Diamond D-130 discone top coil

[jaray]

I have a D-130 discone and am having trouble finding/recalling what the top vertical add-on antenna is. I have what I *think* is the antenna laying around, but I find it odd what I have is labeled as a Hustler SF-2. The bottom is a stud type thread and I suspect this is the correct one that comes with the D-130 - I just don’t recall is being so tall (around 50”).
Can anyone confirm what this removable antenna (or coil) is that comes with the D-130 so I can figure out if that’s what I have lying around?

Thanks so much for any help.

 

[jaray]

Well, after watching a couple videos, I know this longer Hustler I mentioned is definitely NOT what I’m trying to find. Apparently I’ve misplaced the small element that slides into the coil.

 

[iMONITOR]

No that's not it. It should have a smooth black loading coil, maybe about 3-4" long as I recall.

 

[jaray]

No that's not it. It should have a smooth black loading coil, maybe about 3-4" long as I recall.

It looks like there is a small whip that slides into it. Do you know how long this whip is?

 

[iMONITOR]

It looks like there is a small whip that slides into it. Do you know how long this whip is?

It's roughly 32" long including the coil. Mine is not attached to the discone at the moment. Just about all the pro's here on RR recommend taking it off if the antenna is being used for receive only. It alters the true discone design when it is attached. That's why you will see many shown without a top coil/whip of any size.

 

[Fixitt]

I have a new Diamond D130NJ waiting for better weather.

Hope this photo helps.

And it looks like I will be removing the top coil/whip since I am rx only.

 

[iMONITOR]

I have a new Diamond D130NJ waiting for better weather.

Hope this photo helps.

And it looks like I will be removing the top coil/whip since I am rx only.

Member pcrguy and other have made numerous post regarding the modification of removing the top whip on the dicone antennas.

 

[jaray]

Member pcrguy and other have made numerous post regarding the modification of removing the top whip on the dicone antennas.

Let’s be very specific then, Fixitt was referencing what he thought I needed to determine what the part I was asking about looked like. No discussion ensued to rediscuss the merits of of any modification. Thanks for the replies that helped me and I’ll consider this one closed.

 

[prcguy]

Let’s be very specific then, Fixitt was referencing what he thought I needed to determine what the part I was asking about looked like. No discussion ensued to rediscuss the merits of of any modification. Thanks for the replies that helped me and I’ll consider this one closed.

I was going to comment on the coil and whip but I guess its not wanted now.

 

[jaray]

I do apologize...I didn't mean to sound short. I just assumed there was call-out for not researching first,

 

[prcguy]

I do apologize...I didn't mean to sound short. I just assumed there was call-out for not researching first,

The original D-130 whip is a simple base loaded whip resonant around 50MHz to extend the low end response. The base loading coil sort of decouples the whip so it doesn't degrade performance at higher frequencies as much as a full 1/4 wave whip with no coil. However the antenna will perform slightly better in the 100-800MHz range without the whip. With the whip you will notice a big improvement centered around 50Mhz and a little improvement across the VHF lo band and CB.

If you need 50MHz and can't find the original whip your Hustler SF-2 might actually work. Its a base loaded 5/8 wave 2m whip and the electrical length of a 5/8 2m antenna is very close to 1/4 wave at 50MHz. If you have an antenna analyzer you might test the Discone without the whip then try the Hustler and see if you get a good VSWR dip around 50MHz without affecting higher freqs very much. If so and if you need to perk up VHF lo band or a range near where the SF-2 whip resonates you might be ok.

 

[GadgetGeek]

I installed a Diamond D-130 on Saturday. As already mentioned the coil is smooth black and about 5 inches. I installed it and the top whip section. I'm extremely happy with the performance so far.

 

[iMONITOR]

I'm curious, are you using it for VHF/UHF aircraft monitoring?