Posts Tagged ‘windom’

Which antenna is better?

Real world antenna comparisons

I don't have many choices for my antenna at my residential QTH.  I have an 80m OCF Dipole (aka Windom) hung from the peak of my roof at about 25ft and a ladder line fed 40m Doublet folded around in my attic at about the same height.

Generally I've been using my 80m Windom for most contacts because it is resonant on 7 bands and I don't have to tune it.  I've had a number of on-air ragchews where I switch antennas and ask for signal reports but it is often a hassle and I don't like to interrupt a ragchew to ask for that sort of comparison. 

So how do I know which antenna is better for certain bands and directions?

The RBN

The Reverse Beacon Network offers an objective and patient antenna tester.  I just recently learned about this resource and it's a fabulous tool.  When my CQ isn't being answered I'll often bring up the RBN and check my signal reports and then switch antennas to see how they compare.

It has been very interesting to learn that the Doublet in the attic often outperforms my Windom usually by 12db and sometimes by as much as 20db especially on the higher bands.  I'm guessing that part of it is the greater efficiency in the ladder line but that doesn't tell the whole story because the Windom offers a low SWR on most bands and shouldn't be eating up much power in the coax through SWR losses.  Antennas are magic.
Two highlighted records show the difference when I switched antennas and moved the transmit frequency slightly to cause a new report to be sent

Process

Ok so here's what I do... The RBN stations will report only when they see a new frequency or it's been 15 minutes since the last report for a given station, so when I switch antennas I will move frequency slightly to trigger the new report.  Now admittedly QSB or other conditions may change between the reports so you'll need to do this a bunch of times over the course of days and compile some records to get a clear idea of how each antenna is performing in certain directions.  This isn't hard science but it's more real-world than a smith chart or the occasional signal report from a station or two.

If you make use of the RBN I encourage you to donate on their site.

That's all for now...


So lower your power and raise your expectations

72/73

Richard N4PBQ

Can anybody hear me

Calling QRP CQ - Inconceivable


My 80m OCF Dipole has been a surprisingly good antenna and I've made contacts with it on all bands except 6m and 160m.  Based on my past experience trying to tune up short antennas on 160m I really hadn't considered trying to use this Windom for 160m.  But through some email exchanges with another ham in Illinois who had recently put up a 160m antenna we decided to try a scheduled QSO on the top band.  So it was time to give the Windom a shot on 160m.

Amazingly my 80m Windom / OCF Dipole has  4.5:1 SWR native around 1.8 mHz and it matches easily with a tuner across the entire 160m band.  That was a surprise. 

I tossed my mighty 5 watts call out at 1810 kHz not expecting much...

Within a minute of calling CQ I had a faint QRP station from Maine tried to work me.  After about 4 tries I finally copied his call correctly but then lost him.  Immediately another station called me and we exchanged the niceties of signal reports, location, rigs and weather.  I received a nice 579 report for my 5w and I gave him a 599+ report for his thundering kilowatt station.  He needed to work my County so I was glad to be able to provide him with the contact.  Following that call the former QRP station from Maine was back in there and finally we worked each other.  We had a nice QRP to QRP QSO on the top band.  He gave me a 549 report but he was using a 400 ft beverage receive antenna.  I was struggling a bit more to copy him through local QRM on my side and a less qualified receive antenna and reported his signal as 339.

Those were my first two contacts on 160m using CW.  Who'd have thought my cloud burner antenna and QRP power would get me such quick results on the top band.  I just figured no one would hear me.  
So how do you know if and where your signal is getting out ?

The Reverse Beacon Network

I had to quit right after those two QSOs but when I later checked my email the original station with whom I'd planned the scheduled QSO reported that although he had not heard me he said I was getting out and sent me a link to something called the reverse beacon net showing a couple of stations that were hearing me on 1810 kHz.

You mean I can find out in near realtime if and where my signal is being heard by an automated system? No way!  That is cooler than a Ronco Pocket Fisherman.  Recall that I'm relatively new at this stuff and this may be old hat for a lot of you.  But the ability to toss out your call and in real-time check where your signal is getting to just warms the push-pull final transistor in my heart.

The Reverse Beacon Network can give you the last 100 reports of your station. So I took a look and saw some of my weekend activity where I was shooting some fish in a barrel (I mean working contest stations) and there were beacon reports of my call from such places as far South as the Antilles and as far West as Utah.
Map of the last 100 reports from Reverse Beacon stations of my call sign
Color coded by band

So the reverse beacon network report tells you what station heard you, the frequency, the signal to noise ratio (higher is better) and your word per minute (wpm) speed.  

It even includes a speedometer

Being a new CW dude my word per minute speed is of interest to me.  Most of my QSOs in the past week have been at 15-16 wpm.  I'm using a Vibroplex Bug I received last weekend and have slowed it down with a home-made weight attached to a drywall anchor pressed on the end of the pendulum.  I found it interesting that some beacon stations reported me at 19-23 wpm.  I looked at the time and the frequency and realized that the higher speed was from my first on-air QSO using the Vibroplex Bug with N4HAY before I slowed it down with my junk box bug tamer.  
My brief speed key session with N4HAY
So if you are using a manual key and don't know what speed you are sending just check out a beacon to see what speed they are reporting.

Summary

This reverse beacon stuff has been around a while. So unless you're a newbie like me you probably already knew about it.  But if you haven't used before it's very cool, especially with regard to knowing how your QRP station is being heard. Are you making it 1000 mile per watt?  Is your antenna propagating East, West, North or South.  How and where is the skip?  This answers many questions that I had been wondering about as I'm operating.  A shiny new toy, just in time for Christmas

So that's all for now.

So lower your power and raise your expectations

73/72
Richard N4PBQ

DX seems to operate in the fast lane

DX for new CW operators

How to copy those high speed ops?

EA8TL's Hexbeam in the Canary Islands
As a relatively new CW operator my copy skills are still relatively weak, especially at higher speeds.  DX stations seem to send their calls at 25wpm or faster so I often can't copy them without listening to them over and over and usually there are so many other stations working them that it gets confusing.

Well this morning I wasn't having much success getting an answer to my calls on 40m, and 20m seemed dead.  So I popped up to 17m and there was a good signal coming in that no one else was answering.  I listened over and over and finally copied EA8T (op name Jorge) located in the Canary islands off the coast of Africa.  I replied to him and worked him at my relatively slow 18wpm sending speed.  I wasn't very graceful in my response and he got my call wrong on the first go 'round but resent it correctly after that.  The entire time no-one else answered him even though there was plenty of activity elsewhere on 17m.  Are the Canary Islands considered blasé as far as DX?

Anyway I was happy to get the response.  I know (or surmise) that my 80m Windom has some fairly pronounced gain nodes in different directions on the higher bands but I didn't know which directions they pointed.  I guess one of the nodes points toward Africa (yaaay!)
Path from N4PBQ to EA8TL in the Canary Islands
My copy speed is slowly increasing as I've been operating CW for about 3 months now, but I wonder if there are DX stations on some segments of the band plan for slower speed operations.  I spent about 20 minutes sending my call at 18wpm down to 12wpm on the QRP segment of 17m (18.096 MHz) but no one answered.  I know I was getting out given the previous contact.
Do DX operators just not want to bother with newbies such as myself?  I wonder.  I'd appreciate suggestions in the comments section.
That's all for now

So lower your power and raise your expectations

73/72
Richard N4PBQ

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