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attenuator for 7300

1iwilly

Sr. Member
Dec 7, 2008
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Looking for a recommendation for a high-power attenuator pad of 2.5dB for my Icom 7300 for the ALC overshoot
i tried this old skool gadget, but it's no go. The variable is very sensitive . And the overshoot is still there
. This is the one i just tried today:
 

High power 50ohm resistors are a lot easier to find than the oddball high power resistors you would need making a basic pi attenuator.

Could you use a broadband splitter made from an old core and send half the power to a 50 ohm dummy load? 2.5dB vs 3dB, not much of a difference....

Edit: chatgpt said I needed more turns than 7:5:5, more like 24:17:17 on type 61, but that seems like a lot of wire. It kept suggesting wilkinson splitters, but those are frequency sensitive and I assume we dont want that. It also talked about poor isolation and potential instability, but I don't know. Maybe someone who built a few amps can shoot my idea down because big boxes use splitters all the time.
 
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Florida RF Labs has some nice attenuators. Henry Radio as well. I have picked up several off Ebay. I have a 100 watt 10 dB pad to limit drive to a solidstate amplifier.

50 watt 3 dB. attenuator

100 watt 1.0 dB attenuator

The above require a heatsink to be mounted on. Below is a coaxial inline attenuator of 3.0 dB and 50 watts which would be the bare minimum I would use.

Inline attenuator
 
Looking for a recommendation for a high-power attenuator pad of 2.5dB for my Icom 7300 for the ALC overshoot
i tried this old skool gadget, but it's no go. The variable is very sensitive . And the overshoot is still there
. This is the one i just tried today:

If you are thinking about a power attenuator in the TX path, you will also attenuate the RX path, if you don't have a switch, to bypass the attenuator in RX.

This is assuming, you are investigating the use of an external power attenuator, between a transceiver and external amplifier.
 
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