How do you test an ANALOG RF meter?

Cobra 29 cb. The meter never moves on receive, transmit, or ever. An
external SWR meter confirms its transmitting and I can hear my test
signal on receive. Sort of tells me the meter is blown. I have never
tested a meter. What kind of resistance should it have across the
terminals? Can I apply a 1.5v AA battery to it to see if it moves?

I also want to know if I can see the receive and transmit on a
multimeter? If so, do I use the AC or DC setting?

Thanks

 

[Fox's Mercantile]

On 10/11/19 5:40 PM, tubeguy@myshop.com wrote:

Cobra 29 cb. The meter never moves on receive, transmit, or ever. An
external SWR meter confirms its transmitting and I can hear my test
signal on receive. Sort of tells me the meter is blown. I have never
tested a meter. What kind of resistance should it have across the
terminals? Can I apply a 1.5v AA battery to it to see if it moves?

A battery itself is a good way to make sure the meter is blown.

I also want to know if I can see the receive and transmit on a
multimeter? If so, do I use the AC or DC setting?

Use a DVM set on the DC 1 mA range across the meter.
If you read nothing, then something else is dead/broken inside the
radio.



--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[Ralph Mowery]

In article <ur02qe1f2em67526mkvjvq3r94jsq0bjvb@4ax.com>,
tubeguy@myshop.com says...

Cobra 29 cb. The meter never moves on receive, transmit, or ever. An
external SWR meter confirms its transmitting and I can hear my test
signal on receive. Sort of tells me the meter is blown. I have never
tested a meter. What kind of resistance should it have across the
terminals? Can I apply a 1.5v AA battery to it to see if it moves?

You can use the battery only once. It will probably slam the pointer
over to the end and ruin the meter. Most likely the meter will only
have a full scale of 1 miliamp or even less.

Try hooking a digital meter in the voltage or miliamp range across the
meter to see if it shows anything. YOu may be able to disconnect one
wire going to the meter and measuring it with the digital meter set to
ohms. Just tap the leads to see if the meter moves and it may move the
wrong way.

 

On Fri, 11 Oct 2019 18:14:11 -0500, Fox's Mercantile <jdangus@att.net>
wrote:

On 10/11/19 5:40 PM, tubeguy@myshop.com wrote:
Cobra 29 cb. The meter never moves on receive, transmit, or ever. An
external SWR meter confirms its transmitting and I can hear my test
signal on receive. Sort of tells me the meter is blown. I have never
tested a meter. What kind of resistance should it have across the
terminals? Can I apply a 1.5v AA battery to it to see if it moves?

A battery itself is a good way to make sure the meter is blown.

I also want to know if I can see the receive and transmit on a
multimeter? If so, do I use the AC or DC setting?

Use a DVM set on the DC 1 mA range across the meter.
If you read nothing, then something else is dead/broken inside the
radio.

I did what you said. I do get a reading on the DVM. So the meter on the
radio is blown. Ebay has lots of them for $10 or less. So I'll replace
it. Aside from this meter and one bad segment on the channel selector,
the radio receives and transmits well. Now, if only I could find someone
on the CB to talk to....... This radio also has the weather band, so
that will come in handy in my car. I always like to keep track of the
weather, and I dont use a smartphone. My old flip phone is all I'll ever
need.

By the way, this Cobra 29 was made in 1995, so its one of their "newer"
radios.

Aside from the fact that hardly no one uses the CB anymore, I was at a
truck stop last week, near a big city. I was surprised to see how much
CB gear is still being sold there. Apparently the big cities still have
CB traffic. Probably mostly truckers. But it sure aint what it was in
the 70s.

 

[Fox's Mercantile]

On 10/12/19 8:41 PM, tubeguy@myshop.com wrote:

Apparently the big cities still have CB traffic. Probably
mostly truckers. But it sure ain't what it was in the 70s.

Thank God.



--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[Paul Drahn]

On 10/11/2019 3:40 PM, tubeguy@myshop.com wrote:

Cobra 29 cb. The meter never moves on receive, transmit, or ever. An
external SWR meter confirms its transmitting and I can hear my test
signal on receive. Sort of tells me the meter is blown. I have never
tested a meter. What kind of resistance should it have across the
terminals? Can I apply a 1.5v AA battery to it to see if it moves?

I also want to know if I can see the receive and transmit on a
multimeter? If so, do I use the AC or DC setting?

Thanks

Confusing post. Are you referring to the physical moving hand meter
itself, or are you referring to the whole box?

If the meter shows the full scale sensitivity somewhere on the face, you
can compute the resistance necessary to put in series with a 1.5 volt
battery and correctly apply the + and - to the meter movement and see if
it moves.

Alternately, put a 10k ohm resistor in series with your Ohmmeter leads
and test the combined resistance to see if you get 10k Ohms. If so, then
the meter is ok.

Paul

 

On Sun, 13 Oct 2019 01:52:43 -0500, Fox's Mercantile <jdangus@att.net>
wrote:

On 10/12/19 8:41 PM, tubeguy@myshop.com wrote:
Apparently the big cities still have CB traffic. Probably
mostly truckers. But it sure ain't what it was in the 70s.

Thank God.

Since we are commenting on CB use. I too am glad all the kids and idiots
are gone on the CB Band. These days they're all on facebook instead.
I do tend to not understand what happened to all the truckers on the CB?
Channel 9 is really no longer needed. For emergencies, people can just
use their cellphone to call for help now. But truckers cant get instant
road conditions up ahead, or smokey reports on their phones. And you
cant talk to other truckers near you (unless you know all of them and
have their phone numbers). So for truckers or anyone on the road, the CB
still has a lot to offer. Not to mention its against the law to use a
cellphone while driving in many places now. But not the CB.

Two things I hope to never hear on the CB again are those annoying Roger
Beeps, and the echo mics. Neither served any purpose and just made the
CB hard to hear or worse.

One other benefit of CB was that a lot of times in the past, I'd just
talk on the CB to keep myself awake while driving late at night. And I
had a lot of interesting conversations, as well as finding out where the
truck stops are, where to get a good meal, and learning interesting
facts about the area I'm driving in.

I miss the good old days of CB. But not it's later days that partially
caused it's demise due to abuse. Then too, the internet has been on a
similar downward spiral. The early internet was both fun and useful.
These days its been taken over by that repulsive Facebook and if you
want anything useful, such as a repair manual, be prepared to give away
your identity to some crooks, and pull out your credit card. Or just
waste hours sorting thru all the bogus claims that say "FREE" manual or
whatever.