Matching a Vertical with an UNUN

When adding the radials to my 160 T-vertical (72 ft vertical + 56 ft top loading t-wire on each side for a total electrical length of 128 ft) I kept notes on the SWR as I added 3 – 4 radials.  As predicted I had a very good direct feed match starting with only 4 radials…e.g. between 1814 – 1824 the VSWR = 1.1: 1.  But the reactive part of the load X = 8.  According to the books we have not reached anywhere near  peak efficiency.  As I added groups of radials the numbers appeared to get progressively worse…but I believed the experts that the efficiency was getting better.  But with 10 radials X = 0 over much of the band and the SWR was generally 1.2:1. Skipping all the in-between measurements, when I reached my goal of 32 radials (I could only expect 0.3 dB gain going to 120 radials the nirvana)…the VSWR was now  a flat 1.7 – 1.8 between 1800 – 1900…but X = 0 over much of that range….so the load impedence was almost all resistive (R).  On the MFJ 259B R = 38 – 26 over the same range.  But the VSWR being somewhat higher than I would like, I researched putting a 1.56:1  UNUN (unbalanced antenna to unbalanced coax) right at the antenna base.  This would match 32 olms impedenace of the antenna (almost all R ) to 52 ohms of the coax.  Balun Designs, LLC makes baluns of all types and  can  handle  up to 2 KW.  At $69 I thought I would try this approach for the first time.  It took a couple weeks to get it.  Sent USPS Priority.  Looked nice and installed it today.  VSWR is now 1:1 on 1820 and > 1.5: 1 from 1800 – 1870.  At 1900 it’s 1.8:1.  The MFJ will also measure Percentage of Transmitted Power (a backhanded way of stating VSWR) and it peaks at 99% and drops only to 90% at 1900 kHz. I worked ZL8X this morning BEFORE installing the UNUN.  I suspect that this mod will make little difference if any in DXing.  But it would appear practically  all the watts are now going into the antenna.  I think this is probably a good thing.   — W1XX

Varying Speed When Sending Your Call Sign
Varying Speed When Sending Your Call Sign avatar

I still receive emails from Dick, KB1H, about the goings-on in his contest group, despite not having operated at his station for many years. One of the things they have had difficulties with is other stations miscopying their call sign (such as “K6JH”).  In trying to make it easier to copy, it was suggested that they vary the speed and spacing at which individual characters in their call are sent. This may be obvious to some of you but I thought I would mention it. I know other stations do this, as I have heard them during contests. 

By breaking  up a call into more easily discernible parts, you should increase intelligibility and therefore decrease fills and NILs (Not-In-Log) . For example I know on CW, Matt, WE1H gets his call miscopied as “VE1H” quite a bit.  Unlike many character errors (as in confusing a “B” and a “6” and a “1” and a “J” as in KB1H’s case), Matt’s problem obviously doesn’t arise from any similarity between the “W” and the “V” but due to the uniqueness of his prefix’s similarity to the “VE” prefix. In other words, operators may be copying his “W” correctly but then mentally altering the prefix once they hear the “E” to make it fit with a much more prevalent (and therefore probable) “VE” prefix. He might benefit from separating the “W” from the rest of his call by either sending it at a slightly slower speed (~2-4 WPM) than the rest, and/or by slightly increasing the spacing between the “W” and the “E” to make it stand out more. He may already be doing this, but I thought it would make a good example. Maybe he has some input he can give.

I even have to do this on SSB. Many people get confused by the “NG” and the “1G”, and try to make sense out of it by concocting  call signs like “November One Golf Something…” or “November Golf Golf”. This happens even in good or excellent conditions, so I know it’s a recognition issue. So what I do is say my call sign like this: “November Golf <slight pause> ONE Golf”, making sure I emphasize the “ONE” after the pause. I have found that it really helps others understand my call better. It not only separates my call into two distinct phrases but by emphasizing the “ONE” and placing it with the suffix I think it makes the second “Golf” easier to understand. Of course on CW you can’t emphasize a character in the same way, but by altering speed or spacing you can make a character or groups of characters stand out more, producing the same effect and making it easier to copy correctly.

During the CW Sweepstakes I used this method to help with my exchange. I don’t think Writelog provides a way to use variable sending speed within a stored message, so what I did was simply add spaces between parts of the exchange to make them stand out. I could control the overall sending speed, which I did according to receiving operator or conditions, but I think the variable spacing also helped, even at higher speeds. I didn’t get asked for a lot of fills, but I also have no frame of reference since this was my first CW SS. Perhaps my LCR (Log Checking Report) will shed light on my success or lack of it.

It”s one thing to hear someone copy your call incorrectly during the QSO, but it’s another to see how they actually logged it. Even if you correct them and they repeat it back correctly you still don’t know what their brain (or hands) did to your call. The UBN (Unique, Bad, NIL) report and LCR are invaluable tools in post-contest assessment for determining if this is happening to you, and the effects of making your call and exchange as easy as possible to copy should be reflected in those reports. Has anyone else adopted this method?

Great November Meeting at W1AN

Many thanks, John, for hosting the meeting on Saturday AND for you and W1NAN providing such a feast for lunch. It was a grand event!

It was also a very good meeting with thanks to Ed, W1PN, walking everybody in attendance through a “How To” for the new club website (not yet fully ready for prime time, but it’s getting there.)  Hmmmm… I think I’d better put this post on that web site as well as here on the reflector.

Ken K3IU