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VSWR Meter Mystery....

Old 08-18-2020, 09:22 PM
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Default VSWR Meter Mystery....

My Shakespeare meter, to measure VSWR, has me scratching my head. My VHF setup is as follows. 5225xt antenna runs down hardtop into flybridge, where it has 2 pl259 connectors meet via a barrel connector (For easy Hardtop removal for hauling). and off barrel connector runs a 12" jumper cable running to back of VHF. Yes I know many pl 259's..... this is using ALL RG 8x cable.

My VSWR Meter has an RG58 Jumper... Is introducing an RG58 cable into the equation problematic? I would not think so...

So I'm using 1 RG58 Jumper for the meter, and 1 RG8x Jumper going from my hardtop to the VHF...

When RG58 is going from radio to antenna VSWR readings are low... When I leave the RG8x between radio and antenna, and use the RG8 between meter and radio my reading are terrible..

THIS IS SUPER CONFUSING to attempt to put into words... BUT I KNOW radio geeks will figure this out.

Old 08-19-2020, 06:12 AM
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What kind of VSWR meter are you using? Is it made for high frequency?
Unless you are using something like a Bird, they are not too accurate.
Also check top frequency and bottom frequency on vhf band. Most of the small vhf meters are made for "relative" accuracy.
The meter should be as close to the transmitter as possible, short jumper.
If the reading is less than 3:1 across the band, I would not get concerned.
What are the actual readings with the meter in different locations? Both VSWR and Power.
Old 08-19-2020, 06:24 AM
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Originally Posted by Merrily2 View Post
What kind of VSWR meter are you using? Is it made for high frequency?
Unless you are using something like a Bird, they are not too accurate.
Also check top frequency and bottom frequency on vhf band. Most of the small vhf meters are made for "relative" accuracy.
The meter should be as close to the transmitter as possible, short jumper.
If the reading is less than 3:1 across the band, I would not get concerned.
What are the actual readings with the meter in different locations? Both VSWR and Power.
So the meter..it is the "cheapo" Shakespeare unit.. about 100 bucks made for this frequency right? So when RG 58 jumper is used going from meter to antenna (barrel connector'd pl259 junction at antenna) the reading is very low, like 1.5... The jumper between meter and radio is RG8x in this scenario.

When reversed the reading is "Off the charts" high... needle is pinned almost like it's a false reading... BUT in this scenario the RG 58 Jumper is going from radio to meter, and I'm using my RG8x jumper from meter to (barrel connector'd) junction at antenna...

I guess I'm wondering if using RG 8x and RG 58 in essentially the same loop is creating erroneous results... BOTH jumpers test properly with correct resistance..

Last edited by Lima Bravo; 08-19-2020 at 06:36 AM.
Old 08-19-2020, 07:47 AM
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The cable does not matter.

Put the tester where the barrel is. So you have no extra jumpers and try again.
Old 08-19-2020, 07:54 AM
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Originally Posted by smac999 View Post
The cable does not matter.

Put the tester where the barrel is. So you have no extra jumpers and try again.
Great minds think alike.. I did just that and it reads excellent ratio.... BUT can I trust that is a true representation as it's removing the barrel, which is IN PLAY in actual scenario. Follow me? In other words I'm removing a variable that exists in the LIVE environment.
Old 08-19-2020, 08:16 AM
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You most likely have a bad jumper or PL259 connection issue confusing you. I always use a dummy load to walk down the cable/antenna path and to test jumpers individually when things like this happen to me. You just have to qualify all in the equation.

Jim
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Old 08-19-2020, 01:05 PM
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Originally Posted by jfwireless View Post
You most likely have a bad jumper or PL259 connection issue confusing you. I always use a dummy load to walk down the cable/antenna path and to test jumpers individually when things like this happen to me. You just have to qualify all in the equation.

Jim
Is this BOE Jim?? Can't keep up with all screen names any longer :-) I'm upgrading to an Icom regardless after this with you!! If this is you...
Old 08-20-2020, 01:43 AM
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Just asking,....When you reverse the jumper setup are you still keeping the radio inputting on the same "RADIO" side of the ART-2 or ART-3 VSWR tester or by any chance turning that around so the radio is on the "ANT" side of the tester??
Old 08-20-2020, 06:48 AM
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Originally Posted by TTaxi View Post
Just asking,....When you reverse the jumper setup are you still keeping the radio inputting on the same "RADIO" side of the ART-2 or ART-3 VSWR tester or by any chance turning that around so the radio is on the "ANT" side of the tester??
Nope. I left ART Meter in place... removed rg8x and rg58 cables. Put the 58 between radio and actual antenna (ANT slot to antenna), then used the 8x to go from back of radio to input on meter labelled radio.

So the 58 going from meter to pl 259-barrel connector-pl259 on antenna gives good readings..... in this scenario the 8x is between radio and meter. Sounds like you have used these so I think you get it. Very complicated to write out.

One positive during this.. I've ordered all new jumpers with SO 239 and PL 259 on other end for a new jumper... The positive is I found a company I can't recommend enough. Customer service is outstanding!!! Andy at this place expedited my custom build and shipment after hearing my story... They build whatever you want..

https://mpddigital.us/

He was excellent to deal with.. Andy Deluca
Old 08-20-2020, 11:50 AM
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Originally Posted by Lima Bravo View Post
Is this BOE Jim?? Can't keep up with all screen names any longer :-) I'm upgrading to an Icom regardless after this with you!! If this is you...
No this is not Jim at BOE,

JIm

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