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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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 ...
KC3WCR's user avatar
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3 votes
1 answer
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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 ...
KC3WCR's user avatar
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2 votes
1 answer
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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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2 votes
1 answer
107 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....
KC3WCR's user avatar
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3 votes
1 answer
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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
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1 vote
3 answers
155 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
606 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
121 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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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
192 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 ON4DD's user avatar
2 votes
5 answers
188 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
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3 votes
2 answers
616 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
140 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
256 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
312 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
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2 answers
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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
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75 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
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1 vote
1 answer
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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
68 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
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1 answer
114 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
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2 answers
85 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
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3 votes
1 answer
64 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
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1 vote
3 answers
158 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
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1 vote
1 answer
106 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
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5 votes
1 answer
987 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
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0 votes
1 answer
2k 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
108 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
346 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
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1 vote
0 answers
128 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
844 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
579 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
  • 401
2 votes
1 answer
252 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
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6 votes
1 answer
221 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
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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
94 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
477 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
232 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
1 vote
1 answer
897 views

Common-mode choke (CMC) hurting my SWR. Live with it? Drop the choke?

I have been using a Par EndFedz Mk2 Trail Friendly 40/20/10 though using the matchbox from an EndFedz EF-QUAD (with Vibroplex’s blessing) so I could transmit at more than 25W. On all three bands I ...
QuantumMechanic's user avatar
3 votes
2 answers
849 views

Mounting a vertical antenna on a fiberglass mast

I have a multiband SE-X80 HF vertical antenna which works ok from 20 meters to 10 meters with a tuner. It is attached to the railings of my apartment balcony at the moment. This is the antenna : https:...
Engineer999's user avatar
6 votes
2 answers
112 views

HF SSB etiquette when someone is working quick but not contesting and you're not sure they got you?

When someone is working quickly -- clearly trying to work a lot of stations -- but pretty clearly isn't contesting, what's the etiquette when they 73 you and end the contact but you're not sure they ...
QuantumMechanic's user avatar
1 vote
3 answers
397 views

What's the realistic SSB reception range for 25W on 20m and 40m?

Because of my living situation I am using a Par EndFedz Mk II Trail Friendly antenna with my IC-7300, since it can do 40m and 20m and is only 41 feet long. However, it can only handle 25W. Now, for ...
QuantumMechanic's user avatar
11 votes
5 answers
3k views

Why do operators mention the band when calling CQ on phone?

I'm a new-ish ham, licenced for about one year now. Within that year I've heard a lot of CQ calls from other hams on phone (both HF and VHF), and it seems that a large portion of hams routinely ...
Ivan R2AZR's user avatar
2 votes
2 answers
158 views

Does a NVIS antenna have to be exactly below the maximum NVIS frequency to have NVIS characteristics?

For example if the maximum NVIS frequency is 5 MHz in a given region, would a NVIS antenna have to be resonant at less than 5 MHz to have NVIS propagation characteristics or can it be slightly above ...
Aiden Kaiser's user avatar
4 votes
3 answers
498 views

RF ground confusion

I'm a bit confused by RF grounding. Let's take a HF 1/4 wave vertical antenna for example. When current flows through the centre of the coax to the antenna, my understanding is that the current then ...
Engineer999's user avatar
1 vote
1 answer
162 views

How to check second-hand ICOM IC-718?

I’m buying a used IC-718 from a local ham. I can verify its function before I decide to buy. I’ve read the manual and know the functions and capabilities. What should I check / look for, apart from ...
Alexander's user avatar
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1 vote
1 answer
229 views

Recommendations for Antennas installation with Steep slopes

I have a property that I am trying to figure out the right antenna setup for. Transmission Goals North of this property is 900 miles to communicate 80M or 40M. Also want to communicate to another ...
spreckoak's user avatar
3 votes
2 answers
199 views

Understanding low MUF in VOACAP

I've started playing with VOACAP to better plan and predict conditions on 27 MHz (CB). To my utter astonishment, VOACAP says that I won't be able to communicate on that frequency, regardless of ...
Alexander's user avatar
  • 321
5 votes
2 answers
653 views

Choosing a Relay for HF Applications

As part of my 20m transceiver build I'm looking for a relay to by-pass an RF amplifier in the front-end board. So, to be clear, that's after the 20m broad bandpass filter and before the RF mixer (it'...
Buck8pe's user avatar
  • 989
1 vote
2 answers
343 views

Tuning wire with SWR LED

I have a QRP rig (Mountain Topper) and a variable capacitor QRP end fed half wave antenna with an SWR LED indicator. The LED doesn't go fully out in all configurations but there is always a local ...
Bill H.'s user avatar
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