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Questions tagged [hf]

The frequency range 3-30 MHz. HF radio waves often propagate by bouncing off the ionosphere, allowing communication between continents. This tag may also be used for questions about the 160 meter band (1.8 MHz), which while not HF is often referred to as such due to its similar propagation.

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A first homebrew design: Band, antenna, and short distance 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
0 answers
25 views

rsid seems hard coded to be disabled when in PSK31 or RTTY mode. Only works for other modes

So I asked ARRL about the RSID being sent before they make a bulletin transmission, which they said was on but it was not being sent that I could see before the transmission. The RTTY mode just starts ...
elle threethrity's user avatar
0 votes
2 answers
67 views

FT8 not displaying

Why can't I decode the FT8 when using WSJT-X on HF? At first, it decoded one but then, nothing showed up. I didn't change anything. I can still hear the FT8 signals clearly but the software won't ...
o'o's user avatar
  • 404
0 votes
1 answer
50 views

Radials with centre-loading coil

Does a centre-loaded HF antenna need radials? If I put a loading coil 1,5-2m (5-6,5 feet) high, do I need to put radials out on the ground? Feed point would still be near the ground.
S54KZ's user avatar
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6 votes
1 answer
321 views

Why do 9:1 ununs use type 2 material for the core?

I do not understand how a 9:1 unun wound on a T200-2 works. I understand the transformer voltage and current ratios. I have wound several toroid chokes and 49:1 ununs and know how they work. What is ...
Dereck's user avatar
  • 503
3 votes
1 answer
48 views

Rig Expert AA-35 ZOOM Amateur Band coverage in the United States

I am having difficulty understanding the low end of the AA-35 ZOOM frequency range. The tool can help with frequencies between 35 and .06 MHz. Looking at a chart I saw that 60 kHz was Standard ...
Radio Rails's user avatar
-3 votes
1 answer
329 views

Handheld amateur radio

Recently purchased a MY-EMR1 which is a handheld ham radio and I want to synchronize it to my sisters in another state if it is possible, she has the same type of radio. All the frequencies have been ...
cookie1's user avatar
3 votes
2 answers
174 views

What are the best SSB bands for hiking/tourism?

I am relatively new ham-radio operator. I have a goal in mind to hike and have overnight stays in a tent. I keep exploring idea about bringing a radio with me. I am prepping for general license to ...
k1zmt's user avatar
  • 337
1 vote
4 answers
173 views

Connecting two sites in the Arctic and Antarctic with a HUGE equatorial repeater? (Science fiction story advice)

TLDR: With infinite resources but real technology (no satellites, and no other repeaters possible), how would you best connect two ideal sites in the Arctic and Antarctic with an ideal, well-equipped ...
Tris - 2E1OAT's user avatar
2 votes
1 answer
245 views

What is this weird interference/strange radio station?

When I was checking if my antenna is working properly using websdr.org, I came upon this: On 4480 kHz, there are some strange noises. You can also see it in the waterfall here. Is it just some ...
o'o's user avatar
  • 404
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homebrew t match atu issues

my homemade tmatch atu is ok on 80+40m but seems too have too mutch inductance on the bands above 40m,it has a 50mm/20cm roller coaster,i have a 40m doublet+ 4-1 balun+ common mode choke fitted in the ...
paul .a larner's user avatar
0 votes
1 answer
176 views

What can you do to prevent exposure of RF?

When I bought my transceiver, I found out that it only puts out less than half a watt (which can't travel a 1 mile radius from the antenna, according to google). So, I bought a power amplifier. It ...
o'o's user avatar
  • 404
0 votes
1 answer
134 views

Why are the signals that my antenna is receiving weak? [closed]

I recently bought the EFHW antenna kit from ARRL, put it together, and set it up. But, my received signals were not clear enough to hear clearly. Is the problem specific to the antenna from ARRL, my ...
o'o's user avatar
  • 404
3 votes
1 answer
197 views

How do you make a HF contact?

I asked google, but I had no luck. It didn't say anything about what you should say in a contact. It only said how you should start a contact. Also, I have heard that you are supposed to give a RST ...
o'o's user avatar
  • 404
2 votes
1 answer
184 views

Measuring Power - Attenuators and 50 Ohm Termination

I'm attempting to measure the output power of my transceiver + linear amp combination and I would like to confirm that my measurement approach is correct. I need to get the output power down to a ...
Buck8pe's user avatar
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3 votes
1 answer
224 views

Why are there weird sounds in radio?

When I'm tuning through the radio on HF, suddenly, I hear a tone. So, I tune back, and the more I tune back, the more the tone changes pitch. For example, if I tune back 1 kHz, the sound rises by 1 Hz....
o'o's user avatar
  • 404
3 votes
1 answer
142 views

Low power indicated on tuner

Please forgive my extremely basic question, I am brand new on HF and have issues with my setup. I have a Chameleon MPAS antenna in vertical configuration connected to an AT-100 ProII tuner with a 50 ...
kataik's user avatar
  • 133
1 vote
3 answers
315 views

RFI makes 10m almost unusable

Seeing a lot of solid vertical lines on the spectrum scope of my ftdx10 and they’re really annoying. I have a yaesu fp1023a powering and ftdx10. Doesn’t go away if I turn off every circuit in the ...
Chris G.'s user avatar
  • 111
6 votes
3 answers
2k views

Does an End-Fed Antenna need to be straight?

Typical yard and wondering if I can go out a window, to a tree, turn to another tree, turn to another tree simply trying to achieve the length required for 80m band? One video stated it doesn't need ...
Mot's user avatar
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3 votes
1 answer
307 views

Calling in to a contest

Being new to this, am I allowed to call in when hearing a contest? I tx an Italy contact on HF and they asked for my serial number?
MarkW's user avatar
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0 votes
1 answer
251 views

Is 100m too long for hf feed wire?

I have room to erect a DX Commander, multi-band vertical, and to give it a good number of radials on a good clear site. Problem is I would need to run about 80 - 100m of coax feed from operating ...
quanglewangle's user avatar
5 votes
1 answer
347 views

What is this vertical antenna with radials pointing up

I work next to "Koninklijk Marine Kadettenkorps Afdeling Oostende" (Royal Marine Cadet Corps Ostend). They have an antenna that I've been wondering about for years now: It is a vertical ...
Dieter Vansteenwegen's user avatar
2 votes
5 answers
222 views

Garage Door Opener Damaged by HF RF?

Yeah, this is a crazy one. My wife's garage door opener stopped working yesterday. I replaced the battery and it works when very close to the garage door receiver, like underneath. Today, my son tells ...
user11702's user avatar
  • 111
3 votes
2 answers
823 views

HF Vertical antenna with no radial and loading coil but only ATU for 80m to 10m in a boat

I am new to HF antenna designs. I want to build an antenna for my fishing boat. My question is - if I use an ATU (like the ATU-100) and a 10m aluminium pipe as an antenna and fix it with a mast, will ...
Asif Rahman's user avatar
2 votes
0 answers
163 views

What is the best way to ground a whip antenna in a hotel room?

We have a 102" CB whip antenna cut for 10 meters. We're staying in a hotel and trying to figure out the best way to ground this antenna. Right now we're using a pile of wires on the floor, but we'...
kj7rrv's user avatar
  • 179
2 votes
0 answers
441 views

What could cause an Icom IC-756 Pro II to suddenly stop transmitting?

My HF radio (Icom IC-756 Pro II) suddenly won't receive or transmit. I recorded the sound it makes when receiving and uploaded it to https://w7bkg.org/wiki/File:Radio_Issue.wav . It sounds the same on ...
kj7rrv's user avatar
  • 179
2 votes
4 answers
415 views

Why are VHF radios so much cheaper than HF ones?

Why do VHF-UHF radios tend to be cheaper than HF ones? There are expensive VHF radios and relatively cheap HF ones, but finding a cheap VHF radio is much easier than finding a cheap HF radio. Why? ...
Someone's user avatar
  • 604
2 votes
2 answers
1k views

Hi SWR with End Fed HF Wire 9:1 UNUN

Good Day I understand every antenna set up is different, so I'm looking for advice on what I could change to alter my findings. The set up is new including the EFHFW - 20 which was bought off the ...
Simon Hefford's user avatar
3 votes
0 answers
87 views

6.765 - 6.795 MHz ISM band for prototype testing

Not strictly a ham radio question, but I figure this is the most knowledgable community to ask. This question pertains to Canada, specifically. If I were wanting to build a prototype for a commercial ...
Jordan's user avatar
  • 143
1 vote
1 answer
2k views

What balance (radials or counterpoise) do I need for a vertical hamstick as a stealth antenna?

I'm just getting back into operating after a long break. I'm currently in a ground-floor apartment of an old four-plex and I'm trying to set up a stealth-like antenna for HF. I decided on the Shark ...
GVDub KE6EPC's user avatar
1 vote
0 answers
118 views

How do I test if three turns are better than 4 turns?

I built a class ab amplifier kit to use with my qrp radio. 2 watts in creates 50+ out. This was the pa 70 amplifier kit. It is a kit with no instructions, but a whole suite of internet videos and ...
Jeffrey Edward Messikian's user avatar
0 votes
1 answer
152 views

Where can I go for ham radio reviews? [closed]

I was wondering what would be the best startup HF transceiver for the 3-30 MHz band. I have not found any which appear to match my requirements for under $200. What would some ham radio sites be with ...
P.R.'s user avatar
  • 11
0 votes
2 answers
96 views

NooElec for Startup HF Communication

I am working on setting up a Ham Radio shack for long distance communication on the HF frequency. The goal is to transmit 1,200km from Alberta to Manitoba using skywave propagation. I would need to be ...
P.R.'s user avatar
  • 11
3 votes
1 answer
71 views

Measuring effectiveness of vehicle bonding

Is there any objective way to measure the effectiveness of your bonding in a mobile HF setup? Or determining when you have "adequate" bonding? I have a hard time with just throwing straps on ...
Brad Mace's user avatar
  • 421
1 vote
3 answers
204 views

QRP CW on HF using FT-817ND - filter/dsp recommended?

I'm just getting into amateur radio, so just starting to gather the things I want/need. I'm only really interested in CW, and almost exclusively on HF. I'm looking into a mobile/portable setup which ...
upasaka's user avatar
  • 121
1 vote
1 answer
112 views

Centre pole construction for 20 metre half wave dipole

I am about to embark on the construction of an inverted V half wave dipole. It will possibly be multi-band but, for the moment, I want to build it for 20M. Because of the shape of my property, I would ...
jonel's user avatar
  • 11
5 votes
1 answer
1k views

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....
mcandre's user avatar
  • 151
0 votes
1 answer
3k views

End fed long wire antenna for 40 meters length

I have a hex beam antenna that gets me onto bands from 20 meters to 6 meters very well. I wish to have an antenna that gets me onto 40 meters at night very well also. Recently I purchased an end fed ...
Engineer999's user avatar
1 vote
1 answer
123 views

Swan 350 calibration

So my swan 350 needs to sing properly and order it for to do so the VFO needs to be calibrated. I do not have a working frequency counter. How do I get this stuff fixed so I can get her singing right. ...
Ben Madison KO4UXC's user avatar
1 vote
2 answers
488 views

Can an 80 meter band dipole work in a basement?

I don't have an HOA, but I don't: a. have the space outside for an 80 meter dipole, nor: b. does my wife want visible antennas on the outside of the house. So I've been in the mode of finding an ...
scm's user avatar
  • 193
1 vote
0 answers
134 views

Need help in the fabrication of an UHF power amplifier

I recently decided to conceive a 10W class 446MHz amplifier. I want to be able to amplify a 100mW signal into a 10W, for that i'm going for a two stages amplifier : SKY65162 to amplify the signal to ...
Wireless Learning's user avatar
4 votes
2 answers
1k views

Can I use my CB mobile antenna with a 10 meter radio also?

I have a mobile mounted CB antenna that has an SWR of 1.5 on channel 20. Is it possible to use it with a 10 meter radio? I do not have enough room on my car for an additional antenna, so if it is ...
diodes123's user avatar
3 votes
3 answers
840 views

Antenna options for a small urban garden

I've narrowed down my antenna options to fit a small urban garden. It's tough, space is tight and a neighbour three doors down reports everything I do to the council so I'm routinely inspected for ...
rcx935's user avatar
  • 411
2 votes
1 answer
316 views

How do I choose between T37-2 vs T37-6 for this High-Pass Filter?

My RTL-SDR V3 is being overloaded by an AM broadcast so I'd like to build a high-pass filter to block the AM broadcast band. I thought I'd start simple and try making the one shown in Fig 3 of "...
Bezewy's user avatar
  • 153
6 votes
1 answer
303 views

So how do HF nets work, anyways?

I'm familiar with VHF/UHF repeater-based nets and the general concept of how nets work (net controller that you check in with, net controller says who talks, people send it back to the controller ...
QuantumMechanic's user avatar
0 votes
0 answers
35 views

Could my HF antenna cause problems to these other antennas on the roof? [duplicate]

I am planning to purchase a property soon in an apartment block on the top floor. I am very very keen to install a HF multiband Yagi antenna on the rooftop. I notice some small cell towers and a ...
Engineer999's user avatar
5 votes
4 answers
2k views

Do these look like amateur radio antennas?

I am planning to move into a new apartment, and of course would like to install a HF antenna there, on the roof if possible. Today I noticed a small Yagi antenna on the roof of the building , more ...
Engineer999's user avatar
3 votes
1 answer
110 views

What steps to take to secure for G2 geomagnetic storm?

So I see NASA has issued a geomagnetic storm watch for a possible G2-level storm on the 11th. I’m at about 53 degrees north geomagnetic latitude. Is this something I need to care about equipment-wise? ...
QuantumMechanic's user avatar
1 vote
2 answers
549 views

What is the minimum height required for a 60 meter NVIS antenna?

Various answers include 1/8th of the wavelength all the way down to 1/10th, but would 1/15th or even 1/20th of the wavelength be sufficient for a 60 meter (5 MHz) horizontal NVIS antenna?
Aiden Kaiser's user avatar
4 votes
2 answers
277 views

Mounting a hex beam on top of a high urban building

I am moving into a new apartment in the city soon which is on the 24th and last floor of an apartment building. I will have access to the roof of the building also. I'm still trying to understand ...
Engineer999's user avatar

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