New answers tagged equipment-design
1
There's a huge variance in signal levels — the lowest signal that's readable above the noise floor and the strongest signal that won't overload the receiver are probably at least 60dB apart. To get that into a comfortable listening range without AGC, the operator has to adjust the receive level. Maybe that doesn't sound like a big deal (can't you just set it ...
3
The dynamic range of (shortwave) received signal strength varies from noise equivalent field strength (in the order of 250 nV/m in 3 kHz SSB bandwidth) to 1 mV/m (for radio ham transmissions via the ionosphere). Local signal can go over 1 mV/m. In short: dynamic range is in the order of 72 dB. AGC doesn't have to cover that range, but 50 dB is "nice to ...
1
I havent looked into the mechanics too deep, but FlexRadio has a full-duplex feature for those models with 2 SCUs (spectral capture units) in the radio.
Each SCU goes off to a different antenna, and as long as antenna separation and monitoring (or precalculating) dbm levels happens, it works well.
I dont believe however you can do full duplex on the same ...
3
The radio has multiple antenna ports and full-duplex capability, and the operator has selected different antennas for transmit and receive. Or,
The radio just displays the transmit spectrum on the waterfall, and it isn't coming from the antenna at all.
I've used radios with both of those options, so they're both definite possibilities.
4
I don't know what the specific devices you're referring to do, but a couple of things are all technically possible without great effort:
the ADC that is used to calculate the waterfall in receive-only mode is still connected to the antenna, maybe with additional physical attenuation (which you could trivially reverse in digital domain by multiplication with ...
2
As both previous answers mention, the T/R switch functionality is just something that moved into existing boxes, not something that disappeared.
The only ways to make that functionalies disappear would be
making the receive end tolerant of the transmit power and still a sensitive receiver (practically impossible at any significant power – the difference ...
8
Receivers and transmitters are still separated today, they are just in the same box. There is still a T/R switch too, integrated in the box.
In many radios, it's a relay, same as they have been for decades. Relays are hard to beat for isolation and maximum power ratings. Their downside is relatively slow speed, which prevents really good QSK operation. They ...
2
As far as your question regards components: T/R switching is usually done with either relays, reed relays (often faster than other types of relays; also more quiet), or PIN diodes (even more quiet and faster). Where high voltages and/or currents are present (and fast switching is needed) vacuum relays are also used. Circuitry may involve circuits that ensure ...
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