Amplifier, low pass filter, and swr meter connection?

[530]

Mobile setup...
Hooking up an amp with a low pass filter and a swr meter to antenna, in that order. Is that the correct way?
Also, can I hook the amp, filter, and swr meter with direct connectors together or do I need coax in between them for any reason?
Thanks in advance.

 

[ForestRunner98]

The proper way to run them is radio, amp, filter, SWR and antenna. Ask me how I know?LOL

You can try direct fitting of the filter to amp using a barrel connector. I tried that and SWR when up. So I ran a 3ft jumper. Try to see what works in terms of SWR. Connectors were a no go for me.

this is my thread that is my current project.
https://www.worldwidedx.com/threads/cobra-18-wx-st-ii-don’t-laugh.252212/

It’s kinda long because there was a “skip condition” that happened. LOL

 

[Mustang 131]

Its not a bad idea to run a low or band pass BEFORE your amp. Also a watt meter and swr before your amp.
The amp you save might be your own.

 

[Dmans]

Radio>Amplifier>Low Pass Filter>SWR meter = Garbage in AMPLIFIED GARBAGE OUT

73
David

 

[loosecannon]

you're probably ok using the barrel connectors, but i would advise against it, not for RF reasons, but mechanical reasons.

if it's going to be in a mobile, the chances of your setup getting kicked, bumped, groceries put on top of it, or otherwise messed with are much higher than with a base setup.

the leverage you would place on the SO-239 on the back of the amp, should that SWR meter get jarred abruptly will be enough to break it, strip it, or bend the metal on the back of the chassis where it's mounted.

who knows, maybe you have this covered, but i would think it would be much more convenient to use coax jumpers, and be able to place the equipment where i can see it.

oh, and if you really want to make sure all the signal goes out the antenna instead of creeping back up the coax, buy one of those ferrite kits from palomar and snap on the beads right at the feedpoint of the antenna.
mobile installs are notorious for common mode currents.
LC

 

[Mustang 131]

Radio>Amplifier>Low Pass Filter>SWR meter = Garbage in AMPLIFIED GARBAGE OUT

73
David

If the amp is run correctly and built correct, then yes. Garage in, garbage out. Put the filters before amplifying and stressing your amp.

 

[loosecannon]

If the amp is run correctly and built correct, then yes. Garage in, garbage out. Put the filters before amplifying and stressing your amp.

I can see how the idea of this could help, but if the radio hasn't been butchered with coil spreading, and clipped off negative modulation peaks, then there is already a half wave filter and a low pass filter inside the radio to do this job.

now, as for how well they work in the real world as opposed to adding extra filter stages in between the radio and amp, i have no idea.
LC

 

[Captain Kilowatt]

My take on it is that a properly tuned and driven amplifier will not generate garbage on it's own but it will certainly amplify any garbage it is driven with. One article I came across some time ago regarding converting Lo band television transmitter amplifier modules for use on 6m stated that the amps themselves were VERY clean even when driven to full output as long as the exciter was clean. The solution to trying to find a high power filter that would pass 50-54 MHz which are MUCH less common that an HF low pass filter, was to simply place a good quality filter between the radio and amplifier. It only needed to handle the exciter power which was only 10 watts output for a full kilowatt+ on 6m.