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votes
2answers
24 views

what is a good way to study for the tech test

I took the test last week but I failed it I was in a program that went through all the chapters but I just very bad at taking tests is there a way to go around the test
0
votes
0answers
25 views

ISOTRON 80m 75m Antenna Position

I know, a dipole is the way to go, but cannot fit one, only a 'birdhouse' antenna like the 75m 80m Isotron antenna. Is it better to put at 15 feet Above Ground Level outside, or 20 feet AGL ...
2
votes
0answers
30 views

Gain of Yagi turnstile?

I am currently working on a system to communicate with amateur CubeSats. I have decided to use the turnstile crossed-dipole style yagi because it is relatively easy to construct and uses circular ...
-1
votes
2answers
42 views

Is roaming strictly a DMR feature or does it also relate to analog?

I've an AnyTone 878uv pluss and I want to know if roaming is only a DMR feature or if it can be used with analog repeaters?
0
votes
1answer
26 views

Audio too high, how to troubleshoot

I am using a TYT TH-9800 with a 10 m half dipole antenna on low power (5 W) to connect to a WIN linked repeater (+5.0 MHz offset and 123.0 tone). I made contact with two other stations and was told ...
0
votes
1answer
31 views

Can you measure how much radials you are lacking for HF vertical?

I have tried mount ham sticks on SUV and a convertible use trunk lid mount, especially on 40m on the convertible I notice the SWR changes from opening the door and close the door. Now I am quite ...
2
votes
2answers
58 views

Tweak antenna resonant frequency higher

This is a very simple question and I'm sure if I had a bit more background knowledge, I could figure it out myself. Let's say I have a 1/4 wave vertical antenna that is slightly too long, but it is ...
1
vote
1answer
38 views

How to calculate VFO/IFO frequencies?

I am trying to build a simple superhet receiver for listening SSB signals. I read several articles about SSB and got confused so I am looking for some practical explanation. I have 2 mixers, quartz ...
0
votes
1answer
51 views

Inverted L Feedpoint Height

I have this antenna EFHW 40-10 from Maple Leaf Studios. My current configuration: Inverted L with feed point 3m above ground, with "L" at 9m. I have 45 20-foot in-ground radials just below the feed ...
3
votes
1answer
63 views

Is it possible to receive weather satellites with a ham radio rig? (Icom 910)

I would be interested in receiving weather satellites (NOAA and Meteor) with my Icom 910. It has very good filters and could be a better solution than a simple SDR. However, its manual specifies that ...
2
votes
1answer
42 views

Using two VHF antennas vs one because of a large obstruction

We have a VHF Omni directional antenna, 2.5 W and 119 MHZ (approximate) mounted on top of a commercial hanger. Access to the antenna is out of the question because of the lack of fall protection. ...
0
votes
1answer
43 views

How can I manually programme these FRS channels onto my Baofeng UV5R?

I've been using Repeater Book to manually programme some repeaters in my area, up to fifteen miles. I later started programming some FRS, GMR, and MURS frequencies based on the CSV file that someone ...
0
votes
1answer
64 views

Can i use an anaolgue IC switch to change a 10 m yagi's directivity by somehow combining received signals with different variable phase?

Can i use an analogue IC switch being triggered at the same frequency I am receiving on to change a 10 m yagi's directivity by somehow combining received signals with different variable phase either ...
1
vote
1answer
65 views

SO-239 (UHF) vs N connector power handling on 160m

I am curious how much CW power an N connector or SO-239 connector will handle on such a low frequency like 160m band. I know on VHF they will probably handle about 800W before getting too warm. I ...
1
vote
4answers
77 views

Which 10 m antenna will give the most rejection in one direction for received signals which are vertically polarized?

I want to null out a particular direction so that i can't receive some vertically polarized interference on 10 m coming from that direction. Which 10 m antenna will give the most rejection in one ...
-1
votes
1answer
62 views

How would I calculate aperture efficiency for an antenna?

How to calculate aperture efficiency for an antenna with the following parameters: Big reflector diameter= 24 mm Gain= 9.265 dbi Frequency= 11.60 GHz
6
votes
2answers
77 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 ...
0
votes
0answers
35 views

Text transfer From/To SDR

I bought a hackrf one and I don't think it works. Before I return it can someone show me a grc flowchart on how to send text or a text file from a hackrf to a rtlsdr? I have been told you can do it. ...
4
votes
3answers
1k views

Vertical Yagi spun at 1000 RPM: gain properties?

If I were to mount my 10 m vertical Yagi on a pole with a motor attached at the bottom with the appropriate fastening and coax mounted via electrical brushes, if the Yagi is spun at say 1000 RPM would ...
1
vote
1answer
22 views

CHIRP-programmability of the Alinco DR-635T/E

I am a beginner in ham radio and am trying to program repeater data into my Alinco DR-635T/E VHF/UHF mobile radio. The manual that came with the radio is so poorly written that I could not ...
0
votes
2answers
31 views

Batch sampling SDR

I am using RTLSDR on macOS with Cubic SDR, it works great and is very intuitive. Now I want to do a frequency envelope analysis where I need to basically 3-d plot intensity versus frequency and time. ...
3
votes
1answer
59 views

Does copper wire get sold as flat straps to reduce inductance?

The extra book (11-9) safety section mentions that a "large diameter wire, or even better, a wide flat strap, has the lowest inductance and makes the best ground connection." Does anyone actually have ...
4
votes
1answer
179 views

Will painting a 4 element 10 m yagi using conductive paint onto the side of a building work?

Will painting a 4 element yagi using conductive paint onto the side of a building work?
1
vote
0answers
31 views

Why is self-resonance important in a loop antenna?

I visited a "small loop antenna" calculator web site today and fed in my horizontal loop gepmetry, curious to see what it would say. 2" dia wire, 72' circumference, 3.935MHz. Interesting results, ...
1
vote
1answer
34 views

Is there a suitable alternative to using a metal pole to mount a vertical yagi apart from wood and fiber glass?

Does anyone know if a non-metallic pole approx. 4 m long is available that i can use to mount a vertical 10 m 4 element yagi ? that is not wood, PVC or fiber glass as these are either too heavy or not ...
2
votes
2answers
49 views

Will ferrite rings around a metal pole hide it in an RF sense from my vertical 10 m Yagi?

If i mount my vertical 10 m 4 element yagi directly on a metal pole so that the pole is between the elements and so messes up the radiation pattern and input impedance, if i put lots of type 43 ...
2
votes
1answer
180 views

When I am told that a dipole must have a determined length, does that include the space between both elements?

I am trying to build an antenna for receiving NOAA satellites and I need to build two 137,5MHz dipoles. When I enter the frequency and width of the wires in a calculator, I obtain that $λ/2=1.09\,\...
1
vote
1answer
55 views

What is meant by CC 7?

I am seeing a repeater on RepeaterBook 444.8375 +5 MHz CC 7 Portland, Providence Portland Medical Center Multnomah WA7HAA OPEN ON-AIR I'd like to programme ...
4
votes
2answers
65 views

Basic antenna matching theory?

I'm fairly new to antenna matching, other than having built a base loaded vertical. I'm also new to EZNEC and I tried to simulate an horizontal loop. I arbitrarily chose a 10x10M loop, so I added 4 ...
1
vote
1answer
67 views

Grounding for an upper floor shack

My shack is on the second floor, 4m from the ground. My main antenna is a base loaded vertical, using the metal roof (10x6m) as a ground plane. When I operate in 20 and 40 meters, it's pretty ...
2
votes
2answers
55 views

How to estimate a dipole feedpoint impedance?

An ideal dipole, at resonance, will have an impedance around 73 ohms. A folded dipole, around 280 ohms. How can I calculate the impedances when not at resonance? Let's assume I have a span of 15M in ...
0
votes
0answers
24 views

UHF cubical quad VNA analysis interpretation (part2)

This is the follow up to: UHF cubical quad VNA analysis interpretation This is a S21 and S31 analysis of an oversized 385 Mhz 50 Ohm to 90 Ohm balun between 100 Mhz and 600 Mhz I tested phase ...
1
vote
1answer
49 views

Are there any satellite email reflectors?

I'm just getting started using amateur satellites and would like to subscribe to an email reflector, but I can't find one. Is there anything out there?
1
vote
1answer
52 views

Rotatable Dipole & RF Choke

I have a Diamond HFV-5 (rotatable dipole) in the attic fed by ~30ft of coax. The antenna system comes with a Balun at the feedpoint. Would it be worthwhile to add an inline RF Choke (Unun) in addition ...
0
votes
2answers
54 views

Can I make signal transmitter without decoder?

I'm sorry if my title seems weird but I just started to learn about signal transmitting and I don't know where to start I'm searching about simple ways to make diy radio but I can't really ...
0
votes
1answer
55 views

Lead in wire size [closed]

I have a copper wire antenna about 100 feet long that I have relocated and now need about 75 feet of lead in wire. What type & size of wire should I use?
1
vote
1answer
56 views

What is an expected sensitivity of a crystal radio for 7 MHz band?

I'm learning to build radio receivers and transmitters. I've successfully build some oscillators, amplifiers and filters before and decided that to build a simple crystal radio would be a logical step ...
5
votes
5answers
116 views

How to match low impedance of NVIS Dipole?

I want to match a 50-ohm coax feed wire to a 40-meter NVIS half-wave dipole. NVIS antenna examples I've found are usually based on a regular dipole (72 ohms in free air). However the impedance drops ...
1
vote
1answer
98 views

Legal aspects of the HackRF one / SDR in Switzerland?

I would like to know, what I can legally do with SDR / a Hack RF One in Switzerland? What are the limitations concerning sending and receiving? Do I need any licenses for that? If so, which ones, ...
0
votes
1answer
44 views

audio problem with SDR on MacOS

I'm experimenting with SDR on MacOS High Sierra. Trying both CubeSDR and GQRX and experiencing similar issues with both. The applications seem to work, but the audio is choppy and chipmunk-like. ...
3
votes
2answers
76 views

What is really happening during RF ionospheric refraction?

We all know that the ionosphere — when charged — refracts RF energy, but why? In other words, what is actually occurring at a molecular level to cause radio waves to bend back to earth because of ...
1
vote
3answers
73 views

Is there a way to split a frequency into channels?

Is there a way where I can take a single frequency and subdivide it into channels so theoretically I can transmit multiple voice channels on the other?
0
votes
0answers
20 views

Is there and data anywhere showing if amateur radio operators are more likely to get cancer from exposure to RF?

Is there and data anywhere showing if amateur radio operators are more likely to get cancer from exposure to RF ?
0
votes
3answers
96 views

Why are no 2w FRS walkie talkies on the market?

I have read that the new laws regarding FRS radios state that you may use up to 2 watts power, yet I can't find a single 2 way radio that advertises 2 watts power; only .5 watt, or they don't state ...
0
votes
0answers
43 views

Signal Coverage Standard for GIS [migrated]

Is there any Standard data format for Signal Coverage for GIS? Something like GPX or KML (or other XML/JSON/etc-based) for routes, tracks, POI, etc. But for signal strength, base radio stations and ...
2
votes
2answers
92 views

Can I build a Yagi antenna for my Baofeng UV-5R?

I would like to build a Yagi antenna for my Baofeng UV-5R, but I'm a total newbie when it comes to amateur radios. The antenna will be for UHF and shouldn't be too long (like 1.5 meters max). So my ...
1
vote
1answer
27 views

How to use HT microphone with two jacks (Kenwood connector) as a substitue for KX-3 microphone?

The original microphone for KX-3, Elecraft MH-3, is insanely expensive. What changes would be necessary to convert a cheaper speaker/microphone for a FM handheld transceiver? Is there any ready-to-buy ...
5
votes
1answer
79 views

Counterpoise wire voltages?

One practice which seems common when operating temporary or portable QRP, SOTA, etc., is to throw a counterpoise wire out on the park lawn or shrubbery, mountaintop or hillside or parking lot ground, ...
0
votes
1answer
38 views

Using Gaming Headset on FTDX3000

It seems like a gaming headset is a cheap option for my radio, considering I have a 3.5mm to XLR adapter, along with an adapter for the Yaesu mic input (from XLR). However, what I'm not sure about is ...
2
votes
1answer
46 views

Output impedance of TAPR QRPi?

I'm a newly licensed amateur and have decided to start out by trying WSPR on a Raspberry Pi equipped with TAPR's 20m QRPi. The QRPi write-ups I've read always talk about long wire antennas but I'd ...

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