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My favorite QRP group is the Polar Bear QRP gang! We have a good time and enjoy outdoors activities and trying to connect with one another at least once a month with some kind of activity. To escape some of the heat, I got an early start on the day. I wanted to try out a new mini-bac antenna configuration and knew it would take some time to get it up into the trees. BOY WAS THAT AN UNDERSTATEMENT! It was 110 ft doublet with a 40 ft feedline that was setup as a ladder line. Not an easy one to get up single-handed. Thanks to some tall trees, was able to get it up about 40-45 feet in the pine trees. It loaded great on 40m, but was disappointing on 20m so I ended up setting up my W3EDP in an L from my 20 ft Jackite pole to a nearby cedar tree at about 35 feet.  The sun chased me into the treeline where I settled in to chase bears.

Abandoned mini-back doublet feedline hangs in foreground

My xyl Connie took a picture that shows the mini-back feedline hanging in the breeze after I shifted positions and setup the W3EDP in the shade. Grrrrr!

Osprey perched right above my head…cell phone picture

Was able to work a couple of the Polar Bears, Mike W3MC in MD and Guy N7UN up in the mountains on a trail(?) in NJ. I heard VA2SG but he was at ESP level briefly then faded away. I did hear a few others working him though. WA8REI was working Guy but I could not hear him at all and ended up tail ending their QSO to connect with N7UN.

Got to work a few others through the QSB and poor signal strength on 20m including Pastor Les, K4NK in SC, KE5SBZ, Ed in TX, N1FJ in MA, and Phil W3HZZ in Atlanta so it was a nice way to spend a few hours outdoors in the heat.

Connie brought me a picnic lunch and we enjoyed the osprey and bald eagle show as they fished Lake Fredrica.

Had to drink extra coffee to copy speedy W3MC's signal

This is the life… outdoors and ham radio…making QSO's…PTL!

I enjoyed our hamfest in Santa Maria, California this morning and my opportunity to chat up with Richard Norton, N6AA.

We talked about what it takes to move to the next level and he shared a few stories about his 9Y4VT operation as well. The key to successful RadioSport, according to N6AA, is operate as much as possible, guest operate where possible, and call CQ alot even if one is low power, low profile.

Richard mentioned both the art and science of the game will surely follow as one pursues a Box score. I wanted to listen for hours however his duties were first given the hamfest, perhaps, next time N6AA will continue recounting his adventures to 40 zones stretching across the globe.

73 from the shack relaxation zone.

P.S. I purchased a Palomar R-X Noise Bridge and a 2009 ARRL Periodicals CD-ROM with QST, QEX, and the National Contest Journal.

I did a quick lash-up of the UHF FM transmitter module I received a few days ago which I was planning to use in a low-power Echolink node, mainly just to see if it worked. It did, but I discovered a small snag. The audio output isn’t squelched.

The Echolink software requires either normal squelched FM audio or a carrier operated squelch signal on one of the serial port control lines. As neither of those is provided I guess I am going to need to generate a squelch signal derived from noise. But as I am not knowledgeable enough about electronics to design my own circuit I am going to have to find one first. This appears easier said than done, though there seem to be a surprising number of patents on the subject.

It isn’t an urgent problem as I’m not in any hurry to build this project. I’ll probably have more enthusiasm for it once the gloomy autumn weather starts.

Someone commented in the eHam ratings for my blog that I spent too much time complaining about retailers. I’m sorry about that, I only tell it how it is, but it appears that no-one in this country is capable of doing their job properly. Perhaps the government’s policy of sending 50% of people to university means that most people are over-qualified for the job they do and are too bored by it to actually think about what they were doing.

Phase 2 of my shack renovation was completed earlier this week. It should have been finished a couple of weeks ago. Olga designed and ordered a system of wall units including shelves, cupboards and a bureau with a door that drops down to form a working surface. This bureau is to be my workbench – now I can start something and when I have done enough for one day I can just close the door on it so everything stays looking tidy.

The consignment arrived consisting of all 11 boxes as marked on the shipping labels. However as we started to assemble it we found that a few bits, including the entire bureau, were missing. On contacting the retailer they were sure that 12 boxes had been sent, but the bureau was never discovered and they had to order a new one from Sweden – hence the delay.

My workbench is now separate from my operating area so I can no longer use the Diamond power supply that powers my radios to power my projects. So I needed a variable power supply for the workbench. Yesterday I was pleased to win in an eBay auction a refurbished variable power supply from Rapid Electronics for about half what a new one would have cost. The courier delivered a large parcel this morning which was labelled with my address, but when I opened it I found four retractable mains cable extensions that had been ordered by Workington Sixth Form College, together with their invoice. So now I have to wait in while Rapid arranges for its courier to collect the mains extensions. Whether I will ever see the power supply, or whether it will just vanish like our original bureau, remains to be seen.

I’m sure some readers must be thinking “take a chill pill, mistakes happen.” But mistakes seem to happen rather too often, if you ask me. If you were in the mail order business, wouldn’t you put systems in place to ensure mistakes like this don’t happen, because they annoy your customers and cost money to rectify? Rapid Electronics “operates a Quality Management System to BS EN ISO 9001:2008.” What a load of spherical objects that is.

While on the subject of retailers, last week I sent an email to a company that advertises notebook PCs with Linux installed, asking for a quote for a system for my business. I have not received a reply. Why does that not surprise me?

So, here I was at Dayton a few weeks ago and decided to check out the fox hunting/amateur radio direction finding (ARDF) forum.  I forgot who did the forum, but it was actually very well done.  One of the projects I learned about was “The Montreal Doppler”.  This is a really neat project designed by Jacques Brodeur, VE2EMM.

I saw many neat attenuators, offset attenuators….. but this….. well…. it has LEDS!  Pretty lights…. OK, I digress.  Working with a bunch of these LED’s is pretty kewl and looks sweet.  This is a project that is well documented on the web and I’ll provide links below.

The biggest question I had was, where do I get the microcontrollers and firmware.  Not only was I able to acquire the PICS (microcontrollers), but I was able to get PC boards and the LCD for a very reasonable price from FAR Circuits!  I know I picked up the last one he had at Dayton, but he may be able to do more (they cost $45.00).  Check out the FAR circuits website at http://www.farcircuits.net/

A little about this project from VE2EMM’s website, list of features:

–   36 LEDs display; center LED when green = good signal, when red = no signal ,  the direction is frozen to the last good signal.
–   Uses 3 PICs; a PIC16F628A for the display, a PIC18F4520 as the main processor and a PIC12F675 as a frequency divider.
–   Filters; a Max 267, the best bandpass filter that I have ever seen, followed by the Roanoke switch cap filter for very narrow band width (+/- 0.5Hz).
–   My DopplerII integrating and phase detection software in the main PIC.
–   LM386 for monitoring the audio independently from the doppler.
–   Simpler menu selection, turning a selection pot and a pushing a DO switch.
–   It will switch 4 antennas with a + or – going signal, 4 antennas differential, 8 antennas with a + or – going signal.
–   Pushing the DO PB sends the direction to APRS.  The protocol is:  <cr><lf>%359/Q<cr><lf>. The Q (0<8) is the quality of the signal just before the
extraction of the phase information.
–   GPS information goes through the doppler, it will be instantly interrupted when the doppler sends a DF to APRS on a PC.
–   Faster main processor, PIC18F4520.    **** NEW ****  June 06

The model I saw really intrigued me and there are a few really well done websites devoted to this project (it has quite the cult following).

The original site is at:

http://www.qsl.net/ve2emm/pic-projects/doppler3/doppler3-e.html

Here is another page on Jacques site that has some examples from other builders:

http://www.qsl.net/ve2emm/pic-projects/doppler3/md3_photos/dopler%203%20pictures.html

KA7OEI has a neat page with a bunch of information on this project:

http://ka7oei.com/emm3.html

He has a lot of information about an alternate firmware that looks like the image below:

The alternate firmware page is at:

http://ka7oei.com/emm2_mont2a.html

If you have any more information on this project, resources or anything of the sort, please comment below.

This blog is meant to be about my hobby, amateur radio. Occasionally I have given in to the temptation to blog about some other event that has affected me, or let off steam about some topic that has annoyed me. But as I discovered a few months ago when a couple of the American ham radio blogs I read decided to vent about Obama, health care and other issues that Americans care deeply about, it can be very disconcerting to encounter far off-topic subject matter in a specialist blog, especially if the opinions expressed are ones with which you profoundly disagree. So in recent months I have tried to resist the temptation of controversial posts.

Sometimes I still get the urge to write about these topics, though. So to satisfy that urge I have started a new blog. Its title is One Foot in the Grave; the subtitle is Ramblings of a real-life Victor Meldrew. British readers who have seen the BBC comedy series of the same name will know what to expect from this. Readers from other parts of the world will have to see for themselves, though perhaps much of what I will be writing about won’t be of much interest to them anyway since it is going to be mostly about the trials and tribulations of life in the UK.

Nevertheless I hope that a few of you may find it worth following One Foot in the Grave and even telling other people about it.

Welcome to Handiham World!

What coax should I use?

Question:

The repeaters I want to use are all just a bit too far away for me to work with an indoor antenna or a handheld radio. I want to install an outdoor antenna so that I can use several different VHF and UHF repeaters. I already have a dual-band 2m/70cm vertical antenna, but what kind of coax should I use? I am thinking about RG-58 or RG-8X, because they are cheaper and easy to work with than the thicker RG-8 or RG-213. My cable run will be about 100 feet.

Answer:

Since the repeaters you plan to work are probably located in different compass directions, your choice of a vertical antenna is a good one, as long as the repeaters are not so far away that you would need a directional antenna with more gain. The directional antenna usually means an extra investment in a rotator system, a considerable expense and an additional accessory to maintain over the ensuing years.

One thing you will not want to skimp on is your feedline, especially if it is to be used for VHF and UHF work, and when the feedline is going to be run for a considerable distance. A short run of RG-8X, under 25 feet, is probably acceptable for VHF work. The problem with these thin, cheaper feedlines is that they lose quite a significant amount of signal – both on receive and on transmit – and the savings in initial cost for the coax are quickly offset by the poor performance they introduce to your otherwise well-designed system. RG-58 is such thin, fragile coax that it is a poor choice for anything but temporary use or short connecting cables used in test situations. It is very lossy and should not be used over long runs, even for HF operation. Its fragility means that it can easily break.

Let’s take a look at the loss for a typical VHF frequency, 146.52 MHz for three common types of coax, all assuming a 100 foot run.

RG-58: Power in = 100 Watts. Power out = 34 Watts. Total loss is 4.7 dB. Ouch!
RG-8X: Power in = 100 Watts. Power out = 39 Watts. Total loss is 4.1 dB. Ouch!
RG-213: Power in = 100 Watts. Power out = 55 Watts. Total loss is 2.6 dB.

As you can see, the unfortunate truth is that all of these cables have significant loss, but the cheaper cables will end up turning most of your signal into heat. Only the RG-213 comes close to being acceptable for VHF use with a 100 foot run.

Now for something really scary, let’s try a 70cm frequency, 446.0 MHz, with the same cable run.

RG-58: Power in = 100 Watts. Power out = 13 Watts. Total loss is 8.9 dB. Double Ouch!
RG-8X: Power in = 100 Watts. Power out = 15 Watts. Total loss is 8.2 dB. Double Ouch!
RG-213: Power in = 100 Watts. Power out = 32 Watts. Total loss is 5 dB. Ouch!

Discussion:

Even with the best of these three coax types, you are still getting less than one third of your signal to the antenna. Remember that it works the same way on receive. And why would you even bother with RG-58 or RG-8X for UHF work, when 100 Watts turns into only 15 Watts or less? Long runs of cheap, lossy cable might as well just be dummy loads!

As you can see from the results we have listed, the loss per distance unit of feedline goes up when the frequency goes up. Therefore, a cheaper grade of feedline might be acceptable for use on 3.9 MHz, but far too lossy for use at VHF or UHF. Another consideration is that if one intends to use even higher transmit power levels, cheaper coax must not be used because it may arc over and fail. It is generally acceptable only for lower power levels.

The results we listed are for SWR readings that are virtually perfect, 1:1. Since no antenna installation is perfect and minor mismatches occur in even a carefully-designed system, the actual loss will be even higher than what we listed. This makes using good feedline even more important.

To summarize, you will have several important choices to make when you plan your VHF/UHF antenna system. You will want to decide which repeaters you want to work, their compass directions from your station, and whether you will need to choose a directional antenna or a vertical antenna. The supporting structure will add height, which is generally a good thing for effective VHF/UHF work, but also add to the length of a feedline, and longer feedline runs mean more loss. If you want to try weak-signal work on VHF and UHF, you will need a rotator and a horizontally-polarized directional antenna. Unlike repeater operation, weak signal work on SSB and CW absolutely demands good quality feedline for the lowest loss possible. FM repeater operation is less demanding, and will require vertical polarization. You may be able make your horizontally-polarized system work for repeaters, but your vertically-polarized antenna will not be effective for weak signal work on SSB and CW.

Our recommendation is to use good quality feedline for every installation, avoiding higher loss coax except for short connectors and temporary use in sort runs.

Resources:

Are you wondering how we calculated the loss for examples we used in this article? It was easy with the online calculator we found at the KC7HXC website!

For Handiham World, I’m…

Patrick Tice
[email protected]