[VHFcontesting] Moxon Yagi loopers roving

Tue Jul 16 16:06:47 EDT 2013

Hi Rick and all, This is an interesting thread that brings up LOTS of issues besides just comparing a Moxon to a Yagi.. First of all a Moxon is, of course,  just a 2 element Yagi with the ends of the elements bent towards each other to reduce the width and, (since the 2 elements are mechanically connected) I suppose add some strength. Even though it "looks" like a loop it is not and has a directional pattern.. Well everyone probably knows that, but as Rick states, what really is important about 6M antennas is the height above ground.. A Moxon, Halo, 2 element Yagi or 7 element Yagi MUST be higher above the ground than one can travel with on a rover. AA9D, multiop contest station from IL, did some test years ago and compared a halo (not sure which one but it doesn't really matter - they all have gain LESS than a dipole) to a 5 element Yagi (correct me someone if I have the # of elements wrong). The Yagi was at "top of car height", say 7-10 feet, and the halo was at 20'. The halo outperformed the Yagi on all "non-skywave" paths. This is with a difference in published gain of something like 10dB!!!  The reason is the pattern gets elevated when the antenna is close to the ground. (The gain is still there, actually, but not on the horizon) That's why the halo (or any antenna actually) close to the ground works so well when the band is open for e-skip. I used to rove with a 4 element beam on the bottom of a stack of 4 yagis. It was probably 7 or 8 ft off the ground. (yeah it hung out over the sides of the vehicle, having a maximum element length of about 10ft but I never hit anything or got a ticket). BUT.. with this setup I hardly ever worked ANYTHING except really close stations except when there was e-skip at which point the elevated pattern actually made it work GREAT and the shorter the skip, the better it worked.. So now, having learned my lesson, I rove with a home made 2 element beam on a 4 ft boom. It's light weight and easy to stow and I use it with a 18 ft mast. I actually stow the thing connected to the mast and just pop it up at locations on a mount attached to my receiver hitch, so the beam is actually 20 ft high or so.. This setup has yielded many 200-300 mile dead band "ground wave" contacts and I love it. The pattern is quite broad in the e-plane so you don't have to do a LOT of rotation.. (especially up here where ALL stations are basically southwest) Down side is you can't operate 6m while in motion! 

This all leads into my second subject. There are at least 2 ways to skin the rover cat I guess.. Some guys (I am one of them) like to use as big of antennas as they can get (and high power etc) on the vehicle and actually try to work DX from each stop. Others let the vehicle do the work and actually *drive* to the rare grid. I always thought roving with omnidirectional antennas with no gain was pretty ridiculous, but now see that it's not a bad way to go if you like to drive a lot. Hit a WHOLE LOT of grids and keep moving and work everyone you can from each stop and even along the way. The "grid circling" rovers take this scheme to a higher level, but it's the same idea.. Of course driving to lots of grids AND having a station capable of 200,300mile + contacts is even better, but eventually we run out of time or road or whatever.. 

I still recommend reading the late W3IY - Bill Seabreeze's web page.  http://www.w1rt.us/w3iy/   . Bill would hit a TON of grids and even when he was down on the middle Atlantic shore in the FM grids, we'd stand a chance of working him up here in Maine. Read Bill's app note on rover yagi stacking too.. It contradicts a lot of the info out there and I've been working on a presentation to show why - maybe get it to one of the conferences one of these years.. Anyway, Bill turned in really great rover scores.. and he had fun too I can assure you.

Anyway, yada yada.. 

bill, K1DY in Maine

> From: rick1ds at hotmail.com
> To: vhfcontesting at contesting.com
> Date: Tue, 16 Jul 2013 13:38:15 -0400
> Subject: [VHFcontesting] Moxon Yagi  loopers roving
> 
> I have used a variety of all of the above while roving over 20 years. 
> I currently use the 6m Moxon for light weight and ease of handling. It's OK, and when 6 is open, it doesn't matter what antenna you have as a rover, as long as it can radiate. I have written about that in the June VHF summaries in QST of folks' experiences with all sorts of "wet noodles" and low power when 6 is open. Anything goes. The most important concern is that the antenna be high enough above the ground (or vehicle roof and other antennas) to allow it to radiate in the designed pattern. 
> BUT--I have had some issues with the PAR Moxon. Over the few years I have used it, the lighter weight elements have sagged, the wire element has sagged and caught on things and pulled the tubular elements out of their holes. The insulator of the driven element also broke when the unit fell, but the company replaced that piece for free. All these are easy to repair. Overall I think it's a great rover antenna and I will continue to use it. 
> I did use a 3L beam in the past, but I gave it away to a fellow ham who wanted to get on 6m. It was good when I used it, but a little too big for my rover setup. It really didn't make a difference what antenna I used for 6m. I have even used just a dipole. I have a 12 band rover, and the big deal for me is working fixed stations on 2m and then moving them up the bands. We hit 6m last as that is the 1 point band. And when 6 is open, any antenna works and few people stop to run the bands. 
> I use 4 loopers for bands 9EFG and the key to keeping them in better shape roving is to mount them with the loops downward. You learn very quickly that low branches and leaves will catch and bend the loops when they are mounted in the up position. They are all mounted on 1 crossbar that is then fastened to the main mast. Polarization is still horizontal. GL. Rick, K1DS
> 
>  		 	   		  
> _______________________________________________
> VHFcontesting mailing list
> VHFcontesting at contesting.com
> http://lists.contesting.com/mailman/listinfo/vhfcontesting