Questions tagged [antenna-system]

The system composed of an antenna and a feed line, and possibly also an RF ground connection, antenna tuner, balun, phasing device, et cetera.

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9
votes
3answers
562 views

Stealth HF station setup advice

I need some advice on setting up my first HF station in a somewhat restricted townhouse community. If I had a detached house with a backyard I’d probably already have everything setup. But with this ...
4
votes
3answers
666 views

What is the point of high gain antenna with respect to the maximum EIRP

OFCOM states that the maximum EIRP within the UK for 2.4 GHz is 100mW. Simply put, what is the point in being able to buy 2.4 GHz high gain antennas which can say do 24dBi, which already puts the ...
0
votes
1answer
205 views

guard planes in differential antenna PCB designs

The designs I have seen all seem to have this surrounding stitched-to-the-ground copper pour surrounding them. Why put it on a differential antenna PCB like below ? And why are those thin lower left ...
6
votes
4answers
1k views

What exactly is impedance?

I see "impedance" used everywhere. Equipment has an input and output impedance. Antennas and feedlines all have this 'impedance' thing. For someone that understands DC electronics, Ohm's law and a ...
2
votes
2answers
130 views

How to safely connect a digital output to a receiver's antenna input?

Suppose I have a 3.3 or 5V GPIO digital signal (from an Arduino or Raspberry Pi, etc.), periodically toggling at some HF or VHF frequency. Since it has such a "dirty" spectrum, I don't want to hook ...
1
vote
3answers
347 views

High SWR on a Jeep with Spare Tire Mount

I just installed a spare-tire mount and Browning BR-180 dual band antenna on my Jeep JK. Initial SWR testing show nothing higher than 1.4:1 across both bands so I didn't try to tweak it. Then I put ...
0
votes
1answer
296 views

Using the VHF port for 6m on an Icom IC-706mkIIg transceiver

My Icom IC-706mkIIg transceiver has two output ports: one for its VHF/UHF bands (i.e. 2m/70cm) one for the HF bands, and also 6m! I have a couple of broadband VHF/UHF antennas whose transmit specs ...
2
votes
2answers
239 views

Using two antennas with IC751A — one for transmitting and another for reception

Is it safe to use one antenna for transmitting (main antenna PL connector) and another for reception connected to ANT IN connector at the backside panel?
1
vote
2answers
130 views

Serial matching stub combined with RF choke

If I use RG6 coaxial cable in odd multiples of 1/4 wavelength as a serial matching stub, can I also use it, without modifying the length, as a coiled RF choke balun at the antenna feed point?
2
votes
1answer
133 views

What dictates ladder line max frequency? [duplicate]

When using ladder line to feed an antenna, I've seen it written that The spacing should not be over 1 percent of the highest-frequency wavelength, and that’s the only real consideration with ...
7
votes
3answers
2k views

Antenna for a cramped attic

Brand new Ham. I bought a cheapo UV5 right before I got my call sign. I want to set up a decent 2m/70cm station for starters and I realize that a better radio is important but wanted to knock out the ...
3
votes
3answers
505 views

Which is better in my situation: Balanced dipole, or as much wire as possible in the air?

I'm finally getting to the point of hopefully putting up a HF antenna. The idea is to start with a simple, straight wire dipole using trees as support points. (No traps or coils.) However, with the ...
1
vote
0answers
45 views

Can two directional antennas be connected without an amplifier to improve reception? [duplicate]

Can two identical yagi antennas be linked together to improve a cell phone signal? The idea is to put one antenna on the rooftop and the other in the house, and connect the two with feedline but no ...
2
votes
1answer
458 views

What do we mean by “RF in the shack”?

What does "RF in the shack" mean? How does it interfere with devices around coax?
1
vote
2answers
169 views

Match 420 Ω to 50 Ω

Is there any practical way to match the output of my PA which is 420 Ω to my antenna which is 50 Ω at 434MHz? I was thinking about adding a pi-network and using a VSWR Meter with the output of the ...
2
votes
5answers
588 views

What would be the easiest and most cost effective ground system for a startup UHF/VHF station

I just passed both my Technician and General Class license this past weekend, and am now contemplating my first station. To get my feet wet I'm planning on getting a Yaesu FT-7900R Dual band Radio ...
4
votes
1answer
519 views

How to bypass LNA for TX in UHF Antenna?

I want to work with amateur, low power, and/or pico satellites. I would like to use an Eggbeater or Turnstile antenna with my UHF 433 MHz radio, since those antennas are very cheap and easy to build ...
1
vote
0answers
85 views

OCF Antenna Feed Line [closed]

I built a OCF HF antenna. The feed line contains a 4:1 balun and a line insolator (choke) per instructions. When checking the radio end of the coax, I get a "grounded" response between the inner wire ...
5
votes
3answers
1k views

Running ladder line through window from inside shack to outside dipole antenna - what to watch out for?

For HF operating, I am considering running a ladder line from the ATU just inside a window, through the window (squeezing it between the window and the window frame; not actually through the glass), ...
2
votes
1answer
187 views

Should I ground a 2 array crossed yagi-uda antenna?

I am using 2 array crossed yagi-uda antenna operating at 437.025 MHz. Where and how should I ground it? Should I ground at mast of antenna or to its metallic boom?
6
votes
2answers
10k views

Connect two receiving antennas to the same radio

I have built a 1090 MHz ADS-B antenna roughly following some video instructions. It appears to work reasonably. However, because of how it is placed, it captures signals for more or less a half of ...
10
votes
6answers
2k views

While backpacking, is it worth mounting the antenna to the backpack frame (above my head)?

I am planning a trip with a large group in 6 weeks. We will be spread out in small groups on a trail in a mostly desert plateau landscape perhaps 5 miles apart, but mostly in a straight line. I'm new ...
12
votes
3answers
3k views

Share antenna between receiver and transceiver?

I recently put up a fan dipole for 80/40/20/10. I'm looking for a way to share this antenna with a receive-only SDR and my shack transceiver. Obviously I can just switch this antenna between the two ...
10
votes
1answer
734 views

What does a lightning bolt symbol next to an antenna connector mean?

On the back of my Yaesu FT-897, next to each of the antenna connectors, there are lightning-bolt-ish symbols. What do these mean, and is there something I ought to be doing because of that? I have ...
8
votes
2answers
671 views

What are some ways to ground a transmitter+antenna in an enclosed attic?

If I want to minimize "RF in the shack" and lightning hazard, what some good ways to ground a transmitter and indoor antenna in a top floor room or attic with no exterior access? (say a multi-story ...
7
votes
1answer
377 views

Is it safe to mount an active scanning antenna close to an hf antenna?

I live in the centre of a seaside town in the UK. Because of lack of space I have a random wire antenna in the loft of a small house, and pick up a lot of noise on the top band Sunday morning CW ...
6
votes
1answer
120 views

How to ground with little surface area?

Let's say I have a very small device, like an RC airplane, which transmits information as well as receiving commands for control. The body is made out of non-conductive foam, therefore not much ground ...
10
votes
1answer
877 views

Can I have multiple inverted-vee antenna fed by a single coax?

A friend who recently received his call is planning to setup an inverted-vee for 40/20m bands. Our take is the signal will take the path of least impedance into the correct length antenna wire. ...
8
votes
2answers
5k views

Phasing harness for antenna array

I understand that certain antenna designs (particularly phased arrays) require feeding each radiating element with a certain number of degrees of phase separation in order to achieve a desired ...