-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim
Brown
Sent: Tuesday, December 22, 2015 10:33 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] RFI in audio chain
>Yes. I will again strongly urge Jan to STUDY my tutorial on Po
On Tue,12/22/2015 5:57 PM, Don Wilhelm wrote:
That 30-50 ohms resistance may be a shack safety problem. Your shack
ground rod must be connected to the Utility ground rod by a heavy
conductor (#6 minimum, but #4 preferred).
Yes. I will again strongly urge Jan to STUDY my tutorial on Power,
G
Jan,
That 30-50 ohms resistance may be a shack safety problem. Your shack
ground rod must be connected to the Utility ground rod by a heavy
conductor (#6 minimum, but #4 preferred).
That ground is only for AC safety and some part of lightning protection.
It does not present an effective RF G
This is a wrap-up post to the discussion about RFI feedback into the
audio of my K3.
First, I want to thank everyone who offered suggestions, most of which I
tried to follow up.
After numerous failures, I managed to lure a local guru--a ham who makes
his living getting RF and audio things to
Uglies DON'T WORK WELL
Use ferrite
Jim
W6AIM
.
Original message
From: Jan Ditzian
Date: 11/22/2015 4:33 PM (GMT-08:00)
To: Elecraft@mailman.qth.net
Subject: Re: [Elecraft] RFI in audio chain
In response to the balun recommendation from several hams, I apologiz
h.net
Subject: Re: [Elecraft] RFI in audio chain
Jan
The easiest, quickest and cheapest method is to wind yourself an “ugly balun”
in your coax cable line.
It must be located OUTSIDE your shack to choke the common mode currents from
entering the shack.
Wind about 15 - 20 turns of your coax on a 6” PVC
I will continue to try solutions, but they seem to be getting random.
I found my long 50-ohm coax run to the 80-meter vertical. It ends in a
DX Engineering 1:1 balun with terminals. I have tried this before. I
connected one of the terminals to the vertical and the other to the
ground base.
Gee whiz -- I go into the hospital for a week and thing go WAY off the
rails! Thanks to W4TV and W3FPR for intelligently moving the discussion
back on track.
Questions:
EXACTLY what is the configuration the the "vertical antenna?
Quarter-wave with radials or half wave without radials? How m
You have now eliminated the problem from causes in your station
layout and the antenna/feedline to the K3 - as the complete same
using the 730 works fine. True?
Not true ... the Icom uses an electret mic, not the dynamic Audio-
Technica. If the microphone is wired correctly, the issue is in
t
1. I have printed out Joe's directions and placed them in the K3 file -
for future reference.
2. Is you K3's chassis connector OK - loose ground?
3. Have a proper ground from the K3 to your station ground?
4. You are using the same feedline to test the K3 as used to test the
730? If not - do so.
I have followed Joe's directions: I found a two-conductor-plus-shield
cable in the junk box (aka hamshack) and wired it as he instructed. It
works properly as a microphone, but still has extreme RFI on 75 phone.
I rechecked my other microphone, a Ten Tec Model 705 with a home made
adapter fro
Jan,
On an XLR pin 1 is shield/ground, pin 2 is mic hot, pin 3 is mic
return. The proper connections (as I described in another forum
a couple days ago) are:
For *any* microphone with a 3pin XLR one needs a cable with XLR
on one end (for the "professional" mic) and a Foster plug for
the rig.
Joe and Bob,
I decided to chop things up to see what was inside. I found a
surprising result:
The microphone wire is a two-conductor wire, consisting of a single
insulated conductor and a shield. At the microphone XLR end the single
wire is connected to pin 2. At the rig end, this same wi
Joe,
Thanks for straightening that out. I did not recall which pins and lugs
to tell him to use.
Bill W2BLC - K-Line
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I don't like 'ugly baluns', especially for the lower bands. If you do use one,
you should wind the coax as a single layer solenoid, not a "hank" of coax.
Also, as someone else suggested, you need a large number of turns for it to be
effective on 80 m.
Vic 4X6GP/K2VCO
> On 23 Nov 2015, at 2:32
A vertical should have an RF choke at the feed point. This is sometimes called
a 'balun', but in this application it is common mode choke.
To reduce RF pickup with ferrite beads or toroids at HF, especially on the
lower bands, you need to wind multiple turns around the ferrites. Also they
shoul
*NO!* Do not connect the shield to *either* pin 1 (mic hot) or pin 7
(mic return) of the Foster connector. If you must connect the shield,
connect it to the *shell* of the Foster connector (chassis). Chassis
*with no intervening component/impedance* is the only appropriate
connection for a shie
And the shield should be connected at one end only, preferably the
signal receiving end or mike connector at the radio. That way, there
is no current flowing on the shield.
*Except* with a transmitter. Connecting the shield to one side of the
mic element provides a path for any common mode cu
And if you happen to have the connector(s) that do not have a dedicated
ground terminal, then connect the shield and white wire to pin #1, at
the radio end of the cable and leave the shield floating or not
connected at the mike end.
73
Bob, K4TAX
On 11/22/2015 8:20 PM, Bob McGraw - K4TAX wrot
Oh but it is. There is pin #1, pin #2 and pin #3 plus a ground
terminal. The cable between the mike and radio should be 3 conductor
shielded. Thus - Red, Black, White and shield. And the shield should
be connected at one end only, preferably the signal receiving end or
mike connector at th
There is nothing better than "doing it right"! Great job Phil.
73 Bob, K4TAX
On 11/22/2015 7:59 PM, Phil Anderson wrote:
Hi Jan,
I'm guessing, as several others have discussed using a balun at the
base of the vertical, that the problem is interference running on the
outside of the coax fe
I may be way off on this, but I would be into that mic and the connector
before I got involved with baluns, ground straps, and all the
complicated stuff.
Make sure your mic wire's shield is properly grounded (both ends) -
remember, XLR was not designed for RF use.
Bill W2BLC K-Line
___
Hi Jan,
I'm guessing, as several others have discussed using a balun at the base
of the vertical, that the problem is interference running on the outside
of the coax feed. I'm using a STEPPir vertical for 40 through 10. I
tried several baluns with no satisfying success. I then decided to build
You more likely need a common mode choke on the feed line close to the
radio. Perhaps where the feed line enters the house. A common mode
choke can be also known as "The Ugly Balun"
http://www.hamuniverse.com/balun.html or can be a series of ferrite
beads on a section of coax.
Also see Mode
I have a 67-foot elevated vertical that I can use on 80 and 40, and
it works fine on CW. However, on SSB, both bands, there clearly is
feedback; there is no feedback on the other bands where I use a C3
yagi.
Elevated verticals will treat the [outside of the] feedline as a
random length radial.
In response to the balun recommendation from several hams, I apologize
for forgetting to mention that the vertical has an "ugly balun" both at
the antenna and near where the feedline enters the house.
Part of the reason I put the question to this group, after first
thinking that the amps group
Jan
The easiest, quickest and cheapest method is to wind yourself an “ugly balun”
in your coax cable line.
It must be located OUTSIDE your shack to choke the common mode currents from
entering the shack.
Wind about 15 - 20 turns of your coax on a 6” PVC pipe. This will give you
about 2500 ohms
Jan,
Toroids on the mic cord may help, but the real solution is to eliminate
the RF on the outside of the coax shield in the antenna field.
Refer to the writings of Jim Brown K9YC for effective baluns (he prefers
common mode chokes because balun is not a specific thing - some good,
some bad).
I have a problem that appears to be changing, but I could use some
help. The problem is RFI in the audio input (microphone input) when I
use my vertical antenna on 40 meters. Here is a rundown of what has
happened:
I have a 67-foot elevated vertical that I can use on 80 and 40, and it
works
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