[SECC] New Beverage at W8FN

[Bill Coleman]

I have three Samlex SEC-1223 power supplies, and I’ve had to modify each one to be less noisy. I’m surprised you don’t have a problem with the SEC-1235.

I’ve modified all three units:

1) FT50-77 toroids on the AC lines from jack to board.
2) Ferrite beads from the board to the power jack.
3) Bypass caps across the power output
4) Grounding case to the station ground

Without it, there were a lot of strong birdies on 160m.

> On Dec 6, 2020, at 3:44 PM, Randy Farmer <w8fn at windstream.net> wrote:
> 
> Since I don't have a transmit antenna for 160 meters, I spent some time just listening in the 160 contest. Friday night I heard several EU stations quite well, but I was plagued by the noise problem, which shows up as ugly humps of noise with about 60 kHz spacing (a sure sign of crap from a switch mode power supply). Saturday night I went to work and discovered to my relief that it was self-inflicted. It turns out that the noise was coming from my 12V accessory power supply, which does have a SMPS in it. I've been using that same supply for many years to run all my station accessories without noticing the noise before. For the first time, my receive noise level on 160 meters is low enough to make the noise very obvious. I fixed the problem by ripping out the cheap internal supply and wiring in a Samlex SEC-1235 supply I had lying around as a standby. With the noise gone, it became easy to hear weak signals all across the band. I didn't stay up late, but it seemed the EU signals were few and far between Saturday night.
> 
> After lots of listening and switching directions on the NE-SW Beverage over the last week, I'm even more impressed with its performance. As a matter of fact, I now have a second kit on order to put up another one running SE-NW, and I'm busily building a switch box to give me switchable coverage in four quadrants.
> 
> 73...
> Randy, W8FN
> 
> On 12/2/2020 12:29 PM, Randy Farmer wrote:
>> I have no 160 meter antenna so far, so I just spent a few minutes listening on 160 meters. I was able to hear some EU stations on the Beverage quite well. Unfortunately, I also found that there was some kind of ugly local electrical noise on 160 that I'll need to track down and get fixed before I can expect to do anything on that band.
> 
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Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Web: http://boringhamradiopart.blogspot.com
Quote: "Not within a thousand years will man ever fly!"
            -- Wilbur Wright, 1901