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- Subject: Re: [NRC-AM] THREE NAIVE QUESTIONS
- From: Mark Connelly <markwa1ion@xxxxxxx>
- Date: Mon, 10 Aug 2015 20:36:09 -0400
- Delivered-to: irca@xxxxxxxxxxxxxxxx
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(1) Perseus is an excellent receiver in the traditional metrics: Sensitivity, Selectivity, Stability, and Strong-Signal Handling. Bandpass and notch filters are superior to traditional crystal, mechanical, and L-C types. The synchronous AM mode is superior to that in the Drake R8A/R8B and even the vaunted Sony ICF-2010 portable. Besides the manufacturer-supplied software there are other programs which will operate the receiver. Of course spectrum recording is indeed the "killer app" especially for those of us who go to a prime seashore or mountaintop location and scoop up top of hour +/- 3 min. files containing way more DX than could ever be managed with station-by-station tuning. Typically this would be around sunset here on the East Coast or sunrise out your way. Or just about any time of night if a full-boogie aurora is in progress, such as we had here late March.
(2) You can still use tunable antennas and, of course, use the Perseus for live one-frequency-at-a-time DX as you would use something like one of the traditional war-horses (AOR 7030, R8B, R-390A, HQ-180A, SX-28A, etc.). You can even use a tunable antenna and capture spectrum maybe up to 200 kHz width (peaked freq. +/- 100 kHz) with tolerable sensitivity depending on the Q (quality factor or, in layman's terms, sharpness) of the tuned loop, preselector, etc. It is true that the majority of users are interested in broadband capture. Also, with the high noise levels in most residential buildings, indoor antennas of any type are losing favor. There are quite a few Kiwa, Quantum, and d-i-y box loops collecting dust these days, even for users of conventional receivers. Outdoor antennas are what you need now in most settings unless you have taken extraordinary measures to keep your home RF-quiet. One cheapo Chinese wall-wart in the wrong place can crap up reception for a hundred feet or more in all directions. If you have a half dozen or so of these things charging cellphones, powering cable boxes, etc. - not at all unusual - kiss using your indoor antenna goodbye. So what do we want in outdoor antennas? Figure-of-8, omnidirectional, and cardioid pick-up patterns are all relatively easy to produce. The Wellbrook ALA-1530 will give you a traditional loop figure-of-8 pick-up and broadband reception at the same time. It's small enough to mount on a mast strapped to a chimney or elsewhere on a roof. If you want to rig a rotor for it, just be careful that leads going to the rotor do not transfer house RFI to the antenna. For omnidirectional pick-up, there are numerous active whips out there. MFJ, Clifton Labs, DX Engineering, and others have offerings in their catalogues. If a cardioid pattern is what you want, the terminated loop is what you need. Here on Cape Cod, much of the interference is from the New York City area at a bearing of about 255 degrees. Meanwhile, the opposite direction 75 degrees, is a good one for Trans-Atlantics. Similarly 345 degrees points towards the Boston area (also NH and Montreal), so I get quite a bit of interference from there; the opposite direction 165 degrees is great for the Caribbean and South America. At least at this site, cardioid-pattern antennas are "what the doctor ordered". The Kaz Delta, Flag, SuperLoop, Ewe, Pennant, DKAZ, Waller Loop, Bowtie, and K9AY are all variations on the terminated loop theme. You can get by with a fairly small one at a hopped-up shore site but increasing the size definitely improves signal capture and reduces (or eliminates) the need for a preamplifier. Bruce Conti's website ( http://www.bamlog.com/ ) has a wealth of information about these antennas. Also see the K3KY Flag and Pennant Antenna Compendium ( http://www.angelfire.com/md/k3ky/page37.html ). Google search around and you can find write-ups by DXers such as Dallas Lankford, Bill Whitacre, Mark Durenberger, Neil Kazaross, and the late John Bryant. One can also go with the Beverage or the random longwire antenna and take whatever directional pattern they get. To minimize electrical noise, use a transformer to isolate station / mains ground from a separate "field ground" (radials and/or ground rods).
(3) At present the SDR receiver other than Perseus that has the greatest appeal to serious DXers is the Winradio Excalibur. Bruce Conti and others have put that model through its paces in real-world settings both at home and on coastal DXpeditions. There are also competent models made by RFSpace, Quicksilver (QS1R), Afedri, and Elad. Guy Atkins, Bjarne Mjelde, and other "power user" DXers can chime in with their recommendations since they've had their hands on numerous SDR's.
I will be interested in reading what others have to say.
Mark Connelly, WA1ION
South Yarmouth, Cape Cod, MA, USA
(GC= 41.6931 N / 70.1912 W) (= 41Â 41.59' N / 70Â 11.47' W) (grid FN41vq)
Receiver: Microtelecom Perseus
Antenna 1: Cardioid-pattern SuperLoop: 10m vert. by 11m horiz. (peak 165 deg., null 345 deg.)
Antenna 2: Cardioid-pattern SuperLoop: 8m vert. by 15m horiz. (peak 75 deg., null 255 deg.)
See http://www.bamlog.com/superloop.htm for similar antenna type.
-----Original Message-----
From: Pete Taylor <ptdx@xxxxxxxxxxx>
To: IRCA <irca@xxxxxxxxxxxxxxxx>; NRC <am@xxxxxxxxxxx>
Sent: Sat, Aug 8, 2015 7:05 pm
Subject: [NRC-AM] THREE NAIVE QUESTIONS
Not exactly hyper-skilled in the technical arena, I am considering buying a Perseus and have three questions:
(1) Above and beyond its ability to record wide expanses of the spectrum, is it an above-average receiver?
(2) I have a couple of indoor loops which obviously you tune for max signal strength frequency by frequency. What are the Perseus antenna needs so the whole band is at max?
(3) Are there others besides Perseus which I should be looking at for simplicity or other reasons?
Thanks.
Pete Taylor
Tacoma, WA
12225w 4719n
HQ180 & ICF2010
Kiwa aircore & Palomar loops
DX398, SRF-59 & M37V
Eton E100 + Tecsun PL-300/380
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