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Comm Antenna - RAMI

LifeofReiley

LifeofReiley

Well Known Member
Is anyone flying with the RA Miller (RAMI), what was the Antenna Specialist Bent Whip comm antenna AS-AV534? I'm considering this light weight option and would like input on its performance.
 
LifeofReiley said:
Is anyone flying with the RA Miller (RAMI), what was the Antenna Specialist Bent Whip comm antenna AS-AV534? I'm considering this light weight option and would like input on its performance.
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Darrell, that's the antenna I've been using on my plane since 1999. It has worked flawlessly.
 
Been using these antenna for years now on hundreds of installations and they work and hold up. Never have had to replace one.
 
LifeofReiley said:
Is anyone flying with the RA Miller (RAMI), what was the Antenna Specialist Bent Whip comm antenna AS-AV534? I'm considering this light weight option and would like input on its performance.
Click to expand...

Same for me - performs perfectly. And I'm only using plain old RG-58. I've had these antennas on two planes now and am very happy with the performance.

EDIT: Sorry - disregard above - I double checked after reading George's post below - I thought, wait a minute I DO have a BNC connector! I checked, and I have a Comant CI-122 VHF antenna. 45 deg whip mounted on the belly just aft of the gear legs on my -8.
 
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Most of the RAMI antennae use BNC connectors. The stainless steel whip antenna which is super cheap is the only model that does not use a BNC connector it also does not work well over the entire frequency spectrum(118-136mhz).
 
Norman CYYJ said:
Been using these antenna for years now on hundreds of installations and they work and hold up. Never have had to replace one.
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Norman CYYJ said:
Most of the RAMI antennae use BNC connectors. The stainless steel whip antenna which is super cheap is the only model that does not use a BNC connector it also does not work well over the entire frequency spectrum(118-136mhz).
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Ahhhh.......which version are we to believe? :rolleyes:
 
Sam go to the RAMI web site and look for yourself about the various RAMI antennae. All of their anntennae work well if you choose the right one for the application that you want. The stainless whip with no BNC connector was originally used for communications back in the days when the common radio had considerably less channels than 360 or more. If you look at the band width of that model of antenna you will see that it is narrower than the other models. The VSWR of that antenna across the band is 3:1 versus 2:1 with the others. I have install many of these antenna also and they work but not as well on the newer radios. So I don't really understand your comments about my two postings. Many of those rod antenna have been installed and they have more of a tendency to cause interference with other devices because of the higher VSWR. You want as much of the RF energy to be radiated off the antenna as possible. With a high VSWR you will get a lot of RF energy radiated off of the coaxial cable. But what do I know I've only being working in the industry for 45 years.
 
Norman CYYJ said:
Sam go to the RAMI web site and look for yourself about the various RAMI antennae. All of their anntennae work well if you choose the right one for the application that you want. The stainless whip with no BNC connector was originally used for communications back in the days when the common radio had considerably less channels than 360 or more. If you look at the band width of that model of antenna you will see that it is narrower than the other models. The VSWR of that antenna across the band is 3:1 versus 2:1 with the others. I have install many of these antenna also and they work but not as well on the newer radios. So I don't really understand your comments about my two postings. Many of those rod antenna have been installed and they have more of a tendency to cause interference with other devices because of the higher VSWR. You want as much of the RF energy to be radiated off the antenna as possible. With a high VSWR you will get a lot of RF energy radiated off of the coaxial cable. But what do I know I've only being working in the industry for 45 years.
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Norman, I did not intend to denigrate your long career in the avionics industry, your background certainly exceeds mine by a long shot.

I just found your contradictory messages to be interesting and thought you might want to clarify......which you did.

I haven't had any problems with the cheapie whip on my RV-6, it seems to work very nicely at all the frequencies I've used. Maybe I lucked into a favorable installation. :)
 
Sorry Sam for the confusion in my statements. Sometimes installation has a lot to do with how well something works and sometimes a lot of luck. With a high VSWR you never really know where or what if anything may get interfered with. A lot of the newer electronic devices just won't tolerate RF interference and you never know which frequencies may cause the problem. The best is to keep the antenna feed line well isolated from other wiring in the aircraft and the antenna on the belly. The main problem with belly mounted antennae is a lack of range while on the ground especially on tail draggers. The body of the plane makes a good RF shield from the ground stations. You may find that that antenna that you have works better on the lower frequencies than the higher ones above 130mhz. But then again that is sometimes a difficult test to make. As for those that want to spend the extra money on coax use RG400. It won't make a difference in the small runs in the RV's that you would ever notice even if your antenna is mounted in the tail. But the wire is better for shielding and mechanically stronger and won't burn up as fast as the regular coax if you should have a fire.
 
Norman CYYJ said:
Sorry Sam for the confusion in my statements. Sometimes installation has a lot to do with how well something works and sometimes a lot of luck. With a high VSWR you never really know where or what if anything may get interfered with. A lot of the newer electronic devices just won't tolerate RF interference and you never know which frequencies may cause the problem. The best is to keep the antenna feed line well isolated from other wiring in the aircraft and the antenna on the belly. The main problem with belly mounted antennae is a lack of range while on the ground especially on tail draggers. The body of the plane makes a good RF shield from the ground stations. You may find that that antenna that you have works better on the lower frequencies than the higher ones above 130mhz. But then again that is sometimes a difficult test to make. As for those that want to spend the extra money on coax use RG400. It won't make a difference in the small runs in the RV's that you would ever notice even if your antenna is mounted in the tail. But the wire is better for shielding and mechanically stronger and won't burn up as fast as the regular coax if you should have a fire.
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Guess I'm just one lucky builder....the el cheapo is on top on the turtle deck, I used RG-58, the coax runs right through the middle of my wiring, and the silly thing works quite well.

But your guidelines are certainly worthy of consideration and no doubt reflect what you have experienced in the field. Thank you for your insight.
 
Just a comment <getting off topic>... higher VSWRs doesn't necessarily radiate large amounts off the outside of the coax. They reflect the transmitted signal back to the transmitter, where if the return loss isn't great (which it usually isn't) it bounces back to the antenna creating a nice multipath effect (and so on). If the timing is right and the reflections big, you'll get distortion on the transmission all the way up to garbled transmission if its bad enough.

The shielding effectiveness will set the amount of radiation that leaks from the coax with the standing waves that get set up. For a one-reflection path, e.g. reflection at the antenna only, and an open load (max VSWR), we get a doubling of the peak voltage, which is a 6 dB peak power increase along the line.
</on topic now>
 
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