weird question

[Remo]

OK, ready for this? I cant figure it out.

(before I get into any of this.. Im well within a mile of two major interstate interchanges. so I get LOTS of cb traffic here.)


My base is: Uniden PC 68, K40 K30 mag mount antenna on a steel shed.
(SWR is about 1.3)
----- yes i know its not ideal, thats not the issue here, keep reading


My mobile is: Cobra 148, 102" whip.
(SWR is about 1.1 - 1.2)



Base will talk and receive about 1-2 miles tops.
Mobile will talk and receive about 1-12 miles.

Here is the weird part:

The base can not hear me. Even within half a mile, its just barely moving the meter.

I changed antennas to a homemade dipole, and samething. Also changed to a mag mount with a trucker type antenna... samething!!

The funny thing here is.... I can get radio checks here all day long here on my base. As long as its within 2 miles. The base seems to be working fine.
So where is the problem ??

Anyone please ?? ??

 

[fodendaf]

try the uniden mobile, if it works then you know your base aerial or power supply is at fault. If the power supply is at fault then replace it with a car battery.
bring both radios mobile then try the cobra talking to someone. call them on your mobile fone and swap over to the uniden if they can still hear you then you know your output power is good and the radio is just probably deaf which is not an expensive repair. there are many other posts on this site explaining about what parts to replace but it is beyond my experience.

 

[Captain Kilowatt]

The base sounds like the receiver is toasted. If the SWR is good that generally (but not always) means the antenna/coax is OK so that just leaves the receiver. Swap radios and see what happens.

 

[Marconi]

Was the dipole close to the steel shed too?

Check the K40 on your mobile and also move away from the shed, see if it might be the antenna's location. Sometimes nearby all metal structures can seem to suck the effectiveness right out of an antenna unless you can get high above them.

There are areas of Earth that are called "dead spots" and can really play havoc on antenna performance. Again, try the mobile idea above as close to the shed as possible and then drive off aways and compare.

You also say the meter on the base barely moves with your mobile, even within 1/2 mile, and the signals work OK with other radios from the freeway, right? How do you explain that?

 

[Remo]

You also say the meter on the base barely moves with your mobile, even within 1/2 mile, and the signals work OK with other radios from the freeway, right? How do you explain that?

thats exactly my question here.

if im in my mobile talking to the base here (i have a camera setup on the base to check it) i cant really hear myself, nor does the meter really even move. and this is at a distance of maybe 1000 feet.

the mobile seems to work just fine. i can get radio checks all day long, and have no problem shooting skip,

the base seems to work fine, as i can also get radio checks here, as long as they are within a mile or two.

problem is, i just cant seem to talk from the mobile to the base !
see why im confused?

 

[Marconi]

Well Remo, IMO either Captain Kilowatt is right or your base is sitting on a dead spot.

 

[Captain Kilowatt]

Well Remo, IMO either Captain Kilowatt is right or your base is sitting on a dead spot.

While it is true that radio "dead spots" do seem to exist, I highly doubt that being within 1000 feet of a receiver will result in nothing heard even if the receiver was in a dead spot. Unless of course the entire antenna and receiver were enclosed in a faraday cage.

 

[Remo]

but if the base receiver is dead, why am i able to hear the radio checks from the highway about a mile away ?

 

[Marconi]

but if the base receiver is dead, why am i able to hear the radio checks from the highway about a mile away ?

I'm cornfused' too.

 

[BOOTY MONSTER]

does that metal roof have a peak in the middle of it ? if so is the mag mount on the edge of one side ? if yes to both questions may be the metal roof blocking/reflecting a lot of your signal . can you post a pic of the antennas on the roof showing where and how its mounted ?

 

[Remo]

the roof of the shed is flat.

when i get home, im gonna do some more checking to see what the deal is.

 

[packrat]

You might just be way too close at 1000 feet. Might be overshooting the antenna. Try getting a mile or two away and try again.

PR

 

[Marconi]

but if the base receiver is dead, why am i able to hear the radio checks from the highway about a mile away ?

Maybe the radio is not completely dead, or if it's a "dead spot," that does not necessarily mean the area is totally dead.

the roof of the shed is flat.

when i get home, im gonna do some more checking to see what the deal is.

You might just be way too close at 1000 feet. Might be overshooting the antenna. Try getting a mile or two away and try again.

PR

Maybe Packrat is making a good point. There is a theory for 1/4 wave radiators that when the ground plane starts to approach a 1/2 wavelength but is less than infinite the RF from the ground plane will predominate and radiate almost straight up.

I have never experienced this, but maybe Remo's setup, with the large GP, is acting just like a Near Vertical Incident Skywave (NVIS) antenna. I think theory tells us about NVIS antennas that they work very poorly at CB frequencies, so maybe this is what is happening, the RF is radiating mostly horizontal signals and is radiating skyward.

If this is what is happening to Remo, then moving further away from the shed probably won't produce better reception or signals.

 

[W5LZ]

Have you tried swapping radios to see what happens?
Have you tried putting that K-30/K-40 on your mobile with the radio you have in the mobile? Same sort of reception?

Trying to narrow the problem down would certainly seem like a fairly easy thing to do, and will tell you much more than all the speculating being done here. Try it, see what happens.
- 'Doc

 

[Remo]

Problem SOLVED

Ok, so I feel like a complete idiot now. The problem was that the radio in the mobile (cobra 148) was on a different freq than the base!

I have 2 extra switches on it for extra freqs, and I didnt notice on was flipped up, and therefor putting me on different freq than what I thought I was!!! :headbang:headbang

Sorry for the hassle guys. Thanks for comebacks though!