Monday, November 23, 2009

WHOO-HOO! Back On-The-Air!

Spent the day running the coax and tuner power/control cable from the patio area into The Shack. I spent some extra time trying to make it look "pretty" so the fiancee would approve. I could probably get away with sloppy cable runs and dangling wires, but then besides making her shake her pretty little head, it wouldn't say much about my workmanship, would it? So far, the only "problem" is that when I turn on the Astron SS-30M power supply I've been using to power my FlexRadio 5000A, my noise level jumps from about nothing to S-7~S-9! This is a terrible thing to hear, and while it *could* be a problem with the SG-230 antenna coupler, it sounds like typical switching power supply noise. I never really noticed this at my apartment, as I had pretty bad AC powerline noise, and if the Astron really is generating hash, I might not have noticed it.
Oh, well....out to the garage to dig out my Astron VS-50M, a linear supply, which does not generate switching noise. I'll update this later......
Yep, it was the switching supply! Installed the linear supply, and all is quiet.
Now to figure out why the doggone SG-230 won't match the antenna! I bought this used on eBay and never checked it. I noticed that the RF Input connector on the coax seemed "loose", so perhaps that could be causing it. I've got a 'spare' SG-230, so I'll probably just swap it out Tuesday morning, and see how it goes.
The internal tuner in the rig is able to find a match with 1.5:1 VSWR on almost all the bands, so I can live with it for now.

2 comments:

  1. I own a SS-30M and have a harmonic problem with it. With the SS-30M hooked up to any radio, I hear a harmonic about every 40KHz, up thru 21MHz. Is this the same as you "hash"? If so, how did you fix it?

    73's....Mikey, WB8ICN
    wb8icn@comcast.net

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  2. Hi, Mikey
    What you're hearing is the fundamental, and the harmonics, of the switching frequency. Mine did something else, broadband hash everywhere. It made most of HF useless. I have two SS-30 supplies, and the noisy one is the older of the two. I haven't tried the newer one, so I don't know if it's any better. I primarily use these supplies for Field Day, where I operate the satellite station for my radio club, so I never noticed the noise before. Makes me wonder if I was bothering the HF stations!
    You'll have to find out if your noise is conducted (down the power cord and DC output leads) or radiated. If it's conducted, you can try adding some ferrite blocks on the power cord and output leads, placing them as close as possible to the case of the supply. If it's being radiated, make sure the case fits together tightly, and the paint is scraped/sanded from the metal parts where they fit together so you have good electrical contact between the case halves, and make sure the case of the supply is grounded to your station ground.
    Industrial Communications Engineers ("ICE") makes an excellent 'Brute Force' powerline filter that will stop the noise if it's coming down the power cord. See http://www.iceradioproducts.com/filtersrf2.html#4 for more info. Ferrite blocks and cores are available from a large number of suppliers. There's a lot of info on Astron supplies at the Repeater Builder website, http://www.repeater-builder.com/astron/astron-index.html
    As far as "fixing" mine, I swapped it out for a big Astron linear supply, and the noise went away. When I have some time, I'll try the newer SS-30, and if it's better, I'll open the two up and see what's different between them.
    73, Jim

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Keep it civil, please....