[Elecraft] Heil Pro 7 headset with KX3 - RF feedback?

[AL7CR]

Please list your TXEQ settings.

On Thu, Jun 17, 2021, at 12:42 AM, Jim Brown wrote:
> Heil products are wildly overpriced and highly over-rated. No ham needs 
> a boom mic headset better than a Yamaha CM500, which sounds great both 
> in the headphones and one the air, is very comfortable, costs about $60, 
> and has ZERO RFI issues. I'm a Fellow of the Audio Engineering Society, 
> have a storage room full of great mics far better than anything Heil 
> makes, do very serious contesting. and I've used nothing but the CM500 
> for more than ten years. What pro audio folks say about Bose applies 
> equally to Heil -- "better sound through marketing."
> 
> The CM500 plugs straight into the back of an version of a K3 (and 
> probably a K4), and I'll be happy to list TXEQ settings that make it 
> sound FAR better than Heil headset mics.
> 
> I've been a member of the AES Standards Committee Working Group on 
> Microphones for almost 30 years, and I've never met Bob Heil or anyone 
> from his company. That should tell you something about how 
> "professional" he and his company are. :)  This whole thing about "I did 
> sound for XXX rock band is, as my Black friends would say, "a whole 
> bunch of shuck and jive."
> 
> 73, Jim K9YC
> 
> On 6/16/2021 8:36 PM, Drew Arnett wrote:
> > Shield of mic jack goes to bare metal Elecraft thoughtfully left on
> > the chassis metal.  10 nF shunt to ground.  (Need to see where that
> > is, but hopefully SMT and with very small loop area.)  Sheet 9:
> > https://ftp.elecraft.com/KX3/Manuals%20Downloads/KX3SchematicDiagramDec2012.pdf
> > 
> > Heil suggests on their tips page generous ferrite choking of all 3
> > leads of their Y adapter cable:
> > https://heilhamradio.com/support/tips/
> > 
> > Drew
> > n7da
> > 
> > On Thu, Jun 17, 2021 at 3:23 AM Drew Arnett <arnett.drew at gmail.com> wrote:
> >>
> >> Hi,
> >>
> >> In the KX3 for Field Day department, we plan to use it for the GOTA
> >> station for phone on HF.  (Yes, will have antennas not on top of each
> >> other and bandpass filters on ALL radios.)  Would be great to setup
> >> with a headset and foot switch.
> >>
> >> Last weekend, I used my KX3 barefoot on 6 and with a
> >> transverters-store.com transverter (also barefoot) for 2.  6m antenna
> >> was 2 elements about 15 ft above the ground and 2m antenna 6 elements
> >> at 10 feet above the ground.
> >>
> >> I worked a couple of contacts on 2m phone with the headset.  Later,
> >> when I tried to use the headset for phone on 6, seemed like I was
> >> having a feedback problem.  Cabling was the stock cabling that comes
> >> with the Heil Pro 7 headset and a footswitch.  Monitor was on and set
> >> to 4.
> >>
> >> So, ALC didn't indicate anything at the normal level (60), and
> >> increasing it very abruptly caused horrible sounding audio.  (Yes,
> >> acts like positive feedback.)
> >>
> >> I have a small electret mic on a 1/8 plug thing I bought some time ago
> >> from the computer store.  (Meant at the time for adding mic to
> >> laptops.)  I have a 1/8" audio extension cable for it.  I plugged that
> >> in instead of the headset mic and it seemed to act normally.
> >>
> >> Is this purely an RF from the TX antenna getting into the mic audio
> >> problem or is it something else?
> >>
> >> Best practice to avoid this problem?
> >>
> >> On my todo list:
> >> - ask here
> >> - look at KX3 schematic to see if it has RF ingress mitigation on the mic jack
> >> - ask Heil
> >> - unplug the Heil mic element and gator clip my cheap electret mic on
> >> instead and try on 6m in driveway with identical antenna/mast/radio
> >> setup
> >> - look for or assemble an RF filter to inline with the mic jack (tough
> >> to do with this little time
> >> before field day)
> >>
> >> Thanks and best regards,
> >>
> >> Drew
> >> n7da
> >>
> >> ps.  Other than this, KX3 was great in the VHF test.  Worked great
> >> with the transverter on 2 and was a lot of fun running barefoot with
> >> the sporadic E opening Saturday afternoon & evening.
> > ______________________________________________________________
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> 
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