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1answer
35 views

What are the biggest amateur radio contests (“radiosport”)?

What are currently the (5 or 10) biggest amateur radio contests in terms of Worldwide participation (total number of stations or operators on the air during the contest)? Are they the ones with "...
1
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2answers
59 views

Increasing communication range by boosting output and input power

I am trying to increase the range of communication between two SDRs to simulate near space communication. The output power of TX is 10dBm but I would need 37dBm for near space communication. That ...
3
votes
1answer
60 views

Is this “floating” output single-ended or differential and against GND or VCC?

I'm looking at a simple FM transmitter output (see picture). It is from the collector of a transistor and it goes through a DC blocking capacitor before the antenna would be connected. The entire ...
0
votes
1answer
27 views

Hatch Mount Antenna Selection - Dual Band 2m/70cm

I just bought a Diamond CP-5NMO hatch/lip mount and intend to put it on the hatchback lip of our 2018 Subaru Forester and, if it will fit, another one on our 2019 Kia Niro EV. I understand that hatch ...
4
votes
1answer
37 views

License document requirements

Are there any requirements to post, carry, or have available an official paper copy of one's radio license in order to operate in the U.S.? Do any states require physical possession of a printed ...
2
votes
1answer
75 views

In Canada, does a person need to be licensed to buy amateur radio equipment?

I have studied for and am ready to take my amateur radio license test but there are currently no licensed instructors available in my region to administer the test. Can I start acquiring ham radio ...
1
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3answers
77 views

Why is outer coax usually grounded?

I'm building a simple ground plane antenna for VHF, and I'm doing some research on grounding in case I want to permanently install it. I keep hearing that the ground rod is connected to the outer coax ...
1
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1answer
36 views

Output power from the TX/RX port of the USRP N210 decreases as the frequency increases

I am trying to build an FMCW radar using a USRP N210 with a CBX40 daughterboard. I generate a sweep from 1.5GHz to 5GHz. According to their respective datasheets, the daughterboard and the USRP should ...
1
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2answers
33 views

How do I find when my license expires?

I have a general license but I do not know when it expires, please help.
1
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0answers
15 views

Can the AT-D878UV be programmed for dPMR channels?

I am curious whether the Anytone AT-D878UV (which is a DMR radio) can be programmed to receive dPMR channels. I understand that the big difference between DMR and dPMR is the technique used to divide ...
1
vote
1answer
19 views

How to calculate of shielded loop antenna correction factor without extra antenna measurements

A lot of article about 60 cm shielded loop antennas and how to measure antenna factor using antennas with already known antenna factor. But for example if I have one shielded loop antenna (...
1
vote
1answer
16 views

What length and number of radials should be used for a dual band vertical whip backpack antenna?

The Situation: Very new Ham I have a 2m/70cm 48" Abree whip antenna, originally designed to be connected directly to an HT I would like to mount this antenna to the side of my hiking backpack, ...
3
votes
2answers
45 views

Recommendation for hobbyist flight computer radio antenna

I'm a CS college student working on the flight computer of my Rocketry Club's rocket. My flight computer has a 915MHz radio transceiver, and it needs to transmit data to my computer with another radio ...
1
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1answer
40 views

Repeater carrier as access

I'm just getting into ham radio. I'm trying to connect to a repeater here in Ireland: Channel: RU260(RB10) Output: 433.250 Input: 434.850 Call sign:EI7SHR Access: Carrier What does the "...
0
votes
1answer
67 views

Anyone know what this antenna is?

Hello, what kind of antenna is this? I’ve been trying to figure it out for 14 years. None of my neighbors know. Whomever installed it either moved or passed away.
0
votes
1answer
34 views

Ground pass through cinder block — copper pipe, braid, stranded?

What’s the best way to connect a station (desk) ground bus to an outside ground rod? Is it viable to double-sleeve a copper tube through existing PVC pipe? For coax pass thru, I have a 1.5” PVC pipe ...
1
vote
2answers
64 views

Benefits of AGC?

I note that many popular kit and QRP radios do not include any AGC capability. Thus it must be possible to operate successfully without AGC. Are there difficulties involved in manual gain control? ...
1
vote
1answer
38 views

Physical QSL card request procedures?

Is there a way to determine whether a station or operator still sends physical QSL cards, rather than only uploading some data online? (or doing nothing at all.) If so, what is the current procedure ...
3
votes
1answer
60 views

If WSPR can go further than FT8, why do I only see local WSPR signals?

I've been scanning through the bands using WSJT-X to pick up FT8 and WSPR. Using a VHF discone, I decode messages from nearly 10,000 km away, consistently, when listening for FT8. But when switching ...
0
votes
1answer
19 views

Is this result correct ? [ impedance cavity based on emtamaterials using CST Microwave]

In the contexte of my reaserch about antenna conceptions, I'm trying to simulate using CST Microwave a cavity antenna based on metamaterial structure and a slot antenna as a GND,However I got as a ...
0
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2answers
98 views

How do you know if you're on a 10 meter band?

I am just getting into ham radio, and I find it very interesting, but to make phone calls, you have to be on a 10 meter band. Does anyone know how to infer the band you're on is 10 meter? Thank you ...
2
votes
1answer
70 views

Substitute a car roof with radials?

I have a K40 Plus CB antenna, which is supposed to be attached to a car roof for the ground plane. However, I would like to set this up as a base antenna. Could I instead attach the ground to separate ...
1
vote
3answers
49 views

Where to find QRM and/or QRN audio files?

I'm looking for some QRN/M audio files to "show" someone what said noise can sound like, particularly interested in static crashes or lightening bursts. Have Googled same with no joy other ...
0
votes
1answer
51 views

SWR jumps to maximum of gauge

(I'm asking this in the context of a Cobra 29LTD CB, but I think that it also applies to amateur radio in general.) In SWR mode, the needle swings all the way to the right, hitting the limit. The (mag ...
1
vote
2answers
67 views

How many turns of wire inside 60 cm shielded loop antenna (9kHz - 30 MHz). How can I find this number without destroying the antenna?

Lots of information about shielded loop antennas is available on the internet. However, antenna manufacturers do not indicate the number of turns. How can I find the number of turns of a manufactured ...
0
votes
1answer
23 views

Bidirectional motor control using MFJ-4116 with RCS-4

I have the RCS-4 with two MFJ-4116. Prior to installing my motorized HF antenna system topside, I bench-tested the core of the assembly in my shack. The MFJ-4116 near my transceiver was injected with ...
1
vote
2answers
42 views

FT-450D not transmitting with microphone

I've been using FT8 on my Yaesu FT-450D for quite some time. I decided to try to talk on phone frequencies and discovered neither one of my mics will transmit. My mics are the original hand mic and a ...
2
votes
1answer
67 views

Help with Repeating 439 MHz signal

I have a remote wireless water tank level sensor. It transmits at 439 MHz with an apparent max range of 100 metres. Unfortunately I need about 200 metres. How can I extend that range?
0
votes
2answers
98 views

How to use 75ohm (RG6) coax?

I know that there have been many similar threads on this, but I still need clarification. At the moment, the only thing I have is a 500' roll of RG-6 and a (very) tight budget, and I should be ...
1
vote
0answers
64 views

Does the price of ham equipment normally rise during winter?

Recently licensed technician here, and going straight into my general class, I'm keeping an eye on cheap (sub-$400) HF radios. I keep reading articles that suggest used radios that normally sell for ...
0
votes
1answer
29 views

Does the 450D work with Winlink and allow Winlink to control changing frequencies and bands?

Will the 450D computer control program interface with Winlink and allow Winlink to change radio frequencies/bands?
2
votes
2answers
336 views

Broadcast signal deviating with time

I've been just scanning through the HF band at night seeing what all I can pick up, and I'm trying to figure out a particular signal. I'm using a VHF discone, which isn't ideal, but it works well ...
1
vote
0answers
31 views

Retevis MURS radio and encrypted sub codes

I have some Retevis MURS two-way radios model number RT27V. In the programing software there is an option for DCS encrypt. Now I turned on and off the DCS encrypt option and using my NooElec SDR with ...
1
vote
3answers
413 views

What are the properties of the radiation of a magnetron?

It is commonly known that electromagnetic radiation from an antenna is polarized; the electric field is parallel to the rod and the magnetic component is perpendicular to it. What does the radiation ...
2
votes
1answer
83 views

Half wave dipole with parasitic element, (Gain calculation)

good morning all, I have difficulties to find the correct formula that allows me to calculate the gain of half wave dipole in parallel with another parasitic half wave dipole. I'm trying to calculate ...
1
vote
2answers
77 views

Troubleshooting 5BTV antenna

I have a Hustler 5BTV antenna i resurrected after a previous monopole succumbed to birds. It is giving me a world of trouble trying to get it tuned for resonance. For those not familiar with the ...
0
votes
1answer
39 views

Stacked Yagi Gain calculation

I had a quick look at a practice exam for the license in my country and had a question on stacked Yagi antenna. I have been looking around but the only thing I can find is the mention of an additional ...
0
votes
1answer
58 views

SSTV decoder for alredy-recorded files?

I have the full SSTV transmission pre-recorded. Is there any software that will take the audio file and decode it? Edit - or is there a way to select the audio device to receive in any decoder?
0
votes
2answers
42 views

Detecting receiver intermodulation distortion?

On some (most?) receivers, if the RF gain is turned up too high, intermodulation distortion increases due to increasing non-linearities (maybe even clipping, etc.) Is it possible, just by examining ...
0
votes
3answers
58 views

How can the waterfall still be displayed during transmission

I noticed that on some higher-end transceivers, the panadapter/waterwall is still being displayed during transmission. How is this possible? If the panadapter is part of the receiver, it should be ...
0
votes
1answer
39 views

Can I slant-polarize a bay antenna?

I am trying to work a 700mhz LTE signal with a DB2 uhf bowtie television antenna. I find the cellular signal to be horizontally polarized. Can the bowties simply be twisted 45 degrees in both ...
0
votes
0answers
37 views

Simple minimum component RF Amplifier Design

Looking for advice/assistance in Retrofitting sans Cabinet Antique 2 and 3 Dialer 1920's TRF tube radios to operate with low safe Plate voltages.Both Hollow State and Solid State. The plan is to ...
2
votes
2answers
82 views

How does a 40/15m dipole with capacitance hats work?

I followed an article Antenna Here is a Dipole [PDF] by James Hearly, NJ2L to build a dual band 40/15m dipole: The antenna works more or less as expected. My 40m dipole was resonant at 7.030 MHz and ...
0
votes
1answer
45 views

60cm 9 kHz 30 MHz Shielded loop antenna behavior as a transmitting antenna

I know how shielded loop antenna work as a receiver antenna. (How behave electric and magnetic field). But I can not understand how shielded loop antenna works as a transmitter. Will it produce only ...
1
vote
3answers
107 views

What replaces the T/R switch in modern transceiver

I have been watching and reading about the time when receiver/transmitter were separated and T/R switches were used. Current transceivers are still sharing a single antenna to transmit and receive. ...
3
votes
1answer
48 views

Tradeoffs: varicap vs. air variable capacitor for Rx bandpass?

What might be the tradeoffs between choosing varicap diodes versus air variable capacitors in the design and construction of tunable bandpass filters for HF receivers?
6
votes
2answers
226 views

Using radio for musical collaboration — the line between conversation and broadcasting

I'd like to collaborate (e.g. play together) with other musicians in my local area and/or beyond. Coronavirus has made in-person collaboration difficult. Latency makes internet-based collaboration ...
0
votes
0answers
30 views

Using radio for musical collaboration [duplicate]

I'd like to collaborate (e.g. play together) with other musicians in my local area and/or beyond. Coronavirus has made in-person collaboration difficult. Latency makes internet-based collaboration ...
0
votes
1answer
23 views

Hustler BTV coax overhead run

I'm pretty sure this will be fine but thought I'd ask. A Hustler 5btv antenna, the coax from the feedpoint (ground mounted) runs for 3 or 4 meters along with the radials, and am thinking of going up ...
2
votes
3answers
764 views

Why is it bad to put ground rods too close together?

It's understood that ground rods should be spaced by a distance equal to twice their length. I read one source that claimed reduced effectiveness if the rods are closer than that. Is that correct? ...

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