Comet With A Ground Plane

[hsvrandolph]

I have recently turned my modified Yaesu FT-7800 into a base station by adding a 38ft telescoping pole with a Comet CA-2x4SRB multiband antenna since I transmit HAM and VFD freqs. I have also added a MFJ-1401 ground plane. I was wondering if anyone has any experience with this particular Comet antenna and how effective it worked for you. Any reviews would be appreciated. Also does anyone know if the MFJ ground plane antenna below the comet will make a noticeable difference. Thanks for any input.

 

[kb2vxa]

The Comet is a mobile antenna and will only work properly with a ground planing surface such as a vehicle body under it. In your case you're converting it to a base antenna with the MFJ radial kit, absolutely essential.

Don't mind me saying but I don't know why you don't use a base antenna to begin with, Comet has excellent ones.

Then you say you also transmit VFD frequency, no ham antenna that I know of will have acceptable SWR out of band so you need a separate antenna for it tuned for the frequency in question. Another thing, using modified ham equipment for that purpose is illegal not being FCC certified for Part 90 operation. The icing on the cake is the Yeasu is incapable of narrow band operation making it incompatible with the VFD system AND using FM instead of NFM is another violation.

My suggestion is un-modify the Yeasu and use a VFD radio with proper authorization from the Chief or you'll find yourself in big trouble and possibly drag the department into the mess.

 

[hsvrandolph]

If you look up the specific comet antenna I have purchased it is designed to transmit on VHF/UHF ham bands along with public safety bands. As it is actually designed for HAM/Public Safety Operator. And I am aware of the FCC part 90, thats why I use the mod Yaseu for listening to dispatch only and transmit/receive on HAM and transmit to dispatch on my issued handheld. Just was clarifying capabilities. More so my question was has anyone had any use with the comet CA-2x4SRB with a ground plane and any pros/cons. Also wouldnt mind hearing feedback on anyone with the CA-2x4SRB use as a mobile (w/o ground plane obviously) and its pros/cons/personal feedback.

 

[kb2vxa]

OK, now things become clear, as long as you keep it legal that's fine. Another thing that falls into place is Comet anticipates a Part 90 transceiver with ham frequencies programmed in which is perfectly legal but not the other way round.

 

[LtDoc]

I've used that antenna for a number of years, on more than one vehicle. It definitely works. I also have one hung from a porch roof (where the porch swing used to be) for use with an HT. Loop of cord tied to the tip, hang from the 'hook', added a counterpoise (alligator clip and about 19 - 20 inches of wire) to furnish that "groundplane". It works just dandy that way.
I have no idea about that MFJ 'groundplane' so can't say anything about it. In general, having more/longer radials than required is better than having them too short. If that thingy is designed for 2 meters, and since most Pub.Serv. frequencies are higher, it ought'a work.
Have fun.
- 'Doc

 

[dksac2]

The Comet 2X4 is an excellent antenna on a vehicle. I have mine mounted right in the middle of the roof, NMO mount, hole drilled through the top, it talks better than an other I have used. I use it for VHF/UHF and GMRS. The SWR is very low, up just a little, under 2:1 on GMRS, 1:2 on the other bands, it is very wide banded.
I might be able to get it better, just took it from the package and mounted it.
Look at the reviews on EHAM, people love it. I would not trade it for anything. I live in a mountianous area and it works fantastic.

John