[Amps] Multi-meter for HL-2200

[R.Measures]

Lon -- I forwarded this through AMPS because your mail server has my 
adr blocked.

Begin forwarded message:

From: R. Measures <r at somis.org>
Date: August 18, 2005 9:57:41 AM PDT
To: "Lon W. Cottingham" <k5jv at kingwoodcable.com>
Subject: Re: [Amps] Multi-meter for HL-2200


On Aug 18, 2005, at 8:12 AM, Lon W. Cottingham wrote:

> Richard,
>
>         Thanks for the info.  I always learn something every time I 
> talk
> with you.  I really had no idea what the actual DC voltage would be.  I
> picked 3,000 because the actual supply voltage is 3,050 with no load.  
> If it
> is only 1,100 volts, that is still enough to jump across the open relay
> contacts and wipe out the receiver.

apparently, but I have never measured the OC withstanding V of a stock 
SB-220 relay.

>  I was not transmitting when this
> happened.   The amp was in standby.  I suppose the best answer to this
> situation is to use the best quality, RF rated, capacitor that one can 
> find
> for the plate blocking cap.

Strange that a 6kV cap would fail at 0-amperes and 3000v.
>
>         I had to buy a new SB-220 transformer from Peter Dahl a while 
> back.
> His stock replacement has a little more voltage than the original 
> HeathKit
> transformer.  It is about the same as the HeathKit HL-2200 
> transformer.  I
> asked him to put a few more turns on the secondary so that I could get 
> the
> voltage up enough to run 1500 watts out.  He said that he could not do 
> this
> because the core was absolutely full.  I looked at his wire sizes and
> thought about this a while then asked him to down size one wire size 
> on the
> secondary and run that through his  computer and see what it would 
> give.
> The results looked good.  We settled with a secondary that gives 3,600 
> VDC
> at no load and right at 3,300 key down with an output of 1,500 watts 
> on 14
> MHz and around 1,700 watts on 3.5 MHz.  I realize that this is 
> much-a-do
> about nothing as the difference between 1,100 watts and 1,500 watts is 
> very
> little in Db's ( about 1.3 Db).

Using a tuning pulser, a stock SB-220 will do c. 1550w-pep @ 7MHz with 
140w-pep drive.  Do you use 8, 450v filter caps with 3600v?

> But, the customers really like it.  They
> want to see the watt meter go up.  I sell modified SB-220 just as fast 
> as I
> can produce them.  The problem is finding them at a price that will 
> allow a
> profit after all the mods and upgrades are done.
>
> 73 de K5JV
>
>  Lon W. Cottingham
> 1110 Golden Bear Ln.
> Kingwood, TX 77339
>
> 281-358-4207
> 281-358-4234 FAX
> 281-795-1335 CELL
>
>
>

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org



Richard L. Measures, AG6K, 805.386.3734.  www.somis.org