Dual whip antennas & parts needed for installation

[tim292stro]

LOL wow, at that point I would rather have some kind of replica if there was one. I bet if I called to place an order they would be like "are you part of the military?". I can't believe you want four of them dang! I would be able to get into pretty much any frequency at that point.

That's the idea, and with time alignment and fixed/measured distance I can do real-time radio direction finding.

A replica can be done with 4" pvc pipe painted tan...

...As for connecting the whips together for a dual whip antenna, it will not work as well according to my local HAM radio guys. Now all this is according to the head radio geek they had on staff, but he threw out some jargon that backed up his case...

...What he was telling me, is that unless it is just for looks, you're fine, but in order to make it a functioning dual whip, you need to keep the 2 whips separated 9' apart which is equal to a quarter wave and the cable connection would have to have some sort of electrical coupler. I forgot what he was saying, because the dazed me with his radio voodoo sorcery for a bit... ...he was telling me that simply connecting them together with a radio shack T...

It has to do with wave lengths and antenna distance. If you put two antennas within the incorrect wave length the two antennas will cancel out., the further apart they are, the wider the dispersion.

Hi Tim292stro, are you referring to an RFR-105 antenna on which the datasheet is based? Interesting antenna. Very wideband as you said. I'd like to get my hands on one for some testing.

It could work fine for a wideband scanner or even ham transceiver. Looks 'right' on an MV too. I was looking for a spec sheet for (ham use) that would give gain figures and only found one reference stating 0 dBiL (db isotropic, linear polarization). That converts to -2.1 dBd (dipole) if I did the numbers right...

I will tell you that if you are SERIOUS about buying one of those at the rough price I "ball-parked", then talk to them. They do sell to the public (they have sold to colleges, that was my first clue), and they have a full datasheet available if you are willing to go into an NDA, and upon purchase be prepared to sign an End-Use Certificate. That's all I believe I am allowed to say, because I'm under that NDA. Realize that this antenna is current, and part of systems that DoD probably doen't want compromised - part of my delay in purchase is working to ensure I can develop a physical security program to prevent these from being stolen or captured here in CONUS.

 

[cq141]

I seen the mounting brackets on ebay pretty cheap i have a rope that held the antenna down with a clip in my hummwv those cant be expensive its just a rope with a metal clip

 

[jake-cutter]

You can find the antenna mounts on the auction sites but finding the backing plate is very hard.

 

[1 Patriot-of-many]

Great! Thank you so much! Hopefully it has a mount and if not I'll buy them separately. I do have a question though... I want to keep it with the soft top in the back how it is currently, now with the normal mount such as this one: View attachment 608164 would I still be able to put the whips towards the front if I didn't want them up? Or would the soft top be in the way? That's why I'm not sure if I should get the mounts that have an offset such as this one: View attachment 608165

Yes but they rub of course against the side of the top. I just put these on yesterday.

 

[1 Patriot-of-many]

You can find the antenna mounts on the auction sites but finding the backing plate is very hard.

What backing plate?

 

[bikeman]

Can't believe I missed this... here's my input in no semblance of order:

1. If you have dual whips and a full soft top kit, and you do NOT have the stand off brackets, yes they will rub. However, SOP in the Army was to run your 'antenna retaining clips/rope' from the base of the opposing antenna mount (or empty mount or whatever you could tie it to for one antenna) and you form an "X" with the antennas across the rear of the HMMWV as opposed to forward. The whole issue/reason is reducing your height for the whips and keeping them under control.

2. 550 cord is fine to be used "to" the clips for the antennas, but the clips were designed with 2 antenna holding positions in them. 1 was for while travelling and provided a bit of a "break away" capability if the antenna got snagged on something, it was kind of a closed "U" shape. The other part of the clip was more of a "hold until released by operator" and formed an elaborate 7 over the antenna.

3. the antenna being floated is (now) for the Duke Counter-IED system. I would normally say there's no way to get a functioning one (I think someone on g503 got a trainer), but that's apparently wrong, even though I'm not surprised there's some security requirements about it.

4. the antenna clips... we usually tied them around the B-pillar (soft skin), or the side mirrors (up armored). For whatever reason they were oddly hard to order. I'm not sure why just seemed like they always seemed to be unobtanium... that or as soon as they were ordered they disappeared from supply.

 

[jake-cutter]

What backing plate?

Below is the link to an example:

http://g503.com/forums/viewtopic.php?f=64&t=172148

http://g503.com/forums/viewtopic.php?f=63&t=167507&start=75

 

[1 Patriot-of-many]

Is that standard issue? I didn't look inside mine, it had an antenna bracket on it. I'll have to look.

 

[jake-cutter]

I have seen them on very few. A few antennas that were surplused a couple of years ago came with them. Finding pictures is hard. I want one because the aluminum flexes some with just the mount and washers.

 

[bikeman]

If I had a personally owned HMMWV, I'd have one of those...

 

[86humv]

Here's a training use only antenna ** 315 mhz }
Its hollow except for a 4+ inch hand held radio antenna inside.