Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1] 2 Next   Go Down
  Print  
Author Topic: TS-440S SSB TX noise  (Read 4883 times)
KF7YLC
Member

Posts: 8




Ignore
« on: March 16, 2014, 08:26:51 AM »

To make a long and aggravating story short, here is what I got.

Running my 440 into the dummy load on the bypass side of my 949E:

SWR reads equal and below 1.2 on the 440 and the 949E
No deflection on the ALC
TX on FM at 100 watts forward sounds great
TX on AM at 25 watts forward sounds great
TX on SSB sounds horrible at any setting...  Although the modulation is understandable, It's
buried in white noise.  It almost sounds like the mic gain is way to high, but it's not.

So, if anyone has any insight or advice it would be greatly appreciated.

Robert  KF7YLC

Logged
KA5IPF
Member

Posts: 1032


WWW

Ignore
« Reply #1 on: March 16, 2014, 10:20:09 AM »

How are you monitoring your transmitted audio?
Logged
KF7YLC
Member

Posts: 8




Ignore
« Reply #2 on: March 16, 2014, 10:56:15 AM »

I ran all tests on 28.650 and monitored on a 10 meter rig I have installed in my truck.
Logged
KA4POL
Member

Posts: 2086




Ignore
« Reply #3 on: March 16, 2014, 11:45:16 AM »

No offense meant, You are receiving on the correct sideband?
Perhaps you could try without the mic and insert a piece of wire which you can touch with your fingers to produce hum as modulation. I guess you do not have a sine wave generator.
Logged
KF7YLC
Member

Posts: 8




Ignore
« Reply #4 on: March 16, 2014, 12:22:14 PM »

None taken.  I did use the correct sideband and I do not have a sine wave generator. 
Logged
KA4POL
Member

Posts: 2086




Ignore
« Reply #5 on: March 16, 2014, 12:36:40 PM »

So try the hum test to make sure the mic is clean.
Logged
KF7YLC
Member

Posts: 8




Ignore
« Reply #6 on: March 16, 2014, 01:16:41 PM »

I'll need another set of hands to try the wire test.  I hope this isn't a dumb question, but wouldn't
the tests on AM and FM suggest the mic is good?  I have to admit, a new mic would be easier to swing
than the costs of the Kenwood Service Center.....
Logged
KA4POL
Member

Posts: 2086




Ignore
« Reply #7 on: March 16, 2014, 10:52:23 PM »

I would try to get a hold of a ham a couple of miles away who can receive your signal in SSB. There is still a chance of the receive chain being the problem.
Is it just by this test or did someone complain about the SSB modulation?
Logged
KA4POL
Member

Posts: 2086




Ignore
« Reply #8 on: March 17, 2014, 12:49:21 AM »

You said the mic gain is right. Anyway rotate the button counter clockwise to reduce it even more and check again.
Logged
KF7YLC
Member

Posts: 8




Ignore
« Reply #9 on: March 17, 2014, 04:12:11 AM »

Yeah, this whole fiasco began with bad reports on 80, 40 and 20 meters.  However, these were all
on a home brew 43ft. vertical I wanted to try out.  Naturally, I assumed there was a problem with my design and
switched to a home brew vertical I'd built for 10 meters with less than stellar results.  It turned out to be water in the
feedpoint connector.  After that point I have not attempted any contacts but kept things "in house" so to speak.  I did order up
a factory made antenna and feedline for 10-17 meters.  I'll try to make a local contact and see how things go.  At this point I'll attempt
anything.

Oh, and I did try my "in house" test with minimal mic gain.

Logged
KA5IPF
Member

Posts: 1032


WWW

Ignore
« Reply #10 on: March 17, 2014, 06:40:46 AM »

Go to http://www.oz1bxm.dk/TS440/TS440S_Repair_FAQ.pdf and look at the second thing. rx bpf fix.
Logged
KA4POL
Member

Posts: 2086




Ignore
« Reply #11 on: March 17, 2014, 11:35:13 AM »

As I understood the issue it happens during transmit in SSB: 'TX on SSB sounds horrible at any setting... '
I can not see a fix in the document. What may be helpful though is a visit of the 440 Yahoo group.
Logged
KA5IPF
Member

Posts: 1032


WWW

Ignore
« Reply #12 on: March 18, 2014, 07:24:31 AM »

As I understood the issue it happens during transmit in SSB: 'TX on SSB sounds horrible at any setting... '
I can not see a fix in the document. What may be helpful though is a visit of the 440 Yahoo group.

Second item. When the rx BPF diodes leak it causes distorted tx audio.
Logged
KF7YLC
Member

Posts: 8




Ignore
« Reply #13 on: March 19, 2014, 03:14:47 AM »

I did check the BPF board before I started this thread and there was indeed a leaky diode on the 500khz filter.  I
cut the lead on the corresponding diode and reassembled the radio.  There was an improvement, but the problem
remains.  I suppose it's possible that the 20 meter filter diode is leaking...  I also sent a request to join the 440 yahoo group but never got a response.

I want to thank everyone for their help.
Logged
W8JI
Member

Posts: 9296


WWW

Ignore
« Reply #14 on: March 19, 2014, 03:34:44 AM »

I did check the BPF board before I started this thread and there was indeed a leaky diode on the 500khz filter.  I
cut the lead on the corresponding diode and reassembled the radio.  There was an improvement, but the problem
remains.  I suppose it's possible that the 20 meter filter diode is leaking...  I also sent a request to join the 440 yahoo group but never got a response.

I want to thank everyone for their help.

Do you realize when a radio is "tested" with another improperly coupled radio, especially a test receiver with AGC, you get can have all sorts of weird effects that make signals sound bad?Huh?

This is the very same reason we should never set a spectrum analyzer near a radio and use an open "probe" antenna to pick up signal for spectral purity tests. I sat through an entire Agilent analyzer demonstration where the Agilent rep coupled the analyzer wrong! Instead of using a wideband sample tap off the transmitter antenna port, he stuck a short whip antenna in the analyzer input connector!!

An improperly coupled test receiver will pick up stray radiation from RF leaks, many of which are modulated by noises, and that garbage sample that comes from power cords and cabinet leakage is not representative of what is on the air.

Making it worse, if the signal is strong and you have AGC on, you will hear "crap" that is -80dBc when mic gain is down.

I'm not saying the KW is OK, but we should all be aware improper test setups can create significant misleading artifacts.
Logged
Pages: [1] 2 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!