P

PurpleSwamper

Member
I purchased 2 inexpensive antennas from Aircraft Spruce - one for a Garmin GTX327 transponder and the other for an Icom 210 COM radio. These antennas are nothing more than stainless steel rods with delrin insulators for mounts. They didn't come with BNC connectors and according to the manufacturer (Freeway Enterprises), one attaches the core wire of the RG58 cable to the antenna by wrapping it around the rod and tightening down the washer and nut. There is no connection on the antenna for the grounding braid of the cable and so it attached to the metal fuselage.

In my computer life I've only ever terminated coax with BNC connectors. This is the first antenna wiring I've done. Is this a good practice to attach the cable to the antenna with a BNC? Does it degrade the signal? At the very least shouldn't one crimp on an eyelet connector? How do other antennas attach to RG58?
 
That is different, I would use a bnc connector, my transponder ant. Has a connector on it. I think o e would have more loss without a connector.

Bird
 
I would recommend you return them and purchase 2 real antennas, they quit using those about 30 years ago. If you are really desperate, you could use one on the com but you definately should not use this style for the transponder (not approved and will never pass the xpdr test).

FYI: the center conductor goes the the antenna terminal and the shield is attached to the antenna ground plane using a screw/bolt.
 
Walt beat me to it!

Do yourself a favor and just don't use those antennas. They are NOT good antennas for a whole host of reasons (bad for RV speeds, bad for antenna performance, etc..). Those antennas are best used on something like a Cub/Champ/Stearman (and even then barely). Overall they are a POOR choice for an antenna and to be my usual blunt self: this definately is one of those times where that selection is pennywise and pound foolish. As long as you're at it I'd also recommend ditching the RG58 and just putting in RG400 while you're working on it.

Just my 2 cents as usual!

Cheers,
Stein
 
I agree with Stein and Walt.....

If you want some good antennas and save a little money for ones not certified, check out:

http://www.deltapopaviation.com/Home.html

Also, like Stein mentioned, go with RG400.

Pay attention to your connectors. Most are BNC, but Garmin does use TNC connectors on some devices. Also, you need to ensure that the connector is good for the wire you use. The white insulator comes in different thickness, so they aren't always swappable.

Since your new to all this, just go to steinair.com and get the connectors and the appropriate crimp tool. Stein's inexpensive crimp tool works just fine.
 
Thanks for your suggestions but I'm not looking to switch out the antennas or cable... I'm just wondering what degradation if any would be experienced connecting the RG58 to the antenna without a BNC style connector.

My cable lengths are under 20' so I'm expecting RG58 will suffice. I think RG58 vs RG400 has been debated under another topic so will leave it alone here.

Walt: why do you say these won't pass the transponder test? One of the 2 antennas is afterall a transponder antenna currently sold by Aircraft Spruce.

Stein: Can you give me a more technical reason as to why it's a "Poor choice".

I guess I wasn't looking so much for sales-type advice as I was a technical evaluation of the degregation (if any) of using a non-bnc connector to attach the cable to the antenna. There is nothing magical about the BNCs and in the hundreds of BNC cables that I've encountered / installed / troubleshooted, I've found some good and some bad connections.

I suspect the "real antennas" that you speak of are nothing more than a steel rod like these ones, with a BNC connector soldered to the end and piece of fancy looking fiberglass hiding the functional part of the antenna. Am I wrong?
 
PurpleSwamper said:
Stein: Can you give me a more technical reason as to why it's a "Poor choice".
Click to expand...

Poor SWR, poor attenuation, made for planes that go less than 100kts, not robust, terrible performance, almost impossible to keep secured on an RV, ungainly, big, they bend airframe skins skin without huge doublers, unreliable, not recomennded by any avionics mfgr for decades, not used by reputable installers for decades, not installed on OEM airplanes for decades, they bend easy when a dog runs into them, others in the air trying to communicate with you will be unhappy with your whale songs, poor mechanical installation, poor electrical installation, poor electrical connectivity, poor reception, poor transmission,...and they are of poor quality not to mention they are ugly! :)

Last but not least - because Walt said so!

I suspect the "real antennas" that you speak of are nothing more than a steel rod like these ones, with a BNC connector soldered to the end and piece of fancy looking fiberglass hiding the functional part of the antenna. Am I wrong?
Click to expand...

YES, you are wrong and your suspicions are incorrect. There are thousands of pages of technical details all over google which you can read about the bits/bytes. In the end, it's crazy for you to worry about degradation of using a BNC or not when the antennas you're starting with are only 20% usable to begin with....as pointed out by a few folks that know this stuff. Nobody is trying to sell you anything other than some free advice. Lastly, just because something is in a catalog and is cheap doesn't make it a good match for modern radios in a modern plane. Talk about someone trying to sell you something; apparently someone already did! :)

Just my 2 cents as usual.

Cheers,
Stein
 
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"Real" comm antennas have a gamma match circuit embedded in the base and will transmit/receive so much better. I removed a homemade copper foil adhesive strip comm antenna from the windshield of my RV-6 that the original builder installed, and replaced it with a RA Miller (RAMI) AV-17 belly-mount bent whip antenna and gained over 50 more miles of useful comm range! Yeah it cost me about $150 but was well worth it. If you're wanting to save a small bit of money, you can get by with using the cheaper RG-58 coax on the VHF comm radio antenna if the length is short (under 12 feet), but I'd still recommend using the RG-400 coax for the transponder antenna no matter the length.
 
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As soon as you split the coax into the center conductor and a separate twisted braid pig tail, you lose the 50 ohm impedance geometry. This will cause some of that transponder signal to reflect back into the transponder, which means less power to the antenna. If bad enough you won't meet the radiated signal strength requirement, as Walt was alluding to. This little section of wire will also radiate some power, but it is inside the plane, where all it can do is cause RF interference with other avionics. Oh, and make the inside of your airplane like being inside a low power microwave oven. How bad this short wire section is scales like its length compared to the wavelength. So for the com, an inch or two compared to the wavelength of 10 feet isn't too bad. For the transponder, an inch or two compared to the wavelength of 12 inches is not so great.
A good antenna will not just have a BNC; inside the fiberglass the BNC will have a tapered conductor which expands up to the antenna diameter, and around that there will be a tapered shield, looking like a funnel, which maintains the 50 ohm impedance right up to the antenna, to maximize power transfer.
A good connector is gold or silver plated. I'll bet that if you come back in 3 years and look at a copper wire clamped to steel bolt connection it will be badly tarnished and not a great connection.
RG 58 is okay for the com, but again will cost you expensive watts at the transponder frequency.
 
Here's why I don't use RG-58 for comms:

Center conductor--RG-58 can have a solid or stranded center conductor, RG-400 is always stranded.

Dieletric--RG-58 is polyethelyne, which melts easily when you try to solder the center conductor. RG-400 is teflon, which is almost impossible to melt.

Shield--RG-58 has a single braid which can vary in coverage depending on the quality of cable purchased. RG-400 is double shielded to prevent leakage / interference with adjacent wiring.

I find it's much easier to spend money on a good antenna and run RG-400 than to try and save a few bucks and find out that the autopilot pitches up, or the trim indicator goes wacky, or the fuel gages jump around every time you transmit.
 
While we are on the XPonder antenna topic: Is the TED monopole antenna decent? Is a double needed if mounted in the forward bottom skin (0.040)?
11-17995.jpg


Out of curiosity, I tried to find the antenna the OP is referring to on the ACS website, I was unable to locate it.

Thanks,
 
WingsOnWheels said:
While we are on the XPonder antenna topic: Is the TED monopole antenna decent? Is a double needed if mounted in the forward bottom skin (0.040)?
11-17995.jpg


Out of curiosity, I tried to find the antenna the OP is referring to on the ACS website, I was unable to locate it.

Thanks,
Click to expand...

I've installed plenty of these (experimental only) and never had a problem, and at <$20 a pop I can't imagine finding anything much cheaper!
Should be fine without a doubler on the forward skin.

However I do prefer the Comant CI-105 or the delta pop units.
 
Poor SWR
--> What ratio increase/decrease does a BNC connector introduce?

poor attenuation
--> wouldn't the greater surface contact of a non-BNC connector reduce attenuation?

made for planes that go less than 100kts
--> not true. who told you that?

not robust
--> not entirely true... depends what your definition of "robust" is

terrible performance,
--> have you tried one? do you know someone who has tried one?

almost impossible to keep secured on an RV,
--> not true

ungainly,
--> now you're just throwing around adjectives

big
--> not true. Same length as other antennas I've looked at. Smaller diameter and footprint since they don't have a fiberglass casing

they bend airframe skins skin without huge doublers
--> I suspect this is not true. I suspect that the doubles required will have a smaller footprint than many of the fiberglass encased antennas. So what is your definition of "huge"... 1", 2"?

unreliable
--> have you tried one? do you know someone who has tried one?

not recomennded by any avionics mfgr for decades
--> not true. By definition the company who makes them is an avionics mfgr and they recommend them

not used by reputable installers for decades,
--> why is that? poor training?

not installed on OEM airplanes for decades
--> What's an OEM aircraft?... Original Equip Mfr"? In that case my experimental is about as OEM as it gets.

they bend easy when a dog runs into them,
--> you're flying too low

others in the air trying to communicate with you will be unhappy with your whale songs
--> you make a lot of assumptions about the performance I will get with this antenna

poor mechanical installation --> what is "poor" about it?
poor electrical installation --> what is "poor" about it?
poor electrical connectivity --> what is "poor" about it?

poor reception, --> what range can I expect. Perhaps it is adequate for my needs

poor transmission,... --> what range can I expect. Perhaps it is adequate for my needs

and they are of poor quality
--> In what way. They appear to be very sturdy.

not to mention they are ugly! --> Seriously?

"Last but not least - because Walt said so!"
--> If I want to blindly follow someone I'll go to church. Otherwise I need a more scientific explanation.

""Real" comm antennas have a gamma match circuit embedded in the base"
--> How can they predetermine the gamma match requirement without knowing the exact length of the cable used. Wouldn't any pre-installed gamma matching on the antenna be neutralized by variations in cabling. Unless of course they supplied a cable matched to the antenna.


"gained over 50 more miles of useful comm range!"
--> at what height? and what was your initial final range?

"As soon as you split the coax into the center conductor and a separate twisted braid pig tail, you lose the 50 ohm impedance geometry"
--> how is this different when using a BNC connector. As soon as the braiding is peeled back to allow for installation, the 50 ohm is lost.

"Oh, and make the inside of your airplane like being inside a low power microwave oven. "
--> haha haha... you are joking right? I hope so. I'd hate to fly low over one of Sein's dogs and accidentally nuke it.


"Out of curiosity, I tried to find the antenna the OP is referring to on the ACS website, I was unable to locate it."
--> Part# 11-04516 com antenna
--> Part# 11-02759 transponder antenna
 
Installing top-line antennae is certainly a good option and probably the best way to guarantee excellent performance.

However, as a data-point, I have been flying a non-BNC COM antenna on the RV-6 for thirteen years and have been pleased with its performance. Yes, sometimes the fuel gauge will bounce...guess that tells me the final stage of the radio is working. ;)

Would a more expensive antenna work better? Possibly so, but the dire predictions of terrible things happening if the inexpensive antenna is used won't always be reflected by reality.

Your mileage (and range) may vary. :)
 
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PurpleSwamper said:
"Oh, and make the inside of your airplane like being inside a low power microwave oven. "
--> haha haha... you are joking right? I hope so. I'd hate to fly low over one of Sein's dogs and accidentally nuke it.
Click to expand...

I guess it's pretty obvious that you already know the answers to your questions, so I am not sure why you joined the forums to argue, but I can tell you from personal experience and lots of consultations with other builders (as a Tech Counselor), that it is almost impossible not to get RF leakage inside the fuselage with this type of connection. In a tube and fabric airplane, who cares? But in an all-metal airplane like an RV, the RF bouncing around will drive your trim indicators, autopilot, and other receivers nuts.

I am not an avionics technician, dealer, or manufacturer - just someone who has tried to use these antennas and then thrown them away. Except on Cubs of course - they are great with a ground-plane and appropriate mount for a hand-held in those airplanes.
 
PurpleSwamper said:
"gained over 50 more miles of useful comm range!"
--> at what height? and what was your initial final range?
Click to expand...

1000' AGL and higher.
Before, with the simple homemade 1/4 wave copper foil dipole directly attached to a stripped/split RG-58 coax, useful range was perhaps 30-40 miles tops. After getting rid of that, and installing the "real" antenna. I can now hold a conversation, air-to-air, at typical cross country cruising altitudes with another aircraft at distances easily in the 80-100 mile range. Coming back home from Oshkosh last year at 10.5K MSL, I was over Bartlesville, Oklahoma and was still able to talk to a buddy who was near Midlothian, TX south of the D/FW metroplex. That's nearly 300 miles. I had to pull the squelch knob out on my radio to be able to hear him barely in the background noise but he could still hear my transmissions clearly.

Since you seem to be so set on justifying the use of those "on-the-cheap" antennas, then go ahead and use them if you've convinced yourself about them and discount everyone else's advice and experience. It's your decision.

As for myself, I prefer to equip my homebuilt aircraft with known and proven solutions that are built upon the shared experience of all the others who've gone before me and already sorted out what works well and what doesn't. That philosophy always tends to yield a better, safer, and more enjoyable and dependable homebuilt airplane in the end. Sometimes the component prices are steeper than I'd like, but the old saying of "buy once, cry once" applies more often than not.
 
I have a side business of repairing avionics. I also have an MFJ-266 antenna analyzer and have tested these non-BNC comm antennas in the past and have proven a few times to people that have installed them that they don't work worth a hoot. They are poor at best and that's complementing them. Very poor SWR and complex impedance. If you want a poor performing comm antenna, this is a great choice!
 
Brantel said:
popcorn.gif


This is gonna be good!
Click to expand...

Yep, right with ya on this one:D

Ironflight said:
I guess it's pretty obvious that you already know the answers to your questions, so I am not sure why you joined the forums to argue, but I can tell you from personal experience and lots of consultations with other builders (as a Tech Counselor), that it is almost impossible not to get RF leakage inside the fuselage with this type of connection. In a tube and fabric airplane, who cares? But in an all-metal airplane like an RV, the RF bouncing around will drive your trim indicators, autopilot, and other receivers nuts.
Click to expand...

Well put Paul, bit more polite than I would have done.

Wonder if he has any idea who Stein is????
 
This group as a whole tends to have a vast amount of experience on many topics. They are always looking for ways to save money during the build and always provide suggestions to help provide low cost options. However when the concensus is to take the high road I would seriously consider not taking the low road.
 
I have found, in my experience, that asking others for their advice and then arguing with them about what they say does nothing except to alienate you during any future interactions. Come back another time and ask the same individuals about their thoughts on a different topic and see where that leads. Good luck on your avionics issues. Sounds like you will be going down the path you had already chosen before you ever asked advice from the group. I am sure you will get lots of experience and practice dealing with all sorts of issues now that you have made your decision. On the positive side of things, it looks like you will be getting the full benefit of the ". . . For Education and Recreation" on this one! :rolleyes:
 
"As soon as you split the coax into the center conductor and a separate twisted braid pig tail, you lose the 50 ohm impedance geometry"
--> how is this different when using a BNC connector. As soon as the braiding is peeled back to allow for installation, the 50 ohm is lost.
-->it is almost impossible not to get RF leakage inside the fuselage with this type of connection.
==> My point here is that with both types of connections it is necessary to strip back some of the braid. If the amount of stripped braid is equal for both types of connections, wouldn't the RF leakage be the same?


Sam: Do you use rG58? And if so, what connectors do you use at the antenna?


Neial: Thanks for your input but your experience isn't quite the same as what I'm asking. In your case you swapped out the entire antenna for a completely different style. The answer I'm searching for in this topic is what is the impact of using a BNC connector versus another means of connection.


Price isn't the only consideration that I'm looking at here. For example, the TED monopole antenna that got the thumbs up in this topic is less expensive than the antenna I purchased. So, what specifically is it about the TED antenna that gets the thumbs up but the one I've purchased gets thumbs down? Is it the shiny ball on the tip? What does that do anyway besides add decoration? Is it because it has a BNC connector? If that's the only reason then I'm back to my original question.


Rocketbob: In your experience testing them, what VSWR's were you see? -->Did you ever test an antenna with a BNC connector and then test the same antenna without it to iscolate the change in VSWR introduced by not/using a BNC?


Wonder if he has any idea who Stein is????
--> I don't care if he's the pope's brother-in-law. The days of me believing because of who said it instead of what was said, are long behind me.


On the positive side of things, it looks like you will be getting the full benefit of the ". . . For Education and Recreation" on this one!
--> I hope so. That's one of the main reasons I'm building myself instead of purchasing an off-the-shelf solution. I'm trying to sift through the personal advice versus clear technical reasons. I hoped by challenging their input that I would receive more measurable analysis. No offence was intended. Considering how inexpensive most of the "real antennas" are, at this point I'd consider purchasing another set of antennas and comparing results for myself. But I'm still trying to get the plane in the air so that'll have to wait.
 
PurpleSwamper said:
. . . I hoped by challenging their input that I would receive more measurable analysis.
Click to expand...
Ah, but there is the rub! You are challenging their input while at the same time discarding their output. As such you are asking them to "provided me the answer" I seek, then you say: "That is not how I would do it! Now do it differently and then come back and tell me what you find out". Not even you would tolerate another person doing that to you, yet, here you are doing it to them, and after they respond to your inquiry, you chose to chastise them for saying something contradictory to what you believe.

Now that you have chosen this path, you are going to be very limited on how you will be satisfied with an answer. The answer you are seeking will only come from your own mind. Since it is obvious you chose not to accept any results from another individual's mind unless their answer supports what your mind has already concluded, you have no choice but to go seek out your own answers.

The only answer you will be happy with is destined to only come from you. So now you are being forced to DO YOUR OWN RESEARCH to find the answers to the questions you are asking. After all, your current approach is leading you toward that result whether you want it to or not. So, you should really get started on the "Education and Recreation" thing sooner than later.

Just one last thought though. Once you find the answer, be sure to come back to this thread and give us the details of what you find out. After all, isn't that how we all learn from others, and more to the point, why we even read these threads in the first place? To get answers to questions we desire to know without having to go through the process of "re-inventing the wheel". If you figure this out and then tell us what the results are, we will then be able to site your experience as to the reason we believe what we do about this topic. Because you told us so! Otherwise, away I will have to go to -- wait here it comes -- do the research myself and "RE-INVENT the wheel".

Good Luck with your experiments.

Live Long and Prosper!
 
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PurpleSwamper said:
Rocketbob: In your experience testing them, what VSWR's were you see? -->Did you ever test an antenna with a BNC connector and then test the same antenna without it to iscolate the change in VSWR introduced by not/using a BNC?
Click to expand...

Over 4:1. It was nearly down to 1:1 at a few frequencies with a BNC and Don Pansier's antenna. Huge difference.
 
rocketbob said:
Over 4:1. It was nearly down to 1:1 at a few frequencies with a BNC and Don Pansier's antenna. Huge difference.
Click to expand...

So RocketBob,

Would you suggest the DeltaPop unit over the RAMI unit that I mentioned above? The Delta Pop will cost me about $16 less, so there is not a huge cost delta. If performance is the same I will go with Delta Pop...
 
I cannot help myself, I'll take the bait!

Transmission line theory may be hard to grasp sometimes, but I'll try.

Look at an assembled connector. The shield flows smoothly onto the outer metal part, which is now the new 'shield'. There are no gaps. Furthermore, the diameters are carefully controlled so as to maintain a 50 ohm impedance at every location. Look at your stripped pigtails. They look nothing like that. They look more like a little antenna, and that is how they will act.

Careful impedance match at the antenna has nothing to do with the length of coax. That is the whole point of transmission lines, they look like 50 ohms regardless of length.

This is hard to grasp, but while currents flow in the center conductor and the shield, the power propagates as an electromagnetic wave between them. So the quality of the dielectric affects power loss, especially at microwave frequencies. RG400 is less lossy.

Will your system work, at least to some extent? Sure it will. It just seems strange to spend $1k on a transponder and then throw half the power away to save $50.
 
PurpleSwamper said:
Wonder if he has any idea who Stein is????
--> I don't care if he's the pope's brother-in-law. The days of me believing because of who said it instead of what was said, are long behind me.
Click to expand...

This needs to go in Stein's sig line for posterity... :cool:
 
PurpleSwamper said:
Sam: Do you use rG58? And if so, what connectors do you use at the antenna?
Click to expand...

The antenna I have is not the $18 unit (I do, however, have one of those on my Legal Eagle for use with a handheld). My COM is this one:

http://www.aircraftspruce.com/pages/av/antenna_com/av534.php

It does not have a BNC at the antenna, just very short pigtails, and I think I have RG-58 (been 14 years since I wired it).

Wonder if he has any idea who Stein is????
--> I don't care if he's the pope's brother-in-law. The days of me believing because of who said it instead of what was said, are long behind me.
Click to expand...

Probably be a good idea to figure out who Stein is, you might find him to be a good resource at some point. :)

http://www.steinair.com/index.cfm
 
ccsmith51 said:
So RocketBob,

Would you suggest the DeltaPop unit over the RAMI unit that I mentioned above? The Delta Pop will cost me about $16 less, so there is not a huge cost delta. If performance is the same I will go with Delta Pop...
Click to expand...

Yep, they are good antennas. Have installed a few and even on certified aircraft (shhh).
 
BobTurner said:
I cannot help myself, I'll take the bait!

Transmission line theory may be hard to grasp sometimes, but I'll try.
Click to expand...

Here let me make it simple. Lets say you have a garden hose and a nozzle. Think of the hose OD as a shield. You cut the shield, voila, you have a leak. Water gets out. Depending on the size of the hole, some water will still end up going thru the nozzle. That "hole" is the same thing as impedance. The bigger the hole is, the more water will flow out the hole and less thru the nozzle. In essence, the same principles apply to antennas. You may think your antenna is performing ok but its likely leaking RF if the transmission line is not fully shielded to the antenna itself.
 
rocketbob said:
Here let me make it simple. Lets say you have a garden hose and a nozzle. Think of the hose OD as a shield. You cut the shield, voila, you have a leak. Water gets out. Depending on the size of the hole, some water will still end up going thru the nozzle. That "hole" is the same thing as impedance. The bigger the hole is, the more water will flow out the hole and less thru the nozzle. In essence, the same principles apply to antennas. You may think your antenna is performing ok but its likely leaking RF if the transmission line is not fully shielded to the antenna itself.
Click to expand...

I appriciate that explanation. Very well put. I have enjoyed this thread since it has helped to increase my knowlege of antennas. Thanks everyone for their input.
 
Look at an assembled connector. The shield flows smoothly onto the outer metal part, which is now the new 'shield'. There are no gaps. Furthermore, the diameters are carefully controlled so as to maintain a 50 ohm impedance at every location. Look at your stripped pigtails. They look nothing like that. They look more like a little antenna, and that is how they will act.
--> Thanks Bob. That makes a good reasonable arguement for BNC connectors.


It just seems strange to spend $1k on a transponder and then throw half the power away to save $50.
--> Actually I spent $2k on the transponder and the antenna I purchased cost more than the cheap TED antenna that is endorsed in this thread. It's never been about the money and I've never been anti-BNC. In fact I was surprised when my antennas arrived without BNCs since I'd already purchased cables with BNC connectors. My options on receiving the antennas without BNCs were then:
1. send them back to ASpruce and order different ones
2. attach BNCs to the antenna shafts
3. cut the BNCs off the cable ends and either wrap the cores around the antennas or crimp/solder on another type of connector

ASpruce wasn't much help except that they gave me the phone number for the manufacturer in Montana. I chatted with them... very nice people and eager to help. They said that these antennas have been used in both aircraft and aerospace applications. Said their biggest customer was NASA using them on satellites. I discussed the BNC connector with them and they advised to wrap the core around the antenna and secure it with the supplied nut.

Not convinced, I posted the question here.

The thing about consultants is that there are good ones and there are bad ones; some give good advice and others not so good. The trick is that you pretty much have to know as much as the consultant to know if you're getting good advice.

Visually there doesn' appear to be important differences between the transponder antenna I purchased and the TED antenna herein endorsed. The TED also appears to be a stubby stainless steel shaft.

I was educated in this thread that gamma matching is incorporated into the bases of other antennas. I thought that was usually only performed on cables exceeding 100' and didn't even think that it was possible without first preparing and attaching the specific cable for the installation.


Ah, but there is the rub! You are challenging their input while at the same time discarding their output.
--> You're completely wrong. I'm listening to all of the input and evaluating it on it's technical merit -Period!
 
Another data point: I have installed copper foil com, nav and MB antennas on plastic airplanes for 30+ years and, if properly installed with ferrite bead baluns, provide excellent performance and SWR. I routinely get 150nm range on the coms at 10-12,000' and more than 250nm at FL210. I realize this has nothing to do with RV's :D

I wish I had known to use RG400 but the RG58 is buried in the winglets and canards; Jim Weir of RST Engineering was recommending RG58 at the time

deek
 
Ha! It's all good. I'll give Victor the benefit of the doubt; he's new on these forums and likely didn't realize the amount of my post that was my typical sarcastic humor (except for the Dog part, that was true...lots and lots of folks let their dogs run around the hangar, and these types of antennas get bent much more of the time by the animals running into them than do the others). It's also obvious that internet forum etiquette here on VAF is a recently acquired and developing skill that all of us had to learn over time. It sounds like I should make a call to Rome, my consulting gig just isn't paying that well! :)

Even if I'm wrong, Walt is still right!

Cheers,
Stein

PS, The reason a similar antenna kinda works on Sam's plane is because he's an 'old timer gray beard'....when he mined and smelted the bauxite for his plane, he made an extra special aluminum alloy! :)
 
SteinAir said:
PS, The reason a similar antenna kinda works on Sam's plane is because he's an 'old timer gray beard'....when he mined and smelted the bauxite for his plane, he made an extra special aluminum alloy! :)
Click to expand...

Lotta truth to that except the part about "kinda works". The thang has actually worked very well (excellent range with two different radios) except for sometimes making the fuel gauge blink.

Guess I got lucky. :)
 
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The Final Analysis

Thanks for all your input. I've also been researching this non-BNC connector for coax option outside of this forum and have found some information to support the idea that it isn't completely ludicrous, especially when some people say they are operating this way with satisfactory results.

Unfortunately I've invested about as much time into it as I can afford at this time and haven't yielded enough evidence to convince me to follow that route. So tomorrow I'm taking the easy way out and ordering "real antennas" with BNC connectors.

Contrary to what some assumed, this was the default option I owned when I started this thread and was hoping to be convinced otherwise with solid technical reasoning. Peace to all.
.....Victor
 
SteinAir said:
Even if I'm wrong, Walt is still right! Cheers,
Stein
Click to expand...


Don't get me involved in this mess, if you noticed I bailed on this one a long time ago.

Plus its good for the economy, when he goes in for a transponder check the shop (after they stop laughing) will run a new cable and install a new antenna :D
 
SteinAir said:
PS, The reason a similar antenna kinda works on Sam's plane is because he's an 'old timer gray beard'....when he mined and smelted the bauxite for his plane, he made an extra special aluminum alloy! :)
Click to expand...

Sam Buchanan said:
Lotta truth to that except the part about "kinda works". The thang has actually worked very well (excellent range with two different radios) except for sometimes making the fuel gauge blink.

Guess I got lucky. :)
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Ok Stein......you shamed me into ordering a COM antenna from DeltaPopAviation this evening. My old faithful non-BNC antenna will soon be history.

And my fuel gauge happy! :D
 
Good for you Sam! Don P is an all around good RV guy who makes these things here in the USA part time, so it's nice to see the support for the little guy.

Cheers,
Stein
 
I wonder what the pope's brother has to say about my 1/2 wave dipole com in my emmy's empennage. It's a z bend (about 15 degrees to get it polarized vertically), is connected to ring terminals (short leads) on RG58 feeding a KX165. I'm not being sarcastic, I'm really curious.
 
aerhed said:
I wonder what the pope's brother has to say about my 1/2 wave dipole com in my emmy's empennage. It's a z bend (about 15 degrees to get it polarized vertically), is connected to ring terminals (short leads) on RG58 feeding a KX165. I'm not being sarcastic, I'm really curious.
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If sort of depends on several factors. Is this a factory produced antenna (like the AAE ones)? If so, they work quite well in composite airplanes, not so much in our metal ones but AAE makes pretty good antennas. Half wave antennas can be really good or really poor, depending on impedence, center/end fed, material, frequencies, etc.. In the end you could have an installation that really works quite well, or might not work worth a hoot - just sorta depends on the antenna, installation, etc.. There are a lot of airplanes flying with the center fed AAE half wave antennas with very good success. There are also a few homebrew ones that work very well....but there are also some prety bad installations as well.

Just my 2 cents as usual.

Cheers,
Stein
 
It's actually a pair of welding rods for radiators and I copied it from somewhere and adjusted the length for our VHF band. Structur is fabric and plywood all around. I can talk to SLC center from over Pinedale (well over 100 miles). So, did I just get lucky? It's not like I know what I'm doing. I'm mostly a copycat.
 
It's actually a pair of welding rods for radiators... adjusted the length for our VHF band... I can talk to ...well over 100 miles
--> No you didn't. I've learned that's not possible. Just kidding.... I think that's really cool. Makes me wish I'd held out a little longer before ordering the new antennas. I did however hang on to the other set just to play around with, maybe solder on a couple of BNCs and compare performance. :)
 
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