is 266mm ,from bottom of screw in mount to top is 283mm 1/2 wave at 446 mhz
have fun
ratbiker
Guest
Great info thanks Boon.
I have just picked up an aerial like the one you have pictured. The one with the little coil at the bottom. (WSMA-270) with the micro mag mount.
I have a Kenwood TK 3207 which covers frequencies from 446 on the first 8 channels to 462 on the later 8.
Just a couple of questions if someone could help:
1. Is it ok just to take out the little allen screw and just cut the whip and re insert? (Does it matter trimming the coil off?)
2. Would you advise me to use a SWR before cutting to the length that has been shown of 122mm?
3. Would you advise setting the aerial for the lower frequencies, the upper frequencies or is it possible to be able to suit both?
4. And finally has anyone got any good ideas on where to mount it? (I am using a blackbird with full Givi luggage on a wing rack.) I assume the best place is on top of the top box but being plastic it's a non starter. Would it matter a great deal being stuck as per the attached photo?
Sorry for so many questions but I am a complete noobie to all the wavelength and comms topic.
Thanks greatly.
I have just picked up an aerial like the one you have pictured. The one with the little coil at the bottom. (WSMA-270) with the micro mag mount.
I have a Kenwood TK 3207 which covers frequencies from 446 on the first 8 channels to 462 on the later 8.
Just a couple of questions if someone could help:
1. Is it ok just to take out the little allen screw and just cut the whip and re insert? (Does it matter trimming the coil off?)
2. Would you advise me to use a SWR before cutting to the length that has been shown of 122mm?
3. Would you advise setting the aerial for the lower frequencies, the upper frequencies or is it possible to be able to suit both?
4. And finally has anyone got any good ideas on where to mount it? (I am using a blackbird with full Givi luggage on a wing rack.) I assume the best place is on top of the top box but being plastic it's a non starter. Would it matter a great deal being stuck as per the attached photo?
Sorry for so many questions but I am a complete noobie to all the wavelength and comms topic.
Thanks greatly.
Boon
Registered user
Dont cut the watson 270 too soon !!!!!
Its pre tuned for 145mhz and 430/440mhz
It will give an acceptable vswr on 446mhz as is...........and it gives somewhere about 3 db gain on uhf...........means its more receptive and will radiate more power than a cut down 1/4 wave uhf whip like the one in my photo
if you need a small whip then the dimentions of the little watson 138 should hold good for that antenna too.......but bandwidth may not cover 462mhz .......gimme 10 mins and I will test it at 462 mhz
if you can live with the length .........just plug and play bro
If you have a uhf vswr meter,test it first at both frequencies.
The longer the radiator (whippy bit) the larger the frequency coverage.
Use a UHF capable VSWR meter ..........not a cb one!
The vswr is important with equipment that doesent detect rf feedback to the pa stage and compensate for it..............
all thats happening is the rf transmitted power is being rectified thru a diode to read dc component on tx power on the meter,then another diode is switched in to read the reflected rf power in dc on the meter less than 1:2 is workable, more and you may damage the transmitter
Its pre tuned for 145mhz and 430/440mhz
It will give an acceptable vswr on 446mhz as is...........and it gives somewhere about 3 db gain on uhf...........means its more receptive and will radiate more power than a cut down 1/4 wave uhf whip like the one in my photo
if you need a small whip then the dimentions of the little watson 138 should hold good for that antenna too.......but bandwidth may not cover 462mhz .......gimme 10 mins and I will test it at 462 mhz
if you can live with the length .........just plug and play bro
If you have a uhf vswr meter,test it first at both frequencies.
The longer the radiator (whippy bit) the larger the frequency coverage.
Use a UHF capable VSWR meter ..........not a cb one!
The vswr is important with equipment that doesent detect rf feedback to the pa stage and compensate for it..............
all thats happening is the rf transmitted power is being rectified thru a diode to read dc component on tx power on the meter,then another diode is switched in to read the reflected rf power in dc on the meter less than 1:2 is workable, more and you may damage the transmitter
ratbiker
Guest
Dude, Thanks for your reply.
I'm glad someone knows what the hell I'm supposed to be doing! lol
What did you think about the location of the aerial itself...?? Is the top box being in the way going to cause significant problems?
I'm glad someone knows what the hell I'm supposed to be doing! lol
What did you think about the location of the aerial itself...?? Is the top box being in the way going to cause significant problems?
Boon
Registered user
Ok just tested a watson 270( yeh I had one in the garage) at 462mhz .....with 1 watt rf it was 1.5/1
at 446 it was a dead needle.......
Tested the ikle whip at 462 mhz less than1.5/1
dead needle at 446mhz
the 270 is so named because it covers the 2meter and 70 cm ham bands its a great little aerial for local work
my little uhf swr meter is of the cheep and cheerful type and is probrably not a precision instrument but my big one only covers HF and VHF
at 446 it was a dead needle.......
Tested the ikle whip at 462 mhz less than1.5/1
dead needle at 446mhz
the 270 is so named because it covers the 2meter and 70 cm ham bands its a great little aerial for local work
my little uhf swr meter is of the cheep and cheerful type and is probrably not a precision instrument but my big one only covers HF and VHF
ratbiker
Guest
You just happened to have one in your garage? Now thats a cool garage! 
Thanks for spending your time testing it I really appreciate that!
I tried uploading a photo on the site earlier but it seems to have disapeared. Would the top box cause this 'awesome' aerial any problems if the aerial doesn't come above the top of it?
What kind of range do you reckon I might get on 5w?
I know the answer would be using the SWAG (Scientific Wild Ass Guess) method but thats better then I could do!
Thanks for spending your time testing it I really appreciate that!
I tried uploading a photo on the site earlier but it seems to have disapeared. Would the top box cause this 'awesome' aerial any problems if the aerial doesn't come above the top of it?
What kind of range do you reckon I might get on 5w?
I know the answer would be using the SWAG (Scientific Wild Ass Guess) method but thats better then I could do!
Boon
Registered user
A while back I fitted one to a plastic topbox by taping a 5 inch square of metal to the top and fitting a 270............it was for gprs when doing safety bike at a triathlon.....so the control knew where the back marker cyclists were over a big course.........it worked well.
they dont appear to need huge amounts of metal......do you have a rack that the top box sits on?
if so can you fit a tab of metal directly to the rack.....I'm thinking shaped like a ping pong bat but much smaller.........
the 'handle' sits on top of the rack ,a piece of flat bar underneath ,two holes and two small bolts to clamp to the rack and the 'paddle' sticking out a couple of inches.....either to the side or rear...........a nice little platform for the magmount
proximity of objects will affect both tuning and transmission pattern but its better than being in your inside pocket.
they dont appear to need huge amounts of metal......do you have a rack that the top box sits on?
if so can you fit a tab of metal directly to the rack.....I'm thinking shaped like a ping pong bat but much smaller.........
the 'handle' sits on top of the rack ,a piece of flat bar underneath ,two holes and two small bolts to clamp to the rack and the 'paddle' sticking out a couple of inches.....either to the side or rear...........a nice little platform for the magmount
proximity of objects will affect both tuning and transmission pattern but its better than being in your inside pocket.
Boon
Registered user
Many moons ago I was in the electronics trade..........and still dabble from time to time.I must have a dozen antenna of one sort or the other in the garage.
ratbiker
Guest
Yeah the top box is sat on an alley rack. I have a small 'L' shaped metal bracket which is just about the size of the mag mount itself.
But sits right in front of the top box. It does need a little bit of tape to stop it 'twanging' on the box....
Trying to post a photo but struggling!
http://img299.imageshack.us/my.php?image=dsc02629uc7.jpg
But sits right in front of the top box. It does need a little bit of tape to stop it 'twanging' on the box....
Trying to post a photo but struggling!
http://img299.imageshack.us/my.php?image=dsc02629uc7.jpg
Hi, bit of a hijack, but does anyone know if the intaride external antenna kit will work with a pmr 446?
Cheers Tom
Cheers Tom
The Interide external antenna is designed to work on PMR 446 frequencies, its whether your radio has the same fitting as the antenna lead or can be adapted to fit that’s the real question.
Cheers ebbo.
..... and I understand the Interide external antenna is not a very efficient one. The the actual coupling also needs a couple of fairly bulky adapters to connect to the usual BNC found on the coax leading to most supplied antennae - can send you a photo of the arrangement if required
This is probably a dumb question but I don't know the answer so I ask you anyway.
Does the coax / bnc cable need to be a certain impedence or type, in order to work with the pmr?
Thanks in advance as always
Tom
Does the coax / bnc cable need to be a certain impedence or type, in order to work with the pmr?
Thanks in advance as always
Tom
Boon
Registered user
50 ohm
look up the specs and get stuff with the highest shielding factor...........95% plus....
impedence is one of those things thats kinda hard to put in laymans terms
its a kinda reactive resistance...............but wont read 50 ohms when tested with an ohm meter
RG58 is common or garden 5mm transmission coax,suitable for short runs at UHF
I use 10mm RG8 for most UHF stuff but its too thick for vehicle applications
thinnet or RG213(?) is also used ........this is from memory so go look it up to be sure ..........its been a while since I bought a drum of the stuff.
look up the specs and get stuff with the highest shielding factor...........95% plus....
impedence is one of those things thats kinda hard to put in laymans terms
its a kinda reactive resistance...............but wont read 50 ohms when tested with an ohm meter
RG58 is common or garden 5mm transmission coax,suitable for short runs at UHF
I use 10mm RG8 for most UHF stuff but its too thick for vehicle applications
thinnet or RG213(?) is also used ........this is from memory so go look it up to be sure ..........its been a while since I bought a drum of the stuff.
aerial location on base plate
I've just posted this on the Intaride IR-803 post, apologies if it's not good form but it picks up on an earlier comment about using a top box rack to locate the aerial.
--------------------------
Can i offer this as a possible solution for aerial location? I used it on my VFR but am transferring it to the GS. It is made easier by the fact that I'm keeping my Givi luggage so i have a Givi topbox. Because the connection to the aerial is reversable I can have the aerial in the up position when riding without a box, then swop the leads over to have it in the down position with a box. Either way it remains vertical. These pictures are of the trial installation, the final fixing was made with 2mm metal plate, drilled to locate on the bolts that secure the rack arms to the base plate. For the GS I just need to find some slightly thinner rubber washers to keep the height between arm and top plate the same as with the front securing bolts.
I've just posted this on the Intaride IR-803 post, apologies if it's not good form but it picks up on an earlier comment about using a top box rack to locate the aerial.
--------------------------
Can i offer this as a possible solution for aerial location? I used it on my VFR but am transferring it to the GS. It is made easier by the fact that I'm keeping my Givi luggage so i have a Givi topbox. Because the connection to the aerial is reversable I can have the aerial in the up position when riding without a box, then swop the leads over to have it in the down position with a box. Either way it remains vertical. These pictures are of the trial installation, the final fixing was made with 2mm metal plate, drilled to locate on the bolts that secure the rack arms to the base plate. For the GS I just need to find some slightly thinner rubber washers to keep the height between arm and top plate the same as with the front securing bolts.
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