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"FPGA firmware is wrong" on Icom 9700

One day, I turned on the radio and suddenly displayed the picture shown in my picture below. My big wheel is also broken, of course, this is before this incident. The initial suspicion is a firmware ...
BH6QBC's user avatar
  • 1
0 votes
1 answer
16 views

How can I derive mode from a DX cluster spot?

First some background. I am writing some software to control an amateur radio transceiver based on the user's selection of a spot from a DX cluster. My goal is to set the frequency and mode such as ...
pidloop's user avatar
  • 77
0 votes
0 answers
23 views

Morse code help with vocaroo

https://vocaroo.com/1nSJsgpYz2nj trying to decode this but I'm not good at interpreting morse code. First character is B. How can I read the voice clip?
cs95's user avatar
  • 101
1 vote
3 answers
90 views

Gap between a dipole antenna

I need to know how much gap should be there between the two arms of a dipole antenna? I would also like to know how much gap is there between the two rabbit ears antenna and is the loop antenna ...
user10897549's user avatar
0 votes
1 answer
27 views

Programming UV5R with cable

I have 2 of the same model (new) UV5R's, 1 works fine programming and the other I get "Radio did not respond". The cable is all the way inserted and I am following the same steps as with ...
Romtang's user avatar
2 votes
1 answer
53 views

Is there documented FCC/Congressional reasoning behind restricting Tech licensees to CW on HF?

Is anyone aware of documented Congressional/FCC reasoning behind restricting Technician licensees to CW on HF? I'm not (yet) advocating for a change or to keep status quo, rather am trying to ...
webmarc's user avatar
  • 4,353
1 vote
1 answer
74 views

Why FCC band plans so different from IARU?

I just realized how different the ARRL/FCC band plan is from the IARU Region 2 plan, of which the US is a part. For example, on 40m 2700 Hz modes start at 7.125 vs 7.050 MHz, respectively; on 20m they ...
pidloop's user avatar
  • 77
0 votes
2 answers
65 views

Running antenna parallel to steel fence: antenna effects and neighborhood RFI

I am moving into a 55+ community, relatively small lots, single story frame and stucco homes in close proximity to neighbors. However, one edge of the lot is parallel to a golf course and has a steel ...
dlowrey's user avatar
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0 answers
29 views

End Fed 160-10 meter Antenna

The antenna as shown here has a counterpoise, but I can't remember how long it is. Its shape is dictated by what trees and distance I have available. It tunes 160 meters ok with my auto tuner. ...
Bill Smith's user avatar
1 vote
1 answer
40 views

NEC2: Should I model a "tube" or just solid wire (GW) for an aluminum-tube-based antenna design?

I'm considering using this 1/4" aluminum tube to build a cross-yagi antenna in the 2m band. The tube dimensions are 1/4" OD x 1/8" ID x 1/16" Wall (.250" x .120" x .065&...
KJ7LNW's user avatar
  • 759
0 votes
0 answers
37 views

Motorola GM340 flash of LEDs but then no boot up

Recently I inherited 2x Motorola GM340 (no LCD screen version) Vhf mobile radios, The one radio works and seems to have been setup to act as a repeater and I am assuming the other was too. However ...
Jonas's user avatar
  • 101
0 votes
1 answer
43 views

Run antenna coax through hatchback of a Nissan Rogue

I have a 2014 Nissan Rogue and am trying to figure out best place to run my coax from a mag-mount antenna. Seems not many do this anymore and cannot find answer in search. Do not want to run it ...
Robert Gority Sr's user avatar
0 votes
0 answers
40 views

Is there a quick grounding disconnect for coax?

I am setting up my shack again after 30 years off the air. So I have been a ham for a while but my knowledge and experience is thin. I live on an island in Florida with frequent thunderstorms. My ...
David Feder's user avatar
0 votes
1 answer
65 views

Matching antenna at 4.2 GHz using an LC network

I want to match an antenna using an LC matching network: Operation frequency: 4.2 GHz Vacuum wavelength: 7.2 cm Cable: Source Impedance: 50 Ω\ The antenna impedance is unknown, but it is approximately ...
DarkBulle's user avatar
  • 101
1 vote
0 answers
56 views

Risk of lightning strike with wire antenna in tree?

I'm considering putting up a long wire antenna across my yard for reception / DX purposes. Due to how my yard is set up I think one good way of putting it up would be with a metal mast on a secondary ...
Dennis's user avatar
  • 111
2 votes
2 answers
77 views

What do the WSJT-X split frequency options actually do under FT8?

Maybe I have this all wrong, but as I understand FT8, we're all communicating within a slice of the band ~3 kHz wide. Within this slice, we each have our own sub-slice, and the location of my slice is ...
user1172763's user avatar
1 vote
1 answer
51 views

Any better alternatives to bullet connectors for connecting outdoor antenna wires?

I build antennas and sometimes have a need to repeatedly connect and disconnect wire antenna elements, such as loading coils and radials. It is especially the case for portable antennas. I have been ...
gschro's user avatar
  • 344
0 votes
2 answers
75 views

Other radios can hear my Baofeng but I can't hear them with my Baofeng

this may be a dumb question but I am new to this stuff so don't judge me please, I just bought Baofeng UV-5R and I tested it with Topcom Twintalker 1302, which is PMR radio. I set my frequency on my ...
MDdiamond's user avatar
-1 votes
2 answers
60 views

Is the TAOGLAS PCB Antenna Too Long on Purpose?

I have been using a TAOGLAS 915MHz PCB antenna for my remote control. I'm about to redesign the PCB and wanted to try including my own PCB antenna on the board. For the 915MHz band, a quarter ...
user98055's user avatar
1 vote
3 answers
103 views

How to test a simple homebrew CW transmitter - can I use an AM radio?

I've built a simple very low power (10-100mW) CW transmitter, and would like to test it over very short distances before working on my amplifier. (For background, please see A first homebrew design: ...
SRobertJames's user avatar
0 votes
1 answer
85 views

Uplink signal modulation detection (drone related)

Can somebody help me and tell me if the UPLINK signal from a drone is an OFDM signal? I know that the DOWNLINK channel is OFDM, but i don't really find something related to UPLINK. Can I infer on the ...
Carmi's user avatar
  • 3
5 votes
2 answers
90 views

Will 2 ferrite beads taped side by side perform the same as a single-piece binocular core?

I intend to make a beverage antenna and have quite a few spare ferrite beads of various mixes. If you look up binocular core ferrite on amazon you will see they are a single chunk piece of ferrite ...
BBQ-Man's user avatar
  • 51
13 votes
3 answers
3k views

How are secret encodings not a violation of amateur radio regulations?

This question asks if proprietary encodings are "in keeping with the nature of" of ham radio. The accepted answer notes, at least in regard to FCC regulations, that if anyone can buy ...
Mark Adler's user avatar
0 votes
2 answers
67 views

What is the radiation pattern of a center fed dipole on the ground?

What is the radiation pattern of a center fed dipole on the ground? Let's say I have a 1/2 wave dipole and simply place it on the ground. No raising it. What happens? My specific case is 40 m, CW, ...
SRobertJames's user avatar
0 votes
3 answers
91 views

Will antenna insulation protect from RF burns?

Will antenna insulation protect from RF burns? I understand that antennas should normally be built with their insulation on. Will that insulation protect from RF burns? Up to what power level? If not:...
SRobertJames's user avatar
0 votes
1 answer
58 views

Configuring an antenna for (short distance) ground wave propagation on 40 m?

I'd like to use 40 m for short distance (ground wave) QRP CW. My criteria for antenna selection is simple: Works short distance (ground wave) As simple as possible As small as possible Ideally, some ...
SRobertJames's user avatar
2 votes
1 answer
107 views

Can anyone identify what _kind_ of radio this Viking "Mercury" radio is?

I'm usually pretty good at identifying old gear, but this one baffled me - and without a model number, Googling is basically useless. The front panel contains volume and squelch, but that's it. I ...
Geo...'s user avatar
  • 151
2 votes
1 answer
116 views

Two different dipoles attached to three trees

I wish to erect two separate antennas, one 20 meter dipole and one 40 meter dipole. My property has 3 trees that are the correct distance apart from each other. They are oriented such that when the ...
Tony565's user avatar
  • 21
1 vote
0 answers
55 views

Meteor scattering with RTL-SDR RTL2832U

What type of antenna and frequency is best for meteor scattering? I have a RTL-SDR RTL2832U DVB-T tuner dongle and would like to learn how to use it.
Robert's user avatar
  • 11
1 vote
2 answers
64 views

Will a LPF filter on the transmitter prevent CW key clicks?

Reading about key clicks, it would seem that they are primarily caused by the fact that the square wave of turning the key on and off must, by definition, have higher frequency harmonics, which sound ...
SRobertJames's user avatar
1 vote
1 answer
52 views

What are the electrical properties and connectors of a CW key?

I'm working on a simple homebrew design and want to connect a CW key to it. (The basic design can use a simple built in pushbutton key, but I'd like to be able to purchase a proper key and use it as ...
SRobertJames's user avatar
0 votes
3 answers
94 views

Formulae for monopole antenna inductance/capacitance

I am looking to make a wire antenna for a transceiver module I have. My target frequency is ~915MHz, and so with a quarter wavelength model I should be using an antenna of ~81mm. If I wanted to use a ...
user98055's user avatar
0 votes
2 answers
257 views

What is this symbol?

overall schematic symbol in question This is the image from the balanced modulator circuit the Datasheet of MC1496. I mean the circle that is grounded , what is that? it is connected to the pin 10 (...
Ritam Sarkar's user avatar
2 votes
1 answer
82 views
+50

NEC2: How do "currents" and "charges" inform antenna design and modeling?

Question How would you reason about charge and current density in your design to better tune (and understand) your antenna? Background According to the NEC2 documentation, "The output may ...
KJ7LNW's user avatar
  • 759
0 votes
3 answers
62 views

How an Audio Signal is Modulated with FM?

An audio signal can have varying frequency and amplitude and both are the part of the information. But as per my knowledge , Frequency modulation is a technique where the frequency of the carrier wave ...
Ritam Sarkar's user avatar
3 votes
1 answer
86 views

Measure performance of rubber duck antennas

I have a handful of no-name rubber duck antennas which came in stock with different brands of handheld radios. I also have a short Nagoya NA-701. I would want to quantitatively compare them and decide ...
Sergey Kostrukov's user avatar
1 vote
2 answers
89 views

US Permanent Resident operating in Canada

I am a US Permanent Resident with an Extra-class license from the FCC. I'm looking to operate when I visit Canada, but everything I'm seeing on the ARRL and RAC sites specifies Citizen. Are there ...
RoadieRich AE8RL's user avatar
0 votes
1 answer
125 views

Budget Open Source and Open Hardware SDRs?

Recently, I've been playing with an RLT-SDR dongle and enjoying it. While I've designed plenty of PCBs and other electronics, I haven't had a chance to work with RF at all, so I wanted to design my ...
itisyeetimetoday's user avatar
0 votes
1 answer
87 views

Is there a frequency pair appropriate for a temporary mobile 70cm repeater?

I am thinking about building a portable low power 70cm repeater for field and emergency operations. For example it could be placed up high on a mountain to cover the valley. Is there an appropriate ...
Peter Gottlieb's user avatar
1 vote
0 answers
120 views

End fed half-wave dipole only measured 5 ohms

This is a bit unusual but I am trying to diy a simple high impedance antenna running in 2.45GHz, for some explorations in ultra-narrow band applications in WiFi. And I have heard in ham radio ...
Xingda Chen's user avatar
0 votes
3 answers
318 views

Will an earth ground work for an EFHW?

I recently tried using an earth ground (wire in the ground) to ground my EFHW. It does work on any band except 10 and 15 meters. So, I think the wire in the ground is working but can I improve it? I ...
o'o's user avatar
  • 592
6 votes
4 answers
1k views

Why do homebrew designs wrap toroids instead of using off the shelf inductors?

Why do homebrew designs wrap toroids instead of using off the shelf inductors? Off the shelf inductors are easily available in a range of values, including uH and even some mH. And hand wrapping ...
SRobertJames's user avatar
4 votes
0 answers
84 views

A first homebrew design: Band, antenna, and ground wave propagation

I'm working on a very simple homebrew transceiver and request review of our selected band, antenna, and power. Background: A child got very interested in ham radio, as an incentive for to earn his ...
SRobertJames's user avatar
0 votes
1 answer
40 views

I want to connect a headset with kenwood (baofeng) plug to a Yaesu FT-60 HT

The adapter I have keys up instantly when I plug the headset in. Is there a known adapter or do I need to make one myself?
Bruce Ferrell's user avatar
3 votes
1 answer
439 views

Why would you choose a Turnstile vs Crossed Yagi CP antenna?

Question What is the difference between circularly-polarized crossed-Yagi and turnstile antennas used for satellite contacts? From what I can tell, the crossed elements of a Yagi are electrically ...
KJ7LNW's user avatar
  • 759
0 votes
2 answers
53 views

Link budget with transmitter duty cycle (satellite earth station to a 5G terrestrial receiver)

I want to calculate link budget in a communications link where transmitter is a small satellite earth station and victim is a 5G base station. The question that I have is whether we can account for ...
Mat's user avatar
  • 1
1 vote
1 answer
64 views

How does a yagi beam propagate?

Why does the power density of yagi antenna beam propagation diagrams increase as the distance to the source increases? Shouldn't the signal get worse as the distance increases or does that only happen ...
mkocrehjuko's user avatar
1 vote
1 answer
45 views

What type and size Torx bit to remove a Baofeng mic and speaker cover plate?

What type of driver or Torx wrench do I need to remove the 5 Torx-type button-head screws (marked with red dots) in this photo? I need to remove it in order to slightly enlarge the hole over the ...
Mike Waters's user avatar
  • 8,071
1 vote
3 answers
233 views

450-ohm ladder line fact vs fiction

I am considering many possible doublet antenna scenarios for a multi-band antenna (80 meters to hopefully, 6 meters) customized to my specific home situation. Everything is a compromise. I will be ...
Michael's user avatar
  • 13
5 votes
2 answers
390 views

Can the reactance on a transformer load, be "corrected" on the transformer primary, to improve transformer efficiency?

The following question is regarding the ability of a transformer, UnUn or BalUn, to be efficient, if the transformer (UnUn in my case), is feeding a load with reactance, and what can be done about the ...
Louis Seaman's user avatar
  • 1,127

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