What have you done to your Tacoma today? 1st Gen Edition

I have the firering so it looks like diagram 3.

It's a

Procomm Base-Loaded Steel Whip CB Antenna - 3'

 

hmm that sounds like a potential issue.

As you can see from the photo i just posted, the isolator needs to keep the hot signal away from the mount that is grounded. It keeps it from touching it.

 

Okay, so as long as there is no washer between the cable and the mount on the bottom and you used the isolator washer on the top so that it is the right side up it should be good.

 

No it is not. This is what I study at school 1 is ideal.

 

Exactly..in a perfect world.

https://www.arrl.org/files/file/Technology/tis/info/pdf/q1106037.pdf

which never happens of course.

 

In the real world, an swr of 1.0 is a lot like that rare metal just discovered call unobtainium.

 

Here's some pics. Sorry for the bad lighting. The order is Bolt, FireRing, Antenna Mount, Nylon Isolator, (5x) Washers, the threaded adapter, spring, and antenna.

(you can see the grounding strap here)

@Digiratus @Blackdawg

IIRC the antenna came with a washer, and a lock washer. When I put it on the antenna mount there was too much clearance between the threaded adapter (below the spring) and the lock washer. (a couple centimeters) so the antenna would flop around since it wasn't secured properly.

I ditched the lock washer and single washer and bought (I think 3/8) washers and used 5 of them (mainly as spacers) in order to mount it properly.

 

Based on the pics Monte posted, it looks like the plastic isolator is in the correct place. However, all of those washers will make the antenna longer. How come you used so many? Have tried removing them all except for one and checking your swr that way?

 

Spring under

More pics in my build thread.

 

It wouldn't mount right if I used the 1 washer and 1 lock washer they provided. I used so many mainly as spacers. The bolt would only go so far into the threaded adapter before it hits the end of the thread, there was still a lot of room in between the adapter and the mount with just the 2 washers so the antenna would flop around.

The bolt is too long, basically.

I'll have to check the SWR without the washers.

 

Sounds like the firering wasn't designed for that antenna.

Also, you didn't mount the firering upside down did you? Per the video on this page...

https://www.rightchannelradios.com/products/firestik-firering-cb-coax-with-fme

 

I'm sure I put it in the correct orientation. This setup was actually recommended to me by someone from Right Channel Radios. I used the coax, mount, and antenna they recommended after telling them what I needed.

The issue with the Mount was that the bolt that came with the fire ring was too long.

 

Dont mean to bust your bubble but don't think a regular nut on there will work. Thought the nut and washer on all 1st gens were 1 piece. Also bolt should be turned around.

 

Used up some extra LEDs i had laying around.

 

This! I can't stress this enough. It's likely a grounding error. I had to throw a small o-ring on the threads so it didn't ground out

 

so what you just let the boys do all the work while you watch and take pics?

 

what?! you didn't do the welding yourself?!

couldn't hurt to check to see if it is the right way up, same with the isolator

It also sounds like the hole in the mount may be too big though. The isolator and the firering cable should both have small lips on them that go into the hole to keep the bolt off of the mount. If by change the lip is too small you'll have to add something like a rubber o ring or anything that fits to keep the bolt from touching the mount and grounding out.

 

^^^ That's what I did and it fixed it, just had to fine tune it after that

 

We're getting into semantics here, but Monte's point is valid.

Perfect in this case is not physically realizable. Perfect 1:1 VSWR means that your load (the antenna in this case) is a perfect match to the system impedance that it's connected to, thus allowing 100% of the incident power on the load to be absorbed by it and not reflected back to the transmitter. This is never the case outside of mathematical models. So, real world, the ONLY SWR values one can achieve are greater than 1:1, not greater than or equal to 1:1.

'Ideal' really depends on how much reflected power the output stage of the transmitter can absorb before it gets fried, and how much effective radiated power the user needs to makes good comms. That will mean different values are acceptable to some and not to others.

As stated in the link that Monte put up, 2.0:1 VSWR means that just over 10% of the RF power output by the transmitter is reflected right back to it. That sounds like a lot, but in some cases the gear might live with that and the range doesn't suffer too much for the intended use. 1.5:1 means less than 5% is coming back to the radio, and for 1.2:1, less than 1%. I'm guessing that in the case of CB, the radios are generally relatively cheap consumer electronics, and the output stages aren't designed to sustain higher reflected power. So you try to shoot for 1.5:1, give or take. If you can nail 1.2, great. But 1.5 isn't bad at all, you just might lose a bit of range at that tune, and since CB is relatively low power by law, any reduction in range due to the tune may be an issue.

Anyway, sorry for the lecture. I work in the RF world so I geek out on it pretty easily.

 

this is huge considering you're only working with 4w(if you're even lucky your CB actually does 4w). Optimizing the small amount of power is crucial.





or say fuck it and get a real radio like a 2m/70cm HAM radio. Not that that makes it less complex....