Questions tagged [mobile]

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

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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 ...
1 vote
2 answers
55 views

What are the considerations re installing an ID-4100 in a DIN slot in the dash?

I'm looking into installing my ID-4100a into the radio slot in my car. The radio and cassette player (lol yes really) are non-functional so I actually have 2 slots to play with. I haven't come across ...
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 ...
1 vote
1 answer
57 views

How to test real-world performance of a wifi and LTE IoT device

We're developing a product that communicates over wifi and LTE. I'm putting together a test plan for determining that these work, but also what sort of conditions we can expect them to work in. The ...
2 votes
3 answers
468 views

Monopole antenna with no ground connection

I have a SDR device and have a question about using a monopole antenna with them, but the question could be applied to any device which uses an antenna. SDR comes prepacked with a monopole antenna ...
2 votes
1 answer
128 views

Converting an FM Antenna to a 2m/70cm Transmitting Antenna

I have a 2006 Honda Goldwing 1800 with an extra FM antenna that I would like to convert to a 2m (or 2m/70cm) transmitting antenna. Changing the connector to a PL-259 seems to be the easy part and I ...
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 ...
3 votes
3 answers
4k 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
2 answers
3k 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 ...
0 votes
1 answer
121 views

How to create FM Radio Mesh

What (devices transmitters, receivers and transceiver) do i need to create a fm radio mesh, instead of using a single transmitter with big antenna, i want to build fm transceiver mesh radio to cover ...
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 ...
2 votes
1 answer
96 views

Looking for specifications for Wilson Electronics WAU 420 amplifier

Hey there helpful people I'm trying to track down some specifications on a Wilson Electronics WAU 420. I have no idea on its exact age but guessing its from the late 90's. It's likely UHF band and ...
1 vote
3 answers
198 views

QRP CW on HF using FT-817ND - filter/dsp recommended?

I'm just getting into amateur radio, so just starting to gather the things I want/need. I'm only really interested in CW, and almost exclusively on HF. I'm looking into a mobile/portable setup which ...
2 votes
2 answers
699 views

Do I need an antenna tuner for new mobile antenna

I am looking to buy my first mobile antenna, for use with a 2m/70cm HT in the car. The HT needs 50 Ω impedence. I was looking at this antenna, but another ham told me that I need 1/4 wave or 5/8 wave ...
3 votes
1 answer
68 views

Measuring effectiveness of vehicle bonding

Is there any objective way to measure the effectiveness of your bonding in a mobile HF setup? Or determining when you have "adequate" bonding? I have a hard time with just throwing straps on ...
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 ...
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 ...
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 ...
0 votes
1 answer
125 views

What type of Cable Should I use between a Long Wire antenna and a Transmatch?

I installed a Yaesu System 600with a MFJ Versatuner 2 on my 31ft sailboat and Idont know what type of cable should I use between the MFJ and the long wire antenna I have on my back Stay. Any ...
0 votes
2 answers
1k 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 ...
0 votes
2 answers
8k 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 ...
1 vote
2 answers
122 views

Sealing connection between mobile antenna and mount

I've got a brass mount installed on my car which has a 3/8-24 socket. All the antennas I'm looking at seem to have stainless steel connectors. Is packing the connection between antenna and mount with ...
1 vote
3 answers
337 views

Ignition Static on 2m mobile but not 70cm

I have an ICOM 2730a 2m/440 mobile rig in a 2015 Ram 1500. Tx and Rx with truck not running is excellent. With engine running I hear static popping, but only on 2 meters. If I Tx I can hear the ...
1 vote
2 answers
95 views

Adding radio to the car

I got an anytone 778uv that I want to add to my car. I'm looking at adding it with a add a fuse to an open fuse slot, however I see many people just saying to add it to a chassis bolt. I am new to ...
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 ...
1 vote
2 answers
131 views

Can a smartphone with single antenna receive signals modulated by different schemes

I am working on a system whereby a smartphone may receive signals simultaneously from different sources. As we know, the fading and pathloss will make the transmitters send their traffic with ...
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 ...
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 ...
2 votes
1 answer
5k views

Frequencies as 5 digits and 6 or 7 digits

Why are some frequencies 5 digits like 51344 and some six or seven digits long like 158.7600?
4 votes
3 answers
256 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 ...
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 ...
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 ...
2 votes
1 answer
1k 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 ...
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 ...
0 votes
1 answer
206 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 ...
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 ...
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 (...
1 vote
3 answers
181 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, ...
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 ...
2 votes
1 answer
698 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
4 answers
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 ...
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 ...
1 vote
2 answers
1k 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 ...
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 ...
1 vote
1 answer
147 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 ...
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 ...
1 vote
1 answer
197 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
2 answers
145 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
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 ...
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 ...