Say Goodbye to Your CB Radio

[MOguy]

Can you put a repeater in a vehicle?

 

[dreadlocks]

I've got one in my trailer, I dont see why not if it were smaller and less clunky.. mobile antennas are not really the best for a repeater and thats going to be the limiting factor in performance..

 

[Billoftt]

I've got one in my trailer, I dont see why not if it were smaller and less clunky.. mobile antennas are not really the best for a repeater and thats going to be the limiting factor in performance..

I would like to see your repeater set up. I wouldn't mind making one of my own some day.

As far antennas, I would probably just make a 1/4 wave with a N-Female chassis connector and some 14 AWG solid wire for the antenna and radials. Shoot it up into a tree with some fishing line.

Sent from my SM-J320P using Tapatalk

 

[dreadlocks]

Collinear Dipole Array would be the most effective and wont need radials, you could make it somewhat directional or omni directional depending on the location.. I've been thinking about a rigid system I can store flat on the trailer roof and deploy as needed w/a mast mount on the trailer.. I like the mobile antenna though because we can stop at random sights and its ready to go, and if we have family in a caravan it lets everyone use a handhelds with good enough range.

I built this a good while back, its made out of TK-860's and an ID-O-Matic (not pictured), I got the external wiring kit and made my own harness to the id-o-matic.. My Antenna is a Comet CA-2x4SR.. it tucks back into the cabinets in the trailer and is controlled with an external on/off switch on a mosfet.. basically out of sight.. originally I fit this all into an ammo can and manually set it up in the field back when we car camped.



Performance wise, it does the job.. cant expect miracles with Handhelds but it does improve them substantially.. now when inside a structure you dont loose RX, so if your inside the aluminum trailer or an vault toilet you can still get reception.. range between HT's is nicely improved because its like everyone has a 3ft RX antenna 11ft in the air.. If you go to the fringe of two handhelds where you can key up eachothers radios but quality is garbage you can switch to the repeater and it comes in crystal clear and then depending on conditions you can usually push it out twice as far or close too it.. If we camp on the side of a valley it seems like it covers most all of it pretty well.. and I'm about to put a high powered mobile radio in my tow vehicle and I'm hoping to get some serious range between handhelds at basecamp and my SUV.

 

[DaveInDenver]

Using Kenwood radios makes a lot of sense, CHIRP supports several of them such as the TK-860 Dread is using. That's huge speaking as someone with several Motorola and Vertex Standard radios and a box full of very model specific CPS versions on CD-ROM.

 

[dreadlocks]

Chirp was not around when I programmed these, the old dos software for these sucked getting running even back then.. I set em up so its only got one channel on the RX and 2 channels on TX, one is high power and one is low power on same frequency (almost always run low power).. RX is tone activated so people dont randomly key it up.. I have a beacon interval set when in use w/a voice module, and a squelch beep that is useful for telling if your still in range, just key it up for a moment and listen for the beep.. if you dont hear it your out of range and should switch to simplex.

They are decent rugged and cheap radios, though compared to some of my Kenwood VHF radios I use for APRS its RX sensitivity leaves me wanting for more, especially with the mini duplexer.

 

[FJOE]

Only legal in the USA so it has very limited use for any real overlanders.

I've used Midland FRS/GMRS products (to include the Micro Mobiles) in several places abroad to include the Middle East. No issues at all.

 

[sonoronos]

When you say that the RX sensitivity leaves you wanting, is it because of the insertion loss of the duplexer? Wouldn't a duplexer increase selectivity (and, indirectly, receiver sensitivity)?

I would just figure that a >80dB isolation duplexer would be a good thing for Rx...or at least be more selective than the filter banks on a kenwood mobile?

I love your port-a-repeater by the way

 

[dreadlocks]

the TK-860H is 0.28 μV sensitive, my TM-281 is less than 0.18 μV.. the duplexer is a nice filter and would cut down on intermod and stuff nicely, but insertion losses and the fact that im working largely with rather low power handhelds make me want more.. beyond the duplexer I have a diplexer and it goes into the VHF radio for APRS.. and I'm pretty seriously impressed how good the RX range is on that radio.

*edit* fixed units

 

[Airmapper]

I've used Midland FRS/GMRS products (to include the Micro Mobiles) in several places abroad to include the Middle East. No issues at all.

Is that because it's legal or because you didn't get caught?

Granted low power radios are unlikely to cause a ruckus, but would you want to be an American in a country that tolerates but generally doesn't like Americans to make a foreign soldiers radio crackle. Some countries get very upset by such things.

While some countries share frequency assignments and uses with the U.S. it does not mean a U.S. citizen visiting there is okay to do so. What if that country uses those frequencies for their EMS band, or police band? You step on those transmissions a few times and somebody isn't going to be happy.

Just because YOU had no issues, does not mean it's not an issue. And I'm sorry it's you I found my soapbox for, but that is a pet peeve of mine. It's bad advice and poor form to recommend it for others to copy unless you have something to back it up. For example, a statement of what countries you visited which you know for a fact allow foreigners to use GMRS and the fact you used them there, legally, there would be a useful contribution.

I'm not saying you were right or wrong to do what you did, I could care less if you use your radio anywhere you like. But I am saying telling others that it's okay without knowing it's okay, is unhelpful and misleading. Especially in response to someone warning that it might not be okay. In other words, if it's your butt take whatever risks you are comfortable with, don't tell others it's fine.

The use of radio transmitters is regulated by national laws and international agreements. Often radio equipment accepted for use in one part of the world may not be operated in other parts due to conflicts with frequency assignments and technical standards. Some of the roles that the licensed GMRS service fills in the United States are, in other countries, filled by unlicensed or class-licensed services. Generally these services have strict technical standards for equipment to prevent interference with licensed transmitters and systems.

In Canada, hand-held GMRS radios up to 2 Watts have been approved for use without a license since September 2004.[16] Typically these are dual FRS and GMRS units, with fixed antennas, and operating at 2 Watts on some GMRS channels and 0.5 Watt on the FRS-only channels. Mobile units (permanently mounted in vehicles), base stations and repeaters are not currently permitted on the GMRS channels in Canada.

Other countries have licensed and unlicensed personal radio services with somewhat similar characteristics, but technical details and operating conditions vary according to national rules. Many European countries use a similar 16 channel system near 446 MHz known as PMR446, as well as a 69 channel low-power LPD433 which is shared with the ISM band. GMRS equipment that is approved for use in the United States will not communicate with PMR446 radios due to using different frequency ranges.

 

[sonoronos]

Sorry - shouldn't that 0.28mV figure be 0.28 μV Just nit picking...It is interesting to see just how good consumer grade stuff is nowadays compared to commercial radios of yesteryear.

It makes me wonder how much better APRS receive could be if a tuned 144.39MHz duplexer was used. It's just too bad that physics sort of forces things to be baby-huey sized on 2m.

 

[dreadlocks]

oops your right, wth.. I just went and checked the spec sheet PDF.. it clearly says uV, but I copy and paste and it comes out as mV.. SMH

 

[Todd n Natalie]

You have to admit, it is nice to have a 1/4 wave antenna that is 6 inches tall instead of 8 feet.

Sent from my SM-J320P using Tapatalk

I beg to differ...

 

[Billoftt]

Is that because it's legal or because you didn't get caught?

Granted low power radios are unlikely to cause a ruckus, but would you want to be an American in a country that tolerates but generally doesn't like Americans to make a foreign soldiers radio crackle. Some countries get very upset by such things.

While some countries share frequency assignments and uses with the U.S. it does not mean a U.S. citizen visiting there is okay to do so. What if that country uses those frequencies for their EMS band, or police band? You step on those transmissions a few times and somebody isn't going to be happy.

Just because YOU had no issues, does not mean it's not an issue. And I'm sorry it's you I found my soapbox for, but that is a pet peeve of mine. It's bad advice and poor form to recommend it for others to copy unless you have something to back it up. For example, a statement of what countries you visited which you know for a fact allow foreigners to use GMRS and the fact you used them there, legally, there would be a useful contribution.

I'm not saying you were right or wrong to do what you did, I could care less if you use your radio anywhere you like. But I am saying telling others that it's okay without knowing it's okay, is unhelpful and misleading. Especially in response to someone warning that it might not be okay. In other words, if it's your butt take whatever risks you are comfortable with, don't tell others it's fine.

First off, why did you follow me here from www.TheNewX.org?

Now, back to posting something with a point: The United States has reciprocal agreements with almost the entire planet for licensed Amateur Radio operators. http://www.arrl.org/bilateral-reciprocal-agreements

GMRS does not.

 

[DaveInDenver]

Now, back to posting something with a point: The United States has reciprocal agreements with almost the entire planet for licensed Amateur Radio operators. http://www.arrl.org/bilateral-reciprocal-agreements

And even with reciprocal agreements you still have to request authority. The only exception is Canada where our U.S. amateur license gives us implicit permission, we just have to add a VE suffix to our call sign and make sure to follow any differing rules.

Other countries have agreements to the extent that we can apply for a permit that will give us authority once granted. There are larger bodies that streamline this, IARP in the Americas and CEPT in Europe, where one permit authorizes you to operate in many countries.

GMRS does not.

Absolutely true. That's also the case in Canada, the amateur reciprocity doesn't extend to FRS & GMRS even though the service exists in both countries.