# All Questions

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25 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 ...
19 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 ...
153 views

### Can half of a directional antenna (Yagi-Uda, HB9CV) be replaced by a ground plane?

Consider a center-fed dipole antenna. It‘s well understood how the bottom element can be replaced by a ground plane (in practice, generally a few rods but in principle a conducting plate would work as ...
52 views

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 ...
15 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 ...
20 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 ...
51 views

### Looking for criticisms on my VNA-like SWR meter I am designing

I am in the process of building a SWR meter with VNA-like features. I'd be really interested to hear from fellow hams any input, suggestions, or tips they have regarding this before I go get it mass ...
78 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 ...
26 views

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 ...
57 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 ...
298 views

### Recommendations for starting out with HF for an amateur

I'm a beginner who's nearly half a year from receiving my ham license in India. I want to start with HF radio and wish to build my own rig. Currently I have looked and multiple designs using the ...
30 views

13 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 ...
18 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 (...
34 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 ...
42 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 ...
15 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, ...
213 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 ...
31 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 ...
39 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 "...
354 views

### Yaesu FT-817 Won't transmit on 160m to 6m

I'm having the following problem with my FT-817: 1) Receives fine on all bands 2) Transmits fine on 2m and 70cm 3) Doesn't transmit at all on 160m through to 6m 4) Keying the MIC on 160m to 6m, ...
93 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 ...
98 views

### Repeater identification ending (CW)

I am just starting to learn CW, and for practice I have been recording and transcribing repeater identifications that I hear. This is what I heard today: DE W9KIC/R BBG What is the meaning of "BBG"?
242 views

### Getting Started In Ham Radio

I'm 13 years old. I hear all the fuss about ham radio how awesome it is. I really want to join, but I hear you have to get a certification. How much does it cost? How long does it take? How much does ...