Image

Search found 177 matches

by Bluerunner
Saturday, 17 June 2017, 23:01 PM
Forum: ANTENNA HELP
Topic: Dipole on 2x4
Replies: 3
Views: 1112

Re: Dipole on 2x4

102" will be a little too short. Add a piece of stiff wire to the end to get to 108". Wrap the end of the wire around the whip and you can slide it up & down to change the length for tuning.
by Bluerunner
Thursday, 20 April 2017, 21:05 PM
Forum: MOBILE/BASE INSTALL HELP
Topic: Nothing but noise after new install...
Replies: 13
Views: 1628

Re: Nothing but noise after new install...

Is it only noisy with the engine running?

by Bluerunner
Wednesday, 08 March 2017, 19:00 PM
Forum: ANTENNA HELP
Topic: Analyzer Question
Replies: 14
Views: 1979

Re: Analyzer Question

If you are doing anything that needs an antenna analyzer like making home made antennas then you want the MFJ-213, you really want the built in frequency counter. Most of us get by just fine with just an SWR meter. I started with the MFJ- 207, later added an external frequency counter. Too much equi...
by Bluerunner
Saturday, 14 January 2017, 16:14 PM
Forum: GENERAL QUESTIONS
Topic: Heard broadcasting Stations
Replies: 2
Views: 326

Re: Heard broadcasting Stations

Is the cobra tweaked & tuned?

Might have lost some selectivity if the tuning was extreme / broadbanded.

Likely receiving a harmonic of the Japanese stations frequency.
by Bluerunner
Saturday, 14 January 2017, 8:27 AM
Forum: OTHER TECHNICAL QUESTIONS
Topic: Antenna switches used in reverse
Replies: 7
Views: 1039

Re: Antenna switches used in reverse

Any switch should do. Some are the "shorting" type. They ground the antenna / radio to ground when that position is not selected. I sometimes run multiple radios on a 4 way non-grounding switch, and 4 antennas on another 4 way switch. Been wanting to try a grounding switch. Might give more isolation...
by Bluerunner
Thursday, 05 January 2017, 6:17 AM
Forum: ANTENNA HELP
Topic: Base. Antenna help for new guy
Replies: 18
Views: 1506

Re: Base. Antenna help for new guy

What is your noise level? How high is it in S units when there is no talking on the channel? Does the noise level stay the same during different times of the day? A high noise level will plug up your ears. It is amazing how much noise common household devices make. Turn everything in the house off a...
by Bluerunner
Sunday, 01 January 2017, 20:48 PM
Forum: ANTENNA HELP
Topic: Aurora setup
Replies: 12
Views: 1691

Re: Aurora setup

A horizontal dipole transmits & receives from the broadside. Very little signal is received or transmitted off the ends. So with a horizontal dipole you lose signal strength off the ends which can reduce interfering signals from those directions improving the reception from the broadsides. An invert...
by Bluerunner
Sunday, 01 January 2017, 10:52 AM
Forum: GENERAL DISCUSSIONS
Topic: Coax Length
Replies: 25
Views: 941

Re: Coax Length

Sorry, I just noticed some questions on my Shorted stub post. Power Level Question: The shorted quarter wave stub is good for any power level the coax used to make it is rated at. Only out of band frequencies / harmonics go into it and that is a very small (tiny) percentage of your total transmitted...
by Bluerunner
Friday, 30 December 2016, 18:01 PM
Forum: SHOOTING SKIP
Topic: Longest Skip on Lowest Power?
Replies: 103
Views: 3312

Re: Longest Skip on Lowest Power?

Back in the 70's, when you still had to buy a license for CB, I used to talk skip all over the country with an old 2.5 watt (5 watt peak modulation) crystal controlled 6 channel mobile CB (brand unknown). I made it a base station by running it off of a 1 amp battery charger / maintainer that I built...
by Bluerunner
Monday, 26 December 2016, 13:05 PM
Forum: ANTENNA HELP
Topic: Directivity from multiple base antennas?
Replies: 9
Views: 1379

Re: Directivity from multiple base antennas?

Thanks for the model DB. It shows something is going on theoretically anyway. One of those shorting antenna switches my help avoid some problems too. I'll put one on my Christmas list. A FS meter just gets pegged and I would have to use an attenuator of some sort. Just figured a power meter might be...
by Bluerunner
Sunday, 25 December 2016, 23:10 PM
Forum: ANTENNA HELP
Topic: Directivity from multiple base antennas?
Replies: 9
Views: 1379

Re: Directivity from multiple base antennas?

I wonder... If I put a power meter on the unused antenna cable "backwards", terminated in a dummy load, would it indicate an appreciable amount of power consumed from the nearby active antenna? Maybe a 5 watt power meter measuring the field absorbed from the active antenna 20-30 ft away energized wi...
by Bluerunner
Saturday, 24 December 2016, 9:32 AM
Forum: ANTENNA HELP
Topic: Directivity from multiple base antennas?
Replies: 9
Views: 1379

Directivity from multiple base antennas?

Like many I have three (sometimes more) base station antennas, one starduster, one half wave horizontal dipole and a end fed vertical sleeve. They are all about the same height and spaced from 20 to 35 feet apart. I have often wondered if the unused antennas could be acting like directors or reflect...
by Bluerunner
Wednesday, 30 November 2016, 5:44 AM
Forum: GENERAL DISCUSSIONS
Topic: Receive vs Transmit Power
Replies: 6
Views: 495

Re: Receive vs Transmit Power

Putting you mouth where your ears won't go.
by Bluerunner
Saturday, 26 November 2016, 16:45 PM
Forum: RADIO MODIFICATIONS
Topic: Galaxy 88
Replies: 19
Views: 1197

Re: Galaxy 88

Try an external speaker in case the one in the radio is failing.

-- Saturday, 26 November 2016, 17:49 PM --

Checked the microphone & wiring? Many have a audio disconnect on transmit in the mic & wiring switch. Might be shorted to something making a high resistance connection.
by Bluerunner
Saturday, 26 November 2016, 7:55 AM
Forum: ANTENNA HELP
Topic: SWR STAYING OVER 2
Replies: 7
Views: 605

Re: SWR STAYING OVER 2

What kind of vehicle? Where is the antenna mounted?

-- Saturday, 26 November 2016, 8:58 AM --

Are you re-calibrating the SWR meter every time you make a measurement?
by Bluerunner
Friday, 25 November 2016, 19:26 PM
Forum: OTHER TECHNICAL QUESTIONS
Topic: Portable Mobile in a Box Backpack
Replies: 14
Views: 1087

Re: Portable Mobile in a Box Backpack

Might want to look around for one of those DC to DC boost / step=up converters.
It will let you keep getting 12VDC to the radio as the battery runs down to maybe 9VDC.
by Bluerunner
Friday, 25 November 2016, 19:01 PM
Forum: GENERAL QUESTIONS
Topic: Roadtalker Question???
Replies: 3
Views: 236

Re: Roadtalker Question???

I have the schematics for the 0700 roadtalker. PM me with your email address and I can send them to you. It is a 6mb PDF file. -- Friday, 25 November 2016, 20:06 PM -- Ooops. My Schematics are for the 934.38270700 I could only remember the last four digits of the number you posted and thought I had ...
by Bluerunner
Saturday, 22 October 2016, 19:50 PM
Forum: RADIO MODIFICATIONS
Topic: Cb alternator noise
Replies: 44
Views: 1489

Re: Cb alternator noise

I run my power through RG8 coax. One piece is good enough for powering a radio. +12vdc on the center and - 12vdc ground on the shield. It becomes a very long linear capacitor that has low inductance to noise .
by Bluerunner
Monday, 17 October 2016, 17:50 PM
Forum: GENERAL DISCUSSIONS
Topic: Coax Length
Replies: 25
Views: 941

Re: Coax Length

I am a firm believer in the shorted 1/4 wave stub. I think guys may be tired of hearing about it. Often thought I should change my handle to "1/4 wave stub". Not good for multi band antennas like the hams run, but for single band CB it works like a charm. DO NOT USE FOAM INSULATED COAX TO MAKE A STU...
by Bluerunner
Sunday, 16 October 2016, 21:45 PM
Forum: GENERAL DISCUSSIONS
Topic: Coax Length
Replies: 25
Views: 941

Re: Coax Length

Common mode currents (CMC), unwanted Rf flowing on the surface of the coax shield explains many of the observed problems that seem to be resolved by coax length. CMC can make your SWR & power meters lie to you. This is especially a problem with the end fed 1/2, 5/8 etc wave antennas. A simple air wo...
by Bluerunner
Thursday, 06 October 2016, 16:38 PM
Forum: ANTENNA HELP
Topic: vertical beam tower clearance
Replies: 6
Views: 514

Re: vertical beam tower clearance

The supporting mast is already part of the tower and that extends into the middle of the array. I think the tower being wider is insignificant. Any beam-width aberrations cause by all the "untuned" metal in the heart of the antenna most always very close to the hot / driven element is likely unavoid...
by Bluerunner
Monday, 03 October 2016, 19:08 PM
Forum: GENERAL QUESTIONS
Topic: I found 2 solar powered and automated CB boxes in some woods
Replies: 63
Views: 3349

Re: I found 2 solar powered and automated CB boxes in some w

I forgot about the threats & name calling. That is a pretty good clue they are up to no good.
by Bluerunner
Sunday, 02 October 2016, 7:41 AM
Forum: MISC CHAT
Topic: Show your Every Day Carry gear for survival
Replies: 3
Views: 477

Re: Show your Every Day Carry gear for survival

I have a 40 ch Cb walky talky with nicad batteries and a rolled up end fed wire antenna that can be tossed up in a tree. Also a pair of GMRS/FRS walky talkies for radio gear. I found a Volkswagen solar 12 volt solar panel panel that is small & strudy for battery charging. I use one of those metal fr...
by Bluerunner
Saturday, 01 October 2016, 17:33 PM
Forum: GENERAL QUESTIONS
Topic: I found 2 solar powered and automated CB boxes in some woods
Replies: 63
Views: 3349

Re: I found 2 solar powered and automated CB boxes in some w

Sounds like that is a low power rig. Maybe it is someones idea of a CB beacon station. I often wished there was such a thing in my area when tuning antennas for gain & rejection or working on receivers. No such thing as a legitimate CB beacon station and if there were any the low power of CB would d...
by Bluerunner
Thursday, 15 September 2016, 15:49 PM
Forum: ANTENNA HELP
Topic: Mobile antenna for Base setup
Replies: 10
Views: 676

Re: Mobile antenna for Base setup

A small antenna will never be as good as a full size one. Use the biggest that you can fit / afford for the base station.
by Bluerunner
Saturday, 10 September 2016, 4:18 AM
Forum: GENERAL DISCUSSIONS
Topic: Is CB dying?
Replies: 47
Views: 1428

Re: Is CB dying?

Once upon a time it cost $30 to get a CB license and the FCC actively enforced the rules. The FCC routinely served search warrants for illegal linears and prosecuted violators. Guys talked local and occasional skip with 2 watts (4 total modulated). Good performance depended on skill of antenna desig...
by Bluerunner
Monday, 15 August 2016, 7:06 AM
Forum: GENERAL QUESTIONS
Topic: What do you consider essential to your workbench?
Replies: 31
Views: 1284

Re: What do you consider essential to your workbench?

If you like to build things check out circuits for the LM386 IC. It is an audio amp chip that takes a very low simple parts count to make a small amplifier for signal tracing. Build two amps and use one for a signal generator by giving it a little feedback to the input from the output through a vari...
by Bluerunner
Wednesday, 10 August 2016, 7:47 AM
Forum: OTHER TECHNICAL QUESTIONS
Topic: What's the best way to find a cold solder connection?
Replies: 17
Views: 866

Re: What's the best way to find a cold solder connection?

I have had similar problems with radios. Half the time I discover that someone had been tuning on them and gotten the oscillator at a critical point where changing the temp, turning it off & on, pressure, on the board etc was enough to detune the oscillator. Consequently I tune up the synthesizer os...
by Bluerunner
Wednesday, 03 August 2016, 19:57 PM
Forum: GENERAL QUESTIONS
Topic: What do you consider essential to your workbench?
Replies: 31
Views: 1284

Re: What do you consider essential to your workbench?

Something that I find very handy is a bright penlight. The kind EMTs & doctors use, with a concentrated beam. You shine it through the circuit board so you can see the component solder pads and the traces on both sides.
by Bluerunner
Friday, 29 July 2016, 5:25 AM
Forum: BASE SETUPS
Topic: DIGITAL POWER/SWR METER
Replies: 8
Views: 821

Re: DIGITAL POWER/SWR METER

Digital is good for some things, like a digital multi meter, when measuring a steady state.

However when you are measuring something that changes such as power under modulation or varies due to power supply drop analog can't be beat.
by Bluerunner
Saturday, 16 July 2016, 15:50 PM
Forum: OTHER TECHNICAL QUESTIONS
Topic: What do you really need to tune up a CB?
Replies: 4
Views: 632

Re: What do you really need to tune up a CB?

Use a Sams photofacts when possible.
Ask around if you need one. Someone might have the radio you need on a digital file.
Might help avoid a lot of headaches.
by Bluerunner
Sunday, 01 May 2016, 17:20 PM
Forum: GENERAL DISCUSSIONS
Topic: Can you remember your first CB radio?
Replies: 76
Views: 2400

Re: Can you remember your first CB radio?

I got my first CB radio around 1970. It was actually a toy GE walky talky I bought the pair of for my kids at a Goodwill store for $1. Telescopic antenna and ran on a 9 volt battery. All the toy walky talkies back then operated on CB Ch14. Pretty desperate financially back then. Two kids & no extra ...
by Bluerunner
Sunday, 20 March 2016, 5:41 AM
Forum: GENERAL DISCUSSIONS
Topic: cleaning the boards??
Replies: 10
Views: 401

Re: cleaning the boards??

Soap & water will work. However, it must be completely dry before you put the power to it. It is the only way to get the salt out if your electronics gets wet from salt water. I use it all the time to clean up computer keyboards that have had soft drinks & coffee full of sugar spilled in them. I don...
by Bluerunner
Monday, 07 March 2016, 20:03 PM
Forum: ANTENNA HELP
Topic: Antenna choke
Replies: 29
Views: 1024

Re: Antenna choke

For the CB band, 6 turns,close wound on a 4" PVC form is supposed to be the best.

There are opinions as to where to put the choke in the coax line. I put mine 9' below where the coax connects to the antenna. I have another choke where the coax enters my shack too.

Works for me just fine.
by Bluerunner
Thursday, 04 February 2016, 19:31 PM
Forum: ANTENNA HELP
Topic: SWR mistery
Replies: 7
Views: 424

Re: SWR mistery

Put a choke coil at the antenna. Some SWR meters are more easily tricked by Common mode currents than others. If you have strong common mode currents, you can't trust any of the meters to be true.
by Bluerunner
Friday, 29 January 2016, 14:54 PM
Forum: AMPLIFIERS / POWER SUPPLIES
Topic: computer power supplies
Replies: 8
Views: 741

Re: computer power supplies

Try a 150 ohm resistor across the 5VDC output. Supposed to stabilize the 12 & 5VDC output. I use a little 12 volt incandescent light bulb across the 5VDC output. Don't know wattage / type of the bulb. It was just one I had in a ready socket on the workbench and it did Ok. The computer supply is Ok, ...
by Bluerunner
Saturday, 05 December 2015, 7:22 AM
Forum: ANTENNA HELP
Topic: Base vs top loaded antenna modeled on a vehicle.
Replies: 8
Views: 568

Re: Base vs top loaded antenna modeled on a vehicle.

Thanks DB. It is a most excellent and revealing comparison.
by Bluerunner
Wednesday, 12 August 2015, 18:06 PM
Forum: ANTENNA HELP
Topic: 2 element 11 meter beam
Replies: 27
Views: 1400

Re: 2 element 11 meter beam

What kind of antenna did you build?

What are the dimensions and spacing of the elements?

Pictures will help a lot.
by Bluerunner
Saturday, 01 August 2015, 17:29 PM
Forum: ANTENNA HELP
Topic: 2 element 11 meter beam
Replies: 27
Views: 1400

Re: 2 element 11 meter beam

I built a two element quad beam. I used wire and bamboo and fed it with a 1/4 wave piece of RG59 for matching. I spaced it at only 24" between elements and tuned it for max rejection. It gave me a good one S meter number improvement on transmit but it would put a +30 loudmouth way down in the grass ...
by Bluerunner
Tuesday, 30 June 2015, 15:53 PM
Forum: BASE SETUPS
Topic: My crazy base station lol
Replies: 14
Views: 1243

Re: My crazy base station lol

Very Nice! Well done.
by Bluerunner
Tuesday, 23 June 2015, 20:28 PM
Forum: ANTENNA HELP
Topic: No SWR change??
Replies: 4
Views: 297

Re: No SWR change??

Thanks for the insight on the random length coax possibly being the cause of the observation. I went and checked that antenna again. With a 1/2 wave multiple test feedline I get X=0 on ch20 1.2 SWR and it exhibits the bandwidth you might normally expect of 1.5 at ch1 & 40. With the random length Rg8...
by Bluerunner
Tuesday, 23 June 2015, 19:48 PM
Forum: GENERAL QUESTIONS
Topic: Solar Storms
Replies: 5
Views: 370

Solar Storms

I read where we just had some solar storms that petered out Tuesday morning. A lot of auroras were reported farther south than usual.

Supposed to be another solar storm Wednesday & Thursday.

Anyone noticed any unusual skip?
by Bluerunner
Thursday, 11 June 2015, 17:01 PM
Forum: ANTENNA HELP
Topic: So I want a base setup. How do I get an antenna in the air?
Replies: 12
Views: 500

Re: So I want a base setup. How do I get an antenna in the

I made a 25' push up pole with conduit & fence rail: Fence Rail - 1 3/8" X 10' 6" EMT Conduit - 1 1/4" X 10' Fence Post - 1 5/8" X 8' Drill bolt holes so the sections overlap about 12". Seems plenty sturdy enough, especially when attached to the house eves at about 10' Mark them well so you don't pu...
by Bluerunner
Tuesday, 09 June 2015, 12:01 PM
Forum: AMPLIFIERS / POWER SUPPLIES
Topic: Unknown Amp & Power Output?
Replies: 3
Views: 226

Unknown Amp & Power Output?

I have an old tube amp, 4-6JE6 tubes, driving 6-6JE6 tubes. I can't find any brand name or Mfg info on it. Anybody have any idea of what the output power should be and how much power I should be driving it with? -- Tuesday, 09 June 2015, 14:54 PM -- Looks like it is a D&A Phantom 10 tube amp. Anyone...
by Bluerunner
Monday, 01 June 2015, 18:23 PM
Forum: GENERAL QUESTIONS
Topic: S-Meter and squelch jumps when around free wi-fi hotspots
Replies: 13
Views: 413

Re: S-Meter and squelch jumps when around free wi-fi hotspot

The stub is easy, just have to get the length exactly right.

A calculated length will do, but you really need an antenna analyzer to get it perfectly right.
by Bluerunner
Sunday, 31 May 2015, 9:16 AM
Forum: GENERAL QUESTIONS
Topic: S-Meter and squelch jumps when around free wi-fi hotspots
Replies: 13
Views: 413

Re: S-Meter and squelch jumps when around free wi-fi hotspot

Try a T connector and a 1/4 wave shorted tuned coax stub.

It will very likely filter out anything not in the CB band.
by Bluerunner
Monday, 25 May 2015, 16:24 PM
Forum: AMPLIFIERS / POWER SUPPLIES
Topic: Combine two KL-203 (get a HI-Drive 8 MOSFET Amp)
Replies: 25
Views: 734

Re: Combine two KL-203 (get a HI-Drive 8 MOSFET Amp)

I made two co-phasing cables, assembled like a V with each leg 1/4 wavelength long. Intended to use one to feed two amps and the other to combine the two amp output. Seemed cheap enough. Only have about 30' of coax involved. Got some 100 ohm non-inductive high wattage wire wound resistors to use for...
by Bluerunner
Saturday, 23 May 2015, 18:57 PM
Forum: ANTENNA HELP
Topic: quad wrapped ant
Replies: 8
Views: 480

Re: quad wrapped ant

I have seen "folded dipoles" where several wires are used as the element to increase the feed point impedance. Never thought to try it on a 1/4 wave loaded element.

Shortened Loaded antennas tend to have a low feedpoint impedance. Perhaps making the loaded element of 2,3 or 4 wires might improve it.
by Bluerunner
Wednesday, 20 May 2015, 18:25 PM
Forum: MICROPHONE INFO
Topic: Converting a M-80C/U Military Mic for CB use ?
Replies: 6
Views: 465

Re: Converting a M-80C/U Military Mic for CB use ?

Some of the older military microphones used carbon elements, and so they didn't produce any output voltage on their own. A small current had to be run through them which changed as the resistance of the carbon mic changed with the voice. Hook up your DMM on millivolts AC to the mic element wires and...
by Bluerunner
Monday, 18 May 2015, 21:39 PM
Forum: AMPLIFIERS / POWER SUPPLIES
Topic: PS-36KX
Replies: 8
Views: 344

Re: PS-36KX

If you like to build stuff then making your own voltage regulator is just fine. However I found that some very good ones from China that go 5-10 amps and 3-30 volts can be bought for much less than the price of the parts, and come with terminal blocks and on board digital voltage readouts for only p...