Base station dual commercial band VHF/UHF antenna

[LakeMan2]

I saw the recent thread on the mobile wideband antenna, but I don't necessarily need wideband and I am looking for a higher gain base station/tower antenna.

So my question is can I go with a 2m/70cm vertical (or horizontal) and use it un-tuned? Or would it really NEED to be tuned? (I realize tuned would be better, the question is would it have to be tuned).

Would some thing like the Cushcraft AR-270B work? It looks like it can be tuned some, but I am not sure how much. Other than that I saw that Diamond makes the X50C2 which is actually commercial freq.

I also saw a Dual Band Base Station VHF/UHF J-Pole on e-bay that is quite inexpensive and is tuned to the commercial vhf/uhf range. Why would I not use this over the X50C2 or 270B?

I actually don't need it to operate on the ham freq, just the commercial ranges, but I did not find a whole lot of choices for commercial tuned dual band antennas.

Assuming vertical to start width, I am wondering what by best option would be for a base station dual band (commercial freq) vhf/uhf antenna?

 

[popnokick]

The Diamond will work. A similar dual-band is available from Comet, the GP-6NC and it is slightly broader at the high end of the UHF spectrum where GMRS inputs are. But it is almost twice as tall as the Diamond (not necessarily a bad thing). I'm not a fan of the AR-270B for towers. And the j-pole antennas have a tendency to couple into the coax and radiate from it unless isolation is provided. Fine for amateur radio or receive-only work (maybe) but you're not likely to see j-poles used in pro installations.

 

[kayn1n32008]

I saw the recent thread on the mobile wideband antenna, but I don't necessarily need wideband and I am looking for a higher gain base station/tower antenna.



So my question is can I go with a 2m/70cm vertical (or horizontal) and use it un-tuned? Or would it really NEED to be tuned? (I realize tuned would be better, the question is would it have to be tuned).



Would some thing like the Cushcraft AR-270B work? It looks like it can be tuned some, but I am not sure how much. Other than that I saw that Diamond makes the X50C2 which is actually commercial freq.



I also saw a Dual Band Base Station VHF/UHF J-Pole on e-bay that is quite inexpensive and is tuned to the commercial vhf/uhf range. Why would I not use this over the X50C2 or 270B?



I actually don't need it to operate on the ham freq, just the commercial ranges, but I did not find a whole lot of choices for commercial tuned dual band antennas.



Assuming vertical to start width, I am wondering what by best option would be for a base station dual band (commercial freq) vhf/uhf antenna?

Do you need it to talk simplex over a large area, or to access specific repeaters?

For dual band, you are rather limited.

What I have found is that a VHF folded dipole array, like the Sinclair technologies 210-C2/4 are VSWR wise rather flat on VHF 137-174, and actually are resonate on UHF as well. What kind of pattern is really debatable, but in Alberta we have used VHF folded dipole arrays successfully on UHF for link radios.

At a few repeater sites, there were only VHF antennas, and we were un able to add antennas for linking, so we duplexes our link radio onto the same feed line as the repeater. It works, one link is done over 65km(line of site mind you) and is very stable.




Sent from my iPad using Tapatalk

 

[prcguy]

Besides the Comet GP-6NC which is available factory tuned to the commercial bands there is its big brother the Comet GP9 commercial version which is about 17ft tall and has big performance.

I had a few and they were tuned to 155MHz and about 465M Hz center frequencies, so if that's close to where you want to monitor the GP9 would be hard to improve on without going to separate and big VHF and UHF base antennas.
prcguy

 

[LakeMan2]

Besides the Comet GP-6NC which is available factory tuned to the commercial bands there is its big brother the Comet GP9 commercial version which is about 17ft tall and has big performance.

I had a few and they were tuned to 155MHz and about 465M Hz center frequencies, so if that's close to where you want to monitor the GP9 would be hard to improve on without going to separate and big VHF and UHF base antennas.
prcguy

Thanks popnokick and pcguy for pointing out the Comets. I had not come across those.

I took a look at the GP-9NC. It looks like a very nice antenna. A bit pricey at $220, but yea I know, put your money into the antenna first. Given that I am not in a position to increase my base tower height, I think a 17ft antenna would make LOS that much better.

 

[prcguy]

I have a GP9 commercial version laying on my roof, if your near So Cal I'll sell it cheap.
prcguy

Thanks popnokick and pcguy for pointing out the Comets. I had not come across those.

I took a look at the GP-9NC. It looks like a very nice antenna. A bit pricey at $220, but yea I know, put your money into the antenna first. Given that I am not in a position to increase my base tower height, I think a 17ft antenna would make LOS that much better.

 

[LakeMan2]

I have a GP9 commercial version laying on my roof, if your near So Cal I'll sell it cheap.
prcguy

Thanks, if I could, I would. Unfortunately I am about 1500 miles away.

 

[prcguy]

Ok, no problem. I assume you live somewhere near a lake.....
prcguy

Thanks, if I could, I would. Unfortunately I am about 1500 miles away.

 

[LtDoc]

Take this as opinion, since that's what it is...
I've had two of the Comet base antennas, the GP-1 and a GP-6. There's quite a bit of difference between the two. The GP-1 is/was the equivalent of a 'J'-pole (direct 'side by side' comparison). The GP-6 does much better than that. I'd love to have the GP-9 but couldn't afford it. (Ended up with three of those GP-6s so should'a just gone ahead and got the GP-9. Oh well.) They aren't exactly the simplest things to put together, but if you follow instructions they definitely are not that difficult. I'm happy with them...
- 'Doc

(All three of those GP-6s are in use, didn't have any problems.)

 

[videobruce]

Three questions since that was already started;

1. Is there any way the Comet X50C2 be tuned to raise the center for VHF?
2. How far can the AR270 be tuned towards 160/157 MHz centers?
3. Using a commercial dual band whip, are there any decent ground plane mounts with N connectors for base station use?

The intended use is optimum performance for 160 MHz & 457 MHz, but still have reasonable performance throughout the rest of both commercial bands,

Amazing, there are plenty of dual band mobiles, but no base antennas other than 2m/70cm.

 

[rescue161]

Comprod offers a commercial dual band exposed dipole array. They are extremely well made, but definitely not cheap.

 

[videobruce]

I won't even have to ask the price.

 

[rescue161]

Antennas - Dual Antenna Array | Exposed Dipole Antennas | COMPROD Communication

 

[BirkenVogt]

Thanks popnokick and pcguy for pointing out the Comets. I had not come across those.

I took a look at the GP-9NC. It looks like a very nice antenna. A bit pricey at $220, but yea I know, put your money into the antenna first. Given that I am not in a position to increase my base tower height, I think a 17ft antenna would make LOS that much better.

$220 is just barely getting started in the commercial world. If you even stop to think about that amount for a commercial antenna, don't even bother.

 

[videobruce]

The smallest of those Comprod antennas is 12'. Way, way too long. It's not on a mast by itself, it's going above another directional antenna on a rotor.

 

[mtindor]

disregard my question. Found at the Antenna Farm.

mike