Questions tagged [mobile]

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

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6
votes
3answers
9k 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 ...
2
votes
1answer
539 views

CB Radio Ground Plane (or lack thereof)

Notice the vertical antenna on the truck. I believe this first antenna is referred to as a "dipole", mounted vertically. CB to coax, coax to antenna. The shell of the truck is fiberglass. Even the ...
0
votes
2answers
211 views

Yaesu FT-817 Won't transmit Dig, SSB or CW

I have a problem with my Yaesu FT-817 it Won't transmit Dig, SSB or CW, But it does transmit AM, FM and Pkt on all bands. Does anyone know what the problem might be. The Radio receives fine on all ...
7
votes
7answers
12k 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 ...
0
votes
1answer
36 views

Hatch Mount Antenna Selection - Dual Band 2m/70cm

I just bought a Diamond CP-5NMO hatch/lip mount and intend to put it on the hatchback lip of our 2018 Subaru Forester and, if it will fit, another one on our 2019 Kia Niro EV. I understand that hatch ...
12
votes
2answers
4k 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 ...
3
votes
5answers
3k 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 ...
5
votes
1answer
129 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 (...
3
votes
0answers
146 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 ...
9
votes
4answers
20k 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 ...
1
vote
3answers
130 views

Need antenna for mobile mag-mount LPFM broadcast 88.3 MHz

I am doing some temporary FM broadcasting for car events such as COVID-safe car parades and drive-in movies. The terrain is horrible, urban areas with lots of buildings. The cars snake around a city, ...
3
votes
3answers
309 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 ...
17
votes
1answer
24k 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 ...
2
votes
1answer
276 views

Can Yaesu FT-65 be charged from a 12 VDC automotive accessory outlet?

I recently purchased a Yaesu FT-65 handheld radio and quickly discovered it had no 12 VDC power port like other handheld radios I've seen. The charging cradle uses a 12 VDC wall wart for power, and ...
2
votes
1answer
97 views

144/430 MHz antenna on 155 MHz?

We have a local radio shop that started selling us Relm P150s with a high gain 9 inch antenna, and those are ok. He also has thrown in longer 15 to 14 inch dual band antennas saying use those in ...
2
votes
4answers
1k 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 ...
8
votes
3answers
186 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 ...
1
vote
2answers
678 views

GMRS not transmitting within a half mile

I recently got my GMRS license from the FCC, and I wanted to try out a couple radios for hiking and emergency communication. I have two tenway UV-5R pro radios (these do have an FCC ID) that are set ...
4
votes
3answers
579 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 ...
1
vote
1answer
83 views

New quad-band mobile receives while transmitting?

I've got a week-old TYT TH-9800, a quad-band (10/6/2/70cm) mobile, Chinese knock-off of a Yaesu HT-8900. So far, I love it -- several times the power of my HT, and a better antenna actually outside ...
3
votes
4answers
283 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
2answers
525 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 ...
1
vote
1answer
130 views

Connecting radio in parallel with inverter in mobile set up

I've just added a leisure battery, split relay and circuit swap loom to a newly acquired Mazda Bongo. Also added was a 1000W pure sine wave inverter, hooked up directly to the leisure battery. That's ...
1
vote
2answers
103 views

Audio being sent over ground pin on audio jack

I just bought a QYT KT-8900D mobile radio. One of the first things I've noticed is that I cannot use my mixer to completely lower the volume of the radio's 3.5mm TRRS output. When the fader is all the ...
5
votes
2answers
99 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
939 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
3answers
566 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 ...
1
vote
2answers
115 views

How to log contacts when mobile?

I'm just about to get on the air for the first time as a ham. It's been my understanding that it's good to log contacts with call sign, frequency, signal quality, and time of contact. However, for ...
0
votes
2answers
83 views

Proper magnetic mount placement on roof

I have a Nissan Versa 2012 (hatchback). It comes with one of those default antennas at the back/center of the roof, for listening to AM/FM radio stations. I have a dual band mag-mount (TRAM 1185), ...
5
votes
3answers
1k 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 ...
0
votes
1answer
149 views

6 meter mobile antenna grounding

So I've been looking at my different options for 6 meter mobile antennas. My question mainly pertains to grounding. I've heard hams talk about needing a ground to the frame of the vehicle when using ...
1
vote
1answer
88 views

Mobile VHF/UHF antenna coupling to surrounding objects?

Will a mobile antenna --either mag mount or NMO mount-- couple to surrounding objects such as tall trees, taller trucks, buses, or even people walking by? If that is the case, would you get slightly ...
2
votes
1answer
170 views

Is it possible to make antenna for one specific frequency?

I have a GSM Modem that works on 2300MHz Frequency (LTE), but it could only receive 3 bar of signal strength. I plan to make a DIY directional antenna that is made specifically for this Frequency ...
5
votes
1answer
630 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. ...
3
votes
1answer
187 views

ID5100 is a Speaker Mic avail?

ID5100 mounted mobile in center console with only faceplate and mic exposed. Also have bluetooth headset. Besides the speakers built-in and external sp1 or sp2 does a handheld mic AND speaker like on ...
2
votes
2answers
142 views

What wireless communication technologies can travel long distances with a high bandwidth?

I couldn’t find a better place to ask this question, so I have asked it here. I am looking to transmit and receive internet connectivity wirelessly over a distance of 6 miles (9.7 km) with a minimum ...
3
votes
1answer
664 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 ...
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 ...
1
vote
2answers
169 views

Console vs Trunk mount

A little background - I own a 2012 Dodge Charger Pursuit that I am turning into my mobile ham station. It already has most of what I need, but I ran into something I want to ask a question about. It ...
3
votes
1answer
2k 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/...
2
votes
2answers
154 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 ...
6
votes
3answers
449 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 ...
0
votes
2answers
930 views

Do the radials of a quarter or 5/8 wavelength antennas connect to the braid of the coaxial cable?

I'm studying for my foundation license (in the UK) and I have these diagrams: Do the radials in a quarter or 5/8 wavelength antennas connect to the braid/shield of the coaxial cable? If so, how does ...
2
votes
1answer
376 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
3k 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 ...
5
votes
1answer
449 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 ...
0
votes
2answers
5k views

Motorola Maxtrac Programming with windows 7 and DOSBox

I found an old Motorola Maxtrac in a parts truck I bought. I'd like to program some channels into it with a Windows 7 computer and DOSbox. My first issue, is I'm having trouble identifying the radio ...
7
votes
4answers
792 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 ...
2
votes
0answers
466 views

Direction Finder using directional antenna, digital signals amid clutter [closed]

There are several methods for implementing direction finder. 1. One of the method is by using directional antenna pointing to target device, and reading the received signal strength from the target ...
0
votes
1answer
132 views

RF connector between mobile phone and transmitter = complete shielding?

When connecting mobile to transmitter with RF cable: Does RF connector provide complete shielding for the transmitter signal ? Does it prevent the mobile from receiving other signals from other ...