S

Side-show-bob

Active Member
I have just fitted a midland 70-099 radio and it has a range of 30 feet (if i am lucky) i know this as i fitted one to my mates at the same time. We adjusted the squelsh so we could hear each other (very crackly) when the landys are side by side, i think i may have wired the arieal in poorly. I used PL259-6C compression plugs i am not sure if i have wired them up correctly, i think i should have soldered the main center terminal and i am not sure if i put the outer screen in the correct place. Could this be why i have very limited range?
Also can anyone tell me what the hi/low switch is for on the rear of the unit?
Rob
 
Side-show-bob said:
I have just fitted a midland 70-099 radio and it has a range of 30 feet (if i am lucky) i know this as i fitted one to my mates at the same time. We adjusted the squelsh so we could hear each other (very crackly) when the landys are side by side, i think i may have wired the arieal in poorly. I used PL259-6C compression plugs i am not sure if i have wired them up correctly, i think i should have soldered the main center terminal and i am not sure if i put the outer screen in the correct place. Could this be why i have very limited range?
Also can anyone tell me what the hi/low switch is for on the rear of the unit?
Rob
Click to expand...


Have you SWR'd Them both?
 
You must SWR your set up. Meter cost about ten quid. No SWR = blown rig or no idea about the quality of the set up:(. Good earth is a must.:)
 
The hi/lo switch on the rear of the set is for limiting your output power. Set it to HI for normal use (allegedly 5 watts) or set it to low to avoid too much inter-channel interference if in convoy and others are on a different channel. On LO it is a -5db reduction to your output power which translates to approx 0·5w of TX output.

Normally, two sets as close to each other as you describe would hear each other even without an antenna attached. Therefore, I would assume you have shorted out the antenna, on one of them at least, when you fitted your PL59.

The best way to fit the plug is :-

1. Remove approximately 2 inches of the outer insulation and use your fingers to push the outer braid (the woven wire) back over the outer insulation.

1.jpg


2. Now, remove the insulation from the inner core leaving about ¼ inch sticking out from the folded back braid and wind the strands of the inner core tightly (if it's multi-strand.)

2.jpg


5. Personally, I always recommend soldering the inner core into the plug, but many people don't do this and it works for them.

6. To solder the inner core properly, I always tin the wire first (apply hot solder to the inner core you have wound tightly and shake off excess solder while it's still hot.)

7. Next, heat the connecting pin of the plug where the inner core will be soldered and apply a reasonable amount of solder to it inside the pin and a little on the outside, then once again, shake out the excess while it is still very hot. If your have the cheaper type of plug, be careful not to melt the white plastic disc the connecting pin goes into, if you do melt it a little, and the pin moves off centre simply heat it again and reposition the pin and let it cool. If it's a harder brown material it will not melt.

8. Check by looking down through the back of the plug to make sure there is no excess solder on the inside of the body which might short the inner core to the body of the plug.

9. If your PL59 is a two part plug, remember to put the screw cap onto the co-ax.

10. Then, once you are happy with that, screw the co-ax into the back of the plug (or crimp it into place) but make sure that the inner core has gone down through the pin and not got twisted inside the plug. Also, don't screw it in so far that the outer braid goes right in and touches the back of the connecting pin inside the body of the plug.

11. Apply a little fresh solder to the end of the pin to secure the inner core and trim off any excess wire left sticking out. Tidy the end of the connecting pin up with a file and finally, trim any excess braid sticking out the back of the plug.

12. Enjoy having a bit of banter with your mates.

10-4 Good Buddy.
 
Last edited:
Side-show-bob said:
Sorry never had one before what is SWR?
Click to expand...

Firstly, I'd like to apologise to anyone who considers this post to be a bit long-winded or patronising sounding. I do not know how much you know, nor do I know how much you want to know, so, I try to explain everything as fully as possible in as simple a way as I can.

SWR is the measurement of your antenna's efficiency and tuning. A basic SWR meter has a scaled display, a switch, a knob and two PL59 sockets - one marked "XMTR" or "RADIO" and the other marked "ANT" or "ANTENNA." Some come with built-in output power measurements too.

You connect the SWR meter between the CB antenna socket and the antenna itself, using a short patch lead (a short piece of co-ax with a PL59 plug on each end.)

Then, to check your SWR reading, you simply set the meter's switch to "FWD" (forward) and set your rig into TX (transmit) mode. Whilst you are TX'ing, your turn the adjusting knob on the SWR meter until it reaches full-scale deflection (needle goes to the end of the scale to where it says "SET".) Then you switch the SWR meter to "REF" (reflection) and the reading the meter then shows is how much of your output signal is being "reflected" back into the set due to bad tuning. For the best coverage possible, you need the second reading to be as low as possible which means that most of your transmitted output power is being broadcast to the world.

Any reading under 2 on your SWR meter scale is acceptable and no damage should occur to your rig. 1.5 to 2 is reasonable. Under 1·5 is getting good bust best of all is a reading of 1 or as low as you can get it.

You can alter the tuning of your antenna by changing the length of the whip, or in some cases by adjusting a collar or screw, but most common is the whip.

What I do is:-

1. Make sure that there is nothing too close to the antenna which will affect the signal, my body, trees, metal framework, bridges etc.

2. Then (as described above on how to use an SWR meter) I take a reading from channel 1 (lowest frequency) and a reading from channel 40 (highest freq.) You need to re-adjust the SWR meter's knob for each different freq. This will give me an indication of whether my antenna needs to be longer or shorter. If the reading is higher on channel one than channel 40 then the whip needs to be a little longer and vice versa if the reading is higher on 40 than 1. (The lower the freq. is then the shorter the antenna should be.)

3. Then I adjust the length of the whip by about 3mm at a time until I get both channel readings as close to equal as possible.

Once you have done this, then check the reading for channel 20, which is mid-way between 1 & 40 and this will give you your best SWR for the antenna you are using (obviously, if you want to be pedantic this is the channel which will perform best for you, but no-one would ever know the difference between any of your channels.)

Now, don't go making it your life's ambition to get a perfect, dead needle, reading for channel 20, you'll just get frustrated.

My final tip on antennae, when you install your rig & twig where you want them and have run the co-ax between the two, any leftover co-ax should NEVER be wound up into a coil and tucked in a corner. This is the most common cause for high SWR reading I have ever come across. Any excess co-ax should be ticked away in big loops rather than a small neat coil. The RF (radio frequency) waves will generate an inductance (resistance) within the coil and waste some of your output power.

Ron.

P.S. If you need a loan of a cheap and cheerful SWR meter PM me with your address and I'll post one out to you.
 
Last edited:
Or if you can borrow one!
It's the sort of thing u use once when you set up.
Most people on the rig are quite helpful and would probably set it for you. I've just dug one of my old ones out. Can't find my magnum though :(.
But found 3 swr meters that people have given me over time
 
Sasha said:
Or if you can borrow one!
It's the sort of thing u use once when you set up.
Click to expand...


Thats untill you lose your twig off road........ or have it nicked....... or just up grade it, move the twig to a new position, may be run a second rig as well ...... or even change your rig.
 
Big Stu 12 said:
Thats untill you lose your twig off road........ or have it nicked....... or just up grade it, move the twig to a new position, may be run a second rig as well ...... or even change your rig.
Click to expand...

Did have my Thunderpole Springer on the Bracket of the spare wheel carrier was good there but the earth was crap i had to run 2 wires in to the car for an earth. So now it's located in the centre of my lightbar on the Roof, and awy from naughty fingers:D:D
 
Clanforbes said:
Firstly, I'd like to apologise to anyone who considers this post to be a bit long-winded or patronising sounding. I do not know how much you know, nor do I know how much you want to know, so, I try to explain everything as fully as possible in as simple a way as I can.

SWR is the measurement of your antenna's efficiency and tuning. A basic SWR meter has a scaled display, a switch, a knob and two PL59 sockets - one marked "XMTR" or "RADIO" and the other marked "ANT" or "ANTENNA." Some come with built-in output power measurements too.

You connect the SWR meter between the CB antenna socket and the antenna itself, using a short patch lead (a short piece of co-ax with a PL59 plug on each end.)

Then, to check your SWR reading, you simply set the meter's switch to "FWD" (forward) and set your rig into TX (transmit) mode. Whilst you are TX'ing, your turn the adjusting knob on the SWR meter until it reaches full-scale deflection (needle goes to the end of the scale to where it says "SET".) Then you switch the SWR meter to "REF" (reflection) and the reading the meter then shows is how much of your output signal is being "reflected" back into the set due to bad tuning. For the best coverage possible, you need the second reading to be as low as possible which means that most of your transmitted output power is being broadcast to the world.

Any reading under 2 on your SWR meter scale is acceptable and no damage should occur to your rig. 1.5 to 2 is reasonable. Under 1·5 is getting good bust best of all is a reading of 1 or as low as you can get it.

You can alter the tuning of your antenna by changing the length of the whip, or in some cases by adjusting a collar or screw, but most common is the whip.

What I do is:-

1. Make sure that there is nothing too close to the antenna which will affect the signal, my body, trees, metal framework, bridges etc.

2. Then (as described above on how to use an SWR meter) I take a reading from channel 1 (lowest frequency) and a reading from channel 40 (highest freq.) You need to re-adjust the SWR meter's knob for each different freq. This will give me an indication of whether my antenna needs to be longer or shorter. If the reading is higher on channel one than channel 40 then the whip needs to be a little longer and vice versa if the reading is higher on 40 than 1. (The lower the freq. is then the shorter the antenna should be.)

3. Then I adjust the length of the whip by about 3mm at a time until I get both channel readings as close to equal as possible.

Once you have done this, then check the reading for channel 20, which is mid-way between 1 & 40 and this will give you your best SWR for the antenna you are using (obviously, if you want to be pedantic this is the channel which will perform best for you, but no-one would ever know the difference between any of your channels.)

Now, don't go making it your life's ambition to get a perfect, dead needle, reading for channel 20, you'll just get frustrated.

My final tip on antennae, when you install your rig & twig where you want them and have run the co-ax between the two, any leftover co-ax should NEVER be wound up into a coil and tucked in a corner. This is the most common cause for high SWR reading I have ever come across. Any excess co-ax should be ticked away in big loops rather than a small neat coil. The RF (radio frequency) waves will generate an inductance (resistance) within the coil and waste some of your output power.

Ron.

P.S. If you need a loan of a cheap and cheerful SWR meter PM me with your address and I'll post one out to you.
Click to expand...


That's brilliant! thanks, I've now SWR'd my CB, no idea if it works (will test when I next go out with the ShireLrc lot) but very useful post!
 
hext said:
That's brilliant! thanks, I've now SWR'd my CB, no idea if it works (will test when I next go out with the ShireLrc lot) but very useful post!
Click to expand...

Glad I could help.

An alternative is to put your whip right down as far as it will go then do all your SWR'ing on channel 20, again, making minimum adjustments each time. You should see the reading drop slowly, then start to rise as the whip length passes it's optimum size.
 
I HAVE JUST NOTICED AN IMPORTANT TYPO IN MY INSTRUCTIONS ABOVE.

Please note that the lower the freq. the LONGER the whip should be. Higher frequencies need a shorter antenna.

My bad - sorry.
 
I bought a rig as I used to love using CB back in the early eighties.

's a load rubbish now... Nobody seems to use it until late at night when you get a couple of old blokes discussing the size of their thunderpoles.

The bloke in the shop told me that the antenna come pre SWRed for UK frequencies. I thought this was complete bollox as it would depend on many other factors, so I bought an SWR meter anyway - he was right! Ch20 1:1.1 !!!!
 
Many twigs will come pre-swr'ed, but as you say so many factors involved.

I also was a great cb'er even in the old AM days, but I went off channel for a lot of years then came back on for a while when I was trucking up and down between Perth & Carnforth every night, as a lot of my colleagues at Tuffnells were using them (Tuffnells night trunks run on ch26.) Where I live, there no-one using cb these days except the occasional farm worker in the tractors. I still have a terrific set up in my workroom which gets switched on from time to time, but there's never anyone to be heard on it. Also, with so many sat dishes being around these days, it's almost impossible to pick up any distant signals due to the interferrence they cause.

However, I can see where it would be useful to have car to car communications when off-roading or green-laning.
 
Talking of wiggly whips, I'd love a pair of the old fibre glass ones that were dead common in the '60's & '70's. I did have one way back then, but would love to put a couple on my fender now. They were about 10 to 12 feet long and waved about all over the place. Looked a bit like fishing rods - oh here, now there's a thought!
 
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