Another FM DX Day

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Another FM DX Day

Postby jon » Thu Jul 30, 2009 9:33 am

This morning is shaping up into an interesting FM DX day. The 100KW Calgary FM's are even stronger than I heard them at the peak of last week's Regional DX conditions thanks to the Aurora.

One mystery that may turn out to be an FM transmitter in someone's car: 107.9 MHz with "Howard 100 News" (Howard Stern syndication) at 10 a.m. As I say, this could be just an FM car transmitter off of Sirius.
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Re: Another FM DX Day

Postby jon » Thu Jul 30, 2009 12:54 pm

Well, I was close. It is actually an FM transmitter in someone's apartment, providing them with in-house wireless transmission of satellite radio on 107.9.

High voltage overhead power lines likely improve reception.

It didn't occur to me earlier because there are actually no homes anywhere near where I was, but I was high enough up that I could get line-of-sight from apartments in the distance.
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Re: Another FM DX Day

Postby Anotherwpgguy » Fri Jul 31, 2009 12:14 am

I've got 5 watts fed by my Sirius sat rx in my RV with a vertically polarized antenna. Works really well but I'm going to take it out of service soon to act as an exciter for 20 watts at a fixed location and only use 100 mw in the RV.

Also Jon .. I've been meaning to ask for a long time, what rx is that in your avatar .. almost looks like an HR-10 but I know it isn't .. I had one of those with a DX-60 and VFO at one time. Lots of radios have come and gone since those days .. LOL.

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Avatar

Postby jon » Mon Aug 03, 2009 8:39 am

The avatar is a Lafayette HA-230 receiver. A picture some guy took of a perfectly restored model. Mine never looked that good fresh out of the box when I bought it new, in part because I bought the last new one in Vancouver in early 1968, long after that model was obsolete. My father negotiated for Brian Elder and I; Brian ended up with the new model.

The HA-230 totally blew my socks off, both in terms of sensitivity and selectivity, compared to the very early portable Philips transistor radio I had been using up to then.

It was not that much later when Brian and I built (OK, my father helped a lot with mine) 4 foot wide box loop antennas, which further expanded our horizons, DX-wise.

Best example of selectivity is a recording of KOL-1300 Seattle that I have. One hour of zero slop from CHQM. That was on the HA-230, and the loop didn't help, as CHQM's transmitter was the same direction as KOL. But CHQM was 50KW by then, and I have a KOL recording from a couple of years earlier on the Philips with lots of slop, even though CHQM was only 10KW then!

All that said, the HA-230 was pretty much the bottom of the line, money-wise, of communications receivers suitable for DX on 540-1600 KHz. There were lousier receivers, but not at a lower price.... Brian and I paid just over $100 each for our "transistor-free" (i.e. - tube) receivers.
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Re: Another FM DX Day

Postby Anotherwpgguy » Tue Aug 04, 2009 3:43 pm

Jon:

I'd completely forgotten about the Lafayette line of radios, but can identify with the attachment to your first decent performing receiver.

Looking at the underside of the chassis, it looks like 80% of the space is taken up by the band switching and coils and not too much in the way of RF section....LOL


My first one was a converted WW2 aircraft rx, the Bendix RA-DB which my dad had converted from 28 vdc to AC house voltage, but the xformer was undersized for the job and would run very hot to the touch. That meant if I ran it on hot day in the summer, the smell of hot shellac from the windings made my room smell funny. I could decrease but eliminate that problem by setting the behemoth on my bedroom window sill and have the transformer outside in the cooling breezes. That was OK as long as the mosquitoes weren't too active. During the winter, everything was just fine. I spent countless hours listening to WABC, CKLW, WLS, WBZ, WGR, WOHO, etc.

http://www.vk2bv.org/museum/ra1b.htm

The first receiver I bought and paid for myself from my paper route money and a few dollars begged from my grandmother, was a Marconi R-1155 which came from an RCAF Lancaster, and had been converted by the same guy who removed it from the aircraft and saved it from being crushed at the time of aircraft disposal.

http://goto.glocalnet.net/bosradio/marc ... erview.htm

Since those days, I've gone through dozens of other radios, always looking for a steup up in performance .. sometimes my trades worked out, sometimes they didn't.

Now my prized SWL and BCB receiver is the Racal RA-17 which came from a Govt of Canada Radio Intercept Monitoring Site in Wetaskiwin AB and is a genuine spy catcher radio that was used to track Soviet "trawlers" working off the west coast in the early to mid-60's. This is the first receiver I have owned which can actually "channelize" the AM broadcast band at night, in the presence of strong skywave signals. The selectivity can be narrowed down so that the dead guard bands between frequencies can be heard as you tune from one station to the other no matter how strong the adjacent channel signal is ... and I think that's pretty slick.

http://www.recelectronics.demon.co.uk/ra17.htm

While I have new stuff like the Icom Pro 3, my favourite ham stuff is my Collins S Line and 75A-4.

All the best Jon.

Regards from,
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DX Receivers

Postby jon » Wed Aug 05, 2009 9:21 am

I finally found my research on DX Receivers and Antennas, which disappeared off the Vista Desktop nearly 6 months ago.

If I get serious about AM (Medium Wave) DX, the Icom IC-R75 seems to be the obvious choice. Like the HA-230 (and a couple of others) in its day, it is mass produced, delivering decent quality at the entry level price point to true DX receivers.

And, if you are willing to search the U.S. ebay site (searching through ebay.ca only gives you goods that will ship to Canada) and take delivery in the U.S., I would estimate that you can get a good working used IC-R75 receiver for around half the list price. I just checked and a Calgary dealer sells them new for $750, so I'd look to pay $300-$350 U.S. on eBay for a used one.

Of course, there is still the issue of an antenna. Entry point for mass-produced and quality for amplified tuned loops appears to be around $200 U.S. The main contenders appear to be the Quantum QX Loops and the more expensive ($270 U.S.) Palomar Engineers' LA-1 with Medium Wave Loop. The main thing these more expensive loops offer, as well as Sensitivity, is the ability to tilt a weird angles for really deep nulls of stations you want to "eliminate" so you can hear what's underneath. I can attest to the need, as I remember spending long periods of time holding my parents' early Philips portable transistor radio in the oddest positions to hear the less dominant station. Or even just to make it more pleasant to listen to Wolfman Jack on XERB underneath KING Seattle from Burnaby.

Then, the next step is to add a product like the Quantum Phaser ($135 U.S. List), into which you plug your loop into one antenna connection, and a short piece of wire (crude longwire antenna) in the other. The device subtracts everything heard on the short piece of wire from what you are hearing on the loop, to eliminate nearby stations so you can hear something underneath. I heard a recording from some guy not far from New York City who used it on 880 KHz to eliminate WCBS and get good clean reception of CHQT when they were Cool 8-80.

At this point, I'm not sure I want to invest that kind of money. Or the time to DX to justify it.
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