Questions tagged [vhf]
Very High Frequency is the frequency range 30-300 MHz.
128
questions
2
votes
2answers
123 views
How much dB gain do you need from an LNA in front of an antenna for great low-signal reception from satellites in the 2m and 70cm bands?
We are building a multi-stage LNA for a TR module we are building in the 144MHz and 440MHz range. This LNA we are considering (Qorvo QPL9547) provides about 22dB gain in the 2m and about 27dB in the ...
4
votes
2answers
215 views
What is proper procedure for asking for “distant” contacts on 2m FM on simplex?
As a new ham, just for fun, I'm planning to hike up to the local high point (which while not high in an absolute sense does have a commanding view of the surroundings) with my 5 watt FT-4XR and a slim ...
20
votes
1answer
4k views
Why do people say, “get a nickel,” on repeaters?
Sometimes, I'll hear someone say "wait a moment, I'm getting a nickel," and then drop the carrier only to resume talking. Why?
3
votes
1answer
56 views
Is it possible to convert a euro Yaesu 991a to US band plan?
I bought a euro Yaesu 991a . The vhf/uhf band plan is severely limited for use in the US . I have tried the button presses as shown for the earlier 991 and the service mode works to open the frequency ...
4
votes
3answers
344 views
Is testing SWR *practically* less important for 2m/70cm than HF bands?
Totally new amateur operator and I've noticed that a lot of material e.g. Your Tube videos, blogs, forums when discussing metering VSWR mainkly seem to be talking about HF bands. I also see fewer VSWR ...
2
votes
0answers
56 views
Biconical antennas - bandwidth and installation
I am posting this question (and its related question) here because of the unique expertise that Ham Radio Operators have as it relates to antennas. I'm a newish Ham and really appreciate your help ...
1
vote
2answers
202 views
Trying to identify and understand this antenna design - ground independent dual band vertical
This is the insides of a common dual band antenna 2m/70cm, made by diamond or nagoya.
its generally labelled as: 1/2 wave radialless (144MHz), 2 x 5/8 wave radialless (430MHz)
Its meant to be ground ...
3
votes
2answers
123 views
Why am I receiving a local tv channel on a CMB frequency
I am using a simple Baofeng H6 dual band radio and I programmed weather channels.
Well, on frequency 161.77500 I am actually picking up WGN, a local tv network.
This frequency should be reserved to ...
3
votes
3answers
287 views
Use (TV?) Log-Periodic antenna for VHF
I found this old log periodic antenna that I assume was from a TV. Could I, or how would I, use this on the amateur radio bands? My main focus would be VHF, with UHF being secondary and HF would also ...
0
votes
1answer
47 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 ...
1
vote
1answer
103 views
What length and number of radials should be used for a dual band vertical whip backpack antenna?
The Situation:
Very new Ham
I have a 2m/70cm 48" Abree whip antenna, originally designed to be connected directly to an HT
I would like to mount this antenna to the side of my hiking backpack, ...
4
votes
3answers
356 views
Is the Boom Strictly Necessary in a Vertical Dipole?
I'm planning to build a vertical dipole for 4m and a club member pointed out that my design needs to allow for a boom that should be at least a 1/4 wave long. Why does a vertical dipole need a boom ...
4
votes
2answers
228 views
Heat-shrink as dielectric for bazooka balun?
I'm intending to make a sleeve balun (aka bazooka) for 2m, but rather than keep the lossy coax jacket as a dielectric (I have some RG58), was considering to remove it and replace it with heat shrink ...
3
votes
3answers
700 views
Ground-Plane radial sizing, is there such thing as too long?
I'm just trying to make sure I understand the theory correctly.
I have some triband VHF/UHF/800MHz antennas, I need to mount on a tower so I plan on using a "mobile to base" conversion kit. ...
6
votes
4answers
913 views
Any reason not to choose a discone antenna over a Wide/ MultiBand mobile antenna for TX/RX operations
We are setting up a all-band radio in an emergency com center that's intended most for amateur band use, but since its' for emergency use will also be used in the public safety bands; (150-170)MHz, (...
2
votes
1answer
981 views
how does this collinear antenna work?
I was looking for a cheap and easy to build 2M/70cm vertical. I found this: http://vk2zoi.com/articles/dual-band-high-gain-flower-pot/
Here are the plans to build it:
But I don't really understand ...
1
vote
1answer
95 views
Handheld multiband radio for a ham firefighter?
I live half a mile from my volunteer fire station. We are toned out on a VHF frequency by a neighboring municipality, and we provide mutual aid for their fire department that is toned out on an 800-...
2
votes
6answers
2k views
Optimal length of HT antenna for VHF UHF and diminishing return
I see folding antennas of various lengths that people are using for for their HT. My question is about the optimal length. I know it may "depend" on many factors so let me know if I need to provide ...
1
vote
0answers
173 views
Extremely strong QRM on VHF?
I don't usually operate in 2 m, save for FM satellites. I usually go to a nearby park when I do this, for better view of the horizon. But I tried working them from home for the past couple of days, ...
2
votes
1answer
162 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 ...
0
votes
1answer
111 views
How should I stack these folded dipoles?
Looking to stack these 8 folded dipoles on my 100ft tower.
I can not find any information whatsoever on these. I have 4 consecutive serial numbered boxes.
Bluewave Marathon
BME139FN1H0
138 - ...
3
votes
5answers
402 views
Malicious interference to repeater
Our local repeater is severely sabotaged by unknown parties. For example, broadcast radio transmissions are repeated. Other times someone will send a transmission, when a qso is in progress. Local ...
5
votes
2answers
356 views
Wide band TX capable band-pass filter for VHF and Airband
I want to share the same antenna for VHF (TX/RX 144-148 MHz) and for Airband RX-only (116-136 MHz).
I live on a very congested area where filter is a must, so I'm looking for the best solution for my ...
3
votes
2answers
303 views
What VHF & UHF frequencies are important during an emergency?
If something bad goes down (state-wide or nationwide), what frequencies should I be tuning into?
I did see this answer, but I have a BaoFeng UV-82HP which cannot do HF at all, so what are my options?
...
2
votes
3answers
644 views
High Altitude Balloon Antenna Design
I'm designing a weather balloon with a club at college. We want to build the antenna from scratch to learn more about antennas but are at a loss as to which antenna design would actually work for high ...
1
vote
5answers
2k views
Can I contact the International Space Station using my Baofeng UV5R?
I saw this article but I can't imagine the power output, (eight watts max) would be enough to be picked up by the ISS at 200 miles above me.
Similarly, I don't know if the preamp on the receiver ...
1
vote
1answer
85 views
Are there any satellite email reflectors?
I'm just getting started using amateur satellites and would like to subscribe to an email reflector, but I can't find one. Is there anything out there?
4
votes
2answers
71 views
2 meter Mode Options
FM seems to be the most popular in the 144 to 148 MHz Amateur Band .Narrow band is used for spectrum conservation . SSB is also used but is more common on the HF bands .Would SSB provide any ...
0
votes
2answers
58 views
Local Relay with static
On our local Relay there are from time to time transmissions, where only static can be heard. Most transmissions via relay can be heard clearly. What could be the cause of this?
4
votes
1answer
208 views
Does a UHF/VHF handheld transceiver kit exist?
I am a licensed ham looking for a UHF/VHF handheld transceiver kit. Unfortunately so far I was only able to find broken links, i.e. Ten-Tec used to produce exactly such a thing but they just don't ...
3
votes
1answer
117 views
How to simulate two antennas in 4nec2
I need to simulate 2 helix antennae placed side by side, and see the resultant radiation pattern. But after adding the second antenna with a separate and when I try to simulate 4nec2, only simulated ...
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vote
3answers
686 views
Why aren’t emergency services using callsigns?
I’m super new to radio with nobody I know knowing it, so noob alert - plus some extraneous details in case you can comment on any of those.
I got a pair of BaoFeng BF-F8HP radios with recommended ...
3
votes
2answers
405 views
House wiring as an antenna on HF and 2 meters?
The apartment I live in is a 1970s type without access to the outdoors. It does have a balcony. A 2m transceiver is the only radio which will enable me to reach the ham world.
Would be possible to ...
1
vote
0answers
44 views
Unsure how to assemble Shakespeare SSB antenna; not working [closed]
Have 23 foot Shakespeare SSB antenna. Can not connect through the side feed termination band? Antenna not working? What is the band supposed to look like? Is the termination band supposed to be ...
2
votes
3answers
880 views
VHF 50 Ω Antenna Over 75 Ω TV Coax
I have a 50 Ω VHF airband antenna which I’m planning to install in my loft, for use with a RaspberryPi-based RTLSDR scanner/receiver.
I already have a UK-standard UHF/Freeview antenna using standard ...
5
votes
1answer
640 views
Kenwood TH-D72A: what's the difference between Tone and CTCSS?
Kenwood TH-D72A supports 3 types of tone: Tone, CTCSS and DCS.
What is the difference between Tone and CTCSS?
As far as I know CTCSS is basically a continuous transmission of a given low frequency ...
1
vote
1answer
295 views
Colinear Vhf antenna
Textbook colinear vertical antenna designs show coax cable with alternating braid to centre configuration. Commercial whips seem to utilise a single wire as the radiating element with .66 velocity ...
2
votes
3answers
153 views
Weakly directive VHF/UHF antenna
Most resources around the Internet discuss common antenna types, classifying them between directive (like Yagi) and nondirective (like a simple dipole). Directive antennas are good when you know from ...
3
votes
2answers
623 views
RTL-SDR dongle - what antenna should I use for APRS receive only?
I was following this guide to setup an iGate using an RTL-SDR dongle and a Raspberry Pi. It worked, and I have been able to test it by seeing some APRS packets from a separate transmitter (Arduino+...
5
votes
3answers
435 views
Unlicensed TV broadcasting power limit (Band I)
I'm curious what is the legal limit for unlicensed TV signals being transmitted on the VHF Band I?
This seems ill defined. The part 15 FM rules I am assuming don't apply here. And I don't think it ...
0
votes
1answer
186 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
91 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 ...
3
votes
4answers
2k views
Is a copper J-Pole antenna better than a Slim Jim for transmitting?
I live in a fairly sheltered valley but there are several hill-top VHF repeaters that I can receive very well. However the one repeater in particular I want to transmit to, I can't reach well. I ...
3
votes
3answers
1k views
Mounting a J-Pole and Yagi on the same mast
I have two 2-meter antennas, a copper J-Pole and a Hy-Gain VB-25FM. The J-Pole is my all-around antenna, what I use for general 2 meter stuff like connecting to my local repeaters using my main 2-...
3
votes
1answer
692 views
Is a J-pole an appropriate antenna for mounting to a steel handrail?
Last year, a group of us placed a battery-powered 2m digipeater using a J-pole antenna on a mountaintop. We're planning on doing the same this year except we plan to use a surge arrestor from the feed ...
1
vote
2answers
144 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 ...
2
votes
4answers
8k views
If i connect two antennas to one radio using a t connector will it work?
If I connect two antennas to one radio using a t connector will it work?
If a connect 2 antennas (a mag mount + a dipole?) to the same radio with an adapter will it work normally on 2M band and will ...
2
votes
2answers
960 views
What core material do I need to construct a 1:1 unun for 6M?
I want to build a 1:1 unun for a 6M dipole. Power level 100W. What core material should I use?
1
vote
3answers
470 views
Weird Harmonic Issue on Raspberry PI FM Transmitter
So I talked to my neighbor about my Raspberry PI, harmonics and his emergency radio. He told me to fire it up, as we saw the FCC sticker on it, meaning it is in compliance with Part 15. I started my ...
0
votes
1answer
616 views
Gain in long wire antennas
DARA (you know, Hamvention) TNG is looking for projects. Thursday, I will be proposing building and characterizing a vertically-polarized 1 wavelength on a side reentrant rhombic.
Since in doing the ...
