AMERITRON AMPLIFIER AND A YAESU FT-840

[TonyV225]

Now if Im thinking correctly I dont need the external relay box for the ft-840 like I did when I used the ft-757 on this Ameritron do I?? I know the Kenwood TS-440 I had also was simple and I just plugged the realy cable directly into the Amp aswell.

 

[W5LZ]

Check the voltage/current ratings for the amplifier relay in the '840. If it's less than what is required by the amplifier, no, you won't need the external switch. If you already have that external switch, there's certainly nothing wrong with using it though!
- 'Doc

 

[TonyV225]

Ok it says that the band data 8 pin jack on the Yaesu FT-840 that is for the exciter line for an amplifier must be held high +5 to 15V and if the linear requires more than 15v i will need an external interface/mechanical relay such as the FRB-757 relay box.
The Ameritron says it requires a contact closure or keying circuit capable of sinking 100 ma positive voltage (12 Volt) open circuit to ground. Im sure almost all modern amplifiers are in that range.

 

[W5LZ]

Then it sounds like you don't really need that external relay. And I think you're right about the voltage on most modern amplifier's keying lines, but, I certainly wouldn't swear to it. And being a little 'chicken' cuz I do NOT mess with the modern radio's @#$%, if I had that external relay just gathering dust somewhere, I think I'd use it. (The other side of that sort of thingy is that since I don't have one, I don't use one now. ) Take that for what it's worth...
- 'Doc

 

[TonyV225]

I dont have any relay boxes anymorte my last one was sold with a Yaesu FT-757 that I had. But I should be ok and may get another relay anyways

 

[datsun66]

Does that amp need a foot peddle to operate it.

 

[TonyV225]

It would need a peddle if you ued a radio other than an HF rig which come with the exciter (relay hookups) on the back which have to be hooked up to get the smplifier to keyup.