Reading reflect watts help

[lerch256]

Hello again in in the process of building a 2 pill amp first one with used toshiba 2879 my question is when it comes to tuning the input and output I need trimmers ive read but the meter can I use a astatic or dosy meter for this say just hook it up backward from radio to amp for input any help will be grateful thanks

 

[Robb]

Hello again in in the process of building a 2 pill amp first one with used toshiba 2879 my question is when it comes to tuning the input and output I need trimmers ive read but the meter can I use a astatic or dosy meter for this say just hook it up backward from radio to amp for input any help will be grateful thanks

Hello again
In in the process of building a 2 pill amp - first one - with used toshiba 2879's.
OK

My questions are:
When it comes to tuning the input and output, I've read I need trimmers.
The meter; can I use a astatic or dosy for this?
Trimmer caps? Yes
Either meter is fine.

say just hook it up backward from radio to amp for input any help will be grateful thanks
This makes no sense; can you explain a bit better?

 

[lerch256]

Ok using a dosy or astatic meter to check for input reflect do i just hook the meter up in reverse? Thanks Robb

 

[lerch256]

I'm no good at punctuation sorry fellows.

 

[vkrules]

Why reverse?.Hook it up between the radio and Amp to check input VSWR.
And between Amp and dummy load for output VSWR.

 

[vkrules]

And keep the key ups shorts and the power low until tuned.

 

[lerch256]

??

 

[Robb]

Think vkrules is trying to say:

Radio > SWR Meter > Amp under test > 50 ohm dummy load

Radio > Amp under test > SWR Meter > 50 ohm dummy load

The only way to get any testing/adjustment accuracy is to use a dummy load that has a watt rating higher that the amp under test. No exceptions.

 

[338_MtRushmore]

I kinda get the feeling he is wanting to connect the output side of the meter to the transceiver and the input side to the amp to be able to read how many watts are reflecting back from the amp?

What meter are you considering using lerch?

 

[222DBFL]

Think he said an astatic or dosy meter. Don't think those will work. He should be able get accurate VSWR readings doing it the way that was posted.
He would either need to do that with the meters he has or he can get a bird meter and place the slug in reverse. Don't think he will get any kind of accurate readings with either of the 2 VSWR meters he has being reversed, as in, radio to Ant port and amp to Radio port. Get the trimmers and mount them and then like said you will need a dummy load that is rated for the correct power. Don't. I repeat, don't try and do this with your antenna. You will only skew the readings. Use just a dummy load. Also make sure you are re calibrating your VSWR meter when you turn the amp on and key it up as it will show totally different readings than it would without it on. Meaning it's just calibrated for the radio. You have to recalibrate the meter when you key the amp up powered on.

 

[lerch256]

Ok thank yall that's what I was thinking I would need a bird meter for this so I guess I'll be looking into purchasing one asap I appreciate all of yalls help

 

[Robb]

A Bird meter is accurate - but expensive. You really do not need a meter like that for testing SWR. Even the cheaper Astatic will do that. But you do need a quality dummy load that will keep it accurate under the stress of the amp output.

 

[RatsoW8]

I just like to see a post with "reflect watts" in it every now and then

 

[9C1Driver]

Wow, I can smell those burnt 65 dollar 2879's already.

 

[Robb]

So long as he feeds the amp a dead key w/no modulation AM - about 2-3w - he should be able to tune the var caps.