Today's Message Index:
----------------------
1. 01:27 AM - Re: Antenna Yak52 (Brian Lloyd)
2. 09:12 AM - Re: Antenna Yak52 (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
3. 10:08 AM - Re: Antenna Yak52 (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
4. 11:55 AM - Re: Antenna Yak52 (Jan Mevis)
5. 12:24 PM - Re: Antenna Yak52 (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
6. 01:10 PM - Re: Antenna Yak52 (Brian Lloyd)
7. 04:49 PM - Re: Antenna Yak52 (Warren Hill)
8. 08:14 PM - Re: Antenna Yak52 (Brian Lloyd)
Message 1
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| Subject: | Re: Antenna Yak52 |
On Sat, Jul 7, 2012 at 11:35 PM, Walter Lannon <wlannon@shaw.ca> wrote:
>
> Hi Mark;
>
> Just finishing up the avionics installations in my CJ project. I used
> Mil. Spec. M17/128-RG400 for all units. 2 comms, TXPDR and GPS. Had
> intended to use RG 142 for the GPS but the local avionics shop (who have a
> very good reputation) said the RG400 would be fine. It's only a 3 ft. run
> so I assume either would be OK. Both are silver plated central conductor
> and double silver plated shields.
>
> Do you see any problem with that?
>
Nope. RG400 is functionally equivalent to RG-142. The teflon dielectric and
double-shield, silver-plated braid are the keys. And Mark is right that
these coax cables last a lot longer than cheaper RG-58. If you are going to
spend several thousands of dollars on your radios, trying to save $50 on
your coax feed-line is silly.
The one thing I disagree with Mark on is the use of crimp-on connectors. I
use crimp-on connectors for everything. Turns out that crimping makes a
superior gas-tight connection which makes the connection last longer and be
less subject to failure. Combine that with proper application of
self-sealing (heat-activated adhesive inside) heat shrink tubing and you
have a superior termination even to solder-on terminations. That it is
easier and faster to do is just a plus. (You need a good ratcheting crimp
tool with the proper dies tho'!)
And, no, I am not looking for an argument. The information is available
from the manufacturers of the connectors. They have done the testing and
will provide the results if you are interested.
The key here is that you will have no trouble finding best standard
practices in the industry. It is what good radio shops use. Good quality
coax, e.g. RG400, properly terminated with crimp-on connectors, sealed with
self-sealing heat-shrink, IS best standard practice. That is why good radio
shops use this approach over and over again with good success. If it didn't
work, they would be losing money on rework so would change their techniques.
One can argue antennas 'till the cows come home but mechanical issues tend
to outweigh the electrical issues. Standard production aircraft antennas
work just fine with standard production aircraft radios. Yes, you need to
make sure that the base of the antenna makes good connection with the
aircraft skin but that just means cleaning any paint or other coating from
the skin around the bolt holes prior to mounting the antenna. I like to
mount my antennas "wet" by applying zinc chromate to the skin around the
bolt holes just before bolting the antenna down. The wet zinc chromate
allows the metals to come together to form an electrical bond but then the
zinc chromate dries to provide a corrosion barrier.
This is not rocket science.
--
Brian Lloyd, WB6RQN/J79BPL
3191 Western Dr.
Cameron Park, CA 95682
brian@lloyd.com
+1.767.617.1365 (Dominica)
+1.916.877.5067 (USA)
Message 2
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Absolutely not. RG-400 is just as good. Tells me that your Avionics Shop knows
what they are doing.
Mark
________________________________
From: owner-yak-list-server@matronics.com on behalf of Walter Lannon
Sent: Sat 7/7/2012 11:35 PM
Subject: Re: Yak-List: Antenna Yak52
Hi Mark;
Just finishing up the avionics installations in my CJ project. I used Mil.
Spec. M17/128-RG400 for all units. 2 comms, TXPDR and GPS. Had
intended to use RG 142 for the GPS but the local avionics shop (who have a
very good reputation) said the RG400 would be fine. It's only a 3 ft. run
so I assume either would be OK. Both are silver plated central conductor
and double silver plated shields.
Do you see any problem with that?
Many thanks;
Walt
-----Original Message-----
From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E
Sent: Saturday, July 07, 2012 1:07 PM
Subject: RE: Yak-List: Antenna Yak52
MALS-14 64E" <mark.bitterlich@navy.mil>
Roger that Warren. As you know, the feedpoint impedance of a 1/4 wave
radiator is actually about 36 ohms, giving a best match of about 1.5 to 1
VSWR. Whereas in order to feed a 5/8 wave design, you try to make the 5/8
wave antenna appear to be about 3/4 wavelength which will establish a pretty
good match and also give the ideal low angle of radiation that can be gained
with the actual 5/8 wave length of the antenna. This is typically done by
using a base loading coil. Typical aircraft designs avoid 5/8 wavelength
due to the compressed pattern that is good for fixed stations, but bad for a
moving platform with pitch and roll.
Only really cheap avionics shops use RG-58 for the reasons you specified. A
much better alternative and what aircraft owners should specifically ask for
is RG-142 B/U which is a teflon dielectric silver tinned double shielded
coax that has a higher velocity factor than standard coax and thus lower
loss. This coax is good for short runs even at 1.5 GHz, such as a GPS
antenna for example. If more flexibility is needed in the coax (the teflon
is kind of stiff), I recommend RG-223, which is the same as RG-142, except
it has a poly dielectric rather than teflon.
If you are a warbird with LONG coax runs, I recommend RG-393/U which is the
roughly 0.5" variety of PTFE dielectric coax. It has even lower loss (large
center conductor) is also silver tinned. Again if stiffness is a factor,
the alternative is RG-214.
I recommend avoiding crimp on connectors of ANY type. Avionics shops love
them because they are easy and FAST to put on. Putting a standard BNC or
TNC connector takes time, and a little bit of soldering skill. That said, I
never ever use crimp-on's.
But just for giggles let's compare ....... A 20 foot run of RG-142 at 130
Mhz will give a loss of about 0.9 dB But with tongue in cheek, let me
also submit that a 20 foot run of RG-58 will have a loss of 1.0 dB, thus a
difference of only 0.1 dB. At 1500 Mhz, basically GPS range, you are
looking at a 20 foot run of RG-58 having 3.8 dB of loss and RG-142 3.2 dB, a
difference of 0.6 dB
So a true nit-picker would submit that the higher cost of RG-142 is not
worth it ..... but I submit it is much more rugged, and will last MUCH
LONGER compared to anything else.
Of course, the real advantage of RG-393 is that it will handle 10 Kw of
average power at 20 Mhz... needed when you are running a 3CX3000A7 with 7000
volts on the plate.
Take care Warren,
Mark
WA3JPY
________________________________
From: owner-yak-list-server@matronics.com on behalf of Warren Hill
Sent: Fri 7/6/2012 2:47 PM
Subject: Re: Yak-List: Antenna Yak52
Mark,
As you know, a straight 1/4 wavelength vertical radiator has a relatively
narrow bandwidth. The SWR will be good at 1/4 and possibly 5/8 wavelength,
but rises quickly after that. There is no way to make a single element
vertical antenna efficient from 118 to 136 MHz. It can be tuned at the
center frequency and we just have to accept the high SWR towards the ends of
the band. Also, the anodized aluminum panels on the CJ do not always conduct
well between each one.
The other weak point in aviation communications is the coax and the BNC
connectors. RG-58 is pretty lossy at 120 MHz and a poorly fashioned BNC
connector easily has a 1 to 2 dB insertion loss. For every 3 dB of loss the
signal strength is cut by 50%, outgoing and incoming. So... a non-resonant
antenna with a shaky counterpoise, two low quality, crimped BNC connectors
on RG-58 coax and even the best radio may seem less than adequate from 20
miles out.
The good news is that just about everything we do is line of sight and at
these frequencies it doesn't take much radiated power to maintain a
reasonable signal strength.
Warren
On Jul 6, 2012, at 11:17 AM, Bitterlich, Mark G CIV Det Cherry Point,
MALS-14 64E wrote:
> MALS-14 64E" <mark.bitterlich@navy.mil>
>
> I might point out that physics is a problem here as well.
>
> One piece of metal as an antenna cannot be made to provide a
> characteristic impedance of 50 ohms from 118 to 136 MHz. You pretty
> much have to come up a way around that issue. :-)
>
> Mark
>
> p.s. Go ahead Brian.
>
>
> -----Original Message-----
> From: owner-yak-list-server@matronics.com
> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Hans Oortman
> Sent: Friday, July 06, 2012 4:23 AM
> To: yak-list@matronics.com
> Subject: Re: Yak-List: Antenna Yak52
>
>
> Thanks Mark....I can not reach the guts of the antenna myself but found
> a
> small guy who can.... Jan probably has still an antenna, so I'll wait
> what
> he can find.
>
> Buy the way: I hate matching networks, the only thing it does is match
> the
> impedance but pulls down the efficiency....
>
> I'll keep you posted!
>
> Hans
>
>
> Op 05-07-12 00:42, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E
> <mark.bitterlich@navy.mil> schreef:
>
> Point,
>> MALS-14 64E" <mark.bitterlich@navy.mil>
>>
>> The stock Russian antenna has a small matching network inside. If you
> want to
>> go to the effort, the radiator can be replaced. It is actually a
> threaded
>> tapered rod. The best bet would be to ask around and see if you can
> find an
>> old one that someone removed that you can just thread in and be done.
>>
>> Personally, I took the antenna off, then drilled the original plate
> for a more
>> modern antenna and mounted it on the same plate. Doing it this way
> you really
>> should not notice any damage to your paint? In any case, you would
> have to
>> slice around the mounting plate so you could remove it. I think I
> have one
>> that I could take pictures of for you, but it would take a few days
> since I am
>> currently not home. If anyone else has pictures, I am sure that would
> help
>> you much better than this email.
>>
>> Mark
>>
>>
>> ________________________________
>>
>> From: owner-yak-list-server@matronics.com on behalf of Hans Oortman
>> Sent: Wed 7/4/2012 5:11 PM
>> To: yak-list
>> Subject: Yak-List: Antenna Yak52
>>
>>
>> Guys,
>>
>> Has anybody removed or swapped the antenna on a Yak52??
>> Mine is broken and completely corroded so needs to be replaced.
>> If I want to remove it, it means damaging the paint and I was
> wondering if
>> only the radiator could be removed rather than the whole assembly??
>> Pictures or drawings would be appreciated!
>>
>> Thanks!
>>
>> Hans O.
>> RA3326K
>> Netherlands
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
Message 3
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Hello Brian,
I have been expecting your reply to be honest.
First, ... Hey Walt, you're correct (and so is Brian) RG-400 is just fine
Brian, you are welcome to disagree with me. There are many grades and types of
crimp on connectors. And obviously they would work, or there wouldn't be so
many out there. My personal bias is based on the 42 years of experience I have
had with them on aircraft. Some gas tight crimps that are out there, specifically
the types I normally see on 20 Ghz Gore Line for example are indeed superior
to anything else made. These are typically factory assembled and are not
repairable in the field. If they are, you can only replace the end fitting,
and not swage in a totally new connector to the transmission line itself. In
addition, keep in mind that I am talking to aircraft owners/pilots, who might
want to repair their own aircraft.
Typical crimp on connectors, are not gas tight. In fact, there is special coax
designations, or "MilSpec" if you will, that are specifically designated for
gas tight crimps. RG-142, 400, 214, 393, etc., are not gas tight transmission
lines. But yes,.. you could use gas tight crimps on them if you wanted. What
I am referring to is what I'll call "The Standard Crimp on Connector". If
these are assembled and crimped on properly....
WAIT WAIT !!!!! There is that sneaky "IF" word that just crept in. The "IF" means
that you have in your hands, the exact correct type of crimp tool, properly
adjusted, and know how to us it ... if all that is true, you can create a good
operational RF connector on the end of the transmission line. But it is not
gas tight, any more than a manually assembled connector. You mention this
yourself when you commented on a properly ratcheting crimp tool. And in most
cases, an aircraft owner/operator is not going to go out and purchase the best
quality crimping tools and dies out there. Avionics Shops might... maybe. Not
always.
Yes, there is indeed a special connector, historically tracing it's roots back
to the RayChem company, that has self sealing heat activated material inside.
Now we need the proper heat gun, ... or you can just wild ass guess it with a
hot air gun, and in this case a seal is made, that is probably a tad superior
to the rubber self split ring concept of the manually made connectors. However,
I mildly object to the term "gas tight" as that is a phrase normally reserved
for connectors designed to be used on specific gas tight transmission lines.
However, given what we are talking about here, it really doesn't matter.
Finally, we get to the heat shrink tubing that you mentioned putting on the outside
of the coax line. This is the most important thing you said ... in my opinion.
Typical crimped connectors put a physical stress point on the coax line
itself, causing premature failure right behind the connector. Putting not only
heat shrink, but the proper TYPE of heat shrink over that possible flex point,
will improve the life of the crimp on connector. But then, it will do the
exact same thing on a manually assembled, soldered center pin connector. So
heat shrink installed on ANY connector is by and large "A GOOD THING".
You mention that crimp on connectors with heat shrink backing "IS BEST STANDARD
PRACTICE". Well, I guess that depends on what standards you are referring to
Clearly they are best by your standards,
You then said: "That is why good radio shops use this approach over and over again
with good success. If it didn't work, they would be losing money on rework
so would change their techniques." That is, in my opinion, flawed reasoning.
With the General Aviation Avionics Shops that I have experience with, if something
works going out the door, and then you come back a year later with a
damaged connector, they are not going to fix it for free because it did not last
as long as you thought it should. They will fix it exactly the same way again,
and charge you for it. Avionics shops are out to make money, and very few
of them sacrifice their time to make a connector last longer. I am well aware
that using crimp on connectors is "standard practice" for most shops, but that
does not make it the "best method", it makes it the fastest and cheapest method,
and THAT is what they are looking for.
AND... of all the connectors I have seen Avionics Shops put on, few if ANY put
heat shrink on the back, and NONE have ever used a connector with internal heat
activated sealant. Those types cost too much.
The reason I prefer the type I promoted Brian, is because I have been working with
these types of connectors for 42 years on military aircraft, every single
day. It is true that crimp connectors can be made to last longer. However, the
manually soldered on types that I prefer, with heat shrink on the back, last
longer than anything else.
Antennas ... interesting that you brought that up. The mechanical bond between
aircraft skin and antenna is obviously critical for best performance. A funded
study was performed on this issue about 15 years ago by the Department of Defense,
This is a significant issue, especially for USN, and USMC aircraft as
they operate in highly corrosive environments. The result of this study is
that now all USN and USMC aircraft use a very special conductive sealing method
for all external antennas. Give a Google look-up for: "AV-Dec" and read all
about it there. AV-Dec is NOT "best standard practice" by any means. It is
BEST POSSIBLE PRACTICE, and I've yet to see it used in General Aviation, except
on my aircraft of course.
You said: "This is not rocket science". Correct, far from it. Actually it is
your and my OPINIONS being expressed on the YAK List. Not even close to Rocket
Science. .
Mark
p.s. The short version: "I think we'll agree to disagree on this one.
________________________________
From: owner-yak-list-server@matronics.com on behalf of Brian Lloyd
Sent: Sun 7/8/2012 4:23 AM
Subject: Re: Yak-List: Antenna Yak52
On Sat, Jul 7, 2012 at 11:35 PM, Walter Lannon <wlannon@shaw.ca> wrote:
Hi Mark;
Just finishing up the avionics installations in my CJ project. I used Mil. Spec.
M17/128-RG400 for all units. 2 comms, TXPDR and GPS. Had intended to
use RG 142 for the GPS but the local avionics shop (who have a very good reputation)
said the RG400 would be fine. It's only a 3 ft. run so I assume either
would be OK. Both are silver plated central conductor and double silver
plated shields.
Do you see any problem with that?
Nope. RG400 is functionally equivalent to RG-142. The teflon dielectric and double-shield,
silver-plated braid are the keys. And Mark is right that these coax
cables last a lot longer than cheaper RG-58. If you are going to spend several
thousands of dollars on your radios, trying to save $50 on your coax feed-line
is silly.
The one thing I disagree with Mark on is the use of crimp-on connectors. I use
crimp-on connectors for everything. Turns out that crimping makes a superior gas-tight
connection which makes the connection last longer and be less subject
to failure. Combine that with proper application of self-sealing (heat-activated
adhesive inside) heat shrink tubing and you have a superior termination even
to solder-on terminations. That it is easier and faster to do is just a plus.
(You need a good ratcheting crimp tool with the proper dies tho'!)
And, no, I am not looking for an argument. The information is available from the
manufacturers of the connectors. They have done the testing and will provide
the results if you are interested.
The key here is that you will have no trouble finding best standard practices in
the industry. It is what good radio shops use. Good quality coax, e.g. RG400,
properly terminated with crimp-on connectors, sealed with self-sealing heat-shrink,
IS best standard practice. That is why good radio shops use this approach
over and over again with good success. If it didn't work, they would be losing
money on rework so would change their techniques.
One can argue antennas 'till the cows come home but mechanical issues tend to outweigh
the electrical issues. Standard production aircraft antennas work just
fine with standard production aircraft radios. Yes, you need to make sure that
the base of the antenna makes good connection with the aircraft skin but that
just means cleaning any paint or other coating from the skin around the bolt
holes prior to mounting the antenna. I like to mount my antennas "wet" by applying
zinc chromate to the skin around the bolt holes just before bolting the
antenna down. The wet zinc chromate allows the metals to come together to form
an electrical bond but then the zinc chromate dries to provide a corrosion barrier.
This is not rocket science.
--
Brian Lloyd, WB6RQN/J79BPL
3191 Western Dr.
Cameron Park, CA 95682
brian@lloyd.com
+1.767.617.1365 (Dominica)
+1.916.877.5067 (USA)
Message 4
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| Subject: | Re: Antenna Yak52 |
I've crimped hundreds of BNC connectors on coax, back in the eighties when
twisted pair was not used yet for Ethernet. And it took a while before I
was reasonably proficient.
In those days we had to use the crimp tool just because of "production
speed".
I also have seen two radio's with their end amplification transistor blown
up because of a BNC connector, crimped on the coax, and became loose.
I prefer soldering but must also admit that I often take the crimp tool,
just because it's so easy to use. Soldering a BNC connector is not that
simple either, for the layman, isn't it?
Jan
On 08/07/12 19:05, "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E"
<mark.bitterlich@navy.mil> wrote:
>MALS-14 64E" <mark.bitterlich@navy.mil>
>
>Hello Brian,
>
>I have been expecting your reply to be honest.
>
>First, ... Hey Walt, you're correct (and so is Brian) RG-400 is just fine
>
>Brian, you are welcome to disagree with me. There are many grades and
>types of crimp on connectors. And obviously they would work, or there
>wouldn't be so many out there. My personal bias is based on the 42 years
>of experience I have had with them on aircraft. Some gas tight crimps
>that are out there, specifically the types I normally see on 20 Ghz Gore
>Line for example are indeed superior to anything else made. These are
>typically factory assembled and are not repairable in the field. If they
>are, you can only replace the end fitting, and not swage in a totally new
>connector to the transmission line itself. In addition, keep in mind
>that I am talking to aircraft owners/pilots, who might want to repair
>their own aircraft.
>
>Typical crimp on connectors, are not gas tight. In fact, there is
>special coax designations, or "MilSpec" if you will, that are
>specifically designated for gas tight crimps. RG-142, 400, 214, 393,
>etc., are not gas tight transmission lines. But yes,.. you could use gas
>tight crimps on them if you wanted. What I am referring to is what I'll
>call "The Standard Crimp on Connector". If these are assembled and
>crimped on properly....
>
>WAIT WAIT !!!!! There is that sneaky "IF" word that just crept in. The
>"IF" means that you have in your hands, the exact correct type of crimp
>tool, properly adjusted, and know how to us it ... if all that is true,
>you can create a good operational RF connector on the end of the
>transmission line. But it is not gas tight, any more than a manually
>assembled connector. You mention this yourself when you commented on a
>properly ratcheting crimp tool. And in most cases, an aircraft
>owner/operator is not going to go out and purchase the best quality
>crimping tools and dies out there. Avionics Shops might... maybe. Not
>always.
>
>Yes, there is indeed a special connector, historically tracing it's roots
>back to the RayChem company, that has self sealing heat activated
>material inside. Now we need the proper heat gun, ... or you can just
>wild ass guess it with a hot air gun, and in this case a seal is made,
>that is probably a tad superior to the rubber self split ring concept of
>the manually made connectors. However, I mildly object to the term "gas
>tight" as that is a phrase normally reserved for connectors designed to
>be used on specific gas tight transmission lines. However, given what we
>are talking about here, it really doesn't matter.
>
>Finally, we get to the heat shrink tubing that you mentioned putting on
>the outside of the coax line. This is the most important thing you said
>... in my opinion. Typical crimped connectors put a physical stress point
>on the coax line itself, causing premature failure right behind the
>connector. Putting not only heat shrink, but the proper TYPE of heat
>shrink over that possible flex point, will improve the life of the crimp
>on connector. But then, it will do the exact same thing on a manually
>assembled, soldered center pin connector. So heat shrink installed on
>ANY connector is by and large "A GOOD THING".
>
>You mention that crimp on connectors with heat shrink backing "IS BEST
>STANDARD PRACTICE". Well, I guess that depends on what standards you
>are referring to Clearly they are best by your standards,
>
>You then said: "That is why good radio shops use this approach over and
>over again with good success. If it didn't work, they would be losing
>money on rework so would change their techniques." That is, in my
>opinion, flawed reasoning. With the General Aviation Avionics Shops that
>I have experience with, if something works going out the door, and then
>you come back a year later with a damaged connector, they are not going
>to fix it for free because it did not last as long as you thought it
>should. They will fix it exactly the same way again, and charge you for
>it. Avionics shops are out to make money, and very few of them sacrifice
>their time to make a connector last longer. I am well aware that using
>crimp on connectors is "standard practice" for most shops, but that does
>not make it the "best method", it makes it the fastest and cheapest
>method, and THAT is what they are looking for.
>
>AND... of all the connectors I have seen Avionics Shops put on, few if
>ANY put heat shrink on the back, and NONE have ever used a connector with
>internal heat activated sealant. Those types cost too much.
>
>The reason I prefer the type I promoted Brian, is because I have been
>working with these types of connectors for 42 years on military aircraft,
>every single day. It is true that crimp connectors can be made to last
>longer. However, the manually soldered on types that I prefer, with heat
>shrink on the back, last longer than anything else.
>
>Antennas ... interesting that you brought that up. The mechanical bond
>between aircraft skin and antenna is obviously critical for best
>performance. A funded study was performed on this issue about 15 years
>ago by the Department of Defense, This is a significant issue,
>especially for USN, and USMC aircraft as they operate in highly corrosive
>environments. The result of this study is that now all USN and USMC
>aircraft use a very special conductive sealing method for all external
>antennas. Give a Google look-up for: "AV-Dec" and read all about it
>there. AV-Dec is NOT "best standard practice" by any means. It is BEST
>POSSIBLE PRACTICE, and I've yet to see it used in General Aviation,
>except on my aircraft of course.
>
>You said: "This is not rocket science". Correct, far from it. Actually
>it is your and my OPINIONS being expressed on the YAK List. Not even
>close to Rocket Science. .
>
>Mark
>
>p.s. The short version: "I think we'll agree to disagree on this one.
>
>
>________________________________
>
>From: owner-yak-list-server@matronics.com on behalf of Brian Lloyd
>Sent: Sun 7/8/2012 4:23 AM
>To: yak-list@matronics.com
>Subject: Re: Yak-List: Antenna Yak52
>
>
>On Sat, Jul 7, 2012 at 11:35 PM, Walter Lannon <wlannon@shaw.ca> wrote:
>
>
>
> Hi Mark;
>
> Just finishing up the avionics installations in my CJ project. I used
>Mil. Spec. M17/128-RG400 for all units. 2 comms, TXPDR and GPS. Had
>intended to use RG 142 for the GPS but the local avionics shop (who have
>a very good reputation) said the RG400 would be fine. It's only a 3 ft.
>run so I assume either would be OK. Both are silver plated central
>conductor and double silver plated shields.
>
> Do you see any problem with that?
>
>
>
>Nope. RG400 is functionally equivalent to RG-142. The teflon dielectric
>and double-shield, silver-plated braid are the keys. And Mark is right
>that these coax cables last a lot longer than cheaper RG-58. If you are
>going to spend several thousands of dollars on your radios, trying to
>save $50 on your coax feed-line is silly.
>
>The one thing I disagree with Mark on is the use of crimp-on connectors.
>I use crimp-on connectors for everything. Turns out that crimping makes a
>superior gas-tight connection which makes the connection last longer and
>be less subject to failure. Combine that with proper application of
>self-sealing (heat-activated adhesive inside) heat shrink tubing and you
>have a superior termination even to solder-on terminations. That it is
>easier and faster to do is just a plus. (You need a good ratcheting crimp
>tool with the proper dies tho'!)
>
>And, no, I am not looking for an argument. The information is available
>from the manufacturers of the connectors. They have done the testing and
>will provide the results if you are interested.
>
>The key here is that you will have no trouble finding best standard
>practices in the industry. It is what good radio shops use. Good quality
>coax, e.g. RG400, properly terminated with crimp-on connectors, sealed
>with self-sealing heat-shrink, IS best standard practice. That is why
>good radio shops use this approach over and over again with good success.
>If it didn't work, they would be losing money on rework so would change
>their techniques.
>
>One can argue antennas 'till the cows come home but mechanical issues
>tend to outweigh the electrical issues. Standard production aircraft
>antennas work just fine with standard production aircraft radios. Yes,
>you need to make sure that the base of the antenna makes good connection
>with the aircraft skin but that just means cleaning any paint or other
>coating from the skin around the bolt holes prior to mounting the
>antenna. I like to mount my antennas "wet" by applying zinc chromate to
>the skin around the bolt holes just before bolting the antenna down. The
>wet zinc chromate allows the metals to come together to form an
>electrical bond but then the zinc chromate dries to provide a corrosion
>barrier.
>
>This is not rocket science.
>
>--
>Brian Lloyd, WB6RQN/J79BPL
>3191 Western Dr.
>Cameron Park, CA 95682
>brian@lloyd.com
>+1.767.617.1365 (Dominica)
>+1.916.877.5067 (USA)
>
>
Message 5
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Jan, I agree with you 100%.
I was not being at all fair when making the comparison between these two types
of connectors. Specifically in that putting together a manually assembled connector
requires experience and knowledge and is far from simple. After manually
unbraiding and then soldering the center conductor on way WAY too many N, HN,
C, BNC, TNC connectors, which I can now do very well, I despise the amount
of time it takes to do it.
That said, on MY equipment, I choose the harder method, simply because I know if
it is done right, it will work a LONG time without failure.
And of those hundreds of crimped on BNC's ... how many did you put heatshrink on?
I'm going to guess "none". :-)
Both types of connectors require experience and technique. The manually assembled
connectors take longer to assemble, and more experience. The crimp-on's require
exactly the right tools, the best of which are anything but cheap, but
"works pretty well" tools can be obtained at a fair price, and it does not take
too much training to put them on. Don't forget the heat shrink though......
Good point about blowing the finals in the radios due to high VSWR caused by bad
crimp on connectors.
To each their own I guess.
Mark
________________________________
From: owner-yak-list-server@matronics.com on behalf of Jan Mevis
Sent: Sun 7/8/2012 2:52 PM
Subject: Re: Yak-List: Antenna Yak52
I've crimped hundreds of BNC connectors on coax, back in the eighties when
twisted pair was not used yet for Ethernet. And it took a while before I
was reasonably proficient.
In those days we had to use the crimp tool just because of "production
speed".
I also have seen two radio's with their end amplification transistor blown
up because of a BNC connector, crimped on the coax, and became loose.
I prefer soldering but must also admit that I often take the crimp tool,
just because it's so easy to use. Soldering a BNC connector is not that
simple either, for the layman, isn't it?
Jan
On 08/07/12 19:05, "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E"
<mark.bitterlich@navy.mil> wrote:
>MALS-14 64E" <mark.bitterlich@navy.mil>
>
>Hello Brian,
>
>I have been expecting your reply to be honest.
>
>First, ... Hey Walt, you're correct (and so is Brian) RG-400 is just fine
>
>Brian, you are welcome to disagree with me. There are many grades and
>types of crimp on connectors. And obviously they would work, or there
>wouldn't be so many out there. My personal bias is based on the 42 years
>of experience I have had with them on aircraft. Some gas tight crimps
>that are out there, specifically the types I normally see on 20 Ghz Gore
>Line for example are indeed superior to anything else made. These are
>typically factory assembled and are not repairable in the field. If they
>are, you can only replace the end fitting, and not swage in a totally new
>connector to the transmission line itself. In addition, keep in mind
>that I am talking to aircraft owners/pilots, who might want to repair
>their own aircraft.
>
>Typical crimp on connectors, are not gas tight. In fact, there is
>special coax designations, or "MilSpec" if you will, that are
>specifically designated for gas tight crimps. RG-142, 400, 214, 393,
>etc., are not gas tight transmission lines. But yes,.. you could use gas
>tight crimps on them if you wanted. What I am referring to is what I'll
>call "The Standard Crimp on Connector". If these are assembled and
>crimped on properly....
>
>WAIT WAIT !!!!! There is that sneaky "IF" word that just crept in. The
>"IF" means that you have in your hands, the exact correct type of crimp
>tool, properly adjusted, and know how to us it ... if all that is true,
>you can create a good operational RF connector on the end of the
>transmission line. But it is not gas tight, any more than a manually
>assembled connector. You mention this yourself when you commented on a
>properly ratcheting crimp tool. And in most cases, an aircraft
>owner/operator is not going to go out and purchase the best quality
>crimping tools and dies out there. Avionics Shops might... maybe. Not
>always.
>
>Yes, there is indeed a special connector, historically tracing it's roots
>back to the RayChem company, that has self sealing heat activated
>material inside. Now we need the proper heat gun, ... or you can just
>wild ass guess it with a hot air gun, and in this case a seal is made,
>that is probably a tad superior to the rubber self split ring concept of
>the manually made connectors. However, I mildly object to the term "gas
>tight" as that is a phrase normally reserved for connectors designed to
>be used on specific gas tight transmission lines. However, given what we
>are talking about here, it really doesn't matter.
>
>Finally, we get to the heat shrink tubing that you mentioned putting on
>the outside of the coax line. This is the most important thing you said
>... in my opinion. Typical crimped connectors put a physical stress point
>on the coax line itself, causing premature failure right behind the
>connector. Putting not only heat shrink, but the proper TYPE of heat
>shrink over that possible flex point, will improve the life of the crimp
>on connector. But then, it will do the exact same thing on a manually
>assembled, soldered center pin connector. So heat shrink installed on
>ANY connector is by and large "A GOOD THING".
>
>You mention that crimp on connectors with heat shrink backing "IS BEST
>STANDARD PRACTICE". Well, I guess that depends on what standards you
>are referring to Clearly they are best by your standards,
>
>You then said: "That is why good radio shops use this approach over and
>over again with good success. If it didn't work, they would be losing
>money on rework so would change their techniques." That is, in my
>opinion, flawed reasoning. With the General Aviation Avionics Shops that
>I have experience with, if something works going out the door, and then
>you come back a year later with a damaged connector, they are not going
>to fix it for free because it did not last as long as you thought it
>should. They will fix it exactly the same way again, and charge you for
>it. Avionics shops are out to make money, and very few of them sacrifice
>their time to make a connector last longer. I am well aware that using
>crimp on connectors is "standard practice" for most shops, but that does
>not make it the "best method", it makes it the fastest and cheapest
>method, and THAT is what they are looking for.
>
>AND... of all the connectors I have seen Avionics Shops put on, few if
>ANY put heat shrink on the back, and NONE have ever used a connector with
>internal heat activated sealant. Those types cost too much.
>
>The reason I prefer the type I promoted Brian, is because I have been
>working with these types of connectors for 42 years on military aircraft,
>every single day. It is true that crimp connectors can be made to last
>longer. However, the manually soldered on types that I prefer, with heat
>shrink on the back, last longer than anything else.
>
>Antennas ... interesting that you brought that up. The mechanical bond
>between aircraft skin and antenna is obviously critical for best
>performance. A funded study was performed on this issue about 15 years
>ago by the Department of Defense, This is a significant issue,
>especially for USN, and USMC aircraft as they operate in highly corrosive
>environments. The result of this study is that now all USN and USMC
>aircraft use a very special conductive sealing method for all external
>antennas. Give a Google look-up for: "AV-Dec" and read all about it
>there. AV-Dec is NOT "best standard practice" by any means. It is BEST
>POSSIBLE PRACTICE, and I've yet to see it used in General Aviation,
>except on my aircraft of course.
>
>You said: "This is not rocket science". Correct, far from it. Actually
>it is your and my OPINIONS being expressed on the YAK List. Not even
>close to Rocket Science. .
>
>Mark
>
>p.s. The short version: "I think we'll agree to disagree on this one.
>
>
>________________________________
>
>From: owner-yak-list-server@matronics.com on behalf of Brian Lloyd
>Sent: Sun 7/8/2012 4:23 AM
>To: yak-list@matronics.com
>Subject: Re: Yak-List: Antenna Yak52
>
>
>On Sat, Jul 7, 2012 at 11:35 PM, Walter Lannon <wlannon@shaw.ca> wrote:
>
>
>
> Hi Mark;
>
> Just finishing up the avionics installations in my CJ project. I used
>Mil. Spec. M17/128-RG400 for all units. 2 comms, TXPDR and GPS. Had
>intended to use RG 142 for the GPS but the local avionics shop (who have
>a very good reputation) said the RG400 would be fine. It's only a 3 ft.
>run so I assume either would be OK. Both are silver plated central
>conductor and double silver plated shields.
>
> Do you see any problem with that?
>
>
>
>Nope. RG400 is functionally equivalent to RG-142. The teflon dielectric
>and double-shield, silver-plated braid are the keys. And Mark is right
>that these coax cables last a lot longer than cheaper RG-58. If you are
>going to spend several thousands of dollars on your radios, trying to
>save $50 on your coax feed-line is silly.
>
>The one thing I disagree with Mark on is the use of crimp-on connectors.
>I use crimp-on connectors for everything. Turns out that crimping makes a
>superior gas-tight connection which makes the connection last longer and
>be less subject to failure. Combine that with proper application of
>self-sealing (heat-activated adhesive inside) heat shrink tubing and you
>have a superior termination even to solder-on terminations. That it is
>easier and faster to do is just a plus. (You need a good ratcheting crimp
>tool with the proper dies tho'!)
>
>And, no, I am not looking for an argument. The information is available
>from the manufacturers of the connectors. They have done the testing and
>will provide the results if you are interested.
>
>The key here is that you will have no trouble finding best standard
>practices in the industry. It is what good radio shops use. Good quality
>coax, e.g. RG400, properly terminated with crimp-on connectors, sealed
>with self-sealing heat-shrink, IS best standard practice. That is why
>good radio shops use this approach over and over again with good success.
>If it didn't work, they would be losing money on rework so would change
>their techniques.
>
>One can argue antennas 'till the cows come home but mechanical issues
>tend to outweigh the electrical issues. Standard production aircraft
>antennas work just fine with standard production aircraft radios. Yes,
>you need to make sure that the base of the antenna makes good connection
>with the aircraft skin but that just means cleaning any paint or other
>coating from the skin around the bolt holes prior to mounting the
>antenna. I like to mount my antennas "wet" by applying zinc chromate to
>the skin around the bolt holes just before bolting the antenna down. The
>wet zinc chromate allows the metals to come together to form an
>electrical bond but then the zinc chromate dries to provide a corrosion
>barrier.
>
>This is not rocket science.
>
>--
>Brian Lloyd, WB6RQN/J79BPL
>3191 Western Dr.
>Cameron Park, CA 95682
>brian@lloyd.com
>+1.767.617.1365 (Dominica)
>+1.916.877.5067 (USA)
>
>
Message 6
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| Subject: | Re: Antenna Yak52 |
On Sun, Jul 8, 2012 at 1:05 PM, Bitterlich, Mark G CIV Det Cherry Point,
MALS-14 64E <mark.bitterlich@navy.mil> wrote:
> You then said: "That is why good radio shops use this approach over and
> over again with good success. If it didn't work, they would be losing money
> on rework so would change their techniques." That is, in my opinion,
> flawed reasoning. With the General Aviation Avionics Shops that I have
> experience with, if something works going out the door, and then you come
> back a year later with a damaged connector, they are not going to fix it
> for free because it did not last as long as you thought it should. They
> will fix it exactly the same way again, and charge you for it. Avionics
> shops are out to make money, and very few of them sacrifice their time to
> make a connector last longer. I am well aware that using crimp on
> connectors is "standard practice" for most shops, but that does not make it
> the "best method", it makes it the fastest and cheapest method, and THAT is
> what they are looking for.
>
I recommend you contact AMP and get their data on connector reliability.
They make both crimp and solder connectors so they have no axe to grind
either way. I think that you might change your mind once you see the
figures on failure rates under various stresses. Or not. Both ways work
just fine. There is no doubt in my mind but that you can produce an
excellent termination using the solder/gasket type connector. I find that
MY failure rate is lower with crimp type connectors now that I am using
them exclusively. And I use the self-sealing type of heat shrink, of
course. It is readily available from marine chandleries if anyone is
looking for it and is having trouble finding it.
And you can find it here:
http://www.heatshrinktubingdirect.com/adhesive_lined_polyolefin_shrink_tubing.html
AND... of all the connectors I have seen Avionics Shops put on, few if ANY
> put heat shrink on the back, and NONE have ever used a connector with
> internal heat activated sealant. Those types cost too much.
>
Huh. The shops I deal with use heat-shrink. I am trying to remember when a
shop didn't but I have to think back to the 70's. But I am sure there are
shops that cut corners. Hmm, this might be a way to judge the quality of
work coming out of a shop. If the shop does not use heat shrink on the coax
connectors then maybe you should be looking for a different shop.
>
> Antennas ... interesting that you brought that up. The mechanical bond
> between aircraft skin and antenna is obviously critical for best
> performance. A funded study was performed on this issue about 15 years ago
> by the Department of Defense, This is a significant issue, especially for
> USN, and USMC aircraft as they operate in highly corrosive environments.
> The result of this study is that now all USN and USMC aircraft use a very
> special conductive sealing method for all external antennas. Give a Google
> look-up for: "AV-Dec" and read all about it there. AV-Dec is NOT "best
> standard practice" by any means. It is BEST POSSIBLE PRACTICE, and I've
> yet to see it used in General Aviation, except on my aircraft of course.
>
Thank you for the information. I will look it up. It sounds good.
My practice of "wet" assembly using zinc chromate is the technique I was
taught while working as an avionics installer back in the 70's. I am sure
there are better ways now but the "wet" assembly method works very well and
is readily available to people installing antennas on their airplanes using
materials that they probably already have in their hangar.
--
Brian Lloyd, WB6RQN/J79BPL
3191 Western Dr.
Cameron Park, CA 95682
brian@lloyd.com
+1.767.617.1365 (Dominica)
+1.916.877.5067 (USA)
Message 7
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| Subject: | Re: Antenna Yak52 |
Brian,
The purpose of a solder joint is to make the point of electrical contact
water tight. Crimping the braid or a center conductor of coax to a BNC
connector in any environment with moisture is generally a second best
option. For the short term, crimping is fine, but it's never as good as
soldering. Anyone who has done antenna work knows this to be true. An
alternative would be sealing the connection in something like epoxy, but
this is really hard or next to impossible to do for small connectors.
Heart shrink tubing does not make a contact water tight, just looks
nice.
I agree with Mark. The reason the people don't do this is because it
takes time and practice and is not easy to do correctly. There is even a
genuine art to terminating something large, like RG-8 to a PL-259. You
would be amazed / disappointed at some of the stuff that comes out of
repair stations and is passed off as adequate. May work OK for the short
term, which is all that some seem to care about.
Warren
On Jul 8, 2012, at 1:07 PM, Brian Lloyd wrote:
> On Sun, Jul 8, 2012 at 1:05 PM, Bitterlich, Mark G CIV Det Cherry
Point, MALS-14 64E <mark.bitterlich@navy.mil> wrote:
> You then said: "That is why good radio shops use this approach over
and over again with good success. If it didn't work, they would be
losing money on rework so would change their techniques." That is, in
my opinion, flawed reasoning. With the General Aviation Avionics Shops
that I have experience with, if something works going out the door, and
then you come back a year later with a damaged connector, they are not
going to fix it for free because it did not last as long as you thought
it should. They will fix it exactly the same way again, and charge you
for it. Avionics shops are out to make money, and very few of them
sacrifice their time to make a connector last longer. I am well aware
that using crimp on connectors is "standard practice" for most shops,
but that does not make it the "best method", it makes it the fastest and
cheapest method, and THAT is what they are looking for.
>
> I recommend you contact AMP and get their data on connector
reliability. They make both crimp and solder connectors so they have no
axe to grind either way. I think that you might change your mind once
you see the figures on failure rates under various stresses. Or not.
Both ways work just fine. There is no doubt in my mind but that you can
produce an excellent termination using the solder/gasket type connector.
I find that MY failure rate is lower with crimp type connectors now that
I am using them exclusively. And I use the self-sealing type of heat
shrink, of course. It is readily available from marine chandleries if
anyone is looking for it and is having trouble finding it.
>
> And you can find it here:
http://www.heatshrinktubingdirect.com/adhesive_lined_polyolefin_shrink_tub
ing.html
>
>
> AND... of all the connectors I have seen Avionics Shops put on, few if
ANY put heat shrink on the back, and NONE have ever used a connector
with internal heat activated sealant. Those types cost too much.
>
> Huh. The shops I deal with use heat-shrink. I am trying to remember
when a shop didn't but I have to think back to the 70's. But I am sure
there are shops that cut corners. Hmm, this might be a way to judge the
quality of work coming out of a shop. If the shop does not use heat
shrink on the coax connectors then maybe you should be looking for a
different shop.
>
>
> Antennas ... interesting that you brought that up. The mechanical
bond between aircraft skin and antenna is obviously critical for best
performance. A funded study was performed on this issue about 15 years
ago by the Department of Defense, This is a significant issue,
especially for USN, and USMC aircraft as they operate in highly
corrosive environments. The result of this study is that now all USN
and USMC aircraft use a very special conductive sealing method for all
external antennas. Give a Google look-up for: "AV-Dec" and read all
about it there. AV-Dec is NOT "best standard practice" by any means.
It is BEST POSSIBLE PRACTICE, and I've yet to see it used in General
Aviation, except on my aircraft of course.
>
> Thank you for the information. I will look it up. It sounds good.
>
> My practice of "wet" assembly using zinc chromate is the technique I
was taught while working as an avionics installer back in the 70's. I am
sure there are better ways now but the "wet" assembly method works very
well and is readily available to people installing antennas on their
airplanes using materials that they probably already have in their
hangar.
>
> --
> Brian Lloyd, WB6RQN/J79BPL
> 3191 Western Dr.
> Cameron Park, CA 95682
> brian@lloyd.com
> +1.767.617.1365 (Dominica)
> +1.916.877.5067 (USA)
>
>
>
>
Message 8
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| Subject: | Re: Antenna Yak52 |
On Sun, Jul 8, 2012 at 7:46 PM, Warren Hill <k7wx@earthlink.net> wrote:
> Brian,
>
> The purpose of a solder joint is to make the point of electrical contact
> water tight. Crimping the braid or a center conductor of coax to a BNC
> connector in any environment with moisture is generally a second best
> option. For the short term, crimping is fine, but it's never as good as
> soldering. Anyone who has done antenna work knows this to be true. An
> alternative would be sealing the connection in something like epoxy, but
> this is really hard or next to impossible to do for small connectors. Heart
> shrink tubing does not make a contact water tight, just looks nice.
>
Warren,
Thank you for your response. It is not my intention to argue. Suffice it to
say that I once thought as you do. The connector manufacturers have
convinced me otherwise. I recommend you go research their findings on the
efficacy of crimping vs. soldering. As a result, I now use crimp-on
connectors in preference to soldering.
Now that is not to say that soldering is not good. It is. It is just that,
once you fully understand the full mechanism behind the crimped joint, you
might change your mind too.
73 OM
--
Brian Lloyd, WB6RQN/J79BPL
3191 Western Dr.
Cameron Park, CA 95682
brian@lloyd.com
+1.767.617.1365 (Dominica)
+1.916.877.5067 (USA)
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