Author Topic: Inexpensive Vehicle Mount Option for Handheld Tranceivers  (Read 13371 times)

Offline iam4liberty

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Inexpensive Vehicle Mount Option for Handheld Tranceivers
« on: December 20, 2014, 09:23:30 PM »
It can be very useful to convert a handheld transceiver (aka handy talky or HT) into a semi-permanent mobile unit. For as little as $20 in parts and ten minutes of time an effective, safe install can be done.

Parts:

1. Magnetic mount antenna.  Decent units like those of the Nagoya series run from $8 - $12.  Reviews of different models can be found on http://www.eham.net/reviews/products/37



2. Battery eliminator.  This allows for the vehicle's 12 volt system to power the HT thus eliminating battery charging issues.  Removing the battery also makes the unit lighter, enabling more mount options.  Cost of a battery eliminator varies by make and model of HT, but oftentimes can be had for $5 to $8 on ebay.



3. Suction cup mount.  Universal grip mounts are generally more than adequate for securing an HT. If used on car glass generally no other adhesive is needed. Use on flat, plastic surfaces may require the use of suction cup tape or the installation of a disc like those used with GPS.  The unit used in this example install sells for $6 on ebay.



4. Speaker Mic.  This makes the HT's Push-To-Talk function easy to operate.  These often sell for $1 to $5.



Installation

To maximize radiated power, typically the best place for the antenna is centered on the top of the vehicle's roof.  This also allows for the cable to routed to the corner of the hood via the rain gutters.





Once at the corner, the cable can be routed around the door jamb and up on the dash. The corners of molding can be used to keep the cable slightly taunt.  This keeps the cords away from the feet which is a major safety concern.  Also, the turn allows for any rain which comes down the cable to drip off rather than come into the vehicle cab.



The suction cup mount can be placed in numerous locations to put the transceiver in easy reach for changing channels, changing volume, and initiating scans.  One option is to use the surfaces of the nooks and crannies in the dash console.




But I have found that the best location is hanging down from the windshield.  This keeps the antenna wire on top of the dash, allows the battery eliminator cord to hang down directly to the accessory (cigarette lighter) port, and puts the transceiver in the same visual plane of the road without interfering with seeing traffic.  The battery eliminator cord also makes for a good place to clip the speaker mic.




That's it for a safe, effective installation!  Even with the low power of an HT, a setup like this can be very effective for hitting repeaters and for vehicle-to-vehicle simplex communication.

Please note, if there is a desire to regularly remove the HT (e.g. for theft protection or to use when in pedestrian mode) it is good to do another modification, adapting the SMA connector common on today's HTs to BNC.  SMA connectors were not designed for constant plugging/unplugging of antennas and will wear out quickly.  They are also slow to remove and install as they requiring multiple rotations to seat properly.  Using BNC connectors on the antenna and HT is a much more robust and quicker option.  How to do this will be detailed in a later post.

73.
« Last Edit: December 20, 2014, 09:31:36 PM by iam4liberty »

Offline backwoods_engineer

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Re: Inexpensive Vehicle Mount Option for Handheld Tranceivers
« Reply #1 on: December 27, 2014, 05:20:41 PM »
Good tutorial for new hams, and those that can't do a permanent installation.

Offline Carl

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Re: Inexpensive Vehicle Mount Option for Handheld Tranceivers
« Reply #2 on: December 27, 2014, 05:58:05 PM »
I ran a HT on a slightly reformed metal bookend (two for $3.19) and just slipped the belt clip over the metal bookend set in my console ...hand mic and through the glass antenna worked great around town on the repeaters. I like the mount he used here.

Offline Greekman

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Re: Inexpensive Vehicle Mount Option for Handheld Tranceivers
« Reply #3 on: December 31, 2014, 05:19:44 AM »
hmmmm isn't the wire a bit thin?

Offline Carl

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Re: Inexpensive Vehicle Mount Option for Handheld Tranceivers
« Reply #4 on: December 31, 2014, 05:22:17 AM »
Probably RG 174, it is thin and handles 50 watt or so well. Best use is to take weight off of small HT and connectors.

Offline iam4liberty

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Re: Inexpensive Vehicle Mount Option for Handheld Tranceivers
« Reply #5 on: December 31, 2014, 09:14:16 AM »
hmmmm isn't the wire a bit thin?

Thanks for pointing that out, GreekMan.  That brings up an important point I failed to mention.  The antenna used in this example is only for HTs and other low power applications.  They compromise power rating for the ability to use thinner (0.1 inch OD), more flexible coax.  This allows the coax to go around turns and put a lot less stress on the connectors (no need for 'pigtail' extensions).

Probably RG 174, it is thin and handles 50 watt or so well. Best use is to take weight off of small HT and connectors.

Ding, ding, ding...give that man a cigar!  Yep, it is RG-174.  I believe for some manufacturers the power rating can be as low as 15 Watts maximum.  :o  It is incredible stuff for low power applications but has too be really sealed well against water. That is not a problem for this application as the whip end is completely enclosed in the mount and the connector end is in the vehicle.

For those who are interested, this is a handy chart showing coax types for different applications: http://www.radiobooks.com/products/techinfo/coaxapps.htm

Also, if someone is interested in how well these inexpensive antennas tune see here as an example: https://www.youtube.com/watch?v=GhdOIwDWLK0

Offline Greekman

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Re: Inexpensive Vehicle Mount Option for Handheld Tranceivers
« Reply #6 on: December 31, 2014, 09:49:23 AM »
I am actually not concerned with power rating, but with losses

RG-174 has some pretty horrendous losses. 0.9db vs 0.5 for the rg-58 in 145MHz for a length of 9feet

Check loses here
http://www.timesmicrowave.com/calculator/?productId=122&frequency=145&runLength=9&mode=calculate

Offline Carl

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Re: Inexpensive Vehicle Mount Option for Handheld Tranceivers
« Reply #7 on: December 31, 2014, 10:15:10 AM »
A barrel connector has .5 DB loss too, Sometimes you must compromise as 2 inch diameter hard-line will not let the door close.
The HT antenna within an auto will also lose about 20 DB...there is some loss with any path for RF but little problem with the short coax feed on an auto. RG174 survives being shut in the door much better than RG58...I use RG58 but run it through a door that is simply not used on my 4 door auto. I did it because it was the EASY way to feed my $16 antenna.

OOPS , now $25 dollar antenna

http://www.amazon.com/Tram-1185-Amateur-Dual-Band-Antenna/dp/B0045EQUBK/ref=sr_1_cc_2?s=aps&ie=UTF8&qid=1420046001&sr=1-2-catcorr&keywords=tram+mag+mount+antenna

Offline PrepperJim

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Re: Inexpensive Vehicle Mount Option for Handheld Tranceivers
« Reply #8 on: April 01, 2016, 06:19:50 PM »
Thanks for this thread. I did something similar and it works out better than routing through the sunroof. Routing through the sunroof, I had to remove every time I leave the car (rain).