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To cophase or not to cophase

Sergeant Bilko said:
I'm planning to install a Breedlove quick disconnected 102" whip, tuned for 10 meter band
Click to expand...
I didn't real all the posts so may have missed something but...
My thoughts are that 10 meter mobile is quite a waste of time these days. 10 meters is mostly crickets other than during a contest. CB radio is certainly much more useful. 40 meters is always good when mobile (or otherwise) but not for communicating with a lot of other mobile guys.

As mentioned you'll be busting a lot of antennas at that height or at least banging them on a lot of stuff if driving around with them.

Trying to get a perfect omni directional thing going is like good luck! You put up what antennas you can, or can afford, and see how it goes. Later make improvements but that is hard to do in a mobile situation. When mobile or portable you are usually not trying to be a big DX'er so it only has to be so good.
 
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Tallman said:
If you did not get an answer you expected it is because you were somewhat nebulous on your operationing conditions. If you are going to be doing this from a stationary situation you do have possibilities opening up for you. An end fed long wire with balun would do you pretty good and all you would have to take it down would is roll up the long wire and take down a short pole and store it.
Click to expand...

Thank you for your input. I have considered this also but thought that I would get a better omnidirectional, low plane radiation pattern using a vertical. Using a horizontal would place the element very close to the freight loaded on the flatbed trailer. I could simply use quick disconnects on the existing mounts at 1/4 wave spacing, but that would direct the radiation pattern fore and aft, leading me to consider 1/8 wave spacing to reduce that effect and the dependence on ground plane. I am actually enjoying the experience of noodling this out. Antennas are half the fun.
 
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Sergeant Bilko said:
Ok, perhaps this might not be the right forum to find an Elmer but, let me break this down Barney Style for those of you who have confused this thread with Twitter:

I have cophased 11 meter band top loaded antennas for use while underway. Once parked for the night, I can climb the ladder and quick connect the 10 meter band whip(s), switch over the coax, and do some SSB for an hour before turning in for the night. Yes, this requires me to get out of my seat and venture outside for a few minutes but, exercise is good for the body, which is why I chose flatbed over dry van.

Anyone else confused? Anyone have any helpful antenna theory centered comments about the subject at hand?
Click to expand...
Okay I get what you are trying to do now.
More portable on 10 meters than mobile. I still don't find it worth the effort for 10 meters but if I were going that route I would get an Antron A-99 or similar antenna and figure out an easy way of putting it up and down with a pole lashed to some part of the truck for portable use. I know some who do that with their campers etc. Much better performance than regular mobile antennas. But again, 10 meters is pretty much crickets most of the time. Some seasonal openings with sporadic E layer propagation like on CB but almost no local activity unlike CB.

For instance here are the QSO amounts made in the recent CQ WPX contest from here in the Seattle area on different bands by one of the local serious conesters. Keep in mind that any ham DX or not is worth making a contact with.
Even then, only ONE contact on 10 meters in a worldwide contest in the early summer 10 meter E skip season. The big action is most always 20 and 40 meters, contest or not.
---------------- QSOs
1.8 MHz 2
3.5 MHz 106
7.0 MHz 651
14 MHz 797
21 MHz 55
28 MHz 1
 
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Hurricane145 said:
I didn't real all the posts so may have missed something but...
My thoughts are that 10 meter mobile is quite a waste of time these days. 10 meters is mostly crickets other than during a contest. CB radio is certainly much more useful. 40 meters is always good when mobile (or otherwise) but not for communicating with a lot of other mobile guys.

As mentioned you'll be busting a lot of antennas at that height or at least banging them on a lot of stuff if driving around with them.

Trying to get a perfect omni directional thing going is like good luck! You put up what antennas you can, or can afford, and see how it goes. Later make improvements but that is hard to do in a mobile situation. When mobile or portable you are usually not trying to be a big DX'er so it only has to be so good.
Click to expand...

I fear that I was too vague about the conditions while in use: Disconnect and dismount the 10 meter whip using Breedlove quick disconnects, and switch coax to 11 meter antennas while underway. Remount 10 meter whip using quick disconnects and switch coax to 10 meter whip while parked for the night.
 
Hurricane145 said:
Okay I get what you are trying to do now.
More portable on 10 meters than mobile. I still don't find it worth the effort for 10 meters but if I were going that route I would get an Antron A-99 or similar antenna and figure out an easy way of putting it up and down with a pole lashed to some part of the truck for portable use. I know some who do that with their campers etc. Much better performance than regular mobile antennas. But again, 10 meters is pretty much crickets most of the time. Some seasonal openings with sporadic E layer propagation like on CB but almost no local activity unlike CB.

For instance here are the QSO amounts made in the recent CQ WPX contest from here in the Seattle area on different bands by one of the local serious conesters. Keep in mind that any ham DX or not is worth making a contact with.
Even then, only ONE contact on 10 meters in a worldwide contest in the early summer 10 meter E skip season. The big action is most always 20 and 40 meters, contest or not.
---------------- QSOs
1.8 MHz 2
3.5 MHz 106
7.0 MHz 651
14 MHz 797
21 MHz 55
28 MHz 1
Click to expand...

I can't really do an Antron due to storage issues and such. My motivation for 10 meter is rooted in combination transceiver options. The Galaxy 94vhp can be modified for both 10 and 11 meters, using an amp switch to power down for 11 meter use. I have limited space in the cab for hardware. I already have an MFJ-616 for my old, Army damaged ears, and I'll be introducing an MFJ-949E to simplify antenna switching and SWR adjustments related to vehicle placement and other variables. I suppose I could consider more popular bands by getting a second transceiver, I suppose.
 
In that case you do what you can with what you have or, budget constraints. I don't think many people worry much about powering down an export radio to use on CB. Probably a big reason to get an export is to have the built in extra power that they will use on CB!
Not legal to run high power but then the export models aren't legal anyway!
I'd probably get a couple of the longer whips and tune them for around 28.400 put them up and see how it goes if you are going to do the co-phased thing anyway. Not that much more of an expense really.

You can get 3/8-24 quick release adapters that fit any 3/8-24 antenna and mount but you'd need 4 of them for all the antennas figuring 2 CB and 2 10 meter antennas.if it's a co-phased system. Only 2 if not. I don't know the cost of them but it may not be worth the cost. Convenience always costs!!
If you get the antenna tuner you should be able to just use the CB antennas on 10 meters. They are usually not that far off in terms of SWR anyway, it just depends.

This is a "push and twist" quick release adapter for about $8 usually;
s-l640.jpg

I think many if not most here would agree that for what an export CB radio costs, you are better off waiting a while (perhaps) to afford a mobile size ham rig as it has far more to offer for the cost and far better performance. It is of course not legal to use on CB but many do anyway. It is just not as simple perhaps to operate i.e. no channel numbers (although you could program the channels into the memories) and more controls and menus to sometimes dig through. More distractions while driving which isn't good.

I use an Icom 706 (not modded for CB) and a big screwdriver antenna when mobile on a trip. Around town I have a Cobra 29 LTD for CB and a dual band 2/440 rig as well. Neither really get much use anymore.
 
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Why not use a bracket like this one pictured below and use 2-102" whips? You can easily make one or MFJ sells them (MFJ-347). It's a mobile dipole bracket. One side has the insulator and the other doesn't for the RF ground.

A dipole needs no D.C. ground so the truck metal isn't much concern. You can rig up a simple mast on top of your Headache rack and assemble/disassemble a dipole in minutes. The higher the mast, the better. You'll need a long piece of coax to run it out that far plus you should coil the excess coax to make a choke balun.

A dipole actually has more signal gain (both TX and RX) on each broadside over a vertical. Just point the antenna in a NW/SE direction and you"ll be broadside NE/SW and will cover the country and Europe and the south Pacific if the bands are open that far.

You can always rotate it depending what part of the country you are at to maximize your signal.







MFJ-347.jpg
 
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Hurricane145 said:
He isn't an sk yet! He has been on QRZ.com as always in the last couple days.

From QRZ.com just minutes ago;
K0BG was last seen:
Today at 11:06 AM
Click to expand...

Oh. I figured given his advanced age and the fact that his posted email address rejected my email to him, he must have passed.
 
fourstringburn said:
Why not use a bracket like this one pictured below and use 2-102" whips? You can easily make one or MFJ sells them (MFJ-347). It's a mobile dipole bracket. One side has the insulator and the other doesn't for the RF ground.

A dipole needs no D.C. ground so the truck metal isn't much concern. You can rig up a simple mast on top of your Headache rack and assemble/disassemble a dipole in minutes. The higher the mast, the better. You'll need a long piece of coax to run it out that far plus you should coil the excess coax to make a choke balun.

A dipole actually has more signal gain (both TX and RX) on each broadside over a vertical. Just point the antenna in a NW/SE direction and you"ll be broadside NE/SW and will cover the country and Europe and the south Pacific if the bands are open that far.

You can always rotate it depending what part of the country you are at to maximize your signal.







MFJ-347.jpg
Click to expand...

Hmmm. That's an interesting idea. I did consider this option in a vertical orientation however, in one placement, the lower half would be behind the cab...not sure that would work...or I could raise the entire assembly 10 feet up. I never considered doing this horizontally but, that could be fabricated pretty easily. That could work. Ima ponder that one. Thanks.

...Upon further consideration, I could use this bracket with 2 Breedlove fold over mounts so that it can be collapsed, and attach it to a 9 foot pole that can be stored behind the headache rack. Then, all I need to do it fold it out, insert the mast into a quick clamping mounting point, orientate, drop the coax down to an external connection point and BAM. I like that idea.
 
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Sergeant Bilko said:
Hmmm. That's an interesting idea. I did consider this option in a vertical orientation however, in one placement, the lower half would be behind the cab...not sure that would work...or I could raise the entire assembly 10 feet up. I never considered doing this horizontally but, that could be fabricated pretty easily. That could work. Ima ponder that one. Thanks.

...Upon further consideration, I could use this bracket with 2 Breedlove fold over mounts so that it can be collapsed, and attach it to a 9 foot pole that can be stored behind the headache rack. Then, all I need to do it fold it out, insert the mast into a quick clamping mounting point, orientate, drop the coax down to an external connection point and BAM. I like that idea.
Click to expand...
Sounds interesting, post a pic of your final setup.
 

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