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Questions tagged [mobile]

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

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16
votes
3answers
6k 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 ...
16
votes
1answer
19k 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 ...
10
votes
2answers
3k 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 ...
10
votes
2answers
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?
10
votes
2answers
259 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 ...
9
votes
5answers
1k 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 ...
9
votes
3answers
11k 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 ...
8
votes
4answers
10k 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-...
8
votes
4answers
2k 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 ...
8
votes
2answers
140 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?
8
votes
1answer
814 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 ...
8
votes
2answers
162 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 ...
7
votes
4answers
703 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 ...
7
votes
4answers
1k 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 ...
6
votes
2answers
228 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 ...
6
votes
3answers
290 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 ...
6
votes
1answer
586 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 ...
6
votes
1answer
671 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 ...
5
votes
3answers
287 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 ...
5
votes
2answers
193 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 ...
5
votes
3answers
601 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 ...
5
votes
2answers
74 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 ...
5
votes
3answers
412 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 ...
5
votes
2answers
8k 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 ...
5
votes
1answer
124 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 ...
5
votes
3answers
2k 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 ...
5
votes
1answer
1k 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 ...
5
votes
2answers
4k 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 ...
5
votes
1answer
351 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 ...
4
votes
2answers
403 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 ...
4
votes
2answers
2k 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 ...
4
votes
1answer
388 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. ...
4
votes
1answer
839 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 ...
3
votes
4answers
188 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 ...
3
votes
1answer
1k 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/...
3
votes
3answers
255 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 ...
3
votes
2answers
1k 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 ...
3
votes
3answers
345 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 ...
3
votes
3answers
967 views

What should I look for in a modern portable shortwave radio?

I'm looking to buy a shortwave to listen to either solely at home or perhaps if possible in a vehicle when traveling. What should I look for when looking them over? I recall many years ago the ...
3
votes
1answer
394 views

What are the maximum possible speeds of download over Amateur Radio frequencies?

In this scenario, I would have a base station connected to a modem that essentially allows me to access the internet/local network via radio, irately I am not fully aware of what information I need to ...
3
votes
2answers
367 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 ...
3
votes
2answers
772 views

Are chokes necessary for VHF and higher frequencies?

I am trying to install a VHF/UHF antenna on my truck, and I have been studying everything I need to do that. I keep reading about chokes, in particular here: http://www.k0bg.com/choke.html However, ...
3
votes
2answers
407 views

2 meter dipole of work vehicle

I am about to purchase a Baofeng HT. I have one I am thinking of using primarily in work truck. I can't really drill holes or have antenna be too obvious. On Amazon I found a 2 meter 70cm 2m dipole....
3
votes
1answer
79 views

What's the general difference between radiation patterns of stationary and adaptive aerials in mobile communication systems?

I am trying to find general difference between radiation patterns of adaptive and stationary antennas (common difference, calculation difference and any other). I am interesting in any example and ...
3
votes
1answer
118 views

Are the Icom 2300 h and Ftm 400dr DC cables interchangable?

I would like to swap out my 2300h to a 400dr. Would rather not swap out dc power cable. Are the cables the same or is there an adapter for make it possible?
2
votes
2answers
2k views

How to eliminate alternator whine?

On my car's LW receiver, I have a severe case of alternator whine, especially when the headlights are on. It has become worse over time. I have read that capacitors might help. However, two things ...
2
votes
1answer
309 views

What size is the Kenwood TM-D710 panel mounting bracket?

For the purposes of this question, I am considering purchasing a Kenwood TM-D710GA (or a RC-D710). The control panel has a mounting bracket for mobile use which is intended to be attached to a flat ...
2
votes
2answers
150 views

Can RF work while it's in motion?

I have a project idea. It uses a pair of RF transmitter and receiver. The application is a little complicated since it involves motion, typically the speed of a vehicle going on local or even better ...
2
votes
2answers
2k views

Smallest / Thinnest UHF/VHF Mobile Transceiver under $100

I'm looking for the smallest/thinnest UHF or VHF two-way radio under $100. So far I've found: Baofeng/Pofung UV-5R (current solution) Baofeng/Pofung BF-888S (102m x 51mm x 11.35mm) KST K-888 (122mm x ...
2
votes
1answer
626 views

Starter package? [closed]

What are some online resources that can be used for finding an HT package?