Questions tagged [mobile]

Mobile operations (car, motorcycle, boat or other vehicle)

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19 votes
3 answers
34k views

How does a mag mount antenna achieve a ground plane?

I've been thinking for some time about magnet mount mobile antennas and wondering how they establish their ground plane. Consider that many mag mount antennas have some kind of protective coating on ...
Peter KB1AVL's user avatar
16 votes
3 answers
8k views

What's wrong with 220MHz?

It seems like 220MHz is the bastard step-child of the amateur world. Every HT is either 2m or 2m/70cm. Some companies offer tri-banders, but they almost always add 6m (?!), not 220MHz. The only way ...
WPrecht's user avatar
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13 votes
2 answers
5k views

Is there an optimum Antenna Feedline Length for mobile installations?

I bought a ham radio antenna mounting kit for my car that includes ~16' of coax. One end has a trunk lip NMO antenna mount, the other end has a re-solderable PL-259. I asked the sales person if it is ...
BenSwayne's user avatar
  • 681
11 votes
5 answers
33k views

Should I ground my radio to the chassis or battery for a mobile install?

From what I've seen, there are generally two ways to power a mobile radio: Positive lead to battery, negative lead grounded to chassis Both positive and negative leads to battery I know that ...
Ben's user avatar
  • 213
10 votes
4 answers
3k views

Has a vehicle magnetic antenna mount ever caused a road accident?

Some people believe that mag mount magnets lose their effectiveness over time, eventually causing a dangerous situation as the antenna could rip loose from the vehicle and become a projectile or ...
Paul's user avatar
  • 1,455
10 votes
2 answers
2k views

Buddipole model comparison

Can anyone give me some insight into the different Buddipole models available? They look pretty similar to me except for the sizes. What would make you choose one over the other?
s3c's user avatar
  • 837
10 votes
2 answers
311 views

What is the most common amateur identification practice for mobile US amateurs operating in Canada?

When a US Amateur operates in Canada, IT and Canadian regs permit some lattitude on their identification. I have read that some will prefix a "VE3" plus their own home callsign (Ontario, meaning I am ...
Warren  VE3WPX's user avatar
9 votes
5 answers
2k views

How can I prevent my mobile radio from draining my vehicle's battery?

I'm a very absentminded ham. I have a radio mounted in my car, wired directly to the vehicle battery. Fuses and high-gauge wire and all that good stuff. But, if I accidentally leave it on, my battery ...
Dan KD2EE's user avatar
  • 3,966
9 votes
7 answers
16k views

When and why does the size of a ground plane or radials matter?

Consider these three cases: My understanding is that when building or installing an antenna designed to operate over a ground plane (e.g. a quarter-wave vertical), the size of the ground plane does ...
Kevin Reid AG6YO's user avatar
  • 24.5k
9 votes
3 answers
209 views

Can cellular radio be used for communication with a balloon?

(Sorry, I don't know if this is the right forum for this question, but maybe someone will know the answer. If not, which StackExchange forum could be more suitable?) Me and a few friends of mine are ...
ruthra's user avatar
  • 91
8 votes
4 answers
11k views

How to improve VHF/UHF Baofeng UV-82 HT reception in vehicle

I have a Baofeng UV-82 dual-band (2m/70cm) HT with an SMA male connector for the stock "rubber-ducky" antenna. I would like to use it in my vehicle. I would like a high-quality magnetic mount dual-...
Dan's user avatar
  • 1,754
8 votes
2 answers
219 views

Is using an HT and walking considered mobile?

I've seen many contests define mobile as something like being able to legally move and broadcast. Well, using an HT while walking I can legally move. Does this count as mobile contacts for a contest?
PearsonArtPhoto's user avatar
8 votes
1 answer
1k views

Is a VHF antenna on a vehicle's body a bad idea?

For context, I'm brand new, with nothing but an HT & 19" dual band (2m/70cm) whip on it. While I'll likely go with a magnetically mounted vertical antenna, I've been thinking of other more covert ...
conan's user avatar
  • 213
7 votes
4 answers
1k views

How would you get an "I'm alive" message to family in another state using amateur radio?

I'm researching options for getting an "I'm alive" message during a disaster response out to family in another state that aren't HAMs. There are likely to be a lot of possible answers that are art ...
Matthew Wetmore's user avatar
7 votes
4 answers
2k views

Battery sizing for power draw

Note that this question isn't about battery capacity, at least not per se. I have a 100 Watt mobile transceiver. At 12 V and assuming 50% efficiency, that means it draws a little under 20 Amps at full ...
Dan KD2EE's user avatar
  • 3,966
6 votes
3 answers
3k views

antenna in the rain

What kind of changes can be expected in the behavior (resonance, SWR, etc.) of a mobile vertical HF antenna between dry conditions and wet rainy weather? (assume a coax feed-line and low SWR in dry ...
hotpaw2's user avatar
  • 13.3k
6 votes
2 answers
345 views

75 watts and a mag mount antenna

I am planning to get a Yaesu FT2900R 2 meter rig for my 2001 Honda Accord. With my 5w FT60, I wasn't able to reach repeaters that were any more than 10 miles distant (I live among mountains.) How ...
user228's user avatar
  • 61
6 votes
3 answers
13k views

How do I power my radio in a vehicle mobile install?

I want to install a 30W mobile UHF radio in my car. I already have an antenna and mounting bracket - but how do I get power to this radio? It has an SAE bullet connector on the back - do I just need a ...
Dan KD2EE's user avatar
  • 3,966
6 votes
3 answers
744 views

Is there a special term for amateur transceiver speakers or anything that makes them different from any other kind of speaker?

When I bought a secondhand FT-7800R at Field Day 2017, I received an MLS-100 external speaker with it. I installed it recently and having the speaker more than an inch away from the radio's mounting ...
William's user avatar
  • 803
6 votes
2 answers
5k views

What are some good options for covert dual band vehicle antennas?

Would like to have a 50W mobile in my SUV, but I'm not allowed to have a big whip on the outside. What 2m/70cm dual band antennas are available that don't say, "Ham Radio Operator"? Are there three ...
Adam Davis's user avatar
  • 12.1k
6 votes
1 answer
708 views

FM radio in car gets interference from APRS beacon

The FM broadcast radio, factory installed in my car and usually tuned to 88.6 MHz, gets some interference from the 5W APRS transmitter on 144.800 MHz. It sounds like if the sensitivity of the ...
oh7lzb's user avatar
  • 2,391
6 votes
1 answer
937 views

Kenwood D710: loud fan noise when used in the shack

The fan in the Kenwood D710 mobile radio is turning on on every transmission, including the periodic APRS beacons. This happens even when there is no actual need for spinning it, and is very annoying ...
Georg DO1GL's user avatar
5 votes
4 answers
374 views

UHF 70cm unlicensed use

We are farmers with (edit) 25-40w radios mostly old Kenwoods and Motorolas in all of our tractors and vehicles. I'm not exactly sure what frequency we have but the man who programmed them set them up ...
Logan's user avatar
  • 51
5 votes
2 answers
265 views

Amateur Radio for a Nomad [duplicate]

I got my amateur license back in the early '80s, primarily for putting it on my resume for an electronics job. Never used it outside of developing my Morse code speed, and once I got my Advanced Class ...
KiloVoltaire's user avatar
5 votes
3 answers
1k views

Tiger Tail + capacitive coupling... what's the interaction?

I've been working on a 2m setup for hiking. My goal is to have the best possible antenna that can be used while walking, and that won't get damaged if I walk under a low branch or some other forest ...
Dr Marble's user avatar
  • 171
5 votes
2 answers
213 views

Better SWR bandwidth

Good day, I have a Kenwood TS-480HT with a Wolfriver coil and a stainless steel whip in my car. I find that on 40 meters I can get the SWR at around 1.4 (using an MFJ 269) at 7.1000 MHz. But the SWR ...
Danny's user avatar
  • 87
5 votes
3 answers
784 views

Mounting my antenna

I just bought a CB and mounted it in my truck. I ran my antenna to the back and was going to stick it to my tool box but it turns out to be aluminum, so I'm thinking of bolting a metal plate to the ...
B Wingfield's user avatar
5 votes
1 answer
146 views

OK for S/RF light to be illuminated at engine idle?

I just installed a mobile CB (Uniden) into my Jeep. When the key is in auxiliary (car off, accessories on) and the squelch turned all the way down, no S/RF lights are illuminated and the background ...
jonathanbell's user avatar
5 votes
1 answer
770 views

How does this W6NBC "derivative of the classical slot antenna" work?

Via the https://ham.stackexchange.com/a/9883/1362 answer regarding a slot antenna for a 2m mobile application, I was introduced to this (pdf) interesting antenna design: The designer John Portune (...
natevw - AF7TB's user avatar
5 votes
3 answers
1k views

Noticeable difference between trunk and roof mount?

Between trunk-mounting and roof-mounting a 2m/70cm antenna, both as through-hole NMO mounts, is there really that big a difference performance-wise? I mean, I know roof mounting is better, but let's ...
Dominick Pastore's user avatar
5 votes
3 answers
4k views

How to feed coax from inside car?

What is the best (or standard) way to get coax from the radio in the car to the outside of the car without smashing it and damaging the line? If I just put it through the door crack, it seems to ...
Skyler 440's user avatar
  • 7,600
5 votes
1 answer
2k views

How to calculate or estimate surface area of required ground plane for a mobile antenna?

I don't have conditions for installation of a fixed 2 m/70 cm antenna at home, so I'm thinking of using a mobile magnetically mounted antenna on a conductive plate instead. So my question is: What ...
AndrejaKo's user avatar
  • 2,893
5 votes
1 answer
702 views

How can I counter DC-DC inverter noise / ground noise in an electric-vehicle mobile setup?

So, I'm relatively new to all this; and I've gotten an ICOM IC-7100 on sale, which looks like an excellent transceiver … unfortunately, this very specific line shows up in the manual: The ...
ELLIOTTCABLE's user avatar
4 votes
3 answers
660 views

Need batteries for backpack operation

I am building an HF backpack rig using an Icom IC-706MkIIG with a Opek HVT-400B antenna. The specifications on the radio say 20 A draw at high power, so what size and type batteries would be suitable ...
Steven Donnell KG5GRI's user avatar
4 votes
4 answers
499 views

NMO bicycle mount antenna has unexpected SWR

I built a bicycle antenna mount featuring an NMO connector to allow quick changes. With a 2m 1/4 wave monopole it gives reasonable SWR results (1.4 or so in the band of interest), with a particular ...
Chris K8NVH's user avatar
  • 1,042
4 votes
7 answers
4k views

Slot antenna for 2 meter mobile

My primary vehicle is a Smart car, with a roof that's a piece of plastic(100% moon roof). Not the most awesome of cars to use for grounds. I'm building a bumper mounted antenna tower, EMT with some ...
Omagasohe's user avatar
4 votes
1 answer
584 views

Boosting Mobile Phone Reception

Yes, I know, this could very well be a controversial topic, so feel free to close this off if you feel it's not a good fit for this site. That said, I'm posting it here because hams (and as a ...
Buck8pe's user avatar
  • 989
4 votes
3 answers
257 views

antenna coax feed-thru for a car roof

Newbie here, with a 2 meter mobile rig and a magnet-mount antenna. I am currently routing the coax out an almost-closed window and am tired of having rain water enter the car through it. Is there such ...
niels nielsen's user avatar
4 votes
2 answers
767 views

How should I mount a mobile antenna on a vehicle with a non-conductive body?

I would like to mount a self tuning antenna, ATAS-120, matched with the FT-857D transceiver. I would like to make this pair function on an ARGO 8x8 amphibious vehicle with a polyethylene body. There ...
scott's user avatar
  • 41
4 votes
2 answers
4k views

Does effective grounding of mobile (vehicle) antenna mounts address common-mode currents?

While researching how best to install my mobile amateur radio in my car, I didn't understand if there was optimum Antenna Feedline Length for mobile installations? Understanding that this is caused ...
BenSwayne's user avatar
  • 681
4 votes
1 answer
937 views

DIY Triplexer for HF (low), 6m (med), and 2m/440 (high)

I'm looking at picking up the TYT TH-9800, which is a Quad-Band FM radio on 10m/6m/2m and 440 (I'm lucky enough to have some 6m and 10m repeaters in the area). I know there exists quad band antennas ...
Michael KC1MJP's user avatar
4 votes
1 answer
1k views

What are the best APRS SmartBeaconing™ settings for different modes of transit?

There are a variety of websites that give sample SmartBeaconing™ settings – mostly for automobiles, but some for bicycles and pedestrians. I've tried several of these settings and had mixed results. ...
Rafael KR7MJ's user avatar
4 votes
1 answer
1k views

Bicycle mobile antenna

I have mounted mobile verticals (mag mounts) on my bicycle, but I have learnt that a bike does not have a good RF ground because there is nothing close to a plane. Without wasting too much more ...
Skyler 440's user avatar
  • 7,600
3 votes
2 answers
205 views

Rfi in truck with HF transceiver when running

I have an Icom IC-707 in my truck, a 2003 F150, with a stainless 102 inch whip mag mount on the roof. It has a a coil pack 6 cylinder. Without it running I have no problem; as soon as I start the ...
Plumber90's user avatar
3 votes
2 answers
94 views

How to figure out my car battery's capacity?

I was participating in an emergency radio training and I was asked how long I could operate. I'm using an old car battery, which was sometimes not capable of starting the car in winter, which is why I ...
Thomas DK3TU's user avatar
3 votes
1 answer
3k views

Is Part 90 certification something an amateur radio operator should look for in a radio meant for amateur use?

I'm checking out cheap (~$100) mobile radios on Amazon, and often times there's a question asking about FFC Part 90 certification. As an amateur radio operator looking to use a radio for amateur/...
YetAnotherRandomUser's user avatar
3 votes
3 answers
1k views

How do you keep your vehicle clean with a mobile antenna?

I want to add a V/U antenna to my truck, but my wife started asking about weather proofing and car washes and I had no answer. How do you keep your vehicle clean after installing a new antenna, and ...
SandPiper's user avatar
  • 777
3 votes
2 answers
2k views

What is the minimum length antenna I can use with my vehicle setup?

Devices I need to hook up to roof-mounted antennas in my truck. Scanner - 25Mhz-800Mhz (mostly listen to FD/EMS on 2m and 70cm) Handheld HAM (possibly upgrading to mobile unit) - 2m/70cm CB Radio - ...
Jacob K - KD2JAG's user avatar
3 votes
3 answers
1k views

Baofeng radio produces hum when plugged into charger

So I am working on a low cost ham radio beacon using my Baofeng UV-5R radio because it is easy to use and portable. I built a simple PTT interface for a Raspberry Pi and wrote some python to transmit ...
MrSchmuck's user avatar
3 votes
1 answer
489 views

Installing GNU radio on android

I want to install this miracle program on my smartphone in order to get more mobility. I found such a solution exists: https://github.com/bastibl/gnuradio-android However, I could not do everything as ...
Антон's user avatar