PDA

View Full Version : Mounting the HF antenna front or rear


WA6CDE
08-21-2009, 09:33 PM
Ok this should open up some new coffee ...:beer:

I have seen some of the hams mobile antennas for HF.. most in the US are mounted on the rear of the vehicle. (car, PU, etc) Normally on the left side so the dirver can see it (although now we see trailer hitch mounts in the center too)

But, if you go to the AU or British web pages for mobile you see a lot of HF antennas mounted on the front of the vehicle. Now knowing that we all pull boxes of Alu the question is .. which is better front or rear... which presents more problems.. front or rear? :whistle:

So why don't americans put the radio antenna on the front of the vehicle? looks practical or effecency? :hello:

Anyone tried this before? :waggle:

Andy N1ORK
08-22-2009, 05:18 AM
Well, if I were pulling a big metal box and wanted to operate HF/M, I would put my antenna as far away from that box as I could. Unless, of course, my antenna could be mounted on top of that box while I was driving. I guess most mount it on the back because it doesn't obstruct the view out front and they think it looks better.
73
Andy - n1ork (no HF mobile - yet)

wa8yxm
08-22-2009, 10:00 AM
One advantage of a front monuted antenna of the proper height is that it can serve a 2nd purpose.

Overheight truckers often carry a long pole, EXACTLY the same length as the height of the truck.. If they need to go under a "low bridge" they fist "stick it" with the pole to insure they have clearance

An antenna, with the tip at located 1" above the top of the highest object on the roof..... Clearance stick. Very handy

I've taken my 12'6" rig under a bridge labeled at exactly 12'6"... Thankfully I run heavy and that 12'6" Sticker on my MH is MAXIMUM height.. Unloaded. w/o things like wife, cloths, cats, food, tool boxes and Ham gear. So in reality I am a bit... shorter

w3zi
08-26-2009, 09:16 PM
I had always heard that rear bumper gave a better ground plane. Guess I could understand that expecially on my pickup. I have seen some folks with the antenna on the front and even a lip mount in the hood channel on the driver side of the truck.

If you look at it from a practial viewpoint, I am sure my wife would tell me to call the lawyers if I put my Tarheel on the front bumper so its not practical and cheaper to put it on the rear... 73 Mark, W3Zi

Andy N1ORK
08-27-2009, 07:02 AM
As we all say..............'Yes Dear!'
The Boss is always right.

Radio
08-27-2009, 07:21 PM
What about getting away from engine noise?

WA6CDE
08-29-2009, 04:24 AM
Actually in testing we did ... front mounted was actually a little bit better in impeadance than the rear mounted. (we took two screwdrivers.. on on back one on front and tested 'em) Of course we noted the different pattern but it seems that with the low profile of the hood vs the high profile of the camper cap... the signal strenght was a little greater on the front at the other end.

As to noise... no difference. Seems the tail pipe was a bigger problem than having it up around the engine compartment. The hood is a pretty good shield....

As to grounding... front / rear the same frame runs through it.. so to speak

So we sat down and designed up a couple of tabs to be welded on the front brush guard after seeing a heard of cabover campers with antennas mounted on the front and not the back. If you want we can pass them along... as we have one side for the screwdriver/HF and the other side for the UHF/VHF antennas. (CB could be placed their also)

As to using it for a height detector.. well about the time you see it hit.. its too late for the rest at 60 mph... but it does let you know to pucker up... when it hits.. grin...

No matter which antenna you have... either front or rear.. they are not what one calls pretty... to the XYL. But, I am sure if you show her a bicycle and the pax seat in the truck..and ask her to chose for the trip.. she will make the right decision.. with you... grin

wa8yxm
08-29-2009, 09:33 AM
In an earlier post I gave an argument for front mount (doubles as a "Clearance Stick" if properly set.

Well, here is another side to the issue. Distance from the ECC,..

The closer the antenna is to the engine control computer. the greater the likelyhood it will interfere

k8zfj
08-30-2009, 09:52 AM
mine is mounted to trailer hitch