One of the biggest mistakes that newer hams and older ones that don't
understand the rigs that well,
is that they leave on the noise blankers. They can easily make it seem that
there is a dirty signal
near by when it is just a strong one that is tripping the noise blanker.
HF manmade RFI is absolutely terrible today. Some is impulse noise but most
is broad band %#)(*)(#*($ that
comes from CFL , touch lamps and switching power supplies. Some comes from
various internet cables.
In my area it is often S5 or greater.
These guys may turn the blankers on and see a half or full S-unit improvement
and leave it on.
One time I had a ham complaining that a ham was splattering on all the HF ham
bands. I told him that it
was unlikely especially on the bands of lower frequency that the ham was
transmitting on.
They were only a block away from one another and both had amplifiers.
He and the club members did not like my suggestion that it mostly was the old
guys receiver
The other ham was a new guy that the old guy and some of the members had a beaf
with anyway.
73
Bill wa4lav
________________________________________
From: Carl [km1h@jeremy.mv.com]
Sent: Monday, January 02, 2012 3:15 PM
To: Fuqua, Bill L; Dan Mills; amps@contesting.com
Subject: Re: [Amps] IMD
----- Original Message -----
From: "Fuqua, Bill L" <wlfuqu00@uky.edu>
To: "Dan Mills" <dmills@exponent.myzen.co.uk>; <amps@contesting.com>
Sent: Monday, January 02, 2012 1:01 PM
Subject: Re: [Amps] IMD
> If the amplifier is extremely non-linear it can produce key clicks.
> Class-E amplifiers requre a enevelope modulating power supply to
> prevent key clicks.
> I can see that it is possible for hard driven, class-c amplifier with 2
> or 3 times cutoff bias
> could produce very noticable key clicks.
> 73
> Bill wa4lav
Absolutely true about Class C and I had to take special care when using a
boatanchor TX into a big Class C amp on CW. It was as easy as reducing drive
and watching the tuning on the monitor with any of the vintage TX but I
finally dropped the bias to roughly Class B in the amps by adding an
additional relay to the Phone-CW switch.
1500W of deep C CW can aggravate many as I initially discovered several
years ago when returning to my old roots! The funny thing tho was they all
accused me of running an Icom something or other or a Yaesu FT-1000D.
Carl
KM1H
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|