Ok all you antenna craftsmen, got a question.

[k9lestat]

I was watching a video on a bazooka antenna. I had a thought pop into my sick mind. This guy made portable mast which housed a uhf bazooka. I know people make a double bazooka style dipole.

But I was wondering could I create a pvc mast which housed one Vhf and one uhf in the same mast. Using the dual antenna coax like a big truck would have to connect the two antennas to the radio. My inexperienced brain is telling me if people can run multiple length dipoles of the same feed point , could I do the same with vertical bazooka style antennas?

This style of vertical antenna seems fairly easy to build.

Sent from my QMV7A using Tapatalk

 

[k9lestat]

Anyone.?

Sent from my QMV7A using Tapatalk

 

[mpinco]

Not sure I fully understand you're design but sounds like it is similar to a fan dipole. Read the following and see if your idea meets the seperation requirements.

BUILD THIS MULTIBAND FAN DIPOLE FOR ALL BAND HF ANTENNA EXCITEMENT

".....Based on research done by the Stanford Research Institute (SRI) to construct a three-frequency multi-band dipole that would work without any need for cut and try techniques, we pass on this information in the hope that it will help you more easily get this type of antenna on the air quicker.

What they came up with was much improved method over the old cut and prune technique seen at the bottom of this page.

They found that the wires at the center feed point had to be separated by at least 5 1/2 inches vertically and the ends separated by 38 inches in the 2 to 18 MHz range. As in any fan dipole construction, all of the dipoles are connected in parallel but in the SRI method, the separation between them at the feed point must be maintained......."

 

[k9lestat]

Thanks

Sent from my QMV7A using Tapatalk

 

[k9lestat]

Ok now that I'm not all fogged up with meds today I'll try explain it a post a link.

It's an antenna made from coax cable. The cable is stripped with the center solid wire is left with its insulation intact. The braided wire tension is loosened so it can be pushed backwards so its exposed surrounds the unstripped outer insulation. Creating a dipole effect. At the bottom of the exposed the coax is made in 15 turn ballun.

Of course the band dictates the lengths of stripped wire. So on the master version the guy made wrapping loops around outside of the pvc.

So I'm wondering if I made one for 2m and the other for 70cm with them connected at the same feed point with them both inside the mast would this act like dual band dipole?

https://m.youtube.com/#/watch?v=WVFZ77vH2Jw

Sent from my QMV7A using Tapatalk

 

[ghutch]

Yes

 

[k9lestat]

Thanks

Sent from my QMV7A using Tapatalk

 

[TerryD]

I'm pretty sure 70cm is a harmonic of 2m IIRC. I'm 99% sure my 2m 1/4 wave ground plane antenna above my house returns a 1.3:1 on 70cm as well as a 1.1:1 on 2m. I'll have to hook my dualbander up this week to double check but I'm pretty sure a 2m vertical dipole would have a reasonable SWR on 70cm too.

Are you looking for something to stick up when you set camp or an antenna for actual mobile operation?

 

[k9lestat]

Well I'm actually looking for a vehicle antenna and a far second , a home antenna as well. But I really want a vehicle antenna.

Thanks for the response.

Sent from my QMV7A using Tapatalk

 

[TerryD]

Here is the ground plane I use at my house. It's simply slipped into a section of 3/4" PVC for a mast with the end split and a hose clamp tightened to retain it and slid into an old satellite dish mount with a korn clamp to hold it in place. I used S/S welding rod for resilience but it's hard to solder to the center contact.
http://www.hamuniverse.com/2metergp.html

This is the mobile antenna I have right now. I just went ahead and drilled the hole and put in a NMO mount too. It works good on my mag-mount as well for use in my wife's vehicle she won't let me cut holes in.
http://www.amazon.com/TRAM-1181-140MHz-170MHz-Antenna/dp/B00NU7JGMI

 

[k9lestat]

Thanks very much.

Sent from my SM-N900V using Tapatalk