Quick question

[kixntuff]

What is the difference between these 2 antennas? PCI highly recommends there 3db high gain race antenna and say they have awesome luck on the Baja peninsula with it. I know they jacked the price on it and will custom tune it to your frequency with that price, but I wanted to find it cheaper and just do a measure and cut tune. Anyway I think I did find it cheaper. Check out the links.

https://www.pciraceradios.com/collections/antenna-coax/products/3db-racing-antenna

The one I bought. http://www.theantennafarm.com/catalog/pctel-asp7455-746.html

Do you guys think they are comparable or did I screw up? I know nothing about these antennas for I have only ever researched 1/4 wave, 1/2 wave and 5/8 wave. I do not understand the direction or type of wave for these types of antennas. Can this be explained?

Thanks very much for the help!

Kix!

 

[popnokick]

PCI doesn't specify the length of their antenna, but based on price, stated gain, and appearance it looks like a 5/8 wave 3db gain vertical mobile antenna.... which is electrically the same as the PCTEL ASP7455 you bought from The Antenna Farm.

 

[SteveC0625]

What is the difference between these 2 antennas? PCI highly recommends there 3db high gain race antenna and say they have awesome luck on the Baja peninsula with it. I know they jacked the price on it and will custom tune it to your frequency with that price, but I wanted to find it cheaper and just do a measure and cut tune. Anyway I think I did find it cheaper. Check out the links.

https://www.pciraceradios.com/collections/antenna-coax/products/3db-racing-antenna

The one I bought. http://www.theantennafarm.com/catalog/pctel-asp7455-746.html

Do you guys think they are comparable or did I screw up? I know nothing about these antennas for I have only ever researched 1/4 wave, 1/2 wave and 5/8 wave. I do not understand the direction or type of wave for these types of antennas. Can this be explained?

From what I can tell, they're the same antenna. The pciraceradios pic show PCTel on the base. I think you made the right decision.

FWIW, specialty shops like this racing supply place always seem to offer the same goods at higher prices. I steer clear of them and search other vendors.

If you can, find someone with an SWR meter to give you a hand tuning the antenna. The manufacturer's cut chart will get you real close, but the meter will get you even closer.

 

[kixntuff]

Yeah, they don't specify length because they want you to tell them your TX frequency so they can cut and tune the antenna using a meter. I'm sure that's part of the 50 dollars one would end up spending on the "race antenna". When I talked to them on the phone they said they don't use 5/8 wave antennas and the fact that the antenna farm didn't specify wave length had me all tripped up. So in the end, is the one I bought going to be pretty much considered a 5/8 wave antenna?

Thanks!

 

[popnokick]

The full spec sheet for your antenna is here -
PCTEL | Mosaic® Vibration Resistant Collinear Antennas | ASP Series

 

[SteveC0625]

Yeah, they don't specify length because they want you to tell them your TX frequency so they can cut and tune the antenna using a meter. I'm sure that's part of the 50 dollars one would end up spending on the "race antenna". When I talked to them on the phone they said they don't use 5/8 wave antennas and the fact that the antenna farm didn't specify wave length had me all tripped up. So in the end, is the one I bought going to be pretty much considered a 5/8 wave antenna?

Thanks!

I am pretty sure the race guys are not very well versed in antennas and such beyond whatever docs they have.

Here are links to the specs and cutting chart for that antenna. Given the cut lengths for the whip used, it's almost certainly a 5/8 wave.

Product sheet: http://www.antenna.com/artifacts/2015521Mosaic-ASPSeries.pdf

Cut chart: http://www.antenna.com/artifacts/MLCC3.pdf

Personally, I think this is a great choice for a gain antenna.

 

[kixntuff]

Thanks very much for the help! How does one go about determining that it's a 5/8ths wave? I looked at the spec sheet and can't make sense of it.

Kix

 

[SteveC0625]

Thanks very much for the help! How does one go about determining that it's a 5/8ths wave? I looked at the spec sheet and can't make sense of it.

Kix

Measure the length of the whip. For example, at 155 Mhz, we know that a 1/4 wave antenna is about 17" plus or minus a bit. So it stands to reason that a half wave would be 34" and, in turn, a full wave would be 68". 5/8 of 68 = 42.5" which is what the cut chart calls for, again plus or minus a half inch or less.

It's a 5/8 wave antenna.

 

[SteveC0625]

Here's a link that you might find really useful. It describes the differences between 1/4 and 5/8 wave and explains why 5/8 wave is so desirable for mobile antennas. There's also a nice drawing of propagation for both.

antenna - What makes a 5/8 wavelength vertical desirable? - Amateur Radio Stack Exchange

Also, if you do a google search on 5/8 wave radiation pattern and then select the images choice, you will find lots of images of radiation patterns.

 

[kixntuff]

Thanks a million fellas! Excellent tips! So this leads me to ask about tuning this think with an swr meter myself. I think close enough is good enough, but if I can do it with this, Brand New CB Radio Astatic PDC7 SWR Test Meter | eBay
Can one use this for a decent tune?
Why not spend a few extra bucks and learn something new. Come race time, I may find the race course may be better suited with a 1/4 wave. Be good to tune my 2m antenna for around here also.

Thanks again !

 

[N4GIX]

Er, that meter for CB won't work too well for tuning a 2m antenna... :wink:

 

[kixntuff]

My bad. Clicked on the wrong one. 2 Way Radio SWR Power Meter 140 150MHz 430 450MHz 0 200W Nissei RS40 | eBay

 

[N4GIX]

That will work for 2m/70cm...