|[AMRadio] AMRadio Digest, Vol 119, Issue 24|
w3slk at verizon.net
Thu Dec 12 09:14:43 EST 2013
I can appreciate your desire to run plate modulation. An Apache with the
proper audio mods is very nice sounding and can be a pleasure to listen to.
However, I question the use of the SB-220. I just do not think it is a
practical implement to use and as you noted, placing undue stress on its
rather limited power supply. The difference between 100W and 200W will not
make much of a dent during 'battle conditions.' I would suggest building a
simple HVPS, modulator, and RF deck with something like an 833 modulated by
a pair of 810's and using the Apache as an exciter. I know that is more
complex than what you are looking for but you may end up saving money by not
ruining your Heathkit amp. I see too many SB-220 carcasses on that e-joint.
Just my grid bias worth.
----- Original Message -----
From: "Wade Staggs" <tvman1954 at gmail.com>
To: <amradio at mailman.qth.net>
Sent: Thursday, December 12, 2013 8:39 AM
Subject: Re: [AMRadio] AMRadio Digest, Vol 119, Issue 24
* What am I about to get into? We have finished the
restoration of a Beautiful Heathkit TX-1 ( Scratchy Apache ) ... Several of
the coupling capacitors in the audio stages were changed to get some of the
Scratchy out of the Apache. But the high frequency roll off above about
3KHZ was looked at closely and those circuits were left in place. With
Knives and Bear Skins for equipment here. The O Scope waveform looks good.
All mods were aimed at helping out the low frequency response in Modulator.
My thoughts are to run 100 Watts or less until more is needed. Then the
SB-220 would come into play with at most a 200 Watt carrier. Those SSB Amps
just don't have the power supply to hold up to much more carrier. Advise is
needed in this area. We will be using a restored Yaesu FRdx-400 Receiver
until something better comes along. The Receiver seems to be working well
after the repair of some Filter issues. Sure could use an old time Elmer or
two when we try to get the station on the air. My first station was a
Johnson Ranger with a Wells Gardner BC-348Q Receiver. Too many years ago!
We hope to be jumping in and getting wet feet in the AM Window soon. ( Next
2-3 weeks ) Any and all advise is needed. We also have the matching
Transmitter for the Yaesu Receiver. Just can't resist having the Big Iron
Plate Modulated Apache online first. My email address is
tvman1954 at gmail.com <tvman1954 at gmail.com> ..... Advise is appreciated and
Flames will be Ignored. *
* 73 Merry Christmas de Wade/KJ4WS*
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