Launching Antennas With Right Guard

Dedicated LFer, K2ORS (Warren), posted a short video yesterday of his friend's  attempted 'pre-antenna launch' test flight:

"Attempted to use an 8 rotor U.A.V, to lift a string over the trees with
which an antenna wire could be pulled up. However, there were some
control issues..."










   

I'm not sure exactly what went wrong but I hope that beautiful machine was not damaged too heavily.

I've seen a few others using inexpensive quadcopters to get light strings up and over trees and it seems that they would be ideal for such tasks. As these devices flood the hobby-market, their prices seem to be dropping quickly and more and more amateurs are looking at these with antennas in mind.

Over the years I have tried numerous methods of getting a string up and over...slingshots, fishing rods... but nothing seemed to get me past the 35'- 40' mark, if that high. Maybe it was just poor technique on my part as others claim to have good success with these methods. Eventually I decided to try a homebrew 'spud gun' as I needed to get wires up to the top of my 70' Balsam.

I used Schedule 40 ABS pipe, the thick-walled stuff. This is becoming harder to find in the typical hardware outlets as most of it seems to be the lighter foam-core material which should not be used for this.

When I first fired it, I wrapped the breech in several layers of towelling, just in case it blew apart but felt confident enough to remove it after a few test shots.

There are several websites describing spud gun construction and a quick Google-search will bring up some interesting plans. My system pretty much follows this design, found here at spudgunner.com.

The first propellant that I used was hair spray but found that it quickly built-up a layer of sticky-goo on the inside of the cleanout cap and threads, making it very hard to unscrew the cap. I cleaned it thoroughly and changed to Right Guard spray deodorant which worked extremely well, was very clean burning and left no residue.

The first few times I fired the gun I was shocked to hear how loud it was, with a loud 'BOOM' reverberating around the neighbourhood. After a few shots, I fully expected to see the local RCMP arriving but when enquiring a few doors away, I was told that they had not heard anything! Perhaps it is because the thing is right beside you at the time that makes it sound so loud but I have never had any enquiries about it.

I have mounted an inexpensive (Walmart) spinning reel at the very top which has been loaded with a light (10lb) mono filament fishing line. This is attached to a homebrew lathe-turned wooden bullet, about 8" long, as shown below.

The bullet is lowered down the barrel to a peg mounted just above the firing-chamber. Once fired, it pulls line off of the spinning reel, hopefully to land on the ground on the other side of the tree. The initial attempt at launching the line over my 70' Balsam resulted in a perfect shot, but about 100' above the tree! The bullet pulled all of the line from the reel and snapped off. I eventually found it on the beach in a small bay about four properties to my south...oops.
I then backed-off on the amount of propellant and found that just a short one-second squirt was enough for a more controlled launch. It took me a few shots to get the feel of the launcher and compensating for the light wind. It is best to do this when there is no wind at all is it doesn't take much to blow the line and bullet slightly off course.

I have since used the gun many times, both here and at other ham's locations, to fire lines very high. It has always worked very well.

Should you choose to build something similar, be sure to build with caution and follow any safety instructions noted on the various websites. Most importantly, be sure to use the proper material.

More Resistors From China

I suspect that, overall, very few hams actually take the time to read ham radio blogs. Of those that do, there is probably only a small percentage that take the time to read any post-blog 'comments' that might be made by others....so...if you missed the comments regarding my recent e-Bay resistor purchase, the following information may be of interest.

Steve, G1KQH, commented that he had found an even better deal on resistors from China at Banggood, in Guangzhou. I have heard good things about this company, which sells a large variety of items from electronic parts to the latest quadcopters. Steve reported a good buy on 1%, 1/4W resistors...50 different values and 50 of each....2500 resistors in total. The offering may be found here.

Courtesy: Banggood.com

Steve adds: "The values of resistor are: 10M ,4,7M, 2M, 1M, 390K, 330K, 300K, 220K, 200K, 180K, 150K, 100K, 82K, 68K, 47K, 33K, 37K, 20K, 18K, 15K, 10K, 9K1, 8K2, 6K8, 5K6, 4K3, 3K9, 3K3, 3K, 2K7, 2K4, 2K, 1K5, 1K2, 1K, 680R, 470R, 300R, 270R, 180R, 91R, 68R, 56R, 47R, 20R, 10R, 6,6R, 1,8R, 1,2R , 1R.
They are five banded resistors inc one for the tolerance.
Arrived quick and you can use Paypal on Banggood, so no problem getting your money back if things go wrong."

With the free shipping, this is a super price and could be very difficult to beat! In addition, they offer smaller 1/4W resistor kits, a nice kit of 1/2W resistors, SMD kits and capacitor kits.

G1KQH maintains an interesting amateur radio blog, well worth a read. Thanks for the info Steve.

Perseus Deep Search

It's always interesting to use one of the many 'audio viewing' software programs, such as 'Argo', 'Spectran' or Spectrum Lab, driven with receiver audio, to dig deep into a section of the spectrum using very narrow bandwidths. The narrower the bandwidth becomes, the greater the signal-to-noise ratio, increasing sensitivity in effect. The use of digital signal processing software can create the extremely narrow milliHertz  filtering needed to view signals buried deep in the noise...the deeper the search (20db, 30db or more into the noise), the longer the time needed to build up the visual display of signals that would be far too weak to detect aurally.

Recently, rather than using Argo to view a slice of spectrum I set up the Perseus waterfall display to have a deep-look at 1240kHz. This is one of the broadcast-band's 'local' channels and one that BCB DXers refer to as a 'graveyard channel'. Almost all stations on the various graveyard frequencies run a maximum of 1kW day and night. According to the Medium Wave List, there are presently 166 stations in North America operating on 1240kHz...one of the reasons that 'DXing the graveyards' is so interesting.

With this in mind, I recently took a mid-afternoon listen. Just one station was audible to my ear, likely one of the stations to my south in Washington state. Centering Perseus on 1240kHz, the waterfall was set to display a ~50Hz slice of the spectrum...1240kHz +/- 25Hz. The screen below shows the display, ranging from 1239.976kHz to 1240.024kHz. After letting the waterfall visual display slowly build up, it revealed 26 separate carriers. The remaining signals, although propagating to my location, were too weak to be detected aurally.

 

 

 

26 midday carriers visible on 1240kHz

Checking the MWList once again, it shows only 11 stations to be within expected daylight groundwave distance from here...Washington, Oregon and B.C. Evidently there is some mid-afternoon skywave involved or I am seeing some extended groundwave from Idaho, Montana and California. MW List shows a total of 27 possible candidates, assuming extended groundwave, so it would seem that most of them are making it here in daylight.

 

Next I switched to an even narrower filter, at twice the previous resolution, visible on the top-half of the waterfall above. This displayed a ~25Hz spectrum slice, still centered on 1240kHz. Although finer resolution is evident, there appears to be no additional signals except for the three new arrivals slowly fading in at the right as sunset creeps closer.

The screen above was made approximately one hour after sunset (looping E-W) and shows the same 25Hz slice centered on 1240kHz. There are ~70 carriers visible by now, with most of them fading. Some transmitters appear to be rock-solid while most exhibit a cyclical drift, no doubt the result of some form of crystal temperature stability attempt. I'm guessing that the rock-solid ones are using more modern synthesizers for frequency generation.

Listening on 1240 during this period reveals a boiling cauldron of audio, mostly unreadable until one station fades-up and becomes intelligible for a short period before fading to be replaced by another. Sitting on this frequency at the top-of-hour identification time can often catch a few idents with careful listening.

Even comparatively empty 540kHz reveals 22 different carriers, the only audible one being CBK in Watrous, Saskatchewan, the brighter trace at 540.002kHz. The one at the right looks as if it may have just come on the air for the evening. It's possible that many of these are low powered traffic information stations (TIS) running at 10 watts.

630m Crossband Summary

Friday evening's 630m crossband activity was 'interesting' in many respects. Propagation, which had been improving slowly, chose to follow Murphy's Law. The K-index, holding at a quiet '1', rose to level '3' by the time our event had concluded, as the geomagnetic activity ramped up. Additionally, lightning pocketed various areas of the continent, making listening noisy for many.

From here on Mayne Island (CN88iu), good two-way CW crossband contacts were made with the stations in the following order:

• N7IO (Seattle, Washington)
• VE7CA (North Vancouver, BC)
• KK7UV (Missoula, Montana)
• NW7E (Bend, Oregon)
• KU7Z (Ogden, Utah)
• VA5LF (Saskatoon, Sakatchewan)
• K7SF (Portland, Oregon)
• VE7BKX (North Vancouver, BC)
• K6TOP (Los Gatos, California)
• ABØCW (Westminster, Colorado)
• NO3M (Saegerton, Pennsylvania)
• KB5NJD (Duncanville, Texas)
• W7MTL (Independence, Oregon)

'Heard' reports were received from:

• KØSBV (Tucson, Arizona)
• WB6DCE (Seaside, California)
• KO6BB (Merced, California)
• K6CLS (Palo Alto, California)
• WY3B (Kaneohe, Hawaii)
• AA7U (La Grande, Oregon)

More than one of the DX contacts mentioned using just their HF dipole for listening to my signals on 630m and simply 'A-B' switching their transceiver's frequency while two of those sending 'heard' reports were using 100' longwires. Mike Tuggle (WY3B) in Hawaii was using his amazing 1-MOSFET regen and small inverted 'L' !

I was also more than excited to exchange signal reports with Pennsylvania and Texas. Considering conditions, this distance was far beyond my expectation but both of these stations have very efficient, dedicated 630m antenna systems.

John, VE7BDQ, worked the following stations on crossband:

• VE7CA (North Vancouver, BC)
• W7DRA (Seattle, Washington)
• N7IO (Seattle, Washington)
• NW7E (Bend, Oregon)
• KK7UV (Missoula, Montana)
• KU7Z (Ogden, Utah)
• VA7JWS (Delta, BC)
• VA5LF (Saskatoon, Sakatchewan)
• WB6W (Oysterville, Washington)

'Heard'  reports were received from:

• K5HK (Reno, Nevada)
• KØSBV (Tucson, Arizona)
• WY3B (Kaneohe, Hawaii)

It was gratifying to see all of these fellows making the effort to listen for our signals or to attempt the QSO.

This exercise taught me a few things about our new band.

• It is not necessary to have huge antennas and acreage to make this band work. Good solid contacts can be easily made with small backyard antenna systems.
• With good systems on both ends, transcontinental QSO's can be made.
• There really should be more interest by Canadian amateurs in their newest band as so much work has been put into securing this portion of the spectrum as a ham band. It was very disappointing not to work any stations in VE6, VE4 or VE3 land.
• There is already much interest in this band by U.S. amateurs, many of them anxiously awaiting the day that they can also call it a ham band.

I would like very much to continue this type of crossband activity to try and generate more interest in our new band. I'm presently considering a weekly, one-night crossband operation, similar to Friday's event, perhaps running for one hour per week. The main difficulty will be in getting the word out to those that might wish to participate.

E-bay Resistors From China

During the past few projects I'd noticed a serious diminishing of my 1/4 watt resistor stock and decided to see what was available from e-Bay.

Many of the dealers in China were offering various packages at reasonable prices and it is hard to resist 'free shipping'.

After narrowing things down I decided on one particular dealer, electronics-salon, who had only five minor complaints in over 17,000 transactions during the past 12 month period. As well, he seemed to be selling only high-quality components, unlike many of the sellers from China.

The offering was for:

0 to 10M ohm 1/4 Watts Axial Lead Carbon Film Resistors Assorted Kit.
E-12 Series 86 Values, Total 860 Pieces (Each 10).
Resistance Tolerance : +-5%.
Rated Power : 1/4 Watt.
100% New, Never Used.
RoHS Compliant.

With free-shipping, the cost was just over one-cent per resistor and would nicely re-stock my 1/4W trays as well as provide me with many more values to choose from than at present...hard to resist!

So...what happened?

Courtesy: http://www.ebay.ca/

The resistors arrived, packaged as shown, at the normal 'free-shipping' (slow) rate, which I don't mind. I selected three values to test and three samples of each value...120K, 68K and 8.2 ohms.
All resistors were within their 5% tolerance rating except for one of the 8.2's which measured 7.6 ohms... 2% out of tolerance.

I next smoke-tested a 680 ohm resistor for five minutes at slightly more than 1/4 watt dissipation. Measuring the resistor immediately after revealed that there had been no change in resistance.

Overall I am pleased with this purchase and would buy from this particular e-Bay seller in the future.