Messages

31

22 Meter Band HiFER Beacons / Re: Using a 20m Yagi for reception

« on: March 02, 2020, 1949 UTC »

Actually, the difference between the so-called "20 meter" ham band and 22 meters is less than it might seem. The phone portion of the "20" meter band is really much closer to 21 meters wavelength, and so the dimensions of the antenna elements will only be off about 5%...only around 2% if the Yagi is cut for the CW end of "20".

That's enough to throw higher VSWR numbers than you'd want for transmitting, but as K3ZRT said, it won't blow anything up when receiving. It's not a major loss of efficiency either, so long as your receiver's input impedance is a true 50 ohms or greater. As for directionality, I wouldn't worry at all. The difference will be indistinguishable to the ear.  Such a small error in element spacing will slightly affect the depth of nulls and gain of the forward lobe, but has very little effect impact on their orientation.  At least, I've found that to be true with a 3-element Yagi; the more elements the antenna has, the more critical spacing could become, and the more bands it covers, the more chances for the traps to complicate its out-of-band impedance characteristics.

Ed makes good points about isolating the transmission line for control of common mode noise. And, reducing common mode coupling may also have beneficial effects on directional properties of more complex antennas as well.

32

22 Meter Band HiFER Beacons / Re: YCPA 13567

« on: February 18, 2020, 0753 UTC »

"around 135564.9 frequency"

Chris, it looks like maybe there's an extra digit in there somewhere, or else a misplaced decimal. What is the correct current frequency of ABBY, please?

33

22 Meter Band HiFER Beacons / Re: 22m Beacon

« on: January 22, 2020, 2103 UTC »

But I think “nicely elevated” is not quite fully descriptive of the location...

OK... "VERY nicely elevated," then? 

Yes, location is definitely the main secret to Paul's success. He is also one of the few HiFER operators who had access to the necessary field measurement gear to ensure actual formal compliance with the Rules when installing his rig, in addition to his engineering skill in applying antenna and transmission line specs to the problem.

34

22 Meter Band HiFER Beacons / Re: 22m Beacon

« on: January 22, 2020, 0758 UTC »

In principle, Chris, under free-space conditions, an end-fed halfwave and a dipole should radiate very similarly...but in practice, they don't.  Interaction with the earth has a big effect, particularly on the end-fed antenna. The angle at which it is sloped also has a major impact, and not usually a positive one either.

A friend of mine out West had high hopes for an EFHW antenna for the ham bands that had been touted as something of a miracle, but in the end it never matched up well on any of the bands he wanted to work and the radiation angle was too high for appreciable distance. He's gone back to a basic multiband vertical with radials and gets much better results. (Fortunately, he has ample open space at his site.)

A ground mounted 1/4-wave vertical with radials or a good ground screen has the most predictable and repeatable characteristics and the best omnidirectional pattern--or a 5/8-wave for even better low-angle radiation, although it's physically more challenging in many locations.  But unless the ground is sufficiently unobstructed for a wavelength or two in all directions, you'll lose some of that signal locally.

A ground plane antenna or a dipole mounted a little above the earth may avoid some obstructions, but won't necessarily have good low-angle radiation or predictable performance, unless you can get its feedpoint half a wavelength above ground or more. A quarter wavelength above ground is the worst case for take-off angle, in fact. Higher or (if necessary) lower than 1/4 wave elevation is better.

The two most consistent performers here on the prairie are K6FRC from out west in California and RY down east in Maine.  At FRC, the antenna is a relatively tiny 20 meter Hamstick mobile antenna on a metal roof of a small building (a shipping container). It has the advantage, though, of a nicely elevated site with no lossy trees in the immediate vicinity.  RY uses a vertically mounted dipole, suspended from a tall enough tree that its lower end is well above ground and can maintain a low radiation angle. I would refer you to the "What antenna are using on your HiFer" thread on the LWCA message board back in October for more ideas.

Moral: a relatively simple antenna, well placed, can be effective and avoids a lot of the guesswork that goes along with some larger antennas.

35

22 Meter Band HiFER Beacons / Re: 22 meter beacons outside the US (and England especially)

« on: September 14, 2019, 1938 UTC »

One should not confuse ISM bands with license-exempt services. Even though some of them share allocated frequencies, they are not synonymous! The regulations for one service cannot simply be applied to the other.

Example: 44 meters has an international ISM allocation that's implemented in both the US and Canada. License-exempt communication/non-specific-use devices are also permitted on those frequencies in Canada under RSS-210 rules, but not under FCC Part 15 in the US.

Other ISM bands in the US are shared with specific other radio services, like 11 meters (CB radio) and 33 cm (Amateur Radio), and also license-exempt devices.  But over half our ISM bands are simply not available under Part 15, except under tightly limited circumstances, if even then.

Conversely, some of the most popular bands for license-exempt devices are not ISM bands at all: 160-190 kHz, 510-1705 kHz, 49.86 MHz, and the FM broadcast band.

36

22 Meter Band HiFER Beacons / Re: 22 meter beacons outside the US (and England especially)

« on: July 18, 2019, 0617 UTC »

You would need to search Ofcom's regulations carefully and maybe contact them directly.  My reading of IR2030 shows the band to be available for short range license-exempt devices of non-specific purpose, but my copy is from 2011 and may no longer be in effect and/or subject to change if/when Brexit happens.

There was once hobby activity in the band in Holland, for example, under similar field strength limits as the US (except for being measured in A/m instead of our V/m). However, that apparently ended when their regulators decided to interpret the ECC Annex 1 comments of typical use being RFID tags as mandating that specific use.

37

22 Meter Band HiFER Beacons / Re: P 13555.0 CW 1550 UTC 1 Jul 2019

« on: July 18, 2019, 0548 UTC »

This one has been a recurring mystery every summer for at least the past three years, maybe four or five. Need to look up past logs if I still have 'em. It generally shows up a bit excessively strong at first, then backs down to a more typical/honest signal level, and disappears in late summer or fall.

Another anonymous one to watch for that maintains a similar intermittent summer-only schedule is PLM, which was seen around 13557.75 last year.

38

22 Meter Band HiFER Beacons / Why "anonymous" beacons on 22 m?

« on: January 07, 2019, 0551 UTC »

I don't understand the appeal of putting a signal on the air, then leaving listeners to discover it on their own, never knowing what town or even the state/province it's coming from, let alone who the operator is or how to let them know they're being heard.

There may be some survival value to anonymity if you're making up your own rules at a clandestine station in the desert or something, but 22 m is a great band for experimental modes, propagation studies, camaraderie among those who relish a challenge, etc.  So why hide? Why not do like WCK, BNC1, J1LPB and other recent additions who let the community know of their existence here and/or at lwca.org/mb soon after they went on?

Just throwing together a circuit board and going on the air without publishing any accompanying information is about as useful as the following reception report:

"I copied one of the latest unknowns early Sunday afternoon, after it faded up from poor audibility to a strong and steady signal for several minutes.  A lot of IDs per minute made it a little hard for the ear to sync up until reception became good enough, but then it was easy copy. The frequency was nearly 800 Hz higher than recently reported in this forum. It was heard at the same time that some other stations were present whom I won't mention, and gone some unspecified time later in the afternoon, which allowed me to make a rough guess of its geographic origin, which I'll also neglect to mention along with my own QTH."

Those are actual facts about an actual logging, but without the few key items I omitted, it's exactly as useless to the operator of the beacon, as only knowing the call sign and approximate frequency is to serious listeners.  How about it, guys. We've got these great online resources available, so why not make use of them?

39

22 Meter Band HiFER Beacons / Re: NDB2 13554.0 khz

« on: November 16, 2018, 1503 UTC »

"Your kiwi SDR provides an excellent screen shot, Chris."

Indeed it does.  From what I've heard of the KPH Kiwi online, these units also appear to have very good sound quality.  I'm an analog guy by nature, but this seems like a pretty good tool to have available also.

40

22 Meter Band HiFER Beacons / Re: HiFER "AN" 13563.0

« on: October 22, 2018, 0545 UTC »

Copied it again tonight, around 0200 UTC this time. I'm guessing it's probably from California.

I don't think the CW is Farnsworth spaced after all, after having clearer copy with less QRM and QRN tonight.  The frequency did jump around a bit, though, enough to hear sometimes.

41

22 Meter Band HiFER Beacons / HiFER "AN" 13563.0

« on: October 20, 2018, 1551 UTC »

Heard last night a few Hz above 13563.0 just before 0100 Z sending "AN" with Farnsworth spacing. Anyone know who it is?

42

22 Meter Band HiFER Beacons / Re: Signals to Correlate with 22m beacons.

« on: September 01, 2018, 1718 UTC »

I don't really think broadcasters make very good indicators. Their schedules are not that consistent at the times of day when the band is open domestically, plus with power levels 70-80 dB greater than the target signals, well, they'll make it through 99 out of 100 times when a HiFER won't.

Having said that, RNZ may at least be some indicator of when trans-Pacific paths are open.  But otherwise, the ham 20 meter beacons are a more reasonable indicator IMO.

43

22 Meter Band HiFER Beacons / Re: Sunday Morning Hifers

« on: June 17, 2018, 1820 UTC »

Before 11 AM Central, I was hearing P, WV, sometimes MTI, and seeing EH, USC, and sometimes TON on Argo.  Almost could heard TON, too, but it was broken up by codar pulses.  Just after I tuned to the top half of the band, I was able to hear GNK for a little while, but then SWBC sidebands began wiping out everything at that end.

44

22 Meter Band HiFER Beacons / Re: New HIFER Beacon "RF" is on the air!!

« on: April 04, 2018, 2009 UTC »

It does seem a bit touchy trying to adjust the trimmer pot. It's easy to go from a couple of milliwatts to 30 in no time flat. A lower value in the 220 ohm range might be better, and is well within the drive capabilities of the three paralleled NAND gates.