VK Logger Ham Radio Forum Archive

A new transmitter for the VK3RGL 2m beacon (144.530 QF22DC Mt. Anakie) is undergoing bench-testing as I write. The transmitter features an increase in power to 40W compared to the old beacon's 15W (note that this beacon has two 8-dBd yagis, one facing west, the other north-east, with the transmitter power equally divided between its two antennas. This will remain unchanged).

Another improvement is its frequency control. The new transmitter is locked to a 10MHz reference, which at present is an OCXO but in the foreseeable future this will be replaced with a GPS-derived frequency reference.

Now I'd like some input from the audience.

The present transmitter's keyer is rather verbose, sending its call sign and grid square frequently, with only twenty seconds or so of un-keyed carrier. Whilst this was ideal in the pre-digital mode days when the beacon was first installed, I am aware that the short un-keyed carrier period is unsatisfactory for those wishing to study propagation using digital techniques (e.g. Spectran etc.) or for meteor-scatter studies. I propose to reduce the keying cycle to a short burst of Morse (FSK) followed by a long period of un-keyed carrier. I have two questions for which I'm seeking well-reasoned suggestions:

1. How long should the duration of the un-keyed carrier be? I propose 5 minutes.
2. Should the un-keyed frequency be the key-up or key-down frequency? The present beacon has key-up, which makes sense to me, but I note there are other beacons that are key-down.

Replies via this forum, please.

I hope to install the new transmitter some time in March.

Chas
VK3PY

Hi Chas,
as a regular listener to this beacon, could the long carrier period have the occasional diddle on it? When you have a long carrier period it is hard to know if its a birdie or the actual beacon (I have a few birdies near 3RGL) you are hearing.

This was the case with the first version of the new VK7RAE, it ran for minutes with no ID and was often difficult to be sure it was not a birdie.

Regards,

VK3PY wrote: 1. How long should the duration of the un-keyed carrier be? I propose 5 minutes.
2. Should the un-keyed frequency be the key-up or key-down frequency? The present beacon has key-up, which makes sense to me, but I note there are other beacons that are key-down.

1. 1 min (with a short break if longer)
2. Prefer key down

Hi Chas,

I think a 1 minute cycle is a good compromise.

If you are going to eventually have a GPSDO, is it possible for it to begin keying on the minute? That way, if it's very weak and you can only detect it on Spectran, the fuzziness when it keys on the minute boundary gives an indication that it's probably the beacon.

With the ident, all you really need is the callsign and perhaps 4-digit gridsquare once. The sad thing is that a high proportion of amateurs are, err, "challenged" by CW (me included) and any information beyond callsign is completely wasted

Key up, as it currently does, seems to make sense to me also. However, a lot less frequency shift might be desirable.

Regards,
Dave
VK3HZ

Hi Chas.

Good news on the developments with VK3RGL. I note that you're considering including a GPS-derived frequency reference. Have you considered the "encouragement" of a $200 rebate offered under the WIA Grant For GPS Locking Of VK Beacons - a joint initiative between Alan VK3XPD and the Institute.

Now to your questions:

1. If the beacon is locked to its allocated frequency, it should be identifiable by its frequency alone (birdies notwithstanding). However, the licence conditions require ID at intervals of no more than 10 minutes. Shorter intervals obviate boredom for listeners. ID at one minute intervals might be a tad short for eliciting details of some propagation effects; five minutes is obviously better. ID at less than 1-min intervals, while suiting casual beacon band-tuners, would be too frequent. Then again, for those (locals) checking antenna systems and azimuth patterns, longer intervals between IDs is better.

2. If the beacon is locked to its allocated frequency, logically, that should be key-down.

My 2.2 cents.

Hello Chas,
Many thanks for the opportunity to give some inputs.

For beacons I do not like FSK - I don't believe it has a place any more unless your sending RTTY.
It should be straight carrier on and off on the desired frequency with no "unkeyed shifted carrier" or shifting off to some other frequency. (unless it is another complex mode like WSPR, Hell or JT65 etc)

There should be periods of carrier on MAX 1 minute but that should be a small percentage of the cycle.

There should be regular runs of normal CW at say 10-15 wpm - not 25wpm. (even I can read 12wpm)

Important for the DX stations with waterfall displays, weak signals and local birdies - there should be a period of QRSS3 slow Morse code (ie RGL)which makes the signal much easier to ID>

I look forward to the increase in power as I rarely hear the existing beacon here even with aircraft in the path.
Remember with 2 radiating antenna in phase the radiation pattern main lobe is maybe somewhere between the two - better to use 2 big wheels.
Don't forget the guys in Tassy.

Thanks

Chas,

If you ask a dozen people you will get a dozen different opinions.

Personally I am not a fan of a long carrier down period. With so many local birdies in the band these days it is easy skip past a perfectly good beacon thinking it is the neighbors computer. What we have found here in NZ with 2 beacon sites now running JT4 is they give a nice musical tone which is easy to detect when tuning thru even when very weak. It is also easy to peak using the S meter or to the ear - just as good as a continuous carrier.

--
Wayne

VK3HZ wrote:Hi Chas,

I think a 1 minute cycle is a good compromise.

If you are going to eventually have a GPSDO, is it possible for it to begin keying on the minute? That way, if it's very weak and you can only detect it on Spectran, the fuzziness when it keys on the minute boundary gives an indication that it's probably the beacon.

With the ident, all you really need is the callsign and perhaps 4-digit gridsquare once. The sad thing is that a high proportion of amateurs are, err, "challenged" by CW (me included) and any information beyond callsign is completely wasted

Key up, as it currently does, seems to make sense to me also. However, a lot less frequency shift might be desirable.

Regards,
Dave
VK3HZ

X2 Except the CW-challenged stuff

Chas,
Great news regarding a new VK3RGL 144.530MHz beacon.

Most replies so far seem to be pushing personal preferences, so here are mine! I spend many hours monitoring this beacon, searching for meteor burns. The present 7 watts to an 8 dBd yagi pointed N-E, produce FANTASTIC meteor pings and burns. (From memory, I think I sent you an mp3 recording of a great burn.) These meteor burns have allowed me to make many 2 way ssb QSOs with vk3's and vk5's. The proposed increase in power to 20 Watts per yagi will greatly increase the probability of detecting meteor burns.

So please do NOT change the orientation of the yagi antennas.

As to the beacon transmitting format, I have no particular preferences, as long as the beacon is transmitting continuously, (No "sleep" mode). FSK cw id is fine with me as there is no tx "OFF" time. Slow, on/off, cw keying has appreciable gaps between words.. Half a second is a long time in the meteor burn world, so if you do go to an on/off cw id, then make it reasonably fast, say 20 wpm. Surely ANY-ONE can learn the cw id at that speed given that they know what's coming.

73, Adrian. VK4OX.

Perhaps not directly relevant, but for what it's worth: VK3RGL is the magic that got me back on 2m after many years absence from Amateur Radio. It puts such a big signal into Essendon that I could hear it on my first clumsy attempts at a 2m converter a couple of years back. Subsequently, each time I fiddle with and mess up the rx system, I rely on that big signal to blast through and give me something to re-align on, no matter how deaf the system has become. It's a bit analogous to the way I got my first crystal sets going as a young lad many years back, tuning into radio station 3LO - running I think 100KW and not far away. I'm sure whatever format is chosen it will continue to suit my purposes. cheers and 73 Grant

I would like to see ALL beacons GPS locked and run a continuous WSPR format with the Tx frequency on the published one. Most stations who are serious about propagation run a computer in the shack and it is quite simple to run the WSPR program while doing other things. I run two additional monitors on a lap top. One screen runs my Flex1500, one runs the VKlogger and another can run WSPR and/or whatever all without causing the CPU to have a hiccup.

Those who are CW challenged could also use CWskimmer.

My preference otherwise if you use FSK would be for CW ident, Key down on designated frequency and long carrier also on the designated frequency. Carrier for at least a minute. It makes no sense to have them on different frequencies or on a frequency different to the designated one.

David

VK5PJ wrote:... When you have a long carrier period it is hard to know if its a birdie or the actual beacon (I have a few birdies near 3RGL) you are hearing.

+1
I deliberately limited the key-down period on the VK4RTT controller to 15 seconds maximum, for this very reason.
It's annoying to come across a carrier, and realise you've just wasted 2 minutes on a birdie.
15 seconds is ample to peak the beam and/or make receiver adjustments each cycle.

If you have a RTC on-board, perhaps you could even vary the timing aspects?
ie; Longer (relatively) key downs during morning tropo windows, quicker key-downs other times, especially Dec/Jan for Es.
If you're using a GPSDO for stability, you will most likely have date/time data to do this.
A few simple IF THEN lines can alter timing behavior to suit.
(And no, VK4RTT doesn't have a GPSDO to do these interesting things with)

Like VK4RTT, can you run different power levels (and ID them)?

VK3AUU wrote:I would like to see ALL beacons GPS locked and run a continuous WSPR format with the Tx frequency on the published one. David

x2

So many advantages which I have spoken about numerous times

Well, it seems that pretty much all options have been canvassed by now, so thanks to contributors. I would like to remind readers that my request was limited to just two things, namely the duration of the un-keyed carrier and whether it should be on the "mark" or "space" frequency. This was not an open offer from me to build the beacon of your dreams! My intention is just to replace the existing venerable transmitter with something more modern and GPS-locked. Whilst at it, I thought I'd take the opportunity to bring its ident. cycle up to date with more current requirements.

The transmitter already exists. It is a salvaged, former 148MHz 100W paging transmitter which is capable of FSK operation. Its carrier is PLL-derived but has limitations in both its carrier frequency increments and FSK offset increments. It may be possible to fudge the "space" frequency such that "mark" ends up on the assigned frequency. I note that many responses favoured this arrangement rather than having "space" on the assigned frequency with "mark" shifting upwards. As for WSPR and QRSS - sorry, no can do. Also, since most of the transmitter's amplifying stages operate in class-C, on/off carrier keying is not possible due to the wide-band key clicks that would ensue. I don't relish the prospect of biasing each stage into conduction.

Now to realistic matters:

It seems that 1-minute pure carrier intervals are an acceptable compromise between having to wait for identification, yet having a steady signal for spectral digital mode viewing. I had initially suggested 5 minutes of carrier, and Peter, VK5PJ suggested incorporating a recognisable "diddle" (as he termed it) at regular intervals. So long as the "diddle" is unambiguously recognisable, it should serve to at least confirm to a listener that what they're hearing is indeed the beacon, and not a spurious signal.

As for the FSK offset, it has been suggested that a narrower offset than the present beacon's 700Hz or so would be preferable. I think a figure of 200Hz has been mentioned. That seems to be a reasonable request.

David, VK3HZ suggested synchronising the identification cycle to GPS-time. I had already given this some thought, and it appears to be a realistic possibility for future development.

There is general agreement that the beacon should mostly shut up and transmit a continuous carrier signal, with minimal redundant information in its Morse ident. It also seems that 12 wpm Morse speed would be acceptable (That's the speed at which the present beacon sends, near enough).

Just for a laugh (this will turn into a pun, as will be seen below), I've programmed the beacon keyer with the following ident. cycle:

DE VK3RGL QF22DC followed by five, 1-minute periods of key-down carrier interrupted every minute by the word "Hi". Even the most CW-challenged listeners would soon recognise the characteristic sound of "didididit didit" at 1-minute intervals (there's your diddle, Pedro!). Thus at most, a listener would need to "waste" no more than one minute before confirmation that they're most likely hearing the beacon.

Chas
VK3PY

The CW illiterates won't get the significance of the .... .. But the format that you have suggested is a very good one.
Congratulations.

David

VK3AUU wrote:The CW illiterates won't get the significance of the .... .. But the format that you have suggested is a very good one.
Congratulations.

David

better still, have it send 73's so that all of those SSB ops out there that say Seventy Threes can hear what it sounds like and possibly realise that they got it wrong,! (year right)

It has been suggested to me that instead of punctuating the "silent" carrier period with "Hi", it might be more appropriate to use "GL" (an obvious abbreviation for Geelong). No more challenging for the non-CW folk to recognise, at least after a while, and probably more meaningful. Would 30 second intervals be better, or is 60 seconds OK?

VK7XX - I take your point, but this is about making the beacon as useful to as many operators as possible, taking account of their sometimes conflicting requirements, not about humiliating those who are unacquainted with our traditions. Just for your punishment ( ) I'll leave the beacon's yagis pointing away from VK7. Naughty boy [spank].

As an aside, how about the letter "A"? It has a cryptic significance which led to a plane and two lives being lost in 1937. Look up Amelia Earhart and her navigator, Fred Noonan. A tragedy in the making, all for the want of basic radio operating and CW skills. Not particularly relevant to the subject at hand, but a riveting(!) story nonetheless, to while away this propagation-deprived summer.

Chas
VK3PY

VK3PY wrote:It ... might be more appropriate to use "GL" (an obvious abbreviation for Geelong). No more challenging for the non-CW folk to recognise, at least after a while, and probably more meaningful.

How about a few bars from the Toreador song. Anyone could recognise that

VK3PY wrote:It has been suggested to me that instead of punctuating the "silent" carrier period with "Hi", it might be more appropriate to use "GL" (an obvious abbreviation for Geelong).

Why is GL an obvious abbreviation for Geelong? To any cw operator, GL (or gl), sent in cw, is an abbreviation for "good luck".

By all means use gl.. I wish VK3RGL good luck too.

73, Adrian, VK4OX.

Given the monotonous droning on by some CW types about non-CW types I am beginning to form the opinion that CW stands for "continuous wan$"...