Brett:

On the Heil Cable, the Mic negative and shield are tied together at the XLR
End with the Mic Negative running on the shield to Flex pin 7.  So on the
XLR, only pins 1+2 are used.  Pin 3 is not connected.

Seems wrong to me.   What's the definitive answer on how it should be?   The
cable appears to be 4 conductor + shield.   What should go where?  If anyone
has a final answer, I'll unsolder both ends and rewire it properly.

Thanks in advance,

*B
KK2QQ

-----Original Message-----
From: Bret Mills [mailto:bmil...@ecso.com] 
Sent: Sunday, December 05, 2010 4:28 PM
To: 'Bradley Feldman'
Subject: RE: [Flexradio] New 5000A User - TX Audio (severe distortion)
Issues

Bradley, 
I really don't think the Shield is supposed to be connected to pin 7 that is
the MIC's (-) side NOT GROUND. The shield according to the manual is
connected to pin 5 so Pin 5 and the shell should be connected together as
the Chassis Ground. 

 Again Page 5 of the FLEX 5K's owners manual show the proper connections for
the FLEX-5000 MIC connector, I quote "Pin 5 is Chassis Ground, Pin 6 is PTT,
Pin
7 MIC (-) Pin 8 MIC (+)".

>From your previous emails I thought that is how yours was connected.

73's
Bret
WX7Y





-----Original Message-----
From: flexradio-boun...@flex-radio.biz
[mailto:flexradio-boun...@flex-radio.biz] On Behalf Of Bradley Feldman
Sent: Sunday, December 05, 2010 2:12 PM
To: 'Gerald Youngblood'; flexradio@flex-radio.biz
Subject: Re: [Flexradio] New 5000A User - TX Audio (severe distortion)
Issues

Gerald:

 

Since this cable is one I bought from Flex, how should it be wired at the
radio?   Should pin 7 the shield and the connector housing all be tied
together?   Currently the connector housing is not connected to anything and
the Mic - and the Shield are soldered to pin 7.

 

Thanks,

 

*B

KK2QQ

 

From: ger...@flex-radio.com [mailto:ger...@flex-radio.com] On Behalf Of
Gerald Youngblood
Sent: Sunday, December 05, 2010 3:54 PM
To: Bradley Feldman
Cc: Army Curtis - AE5P; flexradio@flex-radio.biz
Subject: Re: [Flexradio] New 5000A User - TX Audio (severe distortion)
Issues

 

Bradley,

 

On the fourth floor, even a connection to earth ground would not be a ground
because of the impedance of the ground conductor at RF.  This could
certainly be one of your issues.

 

With regard to the front panel microphone connection.  Be sure shield is
connected to the connector housing so that it is connected directly to the
chassis.   You might want to read about the "Pin-1 Problem" in XLR circuits.

 

http://www.rane.com/note165.html

 

You may also want to run the PR-781 balanced into the back of the radio.  A
balanced input can be a big help with RFI.  

 

Good luck,

Gerald


Gerald Youngblood, K5SDR
President and CEO
FlexRadio Systems(TM)
13091 Pond Springs Road, #250
Austin, TX 78729
Phone: 512-535-4713 Ext. 202
Email: ger...@flexradio.com
Web: www.flexradio.com <http://www.flex-radio.com/> 

Tune In Excitement (TM)

PowerSDR(TM) is a trademark of FlexRadio Systems



On Sun, Dec 5, 2010 at 2:23 PM, Bradley Feldman
<brad...@bradleyloritheo.com> wrote:

Army, et al:

At this point, I'm suspecting RF as well.   But why with so little power? In
the past, with a traditional rig  I haven't seen a problem like this, but
with the Flex 5000A, with as little as 1W out, I'm having problems.

To answer your question, the reason both temporary antennas are 30M antennas
so I can tune them for 6-40m and run low power SSB.

The MMD antenna is supposed to have a Current-Mode Discriminator which,
among other things, is supposed to prevent RF running back down the
feedline.   The dipole is a textbook dipole fed with coax.

If I transmit into a dummy load (a giant 50ohm resistor I bought at a ham
fest).  I can run full power with no problems whatsoever.  No buzzing, no
feedback, no distortion.  Audio sounds fine in another receiver.

Also, I don't have a traditional RF ground yet and the radio is on the 4th
story of a building.   I do own an artificial ground tuner, which I haven't
tried yet at this QTH.   As I've said, I'm setting up this QTH new, so I'm
trying to minimize what's necessary, rather than hooking everything up at
once.  By spring time, I'll hook up a RF suppressor Ground system (like the
one in the grounding article in the Flex Knowledge center).

I'm just trying to operate on a modest setup for the winter.   Any ideas on
how I can solve this problem and operate under these constraints?

*B
KK2QQ



-----Original Message-----
From: Army Curtis - AE5P [mailto:a...@suddenlink.net]
Sent: Sunday, December 05, 2010 1:48 PM
To: 'Bradley Feldman'
Subject: RE: [Flexradio] New 5000A User - TX Audio (severe distortion)
Issues

Hi Bradley,

I've been following your adventures this morning with your new Flex.
Everything you have said so far points to RF getting back into the
radio/computer/speakers. Your first post seemed to indicate you had transmit
audio feedback from either radio speakers that were reproducing transmit
audio because the Monitor button was activated in PSDR, or you had a second
receiver in the shack to listen to your transmit audio. If you want to
listen to your transmit audio, you MUST prevent the audio from getting back
into the microphone and creating a big feedback loop.

Since the first post, your symptoms now sound like a classic case of RF
feedback (different from audio feedback). You speak of a 30M antenna, first
an end fed model and then a dipole fed with coax. I'm a little confused
here. 30 meters does not permit SSB operation; only CW or digital. Am I
understanding you correctly? Also, a dipole is inherently a balanced
antenna, which you are feeding with coax, an unbalanced feed line. Very
common practice I grant you, but one that is also very prone to bringing RF
back into the shack. Do you have a dummy load? That would be a much better
test if you have one. Hook up the dummy load in place of the antenna, and
try things again. Remember to use headphones to listen to your transmit
audio so you don't have audio feedback, and check things out at several
different drive (output power) levels. Watch your mike levels as you
transmit, adjusting mike gain so the mike indication on the meter does not
go over 0 dB, even on voice peaks.

HF RF can cause the same type of sounds from powered speakers that VHF FM
can, so I don't think you are having an issue with the V/U modules being
keyed by mistake.

I also have a 5000 with all the goodies, and totally love it. I hope some of
these suggestions will help you get the issues worked out successfully. Let
me know please of any of these ideas work for you.

73,
Army - AE5P


-----Original Message-----
From: flexradio-boun...@flex-radio.biz
[mailto:flexradio-boun...@flex-radio.biz] On Behalf Of Bradley Feldman

Sent: Sunday, December 05, 2010 12:26 PM
To: 'Bret Mills'; flexradio@flex-radio.biz

Subject: Re: [Flexradio] New 5000A User - TX Audio (severe distortion)
Issues

One more thing.   I do also hear buzzing out of the amplified speaker for
the radio (separate AC sound amp with ground loop isolator, shielded cables)
and through the computer's speakers (also ground loop isolated).

In the past I've heard this type of buzzing with FM transmit, but never ever
with HF transmit.   Could the VHF/UHF board be keying up with the HF?

*B KK2QQ



-----Original Message-----
From: Bret Mills [mailto:bmil...@ecso.com]
Sent: Sunday, December 05, 2010 12:40 PM
To: 'Bradley Feldman'; flexradio@flex-radio.biz
Subject: RE: [Flexradio] New 5000A User - TX Audio (severe distortion)
Issues

Yep it sounds like it is wired correctly, It must be RF getting into the
Radio some how, Have you tried transmitting into a dummy load to see if
there is still distortion??

RF gets into the MIC TX circuit quite easily if you are in the "near field"
of your Antenna system and you may need to add some snap on MIX 31 ferrite
beads as I have done here that were required when I run my AMP to full power
in my situation, these are just like the ones on the Fire wire cable.

Just a few suggestions that I have ran into in my 2.5 years of running 2
FLEX 5K's and a Flex 3K here.

Hope this helps
Bret
WX7Y


-----Original Message-----
From: Bradley Feldman [mailto:brad...@bradleyloritheo.com]
Sent: Sunday, December 05, 2010 9:54 AM
To: 'Bret Mills'; flexradio@flex-radio.biz
Subject: RE: [Flexradio] New 5000A User - TX Audio (severe distortion)
Issues

The PTT is connected properly to pins 5+6.  Mic positive (XLR pin 2) is
connected to flex pin 8.   Mic negative (XLR  pin 3) and Mic Shield (XLR pin
1) are tied together at the flex side and go to flex pin 7.   The barrel on
the flex side isn't connected to anything.

Does that sound correct?

*B KK2QQ

-----Original Message-----
From: Bret Mills [mailto:bmil...@ecso.com]
Sent: Sunday, December 05, 2010 11:45 AM
To: 'Bradley Feldman'; flexradio@flex-radio.biz
Subject: RE: [Flexradio] New 5000A User - TX Audio (severe distortion)
Issues

Page 5 of the FLEX 5K's owners manual show the proper connections for the
FLEX-5000 MIC connector, I quote "Pin 5 is Chassis Ground, Pin 6 is PTT, Pin
7 MIC (-) Pin 8 MIC (+)".
Measure from the MIC itself and make sure they have the correct one
connected.

73's
Bret
WX7Y



-----Original Message-----
From: Bradley Feldman [mailto:brad...@bradleyloritheo.com]
Sent: Sunday, December 05, 2010 9:25 AM
To: 'Bret Mills'; flexradio@flex-radio.biz
Subject: RE: [Flexradio] New 5000A User - TX Audio (severe distortion)
Issues

On the Heil cable I'm using, the PTT is on pins 5+6.   The mic is on pins
7+8.   Should the barrel of the connector be connect to anything?

*B KK2QQ

-----Original Message-----
From: Bret Mills [mailto:bmil...@ecso.com]
Sent: Sunday, December 05, 2010 10:57 AM
To: 'Bradley Feldman'
Subject: RE: [Flexradio] New 5000A User - TX Audio (severe distortion)
Issues

Check the HEIL MIC adapter and MAKE sure that the MIC ground goes to the
radio MIC Ground and the PTT Ground goes to PTT Ground on the radio.
On a LOT of the HEIL adapters they wired the ground pins backwards and this
may be the cause of your problems, on Yaesu radios this didn't make much
difference but on the FLEX it makes ALL the difference in the world.
Hope this helps and 73's and Happy Holidays

Bret
WX7Y



-----Original Message-----
From: flexradio-boun...@flex-radio.biz
[mailto:flexradio-boun...@flex-radio.biz] On Behalf Of Bradley Feldman
Sent: Sunday, December 05, 2010 8:37 AM
To: flexradio@flex-radio.biz
Subject: [Flexradio] New 5000A User - TX Audio (severe distortion) Issues

I'm new to flex, sdr and this list.

I have a brand new 5000A, fully loaded (including the VHF/UHF board).
Station is completely new -- new QTH, new Mic (PR 781), new temporary
antenna (Miracle MMD 30m).

I've worked through issues on installation and receive and seem to have
those licked including using VAC with digital modes.   Now I'm trying to get
TX working right for working QRP until spring comes and I can set up my
Steppir Bigir that's sitting here in a box.

I've been a ham since 1990, but have largely been on my own with regard to
setting up and solving shack problems-- I don't belong to any clubs at the
moment, so I appreciate any help I can get from this list with the issue I
describe below -- which may not be a "flex issue" but perhaps an ordinary
ham setup issue.  I don't know.

Here's the issue:  When keying up and testing my mic in phone mode (I don't
have a key set up), once there is enough audio level to drive some rf output
power, I start to hear distortion in the audio-- it kind of sounds like the
sound of a helicopter with echo and reverb that continues until I unkey.

I've done Google searches, flex KB searches, forum searches and read the
flex troubleshooting guide to try and find a solution.  Based on that
information, I've tried the following:   I've grounded the radio to the PC
with ground strap.  I installed RS ground loop isolators on all audio
connections to/from the radio and PC.  I put extra ferrites on the PC side
of the stock flex firewire cable.

The issue remains.  Any ideas of what to do next or what additional info is
necessary to help me?

*Bradley KK2QQ






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