Electronics > RF, Microwave, Ham Radio

Automatic Antenna Tuner for general SWL

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cemelec:
I have an ICOM IC-7300 which I am currently using for listening to the amateur bands but also general HF listening

In about 2 weeks I expect to gain my amateur radio foundation license and have been looking to get an automatic antenna tuner for my long wire antenna, for example the mAT-180H or similar.

How does this cope (or not cope) with non amateur frequencies, as you can't use the tune function?
 
The mAT-180H  has manual L/C up & down buttons, but that seems a bit slow and tedious. I realise that the memory functions wont work either without RF going into the box.

Is there an ATU which is more suitable, or should I consider bypassing the ATU when in listening only mode and revert to my receive only ATU, which is very quick and easy to use but has no power handling capability.

Thanks

radiolistener:
ATU is good, but you're needs to place it between antenna and feeder in order to get maximum effect.

A.Z.:
The mAT 180H is an automatic tuner, the buttons only serve to finely adjust tuning if needed, not to tune it

https://www.vibroplex.com/contents/en-us/d9173.html

that said, antenna matching in RX isn't really that important, so you may bypass the tuner if using the antenna for RX only

The point is, how are you going to connect the antenna to your rig ? For a base (not portable) installation I'd advise against bringing the antenna wire all the way to the shack, my suggestion is to hang your longwire as far and high as possible, feed it with an UnUn connected to a good counterpoise and followed by a good choke, then a run of coax all the way to the shack

EDIT:

for further details. see

https://www.eevblog.com/forum/rf-microwave/putting-up-a-random-wire-antenna/

radiolistener:

--- Quote from: A.Z. on October 16, 2021, 07:12:19 am ---that said, antenna matching in RX isn't really that important, so you may bypass the tuner if using the antenna for RX only

--- End quote ---

it is important for a weak stations, but you're needs to use tuner at antenna side. Because RX input is already matched with the feeder, they both have about 50 Ω impedance. But antenna has different impedance, so this is where tuner is needed to pull a weak signal out of noise.

In addition, tuner plays a role of pre-selector, which also helps to receive signal in a noisy environment.

A.Z.:

--- Quote from: radiolistener on October 16, 2021, 07:41:04 am ---
--- Quote from: A.Z. on October 16, 2021, 07:12:19 am ---that said, antenna matching in RX isn't really that important, so you may bypass the tuner if using the antenna for RX only

--- End quote ---

it is important for a weak stations, but you're needs to use tuner at antenna side. Because RX input is already matched with the feeder, they both have about 50 Ω impedance. But antenna has different impedance, so this is where tuner is needed to pull a weak signal out of noise.

In addition, tuner plays a role of pre-selector, which also helps to receive signal in a noisy environment.

--- End quote ---

Agreed on the preselector, other than that...

https://kv5r.com/ham-radio/coax-loss-calculator/

:D

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