----- Original Message -----
From: "Jim Thomson" <jim.thom@telus.net>
To: <amps@contesting.com>
Sent: Thursday, December 18, 2014 12:22 PM
Subject: [Amps] THE SKINNY ON MY AL-82
Date: Thu, 18 Dec 2014 07:14:01 -0800
From: "Jim W7RY" <w7ry@centurytel.net>
To: "Bill and Liz" <magoo@isp.ca>
Cc: AMPS <amps@contesting.com>
Subject: Re: [Amps] THE SKINNY ON MY AL-82
Is he (YOU) SURE it was parasitics? More likely hot switching of the
amplifier T/R relay. This causes LOTS of problems that folks THINK are
parasites.
After I install my QSK system into amplifiers, the arcing completely STOPS
because the relays are no longer hot switched.
ALC overshoot spikes also cause arcing in amplifier capacitors. Mostly
Kenwood has ALC overshot including the TS-590S.
Although, the Icom IC7410 has ALC overshoot problems on SSB. Which is
repaired by Icom for free. Although only the units made before mid 2014
are
affected.
73
Jim W7RY
## The AL-82 is known as the...firecracker ! It’s a parasitic prone
amp, right out of the box.
The Rich measures suppressor will solve the parasitic issues 100%....
except his suppressors
run hot on 10m. Hotswitching wasn’t the issue... but will make it
worse..ditto with overshoot.
A conventional suppressor will work, but the trick is finding non
inductive resistors these days.
To tame the parasitics with a conventional suppressor, it requires
slightly more L.... which will
cause the resistor to run warm / hot on 10m. A 10/15 watt globar is
the real solution...works good.
Then used wide silver plated strap for the suppressor coil.
## KM1H used a method, with caps in series with new style mof
resistors... to cancel out the xl of the
mof resistors. 2-5 x 3 watt mof resistors in parallel will provide
enough heat handling capability on 10m,
but will require 2-5 x series caps. If you can find some old style
Carbon comp resistors, 2-5 of em in parallel
will work. A single 10-15 watt globar is the no brainer solution. Or
leave the rich M suppressor in there,
and don’t operate it on 10m.
## KM1H has had a lot of experience with that amp. Hopefully he will
chime in.
Jim VE7RF
That is the same suppressor Ameritron copied but used a 100 Ohm 3W resistor
and 91pf vs 100pf caps.
I use a 5W 50 Ohm MOX or a pair of 100 Ohm in parallel; only 2 caps needed.
Use the standard 3 1/2T of #16 wound over a 2W carbon resistor or similar.
Place next to the 5W resistor and not wound around it.
You get better suppression with the lower resistance since it further lowers
the Q and broadens the frequency response.
To replace 2W carbons use the 50 Ohm Ohmite OY ceramic resistor, reuse the
original coil external to the resistor.
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2015.0.5577 / Virus Database: 4253/8759 - Release Date: 12/18/14
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|