Wilson 5000 Magnetic Mount Antenna

[Coppenhagen]

Hello, I am new to the site as well to CB radios.

I purchased a Uniden 880 Bearcat which I paid to be tuned. I was told it puts out about 100 watts.

I installed a Wilson 5000 magnetic antenna, centered on the roof of my pickup.

I routed the coax down the back of the cab, underneath the truck and thru a grommet up through the front floor board. The coax is stretched out with no coils or sharp bends, etc..

I bought a Workman SWR power meter model HP201S.

When I key the mike and say something like: AUDIO, TEST, 123, in a normal voice the needle on the meter goes to around 100 or just over when set to the 500 watt setting.

On this meter the directions say to test for SWR: Switch a range knob to DIR and key the mike while turning the SET knob until it reachs the (don't know what is called) symbol all the way in the red range on the SWR scale. Then I am suppose to move the knob from DIR to REF and key the mike.

PROBLEM:

I can never get the needle to the far right side of the SWR side to that symbol, it only goes to around 1.2 no matter what I adjust.

So then with this Uniden 880 it has a built in SWR from what I read is probably not accurate. The 880 SWR reads 1.1 on pretty much every channel.

I tried this with the RF maxed and the mike gain maxed and with both turned down and other combinations and the needle stays the same, as in just slightly moving.

The diagnostic check that the radio does says the volts are 14.2 and the antenna PASSES.

I calibrated the channel so it is darn near the calibrate line.

I am hearing radio traffic and getting back LOUD AND PROUD reports.

So what is the deal? Why can't I get the SWR meter to do what the directions say?

Is there a problem with my setup? Could my SWR be really bad and I not know it or did I luck out and the setup is pretty good with 1.1 readings so says the radio?

I did this test today in the drive way about 30' from the two story house with the doors closed. We live in a heavily wooded area, however the nearest trees to the driveway are easily 40' and further away.

The DK reads about 2 watts.

Could the new meter be bad?

Thanks in advance for any input.

 

[roadrage]

SWR is better with a lower number.

Antennas are a complicated thing to explain so I just kept it very simple.


Did you have an RFX-75 unit installed?

 

[Coppenhagen]

Yes I have an RX-75.

I understand that SWR should be a low number.

Can I truly trust the SWR meter when I can't get it to calibrate correctly?

 

[undertaker]

Yes......

 

[roadrage]

The radio's internal meter may not be spot on accurate , but it isn't going to be that far off either. If the radio is showing a 1.1 SWR reading on all channels, that is fine. Anything below 1.5:1 is considered ideal. Your radio's meter isn't as bad as you might think.

Just to clarify, are you keeping the mic keyed up while you are adjusting the calibration knob?

 

[The DB]

So the set scale on the SWR meter only goes to a 1.2 and no where near the set position. You have an RFX-75. Just curious, do you happen to know how much of a dead key you have? It wouldn't happen to be around 2 watts would it?


The DB

 

[Coppenhagen]

Yes I am keeping the mike keyed while adjusting the knob for the SWR reading.

When I put the meter on 5 watts and key the mike and do not say anything, the reading is around 2 watts give or take a half.

Is it too low of a dead key to get an accurate SWR reading?

I just don't want to screw up the up the radio because I have false SWR readings. If the SWR is truly less than 1.5, I will take that without complaint!

Like I said, the radio diagnostics claim the ANTENNA PASSES, and the SWR is around 1.1. It just concerns me because I have been lurking on this site for a while and have read numerous posts trying to educate myself from the experts on this field and it seems unusual that the SWR reading would be 1.0- 1.3 from channel 1, 20, and 40!

Does the 880 have circuity that will protect it from damage if the SWR is indeed to high in case I am getting false SWR readings from the meter and the radio itself?

Thanks guys for the help on this, I find this stuff fascinating and am gobbling up as much information as I can from this site. What a great resource!

 

[Onthecoast]

The Bearcat 980 that I just bought doesn't seem to match what my external SWR meter is showing either. I haven't double checked to see if it reads more accurately once the external meter is disconnected.

 

[The DB]

Is it too low of a dead key to get an accurate SWR reading?

2 watt dead key... Seen quite a few videos of radios with RFX-75's being set that way...

It's to low of a dead key to get an accurate SWR reading with that specific meter.

That being said, if your radio is saying its 1:1 or 1.1:1 I highly doubt that it is higher then 1.5:1.

I'm not to familiar with that specific radio so can't help ya with the rest.


The DB

 

[TonyV225]

How does that radio do with the RFX-75 addon?? Can that uniden have channels added or are they using a new type PLL chip??

 

[roadrage]

So the set scale on the SWR meter only goes to a 1.2 and no where near the set position. You have an RFX-75. Just curious, do you happen to know how much of a dead key you have? It wouldn't happen to be around 2 watts would it?


The DB

I may be wrong about the direction you are headed in on this one The DB. Is there a minimum detection on that meter? I know that there are meters with a 4 or 5W minimum detection for the SWR scale. I didn't think of that until your post.

 

[The DB]

I may be wrong about the direction you are headed in on this one The DB. Is there a minimum detection on that meter? I know that there are meters with a 4 or 5W minimum detection for the SWR scale. I didn't think of that until your post.

A lot of meters will only go down so far, and every meter has its bottom limit. What an SWR meter is is a directional watt meter. It is measuring only the power going one direction through the coax. After you adjust that to the set position and switch to the reflect setting it measures only the power going the other way, or power that has been reflected back from the antenna or any other mismatch present. How that compares to the first reading is where the SWR reading comes from.

Unfortunately the meter displays that are used typically are designed for smaller amounts of power than is directly available on the feed line so they use resistors to absorb some of that power. The knob you turn is actually a variable resistor, which fine tunes the power needed so you can then set the meter. The meter is likely designed to work with (or a minimum of) 4 watts. 2 watts may simply not be enough to drive it properly.

I have an older meter that cost quite a bit for its day and can measure up to 1,000 watts. The SWR and modulation meters built in will not set unless you have at least 3.5 watts of dead key, so it isn't just the cheap meters that have that issue.


The DB

 

[Coppenhagen]

Thank all of you for the information.

Does anyone know if the radio has circuitry to automatically not transmit if the SWR is really too high and secondly if the radio does have such a feature, could the radio SWR be fooled into not preventing damaging radiation because it to does not have an accurate SWR reading?


It makes me feel better that the radio SWR probably isn't too far off the mark.

 

[The DB]

Thank all of you for the information.

Does anyone know if the radio has circuitry to automatically not transmit if the SWR is really too high and secondly if the radio does have such a feature, could the radio SWR be fooled into not preventing damaging radiation because it to does not have an accurate SWR reading?


It makes me feel better that the radio SWR probably isn't too far off the mark.

I just looked through a manual. It appears that you have to go to a specific menu location to have pass/fail the antenna. That being the case, the circuit that does that test is not always functioning, so automatically reducing or completely cutting off the transmit power output does not appear to be the case.


The DB

 

[Coppenhagen]

Thanks for the input. So I guess the consensus is that my SWR is probably in the acceptable range. I can live with that... I just wish I knew what the actual reading is... LOL.