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Cobra 18 WX ST II (don’t laugh)

Slowmover said:
Coax construction drives how tight.

Some RF Chokes sold use a type that can handle that.

K7CRA (I think)

I’ve made (4) different runs of new coax in this project. $$

Yes, 8-turns. 1.0” Palomar 31
Click to expand...

Oh definitely...I would not be able to turn the JEFA coax real tight. It’s 240 but not flexible enough for a toroid ring. The 18’ of RG-58 is a lot more flexible.

Ha...I knew it!! I think I will try that. Palomar is less than 100 miles where I am so it arrives pretty quick. I did take some measurements and the run from my amp to antenna is about 10-11’...so coiling like you did should be ok!

Brother your not kidding about $$$. LOL
 
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I received my mix 31 ferrite snap on’s from Palomar. A 1 inch and 10 1.4” beads. I wrapped the coax 8 turns as close to the antenna feed as possible. Doesn’t seem like it made much difference. Did make the SWR bump up a tick with the amp. Nothing crazy. Still under 1.5

DEFD83E6-D2E4-4E81-A825-19BBA48AFF7B.jpeg A9A46915-37CF-4F57-AF9A-9014BF6A30BC.jpeg

I added 2 smaller snap on’s for shits...basically the same.

Do I need to add more? I have 8 more snap on’s.

I might have to raise the white flag on this but but I really don’t want to.
 
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ForestRunner98 said:
I received my mix 31 ferrite snap on’s from Palomar. A 1 inch and 10 1.4” beads. I wrapped the coax 8 turns as close to the antenna feed as possible. Doesn’t seem like it made much difference. Did make the SWR bump up a tick with the amp. Nothing crazy. Still under 1.5

View attachment 37471 View attachment 37472

I added 2 smaller snap on’s for shits...basically the same.

Do I need to add more? I have 8 more snap on’s.

I might have to raise the white flag on this but but I really don’t want to.
Click to expand...


1). Something at the radio. Think, treat each end. (Antenna end needs to be OUTSIDE).

2). RF Bonding the vehicle is the rest of it.
Horizontal surfaces are first priority.
Exhaust system the second.

The rest as common sense dictates.

3). Give it a go at the antenna mount backside.

Might work. Might not. Experiment.

Short woven copper braid, per:

www.K0BG.com

The ARRL Library has the books you need (I also need).

.
 
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The choke is outside the truck. It’s underneath the bumper. I can play with it a little more and experiment. I rather not have it right outside the antenna mount. Not the most practical place and also maybe people f**king with it.

All doors, hood, rear hatch and exhaust are bonded. That was one thing that made a huge difference! Not so much in noise but bringing my SWR to a better place. Along with that RF low pass filter.

Here’s where I added the 2 other clip on’s.
B3B85D1B-F559-4F15-9E76-B3C9A6A40DC0.jpeg

Walking around the truck I noticed this!
DA08BB9E-3EEE-49F6-BDBD-AD4A8822FE02.jpeg
I never noticed or gave it much thought. Could be the culprit. I will take the truck for a spin and see how it pans out without that pole right behind it.
 
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ForestRunner98 said:
The choke is outside the truck. It’s underneath the bumper. I can play with it a little more and experiment. I rather not have it right outside the antenna mount. Not the most practical place and also maybe people f**king with it.

All doors, hood, rear hatch and exhaust are bonded. That was one thing that made a huge difference! Not so much in noise but bringing my SWR to a better place. Along with that RF low pass filter.

Here’s where I added the 2 other clip on’s.
View attachment 37486

Walking around the truck I noticed this!
View attachment 37487
I never noticed or gave it much thought. Could be the culprit. I will take the truck for a spin and see how it pans out without that pole right behind it.
Click to expand...

Sorry. I didn’t re-read.

Leaving town is big.

Would be nice if home were “quiet”.

Mine isn’t. Big power lines almost next to my place.

I’d go back to disconnecting Power then Coax. Try another radio. Try different coax (a jumper to the antenna with radio in hand if a temp power run can be done). Etc

Confirm where I am.
 
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I tried bypassing the cheap coax that’s there with some JEFA and no better results. Took the amp out of line, nothing. I was hoping it was the coax that was bad.

So I called Palomar...asked if the man on the line could help. He said ya...I am the engineer/owner. Let him know what was going on. All the stuff I tried that was suggested. He was puzzled. He said I managed to stump him too!!! We spoke for about 20 min. Real nice guy with no attitude!! I did tell him that my radio ground and amp ground were at 2 different spots. Said to place them together. I tried that and I couldn’t tell any significant difference.

He also said, now wait for this Slomover.....”try another radio”. Good job Slo!!! I explained it’s the only one I have. He said if I still have issues to call him. I am starting to think this cheapo radio is the culprit. I added some ferrite to the taillight wiring when I hit the brakes the current doesn’t affect the coax or antenna.

I don’t feel to bad since I can honestly say I am trying to sort this out.
 
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A man can never have have TOO MANY radios.

Hell, I even signed up for the undertaker
Radio Museum Curators Course.

In seriousness (IMO) the basic radio

is the UNIDEN 980 AM/SSB unit
$140 new if you look around.

Don’t open it, just use it.

In the meantime, maybe there’s a CB shop in your area. Get an SWR check (with their radio and test meter). $15 or free (a range). It’s a come-on-in-the-door attractant.

Somebody somewhere to borrow a radio. 5-minutes to test.

I’d say check Craigslist, but who knows what has been done to too many old radios?

.
 
Slowmover said:
Been out of the city?

A nice open area on a hill?

How’s tricks?

.
Click to expand...

No chance to get out of LA County..but I did play with the coax some more.

I put that 1” ferrite snap on but this time with 9 turns. Also 3 1/4” snap on’s before and after the large bead. I did have to install a 6’ Jefa jumper in order to have those 9 turns.

The result is....not totally sure. LOL Although the S levels seemed to drop a tick the amount of far away stations appeared. Could be skip conditions? Maybe but it does seem better. It’s just hard to gauge in this huge noisy county. I calculated close to 19k ohms of choke. Seems like a lot!! That’s with the small, large beads and Palomar box at the radio end. I did also add some beads near the amp and low pass filter.

EBDDC006-C702-4B32-A078-23D72E4568DA.jpeg
69971B16-7A4D-4E97-8542-8BFD8A8F5BC8.jpeg

I did order a few mix 31 toroids and 3’ of rg400 to make another choke. Just for giggles. I would like to get a President McKinley and a clearspkr but I can’t afford it at this time. FUN STUFF!!!!
 
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I’ve seen in your other posts you’ve been able to hear fairly well on sideband. Maybe you were “heard” as well. That’s great!

So it was natural to wonder if you’d gotten off to the hills. Cleared up what was local conditions versus vehicle install related problems.

(Ferrites are sorta like candy, huh? But if you have too many on the mobile, they’ll work fine for the future Base).

.
 
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My radio doesn’t have sideband. Even more reason for a nicer radio! Hard to tell if I was heard. Some heavy hitters on the west coast. Guys in Washington and Oregon pegging red on my meter. Like they were down the street. Insane!!

Your right can’t have too much ferrite candy. There could be a base in the future. Have to convince my wife for a big honking antenna!

Ya would have been nice to go out to a more rural area or mountains. Summer is still young! Hopefully Covid doesn’t wreck havoc here in California more than it has.

I saw on your thread Slo how you made that choke with the two toroids so that got me thinking. I will only try one with 8 wraps and play with that.
 
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