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SWR flip flop with linear in line??
- Thread starter CB590
- Start date
Does the swr's go up with power? At any point does the swr's go DOWN while turning the power ip?
Just made a 3' coax with lmr-240.. my swr went up to like 2.. damn I must suck at soldering.. or 3' is to long compared to the 18" RG8x..
I replaced that with the 18" RG8X jumper and back to 1.2-1.3 it went on 38..
I may just order RG8U premade with pl259 on both and just replace 1 end after coming thru the wall..
Maybe the antenna feed line I made is having same issue and it's not noticable at lower watts..
I don't want this issue with a 2-300w Texas Star..
**Edited. Just reread page 1 and 2.. with the AT5555 I was pushing 30w and the swr was like 1-1 or so.. and then amp on made the 1.5-1.6... so definitely at this point I don't think antenna feed line is the issue.. we'll know soon enough if it's a dirty amp.
I replaced that with the 18" RG8X jumper and back to 1.2-1.3 it went on 38..
I may just order RG8U premade with pl259 on both and just replace 1 end after coming thru the wall..
Maybe the antenna feed line I made is having same issue and it's not noticable at lower watts..
I don't want this issue with a 2-300w Texas Star..
**Edited. Just reread page 1 and 2.. with the AT5555 I was pushing 30w and the swr was like 1-1 or so.. and then amp on made the 1.5-1.6... so definitely at this point I don't think antenna feed line is the issue.. we'll know soon enough if it's a dirty amp.
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You might want to try a dummy load and test again. Also try another radio and see the results.Just made a 3' coax with lmr-240.. my swr went up to like 2.. damn I must suck at soldering.. or 3' is to long compared to the 18" RG8x..
I replaced that with the 18" RG8X jumper and back to 1.2-1.3 it went on 38..
I may just order RG8U premade with pl259 on both and just replace 1 end after coming thru the wall..
Maybe the antenna feed line I made is having same issue and it's not noticable at lower watts..
I don't want this issue with a 2-300w Texas Star..
**Edited. Just reread page 1 and 2.. with the AT5555 I was pushing 30w and the swr was like 1-1 or so.. and then amp on made the 1.5-1.6... so definitely at this point I don't think antenna feed line is the issue.. we'll know soon enough if it's a dirty amp.
Tried 2 different radios. Both had 1-1.1 or 1-1.2 or less without amp inline. One was AT5555 with 12w dk other is McKinley with 3.5w dk.
May invest in dummy load for $35 and MFJ870 meter for $80 to get better readings and more power and pep meter. The Astatic PDC1 I'm using is only a 100w max.
A new meter and load would be a good long term investment.
Both (amps) do not have 52MHz (2nd Harmonic) filters in them.
I would think you'd want to try a filter inclusive to that. The recheck SWR to see if the 2nd Harmonic is "skewing" results.
Else, I would love to see a method of being able to separate the network and reinstall the radios network to the back of the amp and keep going - but that will be the day my ship will come in and I'll be stuck here...
I would think you'd want to try a filter inclusive to that. The recheck SWR to see if the 2nd Harmonic is "skewing" results.
Else, I would love to see a method of being able to separate the network and reinstall the radios network to the back of the amp and keep going - but that will be the day my ship will come in and I'll be stuck here...
Shadetree Mechanic
Delaware Base Station 808
I have seen bad connections make the SWR go up with increasing power. I have also seen SWR go down when modulating like when my 350 was needing the input retuned. I learned how to solder when I was 10 and I am very good at it. But I don't do my own coax. Why? Because it's one of those things that I feel are so critical to keeping my amplifiers alive that it's not worth taking a chance on. I get all my coax assembled from jefa tech.
https://www.jefatech.com/collections/jefa-tech-coax-cable-assemblies
https://www.jefatech.com/collections/jefa-tech-coax-cable-assemblies
That 240 flex looks good. 35' for $42 shipped.. hmmm. Just got to make a 3/4" hole in wall for PL259 to fit thru..
Shadetree Mechanic
Delaware Base Station 808
The 400 is only a few dollars more.... I got some 10ft 400 flex jumpers. One as a lead in to the shack and the others for my amps because the amp rack is beside the radio desk.
I too is pretty good solder technician. I also does not solder no coax connector.
What I do use, crimp connectors. Best thing ever made. No huge holes in the floor or walls, easy to install on big trucks and F A S T - fast! Love it. Have yet to have one come loose and I’ve tried. Solder the center conductor and you’re good go.
Did I mention it was fast? It’s fast. If it’s fast, then it has to be easy, like that girl from high school we all knew. And it’s easy. Oh, and fast too.
What I do use, crimp connectors. Best thing ever made. No huge holes in the floor or walls, easy to install on big trucks and F A S T - fast! Love it. Have yet to have one come loose and I’ve tried. Solder the center conductor and you’re good go.
Did I mention it was fast? It’s fast. If it’s fast, then it has to be easy, like that girl from high school we all knew. And it’s easy. Oh, and fast too.
The problem I have is with with the LMR240 is the inner foil wrap.. I have a basic stripper but to get the foil back abit as not to touch the center hole is a pita. It takes me like 10-15 minutes each to use a razor blade and busted fingernails to peel off that tiny bit so I can get that few 1/8 of an inch with just white foam and not foil..
Hence me also comtemplating using RG8U instead.. no inner foil on some types.. I can solder center conductor all day long.. with the RG8U I can just drop over the shield and screw on the connector. Solder the center conductor and go.
I haven’t had that issue. I absolutely love the crimp connectors, I’ll never go back to the other style. I can see where that could be a problem, I don’t own a stripper or one of those tools to remove the coax jacket. See what I did there? Haha.
I just use a razor blade. Wish I had a stripper. Oh and that tool too.
I just use a razor blade. Wish I had a stripper. Oh and that tool too.