Linked Questions

5
votes
3answers
1k views

Determining Impedance With An Antenna Analyzer

I need some help interpreting some information from my antenna analyzer (RigExpert AA-35). I want to use the information to impedance match my AM receiving antenna system to AM radios. No ...
5
votes
3answers
2k views

How to feed coax from inside car?

What is the best (or standard) way to get coax from the radio in the car to the outside of the car without smashing it and damaging the line? If I just put it through the door crack, it seems to ...
4
votes
3answers
420 views

Receive directionality of a sub-optimal Yagi

How do I build the best antenna for a given VHF frequency given that an optimal design is too large? I am trying to understand the properties of a directional antenna of sub-optimal design. All the ...
2
votes
3answers
5k views

How does the antenna length affect signal transmission/receipt in different bands?

My Canadian Amateur Radio Basic Qualification Study Guide tells me that my antenna length is specific to the wavelength I wish to broadcast on and gives a formula that equates to antenna length = half ...
1
vote
3answers
1k views

How to attach a magnetic loop antenna to the 50Ω coax of an RTL SDR?

I'm planning to make a magnetic loop antenna mainly for receiving LW, MW, and SW radio broadcasting bands, as well as perhaps the 2.2km band and 630m band. (Not all of them with the same antenna, I'mm ...
9
votes
2answers
759 views

If two antennas of 50 Ω and 377 Ω have VSWR=1:1, then which one is more efficient?

If there are two antennas of 50 Ω and 377 Ω (same as the intrinsic impedance of air) impedance with 0 $\Omega$ ohmic resistance, and they are exactly matched with their transmission line, then which ...
6
votes
2answers
116 views

Why aren't “ghosts” and intersymbol interference due to unmatched impedance (high SWR) a concern for HF receivers?

In amateur radio, we care about impedance matching when we need to keep the load within the equipment's specification (for best performance, or just to avoid damaging a transmitter), when we want to ...
6
votes
2answers
598 views

Choosing capacitor for high-pass filter with cutoff of about 160 MHz

A strong (100 kW) local FM transmitter causes interference to or overloading of receivers in the VHF/UHF bands. It seems like a single, properly chosen, capacitor could make an effective passive high-...
5
votes
2answers
7k views

How to construct a loop antenna for receiving HF?

I have a unused hula-hoop in my garage, and I ran some stranded speaker wire around it once, and attached one side of the wire to the coax shielding, and the other to the coax core wire. Is this the ...
4
votes
2answers
1k views

What impedance matching do I need between my 300Ω feedline and Softrock receiver?

I will be assembling a Softrock Ensemble II HF receiver, and I know I'm going to want it on air as soon as I build it, so I'm challenging myself to build an antenna for it first. The plan is to do a ...
2
votes
2answers
162 views

Reciprocity and SWR [duplicate]

If someone has a high SWR, obviously their signal will not make it out as far due to reflections. However, they will still be able to hear relatively well. I have noticed for receive, a high SWR may ...
2
votes
2answers
2k views

Does increasing the number of turns on a loop antenna decrease frequency operation?

Lets say I want to make a VLF loop antenna for a Sub AM radio band. I don't want a full wavelength because that would be a humongous antenna. Would I wind more turns of wire to decrease the frequency ...
10
votes
1answer
2k views

How does a “chip antenna” work?

How does a tiny surface-mount "chip antenna" for the 2.x thru 5.x GHz frequency bands work? What allows such a tiny item to radiate or receive RF with some amount of efficiency? What allows a chip ...
9
votes
1answer
536 views

How can I calculate the effects of an LNA, antenna gain, etc. on noise performance?

There are many things I might do enable my station to hear weaker signals that would otherwise be buried in noise. Just a few possibilities: Install a nice LNA Increase antenna gain Reduce feedline ...
3
votes
1answer
652 views

Receive antenna design for a small apartment

I am looking to make a simple receive antenna from some wire, and I have some questions about resonance. Being that this wire can only be so long (about 3 meters maximum, as it must fit inside my ...

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