Clean VHF/CB radio installs

I made a little better SWR yesterday with cable length.

I originally have 18' RG-8 coax with the whip and spring, where I was generating the high 2.5 - 3.0 SWR. Went out to an open area across from BWI and tested:

18' RG-8 with spring: 2.5 (CH 1) - 3.0 SWR (CH40)
18' RG-8 with without spring: 2.5 (CH 1) - 3.0 SWR (CH40)

Then...

25' RG-8 with without spring: 1.5 (CH 1) - 1.5 SWR (CH40)
25' RG-8 with with spring: 1.5 (CH 1) - 1.6 SWR (CH40)

So I'm getting better SWR with a longer coax cable. Hmmm.

I also discovered two days ago that all three aluminum panels of my Diamondback appear to be grounded, there is not open circuit of them when testing with a multimeter. Anyway... I ordered and received copper grounding straps and will see if I can make a better grounding with them.

 

sounds like something with your first cable isn’t good , maybe that spring was bad

 

Something wrong with your cable?

 

Am unsure. Continuity is good for the ground and the center conductor. On another forum elsewhere, I was told that:

If your coax length makes a difference THE SWR HAS NOT CHANGED, you are just measuring SWR at a different point in the sine wave. Use a 4-6" jumper and measure at the antenna, it will be the most accurate for your troubleshooting.

It's all becoming voodoo to me at this point.

 

Measuring swr at antenna will show a narrower dip, but it's not more accurate. Adding the loss of the coax widens the bandwidth of the swr curve.

What are you measuring swr with? If you see a dip somewhere inside the 11 meter band, you should be fine. If you have a network analyzer you can see if your coax length is a multiple of a wave, or you can use the velocity factor and math to figure it out.

 

I’m just using a external SWR meter commonly found, like this:

 

I guess that's better than nothing, but I wouldn't live or die by what it says.

VNAs are $60 bucks on Amazon.

I'd also put a quarter wave piece of wire at the ground and see what that does.

 

I just discovered something interesting about the bottom half of my mount's SO239 connection to the antenna stud.

As you can see in the picture, the bottom half is screwed together. I was again checking continuity (yes, I'm beating that dead horse again) and I was getting very sporadic readings from checking these two halves that are screwed together (the ground portion of it outside the insulator - not the stud)). Took two wrenches and gave it a snug and to my surprise it moved 1/8th of a turn. Tested ground continuity again and it's now constant.

How much more tighter can I tighten this? I don't want it to snap.

 

Finally mounted.

 

Just got my DigiRig Lite in the mail this week. Have been testing it out with a Baofeng because I can't find my other DigiRig Cables.
But will be ordering a new cable and setting the truck up as a mobile data hub for off grid comms soon.

If you haven't seen it yet, the DR-Lite is featured in this video by The Tech Prepper. I like his videos better than most Ham-Toobers because he shows a practical real world application.

This is partially why I was asking above about the phone mounts. I'll now need a place for my iPhone, my Android Phone (no sim card - functions like a very small tablet), Radio Mic, and maybe the wife's iPhone too.

But being able to crank out 50w of power on an antenna that gets a 3di gain lets me push a good data signal pretty far from some of the elevations I like to off road and camp at. Will be nice to let my wife and other family members know where I am and that I'm safe (because they worry about me more than they should) while out of Cell Range. Yes all of this can also be accomplished with Sat Phones and Garmin devices but they cost a lot and require a subscription service.

All in, adding a DR-Lite to the Truck will cost:
DR-Lite - $50 after shipping
Cables - $30 after shipping
Extension Cable because my radio is under the seat (I have one I'm salvaging for free) - $10
Android Phone - Got mine free but you can snag a used one for $50 to $100 depending on your tastes.
Apps to run digital FM - $20

So I will have spent $90.
You might spend $200 on the high side or if you already have an Android, maybe around $100.
There is no satellite based comms solution that can be had for that cheap and requires NO subscription.

 

Nothing like a nice $15.00 speaker from Amazon making us of the area where the wireless charger is to prevent me from saying "Say again your last" on the radio!

 

Has anyone installed a screwdriver type HF antenna on their Tacoma? I have a Little Tarheel 2 coming for it. I haven't decided how or where to mount it. I probably want some sort of folding(maybe electric) mount for it so I can still get into parking garages/car washes etc.

 

I had a little tarheel, until it burnt up. I didn't pay attention to the fact that it's only rated for 50w PEP on CW.

I had it mounted on a metal toolbox in bed. I switched to ham sticks. Much more efficient.

*Edit. I have the burnt tarheel body if anyone wants it for parts*

 

I run an ATAS 120 on mine.

 

I could always use the parts for the tarheel. Let me know.
I only use phone or FT-8. FT-8 might be tough for me to build a mobile setup with the TS-480SAT I'll be installing. I'd have to run a Signalink USB or rigblaster, and a laptop.

Where/how do you have it mounted?

 

Looks good. I have the same mount, I just have to figure out the 3/8x24 mount to coax for that bracket.

 

If you are going to use a 3/8x24, you might have to ream the hole a tad to get the insulator to fit perfectly and not short out the mount. You will definitely need to knock off the powder coating for sure to get a good bond to the mount and also at the mounting bolts. I added some braided straps behind the tail light to other side of the mounting bolts and bonded to the frame. I would look into the fire stick
“HS818TNKT” low profile coax.

I ran a UHF mount and keep UHF -nmo and an uhf -3/8x24 adapters around in the event I want to run another type of antenna and not have to rerun the coax.


The UHF mount uses the micro coax ( rg-316) which allows for the feedline to be easily routed. The loss on HF is not noticeable.

 

Hey Ham Gurus, I have an SWR question for the 2 meter band.

Does the length of the cable between the radio and the NMO mount have an influence on the antenna's SWR? Or is it only the length of the antenna itself that matters?

 

Kind of:

The more feedline loss you have , the lower your reflected power will be and can skew your readings

Also, it is possible for your meter to be measuring a portion of the sine wave at the lowest point of the cycle and also the highest point of the cycle giving false readings.


The best method of measuring your antennas resonance is by measuring return loss , but the practicality of that is not for the average radio operator. Not to mention takes calibrated equipment that would typically cost a few thousand dollars.


But the basic answer is you have to take the entire antenna system into account when measuring VSWR. Connectors, feedline, antenna, mount etc