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1500 questions
5
votes
4 answers
How can I inject an oscillator output into the RF input to my radio?
I have a Bodnar GPS disciplined oscillator, and I would like to inject its output into the antenna input to my HF rig. This will allow me to compare the frequency of received unknown signals to the highly accurate Bodnar signal. There are a couple…
Bill KG5RMJ
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5
votes
3 answers
does the shape of an antenna ground plane matter?
I would like to test a tranceiver setup I created before I mount it in my car. In my backyard, there's a length strip of metal; 10m in length, 10cm wide. Now I wonder if I can use that as a ground plane for an antenna.
Is it important for an antenna…
Folkert van Heusden
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5
votes
3 answers
Why do so many hams prominently display their callsign in the shack?
By ham standards, I'm far from being a long-time adept of amateur radio, but I've seen my fair share of shacks, both on the internet and in person.
What's always attracted my attention is that almost every one of them has some sort of platter with…
Ivan R2AZR
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5
votes
3 answers
How are capital letters sent in Morse code?
There is only one alphabet in Morse code, so is there a recognised way to indicate a capital letter?
Harry Weston
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5
votes
4 answers
Help designing a random wire antenna to work with my tuner
I recently picked up an Icom M802 marine HF radio that includes ham bands and an Icom AT-140 antenna tuner. I have a ham license, but have been away from HF for many years and have never used a random wire antenna before.
Ultimately I may want this…
Jim Archer
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5
votes
3 answers
Do I need a precision wattmeter or will a $50 one suffice?
My transceiver has a built-in wattmeter but I've decided to buy an outboard one to monitor the antenna system before it reaches the ATU. I'm capable of putting out 100 Watts and I see that several manufacturers offer meters in the $50 range that…
Dax
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5
votes
2 answers
How to play spectrum recordings made with rtl_sdr in gqrx?
I have an R820T DVB dongle and the rtl_sdr software on a linux computer.
I can listen to various frequencies using the gqrx software which uses the rtl_sdr library as a device driver for the USB-attached dongle. I also (obviously) get the spectrum…
Paul
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5
votes
2 answers
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 several high gain lobes shooting energy off in…
Dportology
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5
votes
2 answers
What happens if I “open” a folded dipole so that the two wires are not connected anymore?
A folded half wave dipole consists of two wires in parallel with only one of the wires driven, but the ends of the two wires electrically connected. As I understand it (and I may well be wrong there) the folded dipole still behaves similarly to a…
anyfoo
- 153
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5
votes
1 answer
What lengths of counterpoise is suitable to support a 58 foot "random wire" antenna?
I am a technician interested in building my first antenna. I want to explore HF bands, 160m - 6m. Quick impedance calculations indicate that a 58 ft "random wire" antenna could work for this. But I am unsure which counterpoise length to select.
I…
mcandre
- 151
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5
votes
2 answers
Understanding Impedance (R+jx)
In a typical antenna (lets say dipole for this discussion), the pattern below is observed in the impedance (R+jx) graph:
I'm trying to wrap my head around this graph.
Why does the resistance spike, and what is the significance of the interval it…
t252
- 687
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5
votes
2 answers
14dB insertion loss for bandpass filter acceptable?
I'm busy with a direct conversion receiver for the 20m band, using a VXO and a 14.060 MHz crystal.
I designed a bandpass filter with the following components, using this design calculator.
Someone gave me a nanoVNA to check the shape of the filter…
Hans Fong
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5
votes
2 answers
Why do Baofeng radios have such poor reception reliability?
What is the nature of Baofeng radios' poor receiver performance?
This brand of handhelds has somewhat notoriously poor receivers. I hadn't noticed this much when using them for short distance simplex work on hikes and whatnot, but during recent…
natevw - AF7TB
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5
votes
3 answers
What kind of soldering iron is best for PL-259 (UHF) connectors?
What do you use to solder connectors onto bulk coax cable?
Soldering the UHF connector to the coax shield on a PL-259 is described as requiring a bit of "experience and skill" in Dave Casler's video.
UHF Connectors 274
The trick is to solder through…
Dax
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5
votes
1 answer
Boefeng UV-5RE scanning capability
Since the factory manual is simple and basic, is it possible to use the Baofeng UV-5RE to do these things?
Listen to FM radio, while scanning 2m and 70cm bands in the background (as in hiking)
Set the scan low and high limit, via keypad and/or PC…
EEd
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