NOOB 06 Trailblazer mobile install

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KC9ZNV

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#1
Hi folks,

I am relatively new to HAM, I just received a brandy new Kenwood TM-V71A and I intend to mount this in my 2006 Chevy Trail Blazer. I did my best to search all of the forums on this site for answers with out much luck. This is my main forum for radio stuffs.

The last radio I installed in a vehicle was over 10 years ago and it was a cobra CB that I just wrapped the wires around a non essential fuse like the blower fuse for power and ran an antenna cord. I think this will be a little bit more delicate.

I need some ideas and things to consider about the install, I post what is in my head and we can go from there. I haven't taken the full time to completely look up each and every component of what I wish to put in and that's why I'm here, I figured you folks may have some Ideas.

OK here Goes...

Independent power line from the battery into the vehicle trying to avoid and vehicle control modules, Fuses at the battery side, I'm guessing about 8 gage wire to handle voltage drops and amperage. I haven't been able to figure out main fuse or breaker size yet. I will list my anticipated gadgets to be put in line to qualify the 8 gage.

Some type of fuse box or way to break out the power to individual components, I'm not crazy about Anderson power poles in a mobile, it may be conceivable to just build a separate jumper to each components connector and then attach to poles if needed later.

I forgot the manufacturer but someone makes a switch that shuts off the circuit if the battery voltage gets to around 11 volts incase the radio is left on or there is some type of parasitic draw in the radio or other components. It will be a while before I find out if a solar panel is right for me, so a vehicle that starts is great.

I intend to build the system to allow for the use of this radio, 1-3 additional vehicle accessory ports for inverter or other device (I have 2 now that are usually full), the capability to add another radio if room permits, add of something like a tiny trac 4 APRS tracking or upgrade to a D710, add linear amps if I find the Xband repeat function is required often or I just want more out put power on xmit and rec, and maybe a spot for a blinky light on the top of my truck in an emergency. and that's about it for that part of the system.

The radio will be mounted on the floor behind the HVAC control and vehicle radio system. It's roomy and I can somewhat monitor the temp in the WI winter and cool the area while broadcasting on high in the summer. The control head will most likely be mounted on the dash or up high depending on visibility requirements. I don't want any tickets.

Antenna... I'm sorry but I have a sunroof and use my cargo racks. There will be zero drilling of holes to mount a NMO on the roof. The tail light mounts I don't feel will work, Frame mounts will not work because I drive off road and through woods not to mention the salt accumulation, a roof rack mount may cause issues down the road with positioning the cross members on the rack despite anything that folds over, rear glass may not work so well and I constantly use both the glass and metal hatch. Short of a spring to survive encounters with vegetation I think a lip mount mounted on the hood may work. I currently have an mfj 1422 mounted on mag mount I stick up top for my ht from time to time and love it, I am considering the mfj 1432 for the lip mount but I'm open to ideas short of Larson or comets. I have bent the MFJ and easily bent it back, Its water proofing leaves a lot to be desired.

So that's what's in my head today, I need to start figuring this out as I want to have the radio on the air by JULY or earlier, especially with the skywarn and races seasons being at a peak in the spring.

So any recommendations or advice is welcome. Thanks in advance

73 KC9ZNV
 

KC9ZNV

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#2
Whoops, I forgot. I do not fully undertand the chokes and Im sure something needs to go in there.

Also, I will need around 2 feet of extension for the mic.

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#3
For the extension, just use regular cat 5 with an adapter from nearly anywhere that sells network equipment.

There is a grommet in the firewall next to the steering column, push everything through there.

Sounds like your limited to a hood channel mount. Simple easy, almost any dual band antenna will do (I'm a big fan of Larsen antennas).

Personally the only good place to mount radios in a stock trailblazer are dash and sides if the center console unless your going with remote mount. I currently have a FT-2900 on my dash, Icom F221 on the side of the console, getting ready to install a Motorola GTX on the other side of the console. Setup for aprs using a hood channel mount, the 900 and VHF/UHF stuff is all on the roof.

My jeep is set up a little differently but very similarly.






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KC9ZNV

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#4
Most definatley will mount the the head onbthe dash unless I can squeeze it it in where the optional garage door opener goes. Not sure it it will fit and clear the rear view mirror.

Thanks for the channel mount, I thought I needed a llip mount. If I can open the hood without removing the antenna. That would rock.

I will look at pl 239 and nmo mounts. And covers for gooing through brush.

Its about 3 degrees outside so I will have to look later to see if I can moint it on the left side. Don't recall where the modules are.

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#5
Highly recommend a NMO base over a UHF base. N bases are okay, but I'd still trust NMO more, especially with the bigger and heavier antennas (such as Comet's like I have on the hood of my Jeep).

Larsen offers a spring option for all of their antennas. They use a common threading and a spring can be put on any of their low band or high band VHF/UHF products (including the 2/70) though it is not often needed. The far back antenna on my Jeep is a Larsen low band antenna tuned to 11m...no need for a spring how I have it mounted. On the roof, you can't see it, there is a VHF 1/4 wave antenna on a spring for APRS, the whip doesn't really need it but it does flex occasionally.

Most of the Comet antennas have a fold over feature. Personally, I don't see the added price in a Comet over a Larsen or Tram but YMMV.
 
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#7
The "T" connector the radios come with works just as well though it is helpful to run power strip (most of the radio one come setup for power poles) from MFJ or Powerwerx as well as include all the inline fuses you need. I cut out my T's for power poles (except for my Motorola stuff) but I currently don't have a power distribution setup on any of it.

I will say, if you fuse a ground, they all need to be fused. If you're only fusing VCC, then they all need to have VCC fused.
 
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KC9ZNV

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#8
Well maybe I will go with anderson poles. The rig runner 4005 looks like the ticket, except I don't know if I can run 6 or 8 gage wire to it and I shudder at the price of the crimper.

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#9
Well maybe I will go with anderson poles. The rig runner 4005 looks like the ticket, except I don't know if I can run 6 or 8 gage wire to it and I shudder at the price of the crimper.

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If yours is anything like mine, there should be a power block inside the vehicle underneath the rear seat on the drivers side; that's where I will be tapping the power for my radios eventually, and I will be using Anderson Power Poles. I've even got the crimping tool.
 

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#10
Now that you mention it there is. I forgot about that. Im not sure what is hooked up to that and I'll have to trace it. I'm worried its air bag based on location but I've been out of the auto industry for 8 years and that build of trail blazers was just starting into the market when I worked for a gm garage.

My autoshop instructor would lower my grade. I'm trying to calculate the voltage loss from each connection.

If my memory serves me correctly it was 0.2 volts per connection but online I read .5 volts. I can not remember if it levels out at 1 volt. 12.8 volts is acceptable. 13.8v +/- 15% I may have to dig out my book from trch school.

I was hoping to use 6 awg from the battery source to a 75w app to a 1 foot adapter cord (10 awg) with 15/45 to connect into the power guard.

Today I think I would skip the rig runner and hook right into the radio just on cost at the moment. Not only does powerwerx market a system there are other companies that build similar units that may work.

Im just stuck on the whole voltage drop/loss thing. I found a calcuator that once you double the wire length (positve and negative cables both count) it figures it out pretty close.

I have a couple guys still in the auto world I can call.

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KC9ZNV

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#11
Need to double check my math

Okay, If I did my math correctly. (I'm so rusty) I forgot about the power point under the rear seat, I will have to investigate that. I'm trying to bypass anything GM put in the system. So I figured this at a bigger set of numbers than will be common.

The radio specs are 13.8v +/- 15% so 13.8 nominal, 11.73v LCL and 15.87v UCL
Everything is factored at a 40 Amp Load. This is max on all except the radio and the power leads will be fused at 35-40Amps The best I could find for resistance of the poles is .016 voltage drop.

Okay battery 13.8
Volt loss at the battery connections. 0.5v ( I hope and not 1 volt for both but it may be)
Starting Voltage 13.3
20 feet of wire (6AWG) total pos + neg length. (will be shorter) Voltage at 75 amp powerpole 12.962v
next component is a 1 foot harness coming from a 75amp pole to 2 strands of 10 AWG to a 15/30/45 set of poles, Calculated as 2 feet of wire would be 12.946v
Next the pwrguard plus which when on will cause .2v loss reading should be 12.746v
then the radio will receive 12.73 volts after its connection. This is not including a rigrunner at this time.
I simplified it until it's needed. The best I can tell for an amp is that I may need a battery booster. This system should give me some flexibility. The peak I read in the book is around 20 amps and the main power lead will be about 7 feet but for the sake of theory I went with 10.

I do know the shorter the wire the less loss from wire. It's the all of the power poles that worry me. I haven't performed calculations like this since 1999 so... I may have got something wrong.

If anyone wishes to correct this I'm game. So it looks like I will lose 1-1.5 Volts I wanted to get as much voltage to the radio in order to fully take advantage of it.
 

KC9ZNV

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#13
Ive got the main wiring figured out now its mounts... I was looking at the lido mounts but not sure wjat to do with the wires.

I dislike wires all over the place.

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#14
That's the grommet. I'm headed into Lubbock tonight from Colorado. Unfortunately I left my trailblazer in Austin so I'll show you some of what I did when I get back tomorrow.


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KC9ZNV

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#15
That's the grommet. I'm headed into Lubbock tonight from Colorado. Unfortunately I left my trailblazer in Austin so I'll show you some of what I did when I get back tomorrow.


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Cool thanks! I took some photos of possible points to mount it. I will have to take off the cover in the center. When I ripped out the sat radio antenna. I thought I found more room it was 25° so I looked but still to cold to dissassemble it.

I wish those shelves that replace the sunvisors had specs or I would mount it high.

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KC9ZNV

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#16
While im wating for w5pky to share his info, I'm double checking the my power circuit theory and investigating my irf exposure limits. Because this forum is searchable by engines other people may end up here. I figured someone may want to read this right from GM. I haven't called in the part numbers from my local dealer to see what gage wire they will handle.

http://service.gm.com/techlineinfo/radio.html
Ford has one as well. Reference tge ARRL handbook for that pdf.

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#17
This is just how I did it...little back asswards from how everything else says to do it. GM's instructions are kinda eh, sometimes it works but most of the time you run into different cases.

I came off the fuse distribution input on the fuse block (under the hood), the radio is grounded to the steering column support (a piece of 2x2 steel that the steering column mounts to that runs under the dash).


Then there is the grommet (it's a big grommet for such a small bundle of wires so I just made a new hole off to the side). It's actually a double walled grommet.



Then there is the how the radio is mounted on the dash (unless the windshield is out or you have a 90 degree adapter you will not be able to drill the mount in here (double sided 20 lb 3M tape works good for this depending on the radio size).



And I thought I'd give you a close up for the hood channel mount.
 

KC9ZNV

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#18
Wow thanks w5pky! Ive actually been looking for a mount like that only with an NMO. Still searching. Lol. I will probably keep the actual radio off of the dash and try to mount the radio head up there. That way I don't have to remove a lot of dash parts. I hate dashwork because theres always missing screws, blood, and probably something rattling. I will go through the grommet but I think I ill build a seperate circuit, though perhaps it may be better to do it yoour way. I have no idea if the pcm monitors the voltage or not. Thanks again.

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#19
I really don't chime in on someone's install. But, a Radio Shack temporary PL-259 for a transceiver? I understand that you had little room to work with, but I wouldn't transmit on high power with that set up. Have you checked how good the ground is? There are times the small screw pierces the ground and touches the center conductor. And sometimes it doesn't touch the ground.
Hate to see you mess up that nice Kenwood.
Larry
 
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#20
KC9ZNV, that actually is a NMO. That setup there is a Tram 5/8 wave VHF antenna (3 dBd gain, haven't tested myself though) with a NMO fender bracket. Both of which can be found at the antenna farm.

N8IAA, Like I said, I don't use that radio much anymore (it did have an actual connector that got damaged and that was just a temporary fix). In fact, a few hours before I took the picture I had thrown it on my times tech t100+ and saw evidence of that short with the screw on the swr and impeadance values. About an hour after I took the picture I went out to get some proper UHF crimp connectors (all I keep around is type N stuff) but now that I think about it I actually had a UHF to N adapter I could've used as well.

That's actually a yaesu ft-2900. Beast of a radio.

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