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setting up a radio work shop

daddyo

Member
Jan 23, 2016
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I'm setting up my work shop for working on cb's. Now my question is I put up a 102" whip on chimney on house about 18' from ground and put another 2' firestick in work shop. Antennas are 25' apart radios in shop are only 2' apart when I key mic on cobra25 w/ ranger 158 mic it squels real bad until I turn mic gain down to half cobra29 has ranger sra198 n/c mic when keyed does not squel even when put on cobra25. Is it the 158 mic or is my setup not quite right. Swr's are alittle high but it gets out about 4 miles with good audio just trying to get started I will upgrade all of this later. Any suggestions would be appreaciated. daddyo
 

Midnight Special, yes I am testing radios but also wanted to be able to hear them to see the difference in audio being louder or not. And if any noise or whine's are present. Thanks daddyo
 
Thanks, robb I will do that. I was just wanting to hear them on the air to check my work as you said. Radio shack here in town is getting irf-520's erf-2030's and all companion parts from a outside source so I'm buying some to try different things and to see how it affects the final outcome. I fixed the whine and heat issue I had the other day again just played with different caps & resistors. Then it was fixed. Thanks daddyo.
 
"...A dummy load is a device used to simulate an electrical load, usually for testing purposes. In radio a dummy antenna is connected to the output of a radio transmitter and electrically simulates an antenna, to allow the transmitter to be adjusted and tested without radiating radio waves."

IOW, a dummy load connects to the radio's output PL-239 connector and always has a perfect SWR but does not work like an antenna; it does not radiate radio waves. But you can key the mic and test the radio with test equipment without hurting the radio's final transistors.

If you are trying to use an antenna instead of a dummy load, then you won't get honest readings, because any antenna reacts differently at different freq's. So, a dummy load is used because it always has a perfect SWR no matter what freq you are using. Because it doesn't change or react, the reading that you will get from your watt meter will be as accurate as the quality of your watt meter has.

http://www.dxengineering.com/parts/mfj-260c?seid=dxese1&gclid=CMzf1Jfy88oCFdcTgQod9c8GHw

I cannot see how you can begin to build up a radio workshop without one.
Impossible . . .
 
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I'm setting up my work shop for working on cb's. Now my question is I put up a 102" whip on chimney on house about 18' from ground and put another 2' firestick in work shop. Antennas are 25' apart radios in shop are only 2' apart when I key mic on cobra25 w/ ranger 158 mic it squels real bad until I turn mic gain down to half cobra29 has ranger sra198 n/c mic when keyed does not squel even when put on cobra25. Is it the 158 mic or is my setup not quite right. Swr's are alittle high but it gets out about 4 miles with good audio just trying to get started I will upgrade all of this later. Any suggestions would be appreaciated. daddyo

Are you intending charging people for repairing CBs?
 
IOW, a dummy load connects to the radio's output PL-239 connector and always has a perfect SWR but does not work like an antenna; it does not radiate radio waves.

Actually it does. I had a 50 Ohm dummy load on my Flex 6500 transverter socket for transmitting and another 50 Ohm dummy load on Antenna 1 socket used for receive to demonstrate full duplex operation. Even though the transverter was only outputting 100mW into a 50 ohm 1/4 watt resistor soldered across a BNC connector and the receive antenna was a 50 ohm dummy load it still received it as a strong 0dBm strength signal (for reference S9 is -73dBm or 20 million times weaker)

Plenty of people have reported having QSOs on a dummy load when they've forgotten it was still plugged in.
 
m0gvz, i did that a few weeks ago there was a truck driver in a shopping center 3 blocks away and he could hear everything i was doing,, testing out a radio into my cantenna and he thought i was going thru base antenna.....
 
Actually it does. I had a 50 Ohm dummy load on my Flex 6500 transverter socket for transmitting and another 50 Ohm dummy load on Antenna 1 socket used for receive to demonstrate full duplex operation. Even though the transverter was only outputting 100mW into a 50 ohm 1/4 watt resistor soldered across a BNC connector and the receive antenna was a 50 ohm dummy load it still received it as a strong 0dBm strength signal (for reference S9 is -73dBm or 20 million times weaker)

Plenty of people have reported having QSOs on a dummy load when they've forgotten it was still plugged in.
Yes, I know they can. Thanks for bringing that up. But not anywhere near what an antenna will. This is getting off the real point; isn't it?

He needs to understand - since he is trying to get something together - what he needs and why he needs it.
 
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Just working with what I have for now. I completely understand what I need but as I said before I am laidoff from work until the end of march funds are limited and I do have a 5w dummy load I ordered a few days back I use it but I also like to hear them on the air. As far as charging people to work on cb's I just want to help people out if I can I might make a few dollars here and there but I'm not going to get into it as deep as you guys seem to be. Can't knock a guy for trying.
 
Not knocking you one iota; wouldn't do that.
You must realize - however - that you must understand just what these pieces of gear are and just exactly why they are intended for.

Hearing a radio through another radio gives you absolutely no idea if the radio is a dirty bird - or not. You simply would be making a huuuuuge mistake to judge your adjustments to some radio you are working on by simply listening to it on another radio. It can - and probably would be - still far out of whack. Nor would I recommend that method to anyone for those reasons.

A scope, dummy load, and a RF pickup are really more important than a watt meter, as far as getting any kind of useable information on tuning a radio. I would not even work on someone else's radio at all if I didn't have those - if that was the case. You really wouldn't be helping them at all, regardless if you can do a swing mod or put it a mosfet. In truth, you would be doing them harm in both the short and long view . . .
 
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Not knocking you one iota; wouldn't do that.
You must realize - however - that you must understand just what these pieces of gear are and just exactly why they are intended for.

A scope, dummy load, and a RF pickup are really more important than a watt meter, as far as getting any kind of useable information on tuning a radio. .

A good calibrated frequency counter is absolutely required if you are doing any kind of alignments. If you are not trained to at least an electronics technician level I would recommend that you do not start modifying or aligning any radios.
 
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m0gvz, i did that a few weeks ago there was a truck driver in a shopping center 3 blocks away and he could hear everything i was doing,, testing out a radio into my cantenna and he thought i was going thru base antenna.....
If you had the lids off of the radio you will be on the air for some distance.
 
As far as charging people to work on cb's I just want to help people out if I can I might make a few dollars here and there but I'm not going to get into it as deep as you guys seem to be. Can't knock a guy for trying.

If you don't understand why you're getting squealing and you don't even have rudimentary things like a dummy load which is something every shack should have you don't want to be putting your hands inside other peoples radios because quite frankly you lack basic knowledge and are at risk of following the "A little knowledge is a dangerous thing" rule. Instead build your workshop and concentrate on buying rigs that don't work and making them work again. Not only will you learn a lot but you should be able to make some money selling them when they work and all without the risk of losing friends or getting a reputation locally as a repair shop where rigs leave in worse condition than when they arrive which will kill it before it ever gets past first base.

Learn to walk first.
 

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