Questions tagged [vhf]
Very High Frequency is the frequency range 30-300 MHz.
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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 ...
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1answer
543 views
2m loop with sense antenna for DF
I would like to construct a 2m Loop with a sense antenna. I have built just a loop antenna with great success that is resonant at 2m finding null's works quite well on local repeater outputs.
I would ...
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1answer
64 views
VTS messages vs AIS
When arriving in a port, complementary to her AIS signal (encoded VHF message) it seems that the vessel also has to emit a voice message on a predifined VHF frequency to identify herself as part of ...
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2answers
551 views
Airband VHF antenna challenge
I have a very difficult antenna design/installation challenge. I need to install an VHF antenna (118 to 140 MHz) into a nearly all carbon fiber glider. The radio provides 5 watts and 50 ohm, and most ...
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1answer
54 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, ...
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1answer
304 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 ...
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1answer
494 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 ...
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1answer
159 views
UHF Into VHF Power Amplifier
What would be the result of accidentally applying a UHF signal to a VHF power amplifier? Say a 70cm transmission from a dual-band 2 meter / 70 cm radio into a 2 meter PA, assuming the input power is ...
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1answer
94 views
Antenna for 6M, or Antenna system?
Here, in VU-land, 6M allocation is from 50 MHz through 54 MHz... which is a fair chunk of spectrum.
If I think about a half-dipole antenna; between 50/54 MHz it's length varies by over a foot ... and ...
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1answer
788 views
VHF / UHF - Terrestrial Circular Polarized Antenna
I've been doing mostly HF for the last 20 years and just recently installed a 2m/70cm mobile rig in my shack for base station work. I like to work FM simplex and repeaters when the HF bands are not ...
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1answer
419 views
What is the best resonator in Yagi antennas?
As we saw many design for this Yagi feed point.
Q1 . Which one would be the best resonator / driven?
Gamma match, T-match, delta match, folded dipole, quad, loop?
Q2. And what is the reason if ...
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176 views
How do I alter the low power setting on a QYT KT-8900
There is no difference between the High and Low power settings. Both being around 25 watts.
Is there an internal adjustment or do I have to re-program the radio?
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57 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?
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1answer
84 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 - ...
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2answers
156 views
What type 2 m /70 cm antenna to use when I want to receive a number of spacially separated beams?
So I have a 1.5 m by 1.5 m window. Through it, I have a number of spatially separated ~10 cm wide "beams" coming from local repeaters.
It looks something like this:
Outside of the marked areas, ...
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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 ...
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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 ...
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2answers
132 views
Any ideas as to what I might be picking up on SDR?
Any ideas as to what I might be picking up on SDR? They make for some strange patterns. Picked them up at the following coordinates: (31.514596, 74.345092) using GQRX, tuned to 217.25 MHz. As for the ...
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252 views
Amplified antenna & typical boombox radio
Can an amplified antenna be connected to a typical boombox radio with a telescoping antenna without damaging the radio?
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4answers
2k views
Good Hidden Antenna For 2m
I would like to have an antenna outside for 2 meter VHF use but I do not want it to be expensive and I won't be allowed to put it up if it stands out too much. Does anyone know a good antenna to buy ...
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1answer
239 views
Using RF6886 Power Amplifier for VHF design
I want to use RF 6886 power amplifier for VHF band design. The datasheet doesn't mention VHF design specifications. Has anyone used the PA for VHF design? If yes then please share your designs.
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1answer
163 views
Using 'amodem' to transfer digitally using a UV5R
I reviewed docs for amodem, and it looks like I can send files and possibly other things with this.
I should only need to prep my computer as per the doc and set VOX correctly. Does anyone have ...
