Wellbrook ALA1530 vs PAR EF-SWL. Who'll win?

[zl2taw]

Originally Posted by nickcarr

Yep it's very odd recently. I use to have issues with 3/4 meg bands and now those are fine. Now it's mainly 6 thru 7 meg bands that suck -- which is where a lot of fun signals are...

Yeah even with the loop I have the same issues here with the 6-7mHz range

I just cant seem to isolate where the RFI is coming from

[TassieJay]

Originally Posted by zl2taw

I just cant seem to isolate where the RFI is coming from

Occasionally I have that problem too, and can't be nulled out. That says to me the noise is mains-borne and travelling down power lines for some distance. That, or multiple neighbours in the vicinity have purchased the same cheapie special plasma TV.

Hertzian has a great point: floating your setup. When the local noise has eased somewhat, I can get comparable, and sometimes even slightly better SNR with a battery portable & long wire compared to the 1530. But that's only rare occasions.
Whoa, a 300 Megohm resistor... a piece of perspex perhaps? 5-10 megohm is about as high a resistor as you can get around here - but that'd probably be fine for this application anyway, I'd have thought.

[nickcarr]

That's the problem with these new, wide-spectrum digital noise sources. They are much hard to track down than simple power line noise. (I'm being sarcastic as PLN can be tricky to isolate too.)

I've tried to hunt down the source of my 6-7Mhz noise and the problem is the 'strongest' signal will change by the time I can get out and start searching.**

I believe it's a combination of old homes (with poor or inadequate grounding), lack of a filtered surge protector(s) on digital devices and poor power line maintenance by utility companies. (I don't think it's just power utilities though.)

They simply just don't care about a little HF leakage here or there. These companies are trying to save costs any way possible so they're not about to send out crews to check out some minor complaint from a radio geek.

**I finally got a much needed DC-DC converter for my Perseus. I plan on driving around with my Perseus active while in the SUV. I have just a simple hamstick whip antenna but it should make for some interesting RFI discoveries.

[hertzian]

Originally Posted by TassieJay

Whoa, a 300 Megohm resistor... a piece of perspex perhaps?

Oops - I meant 3 megohm. Actually just 1 megohm in series, but anywhere from 1 to 3 seems to be fine.

Part of my floating setup is not only due to a noisy ac line where the gear is located, but also while I have tested for a good AC safety ground, one outlet acts like a long elevated random wire in the walls from an RF standpoint. It took me a long time to figure out why I was getting strange directional results and bizarre analyzer readings since I couldn't establish a good ground indoors. Thus I went isolated, and ran my own radials with much better results and far less sensitivity to the indoor environment - although obviously it still isn't like being outside. Plus I choke almost all antenna feedpoints.

Keep an eye out for new solar installations too - many grid-tie systems use "mppt" charge controllers, which are dc switchers and even increasing in popularity for the 12v hobbiest crowd. Some may be clean, but for now I'm only running with the older "pwm" style controller which doesn't use high-frequency dc switching techniques.

[benbenrf]

Wellbrooke - fantastic loop antenna - throughout the HF spectrum, but especially in the lower bands.

For those who would like to read up on some additional detail take a look at the following online PDF article:

http://www.cliftonlaboratories.com/D...inal-Final.pdf

Jack Smith designed the pre-amp in Wellbrooke's latest HF loop offering - and a darn nice job he done of it as well.

[GKolo]

Who sells this antenna ? I have a Kaito 1103 also and would like to try it.

[nickcarr]

Originally Posted by benbenrf

Jack Smith designed the pre-amp in Wellbrooke's latest HF loop offering - and a darn nice job he done of it as well.

No, he designed the preamp for Pixel Technologies Pro-1B ... not the Wellbrook.

[nickcarr]

Originally Posted by GKolo

Who sells this antenna ? I have a Kaito 1103 also and would like to try it.

You can buy at the link below but this antenna would *destroy* your Kaito. It's not for use with portable SW radios. You would need a HF receiver at a minimum.

North American Versions

[TassieJay]

The Wellbrook 1530 works just fine with my Degen DE1103. Admittedly it works that little bit better with the Kenwood TS2000, but $100 vs $2000 radio, you'd want to hope so!
Don't forget that the little high impedance matching circuit is switched out when you plug in an external antenna to the 1103, and if you have any problems, a real RF attenuator operating at the front end, not the IF stage, is available to assist.

[mondomusique]

Originally Posted by nickcarr

You can buy at the link below but this antenna would *destroy* your Kaito. It's not for use with portable SW radios. You would need a HF receiver at a minimum.

North American Versions

Hehe, no I don't think the Wellbrook would destroy a portable, especially in North America (no flamethrowers other than maybe WWCR). The general quality of the Wellbrook antenna is a lower noise floor not higher gain. I used a Wellbrook ALA-100M for a time with a Sony SW55 portable with the only problem being connecting the antenna's PL259 connector to the portable's 1/8 inch antenna jack (my solution involved adapters and rubber bands to prevent strain on the portable's antenna jack -- not ideal).

I would like to see some signal gain charts for the various Wellbrook antennas, though.

[TassieJay]

Originally Posted by mondomusique

I would like to see some signal gain charts for the various Wellbrook antennas, though.

Perhaps not signal gain, but something similar: a gain correction factor chart calibrating V/M field strength to uV output for the ALA1530 can be found here:
http://www.wellbrook.uk.com/images/ALA1530cal.pdf

[mondomusique]

Originally Posted by TassieJay

Perhaps not signal gain, but something similar: a gain correction factor chart calibrating V/M field strength to uV output for the ALA1530 can be found here:
http://www.wellbrook.uk.com/images/ALA1530cal.pdf

Hey TassieJay:

It took me awhile, but that is the kind of chart I'm talking about. It would be good to see all the Wellbrook antennas on the same chart to see how the different model compare over 0-30 MHz.

Did Jack Smith do a 0-30 MHz chart comparing the gain of the Pixel Pro 1B against the Wellbrook ALA-1530?

[karldotcom]

How about something this big?