Measure swr with amp and filter

[ForestRunner98]

The President Andy is a nice small AM radio too. Presidents ASC(automatic squelch Control) is a nice feature.

The weak link in the Jeep would be antenna placement. Take it from me. Using a bracket for the antenna does not make good ground. Like earlier mentioned bonding helps. I also had a 4’ antenna and went with a 6’ which helped a ton!

 

[Littlears]

PRESIDENT is a high quality brand with several quite small radios. I think there’s even a a Wrangler Mount bracket for that size. (Tera?).

The Johnny III has some nice features (VOX & two types Squelch). BELLS CB carries it.

The real problem is a decent antenna mount for the Wrangler. (For correct performance).

.

Do you have any thoughts on the right place to test swr?
I ran a quick test between filter and antenna and it was 1.5 /1.6 @ ch1 & ch40.

but other suggest I should be testing between amp and filter? And then otherS say test between radio and amp?

It appears all 3 spots will give different swr readings, and I don’t want to mess up my radio while tx due to bad swr . Color me confused.

 

[Slowmover]

Get a little notebook fits in glovebox. Rubber band a shortt pencil around it.

IMO, install SWR Meter at the end of the coax from the antenna.
(Before whatever you have in-line from radio).

SWR below 2.0 is adequate. At 1.5, leave it alone. Ck 1,40 & 20. Tune antenna per instructions. (Or, if mainly/only on one channel, do that one). Measure & make a note

Ck condition & tightness of connectors (mic, too, the one I forget). Don’t crank them down, but make them more than snug.

Get things as good as possible at home. Then go find a wide-open rural area with nothing at all nearby. Re-do. Make notes.

That’s it.

To set RF Gain, find a close empty channel. Back down a touch till it moves. (Note). With Squelch next, back down till silent. Then open up a little. (Note). Then return to usual channel.

Mic Gain closest to wide-open. Ask for reports and move it from half to full open. Set spot. (Note).

Re-write notes to show what were these baseline settings. No confusion five weeks or months from now. Clock-face numeration, or . . .

.

 

[ForestRunner98]

What numbers do you have after the filter with the amp on? I was instructed after the filter before the antenna. You want to see what the numbers are when you TX amp on. Ya you will probably get a different reading when the amp is off.

 

[Slowmover]

One “shouldn’t” see a change after amp kicked in, but very much of one means problems with coax, and most likely with antenna, mount itself, and location.

This Peterbilt has two of those three. Without amp, it’s flat perfect. WITH amp, it ain’t.

So, yeah, take amp out to get antenna ideal.
Take out everything.

(I was thinking Step Three, not Step One).

It’s in being methodical and writing things down, that gets lost.
Introduces confusion.

.



.

 

[Littlears]

What numbers do you have after the filter with the amp on? I was instructed after the filter before the antenna. You want to see what the numbers are when you TX amp on. Ya you will probably get a different reading when the amp is off.

after the filter and before antenna, while dead key, my quick test showed 1.5/1.7 swr. Amp is on and inline. (Actually there isn’t an on / off switch, it only turns on when mic is keyed)

 

[Littlears]

The President Andy is a nice small AM radio too. Presidents ASC(automatic squelch Control) is a nice feature.

The weak link in the Jeep would be antenna placement. Take it from me. Using a bracket for the antenna does not make good ground. Like earlier mentioned bonding helps. I also had a 4’ antenna and went with a 6’ which helped a ton!

100% agree. I was up in the 2’s and 3’s with regular tailgate mount. Then I scraped paint off the mount to let bolts touch metal to metal and got low 2’s.

Then I added tinned braided copper ground straps from mount to tailgate metal & tailgate to body frame and got mid 1’s.

think that’s about as good I’ll get it , with maybe some marginal improvement if I do more bonding. We shall see..

 

[ForestRunner98]

after the filter and before antenna, while dead key, my quick test showed 1.5/1.7 swr. Amp is on and inline. (Actually there isn’t an on / off switch, it only turns on when mic is keyed)

Ah ok. My 203 has the on/off switch. Those numbers aren’t too bad!!

100% agree. I was up in the 2’s and 3’s with regular tailgate mount. Then I scraped paint off the mount to let bolts touch metal to metal and got low 2’s.

Then I added tinned braided copper ground straps from mount to tailgate metal & tailgate to body frame and got mid 1’s.

think that’s about as good I’ll get it , with maybe some marginal improvement if I do more bonding. We shall see..

I would go with what you have now. You’ll be ok. If you want to bond more, go for it.

Enjoy your radio!!!

 

[Littlears]

So I went and did some more readings. Wondering if any of you had thoughts on these numbers

Radio -> amp -> filter -> antenna

operating on 11 meters in my mobile unit.

Between filter and antenna (With amp on and inline )
Chan 1 1.7
Chan 20 1.7
Chan 40 2

Between amp and filter (With amp on and inline )
Chan 1 1.7
Chan 20 2.0
Chan 40 2.25

Between radio and amp (With amp on and inline )
Chan 1 1.1
Chan 20 1.1
Chan 40 1.1

Without the filter between radio and antenna (With amp on and inline )
Chan 1 1.8
Chan 20 1.8
Chan 40 2.1

Without the amp (but with filter )

Radio -> filter -> antenna

Chan 1 3
Chan 20 2.75
Chan 40 2.1

Without the amp or filter
Radio -> meter ->antenna

Chan 1 3.15
Chan 20 3
Chan 40 2.1

 

[sp5it]

It seems that antenna is too long and filter is crap. Probably meter too.
Mike

 

[Road Squawker]

...
Then I added tinned braided copper ground straps from mount to tailgate metal & tailgate to body frame and got mid 1’s..

Thats pretty normal for bonding around hinges.

doors, hoods, trunk lids, ect all have sliding hinges and should be bonded around the good grounds.

 

[dave457]

What low pass filter are you using?

 

[Littlears]

What low pass filter are you using?

https://www.rmitaly.com/en/product/low-pass-filter-27-586-2/

Hey there. I’m using this one.

 

[ForestRunner98]

Wait...your numbers don’t make sense to me. Without the amp your getting those high numbers? Even with the amp in-line but off the numbers should be low. I would guess 1.4 the highest. But there is no on/off switch so it’s always on stand by till you key? Just radio and antenna (amp removed from line) you should get good numbers. Not low 2’s to 3’s.

I still think the Achilles heal is the mount. I get it, it’s a Jeep and mounting is limited. Bond as much as you can. Besides the mount and bonding I think your at the point where that’s the best it will be. Does the amp heat up? I don’t remember what your DK was. From experience if you DK near 4w it will get warm pretty fast if your doing a lot of talking. Throw a fan on it and have fun with it!

 

[Littlears]

Wait...your numbers don’t make sense to me. Without the amp your getting those high numbers? Even with the amp in-line but off the numbers should be low. I would guess 1.4 the highest. But there is no on/off switch so it’s always on stand by till you key? Just radio and antenna (amp removed from line) you should get good numbers. Not low 2’s to 3’s.

I still think the Achilles heal is the mount. I get it, it’s a Jeep and mounting is limited. Bond as much as you can. Besides the mount and bonding I think your at the point where that’s the best it will be. Does the amp heat up? I don’t remember what your DK was. From experience if you DK near 4w it will get warm pretty fast if your doing a lot of talking. Throw a fan on it and have fun with it!

I think part of my problem is too many braided copper bonds on 1 bolt / screw.

have you ever seen a way to merge multiple bonding straps? Perhaps there’s something like an alligator mouth that can Be crimped onto one and “bite” into the next?

Or just go hunting for more available points