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Questions tagged [vhf]

Very High Frequency is the frequency range 30-300 MHz.

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Why are VHF bands closed all the time?

Why are the VHF bands closed every day? Is it getting abandoned? Every time I check the solar conditions, it says that the VHF bands are closed. GlobalNorth says, "As the big public safety and ...
o'o's user avatar
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4 votes
2 answers
137 views

Shifting Frequency of a VHF Crystal?

I have a boatload of 165.550 MHz Regency 10.7 MHz IF Crystals. I need them to resonate for 165.500 MHz. How can I shift the crystal frequency down 50 KHz without opening the 'tincan' and messing ...
Station51's user avatar
1 vote
0 answers
70 views

TYT TH-350 unlocking to receive 160-161 MHz in the USA

Recently purchased the TYT TH-350 because it is triband. My version allows for TX/RX 144-148/222-225/420-450. Every other HT I own allows for extended receive only. The TH-350 has a European version ...
Radio Rails's user avatar
-3 votes
1 answer
318 views

Handheld amateur radio

Recently purchased a MY-EMR1 which is a handheld ham radio and I want to synchronize it to my sisters in another state if it is possible, she has the same type of radio. All the frequencies have been ...
cookie1's user avatar
0 votes
2 answers
152 views

Using Aviation VHF radio on different frequencies

I have an old Icom A-5 aviation handheld with a frequency range of 118.000-136.975 MHz on top of WX, AM, and FM receive functions. Is there any way with little modification, or a simple static build ...
ChamomilePurple's user avatar
4 votes
0 answers
60 views

Optimizing Half-Duplex Sequencing: Consolidating RF and Power Connections with Bias-T and VOX

I've successfully implemented a half-duplex sequencing mechanism, which I've illustrated below. The outdoor components are represented in green. In my current setup, I utilize a PLC to control both an ...
Moses Browne Mwakyanjala's user avatar
2 votes
3 answers
551 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 ...
Dan's user avatar
  • 311
1 vote
1 answer
94 views

Pulsing static on 6m

Located in Illinois, US, I recorded this http://loami-windmill.com/sounds/6m_noise.m4a on 28-June-2023 at 1603 UTC on 50.074MHz USB. The static has regular "pulses" where it gets slightly ...
Duston's user avatar
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1 vote
1 answer
223 views

Creating a single feed wearable wire antenna

When I was deployed, our commo guys gave us wire antennas we could thread through our body armor (through the MOLLE loops). These antennas were just lengths of 50Ω coax that had the insulation ...
Jesse Knott's user avatar
2 votes
1 answer
181 views

UnUn for VHF and UHF

Is it possible to build an UnUn for VHF or UHF like in HF? Goal is to use a simple endfed wire or piece of metal as an antenna. EDIT: I meant "endfed halfwave".
microfox's user avatar
2 votes
2 answers
140 views

Is the noisy spectrum from 20MHz to 330 MHz normal?

I have recently been testing some VHF/UHF antennas for reception in my Lab, and have noted something I could not explain. Following are the spectrum plots captured on our R&S FSV spectrum analyzer,...
Asad Ul Haq's user avatar
1 vote
1 answer
347 views

A new ham should start with Digital or Analog Portable Radio?

I am interested in acquiring two portable radios to talk between a family member and me (both new hams), e.g. when we go trekking in a National Park or to communicate in the same city. We used PRM ...
Fabián Iglesias's user avatar
0 votes
1 answer
352 views

How does nitinol shape memory wire work as an Antenna in 60 MHZ whip antenna?

I'm trying to make a body whip antenna for some friends of mine running at 60 Mhz at 10 W power. We are in the military, and we are trying to make an antenna that can be routed through our gear to ...
Mackdice35's user avatar
2 votes
1 answer
234 views

Portable indoor VHF antenna for SDR

I want to make / buy VHF antenna that can meet the requirements below: Portable (easy to install and transport). Indoor (I want to install the antenna at a windowsill). Low noise level, no (or not ...
ALEX's user avatar
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2 votes
4 answers
413 views

Why are VHF radios so much cheaper than HF ones?

Why do VHF-UHF radios tend to be cheaper than HF ones? There are expensive VHF radios and relatively cheap HF ones, but finding a cheap VHF radio is much easier than finding a cheap HF radio. Why? ...
Someone's user avatar
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3 votes
2 answers
5k views

When to use TSQL vs TONE for a (2m) repeater?

I'm trying to understand when to use TSQL and when to use TONE in the configuration of a repeater. I got a repeater file to import into my radio from http://www.dstarinfo.com/repeater-list.aspx and in ...
Pablo Fernandez's user avatar
-1 votes
1 answer
163 views

How to build the best bang for yhe buck uhf vhf antenna or should i just buy one [closed]

Help with antenna build what makes up a great antenna what can I use for elements and would a dush network dish be good reflector and how to wire the elements like the copper to one side and the ...
vanny tran's user avatar
3 votes
1 answer
309 views

ISS repeater on a Baofeng?

I know people have RECEIVED a signal from the ISS on a Baofeng UV-5R, but I'm interested in TRANSMITTING. I'm going to be using a Baofeng UV-5RTP (basically an 8W UV-5R) with a Nagoya NA-771 that ...
Spaceboy1010's user avatar
0 votes
2 answers
265 views

1/2 wave dipole instead of 1/4 wave + ground plane

I have a transceiver operating at 150MHz using a 1/4 wave vertical whip and horizontal ground plane at 90 degrees. My end user doesn't like the antenna sticking up in the air (trip hazard) so I'm ...
P_J's user avatar
  • 43
5 votes
2 answers
203 views

How do antennas over 1/2 wavelength work?

I've been told countless times that an antenna should be 1/4, or 1/2 wavelength. That increasing this size to a higher multiple of 1/4 will work, but it will distort the radiation pattern to include ...
Dportology's user avatar
1 vote
0 answers
75 views

Design of an LNA housing box for a UHF/VHF satellite ground station

I'm currently designing a waterproof metallic case to house LNAs, power cables, and RF switches for a UHF/VHF satellite ground station. As shown in the diagram below, the antennas are connected to an ...
Moses Browne Mwakyanjala's user avatar
3 votes
1 answer
486 views

Using threaded rod for VHF radials

I've been thinking about building a VHF antenna using stainless threaded rod for the ground plane's radials to mate with a hub I already have. My theory is that will make life easier than trying to ...
user3486184's user avatar
  • 1,957
0 votes
1 answer
190 views

YouLoop antenna for amateur satellite reception

I recently learned about the commercial YouLoop antenna and it seems to be quite simple to set up. They said it was possible to receive satellite signals on amateur VHF (e.g. NOAA and other CubeSats ...
Moses Browne Mwakyanjala's user avatar
3 votes
2 answers
247 views

VHF Balancing, necessary? Methods?

This is a question about power dissipated due to radiation and ohmic heating caused by common mode current in the coaxial shielding, specifically at VHF frequencies. When a balanced antenna (such as a ...
elplatt's user avatar
  • 160
1 vote
1 answer
143 views

Is SSB and FM voice considered TDD or FDD (and what are TDD/FDD)?

We are looking at the Qorvo QPL9547 LNA and the datasheet notes: For TDD Applications: R1 = 0Ω & R2 = 100K For FDD Applications: R2 = 100K ‘OR’ Pin 6 tied to ground. R1 = DNP/Omitted This will ...
KJ7LNW's user avatar
  • 723
2 votes
1 answer
212 views

Automatic identification system (AIS) on aprs.fi - Long Rx -> Tx distances

I've been looking into some of the info available on aprs.fi, which also makes available AIS data, but most of the reports I see have such large Rx->Tx distances that I'm not clear on how things ...
Jared's user avatar
  • 201
0 votes
2 answers
196 views

How do vehicle anti-theft trackers work on VHF? [closed]

I'm looking in to vehicle trackers, the kind that allow police to track stolen cars such as Tracker (UK) or LoJack (US), and I can see there is quite a lot of variants out there. The common consensus ...
cosmarchy's user avatar
  • 109
2 votes
2 answers
194 views

How to choose antenna "pigtail" pragmatically?

I'm starting to tinker with an RTL-SDR (generic, and cheap, so nothing fancy in any respect, hence the "pragmatic" in my question title). It's clear that the antenna provided (about a foot ...
Toby Eggitt's user avatar
11 votes
5 answers
3k views

Why do operators mention the band when calling CQ on phone?

I'm a new-ish ham, licenced for about one year now. Within that year I've heard a lot of CQ calls from other hams on phone (both HF and VHF), and it seems that a large portion of hams routinely ...
Ivan R2AZR's user avatar
2 votes
2 answers
707 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 ...
KJ7LNW's user avatar
  • 723
4 votes
2 answers
647 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 ...
QuantumMechanic's user avatar
21 votes
1 answer
5k 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?
webmarc's user avatar
  • 4,210
3 votes
1 answer
1k 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 ...
rocco's user avatar
  • 31
4 votes
3 answers
2k 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 ...
Jason Tan's user avatar
  • 151
2 votes
0 answers
129 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 ...
FontFamily's user avatar
1 vote
2 answers
2k 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 ...
Hayden Thring's user avatar
3 votes
2 answers
290 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 ...
fiacobelli's user avatar
3 votes
3 answers
522 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 ...
Galaxy's user avatar
  • 199
0 votes
1 answer
220 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 ...
William's user avatar
  • 803
1 vote
1 answer
370 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, ...
hehe3301's user avatar
  • 157
4 votes
3 answers
2k 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 ...
Buck8pe's user avatar
  • 989
4 votes
2 answers
477 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 ...
webmarc's user avatar
  • 4,210
4 votes
3 answers
4k 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. ...
Frank's user avatar
  • 349
6 votes
4 answers
3k 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, (...
Frank's user avatar
  • 349
2 votes
1 answer
5k 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 ...
hjf's user avatar
  • 1,199
1 vote
1 answer
193 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-...
colboynik's user avatar
  • 115
2 votes
6 answers
8k 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 ...
Bort's user avatar
  • 215
1 vote
0 answers
489 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, ...
hjf's user avatar
  • 1,199
2 votes
1 answer
739 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 ...
Dean M.'s user avatar
  • 21
0 votes
1 answer
541 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 - ...
VE6RSO 's user avatar