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Antenna impedance (was: HT Leads)

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brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Mon Mar 27, 2006 9:38 pm Post subject: Antenna impedance (was: HT Leads)

Antenna impedance is a function of physics, not nationality. If the 

Russian antenna is a whip type (1/4 wave monopole -- about 24" long) it 

will have an impedance of about 35 ohms and will work just fine when fed 

with RG-142 (50 ohms).



Dennis' suggestion of using a VSWR meter is a good one. If you use that, 

check the VSWR at the bottom (118 MHz), center (127 MHz), and top (136 

MHz) of the band. VSWR should be under 3:1 across the band. A VSWR of 

1:1 is perfect but a VSWR of up to 3:1 is acceptable.



-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

_________________
Brian Lloyd
brian-yak at lloyd dot com
+1.916.367.2131 (voice) +1.270.912.0788 (fax)

I fly because it releases my mind from the tyranny of petty things . . .
- Antoine de Saint-Exupery

Rob Rowe

Joined: 10 Jan 2006
Posts: 124
Location: Berkshire, UK

Posted: Tue Mar 28, 2006 2:56 am Post subject: Re: Antenna impedance (was: HT Leads)

 	  brian wrote: 	
		   ... If the Russian antenna is a whip type (1/4 wave monopole -- about 24" long) it will have an impedance of about 35 ohms and will work just fine when fed with RG-142 (50 ohms).

	




FWIW - assuming the Russian principle of "one size fits all" applies to antennae too ... then there will be a R105 (P105 Cyrillic) filter incorporated into the antenna mount base. This appears to be a simple high/low pass (LC) filter to allow the radio (high pass) & ADF (low pass) to share the same 1/4 wave monopole antenna. Cannot find any info on the characteristic impedance of the filter outputs ... presume it's the "standard" 50 ohms.



As a long shot ... if you had a Russian ARK-15M (APK-15M Cyrillic) ADF as part of your original avionics fit ... and have now disconnected it ... then may be worth fitting the ADF RF cable with a 50 ohm terminator. Just in case the R105 filter does not like having an open port (ADF) output that's disturbing the matching between the antenna and the radio. 



If you've only ever had a Baklan 5 radio fitted, & no ADF, then ignore the above!



Rob R

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Tue Mar 28, 2006 7:22 am Post subject: Antenna impedance (was: HT Leads)

Rob Rowe wrote:



 	  Quote: 	
		   FWIW - assuming the Russian principle of "one size fits all" applies to antennae too ... then there will be a R105 (P105 Cyrillic) filter incorporated into the antenna mount base. This appears to be a simple high/low pass (LC) filter to allow the radio (high pass) & ADF (low pass) to share the same 1/4 wave monopole antenna. Cannot find any info on the characteristic impedance of the filter outputs ... presume it's the "standard" 50 ohms.


	


That would make sense if they are using the whip as an ADF sense antenna

too. And, yes, the VHF port should be about 50 ohms as that is what

physics dictates for a resonant monopole antenna.



BTW, for those of you with CJ6A's, the Chinese comm antenna is a

standard 1/4 wave monopole and will work just fine with US radios once

you adapt from the Chinese connector to western connectors. It looks

like a PL-259 connector but the threads are metric. Just like using the

chinese B-nut with US fittings, you can probably use the Chinese outer

shell with a western PL-259 center assembly.



 	  Quote: 	
		   As a long shot ... if you had a Russian ARK-15M (APK-15M Cyrillic) ADF as part of your original avionics fit ... and have now disconnected it ... then may be worth fitting the ADF RF cable with a 50 ohm terminator. Just in case the R105 filter does not like having an open port (ADF) output that's disturbing the matching between the antenna and the radio. 


	


In this it shouldn't matter if the port is terminated and a 50 ohm

termination is probably NOT correct. At ADF frequencies the monopole is

no longer an antenna per se because it is so short compared to a

wavelength. The antenna's impedance is nowhere near 50 ohms. (The

characteristic impedance of a very short antenna is extremely low (under

one ohm probably). I bet that port impedance is NOT 50 ohms either. They

are probably using a low-cap low-loss coax that is not 50 ohm impedance

for the ADF sense antenna, like the stuff we used to use for unamplified

LORAN whip antennas.



 	  Quote: 	
		   If you've only ever had a Baklan 5 radio fitted, & no ADF, then ignore the above!


	


-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

Rob Rowe

Joined: 10 Jan 2006
Posts: 124
Location: Berkshire, UK

Posted: Tue Mar 28, 2006 9:27 am Post subject: Re: Antenna impedance (was: HT Leads)

 	  brian wrote: 	
		  

That would make sense if they are using the whip as an ADF sense antenna

too. And, yes, the VHF port should be about 50 ohms as that is what

physics dictates for a resonant monopole antenna.

	


Checked the schematics & they're using a 2 metre length of 50 ohm coax PK50-7-11 which other sources equate to RG213.



 	  Quote: 	
		   

The characteristic impedance of a very short antenna is extremely low (under one ohm probably). I bet that port impedance is NOT 50 ohms either. They are probably using a low-cap low-loss coax that is not 50 ohm impedance for the ADF sense antenna, like the stuff we used to use for unamplified LORAN whip antennas.

	


My mistake ... checked the schematics which show a (max 20cm) length of unscreened multi-strand PVC coated wire (BPVL 1,5) from the filter ADF port into an impedance adapter unit which provides a 75 ohm coax (PK75-3-21) interface into the ADF RF input. So the ADF filter port has an inconsequential impedance but the ADF itself requires 75 ohms.



Rob R

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Tue Mar 28, 2006 10:15 am Post subject: Antenna impedance (was: HT Leads)

Rob Rowe wrote:

 	  Quote: 	
		   brian wrote:

> That would make sense if they are using the whip as an ADF sense antenna

> too. And, yes, the VHF port should be about 50 ohms as that is what

> physics dictates for a resonant monopole antenna.

>

 Checked the schematics & they're using a 2 metre length of 50 ohm coax PK50-7-11 which other sources equate to RG213.

RG-213 is fine as is RG-142 with an appropriate adapter (different 

outside diameters). Both are 50 ohm coax.

 	  Quote: 	
		  > The characteristic impedance of a very short antenna is extremely low (under one ohm probably). I bet that port impedance is NOT 50 ohms either. They are probably using a low-cap low-loss coax that is not 50 ohm impedance for the ADF sense antenna, like the stuff we used to use for unamplified LORAN whip antennas.

>

 My mistake ... checked the schematics which show a (max 20cm) length of unscreened multi-strand PVC coated wire (BPVL 1,5) from the filter ADF port into an impedance adapter unit which provides a 75 ohm coax (PK75-3-21) interface into the ADF RF input. So the ADF filter port has an inconsequential impedance but the ADF itself requires 75 ohms.

That makes perfect sense.

-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)

I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

BitterlichMG(at)cherrypoi
Guest

Posted: Tue Mar 28, 2006 5:01 pm Post subject: Antenna impedance (was: HT Leads)

 Brian Lloyd <brian-yak(at)lloyd.com> wrote:   

 	  Quote: 	
		  Antenna impedance is a function of physics, not nationality. If the  

Russian antenna is a whip type (1/4 wave monopole -- about 24" long) it  

will have an impedance of about 35 ohms and will work just fine when fed  

with RG-142 (50 ohms).   

It does.  Been there and done that.  I also removed the matching circuit that was in mine, and noticed no change to the VSWR across the range.  The best idea though is to replace it (the Russian antenna) with something like a COMINT version.  I personally like the one that combines a GPS antenna with a VHF Com antenna.  You can expect below a 2:1 VSWR across the whole aircraft VHF spectrum with one of these. You'll see them used on the newer Sukhoi's.  
	


 	  Quote: 	
		  Dennis' suggestion of using a VSWR meter is a good one. If you use that,  

check the VSWR at the bottom (118 MHz), center (127 MHz), and top (136  

MHz) of the band. VSWR should be under 3:1 across the band. A VSWR of  

1:1 is perfect but a VSWR of up to 3:1 is acceptable.   

I concur...Great suggestion(s).  The problem is in finding a fairly accurate VSWR meter for the 108 to 138 Mhz. range. That one you have laying around for the ole CB radio is not up to the task.  That leaves using a wattmeter and checking for forward and reflected power and then applying the formula: SWR = (1+(SQR(PR/PF))) / (1-(SQR(PR/PF))) But then, finding a good wattmeter is not an easy task either.  My Bird 4410 kit was $1800.    
	


A great solution here is to purchase a good antenna analyzer such as the MFJ series.  Expect to pay between $150 to $250 dollars.  That may sound like a lot, but consider this.  These devices will check coax, connectors, filters, ... well, pretty much everything from 1-170 Mhz. What is even better about them is that you don't need to have the radio connected and you do not need to "transmit" on your radio to make measurements.  Now $250 might seem like a LOT of money.  But think carefully... how many people need to make tests on their aircraft antenna system because they think something might not be just right?  How much does an Avionics Facility charge for such a test?  I use mine for a lot more than aircraft radios, but taking it to the airport was where I used it enough to buy the next best model within a year.  The Avionics Shop folks are pretty much unaware of this product.. and you can really put them to shame in short order with this puppy.    

There are other companies that make them, but the MFJ versions seem to work well for me.  Here is some product information for the $250 model.. and no, I do not own stock in this company, but sure wish that I did. Realize that 99% of what this thing can do, are things you will probably never use.  Just checking aircraft antennas alone paid for mine.    

------------------------------------------------------------------------------      

The World's most popular SWR/RF analyzer just got incredibly better and gives you more value than ever! 

MFJ-259B gives you a complete pictures of your antenna's performance. You can read antenna SWR and Complex Impedance 1.8 to 170MHz  

Read Complex Impedance as series resistance and reactance (R+jX) or as magnitude (Z) and phase (degrees). You can determine velocity factor, coax cable loss in dB, length of coax and distance to a short or open in feet. You can read SWR, return loss and reflection coefficient at any frequency simultaneously at a single glance. Also read inductance in UH and capacitance in pF at RF frequencies. Large easy-to-read two line LCD screen and side-by-side meters clearly display your information. Built-in frequency counter, Ni-Cad charger circuit, battery saver, low battery warning and smooth re-duction drive tuning and much more. Super easy to use! Just set the bandswitch and tune the dial -- just like you transceiver. SWR and Complex Impedance are displayed instantly!  

Here's what you can do 

Find your antenna's true resonant frequency. Trim dipoles and verticals. 

Adjust your Yagi, quad, loop and other antennas, change antenna spacing and height and watch SWR, resistance and reactance change instantly. You'll know exactly what to do by simply watching the display. Perfectly tune critical HF mobile antennas in seconds for super DX -- without subjecting your transceiver to high SWR. Measure your antenna's 2:1 SWR bandwidth on one band, or analyze multiband performance from 1.8 to 170Mhz! Check SWR outside the ham bands without violating FCC rules. Take the guesswork out of building and adjusting matching networks and baluns. Measure distance in feet to a short or open in faulty coax. Measure length of a roll of coax, coax loss, velocity factor, impedance. Measure inductance and capacitance. measure resonant frequency and approximate Q of traps, stubs, transmission lines, RF chokes, tuned circuits and baluns. Adjust your antenna tuner for a perfect 1:1 match without creating QRM. And this is only the beginning! the MFJ-259B is a complete ham radio test station including -- frequency counter, RF signal generator, SWR Analyzer, RF resistance and Reactance Analyzer, Coax Analyzer, Capacitance and Inductance Meter and more!

BitterlichMG(at)cherrypoi
Guest

Posted: Tue Mar 28, 2006 5:05 pm Post subject: Antenna impedance (was: HT Leads)

Rob Rowe wrote:

 	  Quote: 	
		   brian Lloyd replied:

>  That would make sense if they are using the whip as an ADF sense  antenna

> too. And, yes, the VHF port should be about 50 ohms as that  is what

> physics dictates for a resonant monopole  antenna.

>

 Checked the schematics & they're using  a 2 metre length of 50 ohm coax PK50-7-11 which other sources equate to  RG213.

RG-213 is fine as is RG-142 with an appropriate adapter  (different

outside diameters). Both are 50 ohm coax.

My 2 cents: 

Actually,  RG-213 is a single shield milspec version of RG-8. Using a Poly E dielectric it  has a stranded center conductor and at 125 Mhz the loss of a 15 foot length  would be right around 0.4 Db.   The O.D. is .404"

RG-142 on the  other hand is a double shielded, solid center conductor, all silver plated and  has a Teflon dielectric. A 15 foot run at 125 Mhz would have close to 0.6 Db  loss.  The O.D. of this coax is .195"

Without question, in any  General Aviation aircraft I would strongly recommend RG-142 over RG-213. It is  about half the size and weight, and the 0.2 Db loss difference for a 15 foot run  is very small.  The Teflon dielectric means it will not melt, and in turn  the center conductor will not "migrate" on sharp turns/curves over time with  higher than normal temps. causing impedance mismatches.   In addition it is  double shielded and that is a rather big deal in high (RF) noise  environments.  

Mark  Bitterlich 

N50YK

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Tue Mar 28, 2006 5:29 pm Post subject: Antenna impedance (was: HT Leads)

Bitterlich GS11 Mark G wrote:

 	  Quote: 	
		   A great solution here is to purchase a good antenna analyzer such as the 

 MFJ series.  Expect to pay between $150 to $250 dollars.  That may sound 

 like a lot, but consider this.  These devices will check coax, 

 connectors, filters, ... well, pretty much everything from 1-170 Mhz. 

 What is even better about them is that you don't need to have the radio 

 connected and you do not need to "transmit" on your radio to make 

 measurements.  Now $250 might seem like a LOT of money.  But think 

 carefully... how many people need to make tests on their aircraft 

 antenna system because they think something might not be just right?  

 How much does an Avionics Facility charge for such a test?  I use mine 

 for a lot more than aircraft radios, but taking it to the airport was 

 where I used it enough to buy the next best model within a year.  The 

 Avionics Shop folks are pretty much unaware of this product.. and you 

 can really put them to shame in short order with this puppy. 


	


And you can split the cost with the other guys in your EAA chapter. (You 

all do belong to an EAA chapter, don't you?)



 	  Quote: 	
		   There are other companies that make them, but the MFJ versions seem to 

 work well for me.  


	


Might Fine Junk. 



 	  Quote: 	
		   Here is some product information for the $250 model.. 

 and no, I do not own stock in this company, but sure wish that I did. 

 Realize that 99% of what this thing can do, are things you will probably 

 never use.  Just checking aircraft antennas alone paid for mine. 


	


It is a slick box.



-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Tue Mar 28, 2006 5:35 pm Post subject: Antenna impedance (was: HT Leads)

Bitterlich GS11 Mark G wrote:



 	  Quote: 	
		   Without question, in any General Aviation aircraft I would strongly 

 recommend RG-142 over RG-213. It is about half the size and weight, and 

 the 0.2 Db loss difference for a 15 foot run is very small.  The Teflon 

 dielectric means it will not melt, and in turn the center conductor will 

 not "migrate" on sharp turns/curves over time with higher than normal 

 temps. causing impedance mismatches.   In addition it is double shielded 

 and that is a rather big deal in high (RF) noise environments.  


	


Sure RG-142 is probably better but, as I said, both will work just fine. 

The Chinese antenna connector works with an RG-8-sized cable. You might 

want to use some RG-213 just to make an adapter to RG-142. Terminate the 

RG-213 in a type-N connector, connect that to an N-to-BNC-female 

adapter, and then use RG-142 terminated in type-BNC connectors from 

there on.



Heck, if you want real performance you might want to look at LMR-195. 



And I am certain that we have gone way beyond what anyone else cares 

about. 



-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

BitterlichMG(at)cherrypoi
Guest

Posted: Tue Mar 28, 2006 5:54 pm Post subject: Antenna impedance (was: HT Leads)

Brian Lloyd wrote: 

 	  Quote: 	
		  Heck, if you want real performance you might want to look at LMR-195.    

Mark Bitterlich Replies:  
	


Aw heck, let's go with Inch and 5/8 Heliax where the connectors alone cost $250 ... each!  And, let's use a nitrogen/air dielectric so we can REALLY get that velocity factor up there!   (When are you going to suggest a balanced line?)    

 	  Quote: 	
		  And I am certain that we have gone way beyond what anyone else cares  

about.    

Yes, obviously we both know a fair amount about coaxial transmission lines.  It is also obvious that we are both ham radio operators.  I wonder how many more are out there?    
	


Mark 

WA3JPY

johnwcox(at)pacificnw.com
Guest

Posted: Tue Mar 28, 2006 6:31 pm Post subject: Antenna impedance (was: HT Leads)

Mark, as a fellow ham W7COX the idea of a pigtail to adapt improved coax to the existing avionics in a classic aircraft is a great idea but isn’t there a clearly known Db loss with the addition of a male and female connector to complete the task?  

John Cox  

From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Bitterlich GS11 Mark G

 Sent: Tuesday, March 28, 2006 5:55 PM

 To: yak-list(at)matronics.com

 Subject: RE: Re: Antenna impedance (was: HT Leads)  

Brian Lloyd wrote: 

 >Heck, if you want real performance you might want to look at LMR-195.    

Mark Bitterlich Replies: 

 Aw heck, let's go with Inch and 5/8 Heliax where the connectors alone cost $250 ... each!  And, let's use a nitrogen/air dielectric so we can REALLY get that velocity factor up there!   (When are you going to suggest a balanced line?)    

 	  Quote: 	
		  And I am certain that we have gone way beyond what anyone else cares 

 >about.    

Yes, obviously we both know a fair amount about coaxial transmission lines.  It is also obvious that we are both ham radio operators.  I wonder how many more are out there?    

Mark 

 WA3JPY

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Tue Mar 28, 2006 6:48 pm Post subject: Antenna impedance (was: HT Leads)

John W. Cox wrote:

 	  Quote: 	
		   Mark, as a fellow ham W7COX the idea of a pigtail to adapt improved coax 

 to the existing avionics in a classic aircraft is a great idea but isn’t 

 there a clearly known Db loss with the addition of a male and female 

 connector to complete the task?


	


Yes but it is usually minimal, especially if you are using constant 

impedance connectors like type-N or BNC. VHF comm and nav signals 

usually have ample margin and an insertion loss of .1dB for a good 

adapter is not going to be an issue. This isn't weak-signal tropo or EME 

where .1dB makes a difference.

-- 

Brian Lloyd, WB6RQN

brian-yak at lloyd dot com

I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

BitterlichMG(at)cherrypoi
Guest

Posted: Tue Mar 28, 2006 6:55 pm Post subject: Antenna impedance (was: HT Leads)

Hi  John, 

  

 Yes,  you are correct... there is.  But ... it is not very much.  The exact  amount of loss is of course determined by the exact series of connector and the  frequency being used, but usually you can assume that a connector with constant  "Z" (such as BNC, TNC, N series, etc) will have a loss of about 0.05 Db  each.  In the worst case, using something awful like a PL-259, you can  expect about 0.1 Db per connector.  Of course, we're not talking about GPS  at L1 (1565 Mhz) either!  Over 300 Mhz or so, I would be much more  careful.  

  

 Again,  it is true that every darn bit of loss you can eliminate adds up in the  long run.... I personally believe that as long as the total loss.. from end to  end.. is less than 1 Db.... you're really splitting hairs to ask for more.   After all, the way I look at it.... we're not doing Moon bounce here in our  airplanes.  

  

 A  standard aircraft radio installation will have a minimum of 4 connectors... so  there is 0.2 Db.  Add another 0.6 Db for coax... and you're still under 1  Db.  Add your pigtail disconnect, and you're now up to 0.9 Db.  Plus..  you're coax is probably less than 15 feet long.  Not much to worry  about.  But while we're talking about it, let me say that I would NEVER put  in a pigtail with anything other than a constant impedance connector series,  typically BNC.  Avoid PL-259's when ever possible.  HF... well,  OK.  Anything higher... try not to use them unless you have no other  choice.   

  

 Mark Bitterlich 

 WA3JPY

 N50YK

  

 --

pa3arw(at)euronet.nl
Guest

Posted: Wed Mar 29, 2006 1:06 am Post subject: Antenna impedance (was: HT Leads)

OhOh, the worst breed there is,…..Yak pilot AND ham……  

Hans  

Yak pilot AND ham  

Pa3arw  

Van: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] Namens John W. Cox

 Verzonden: woensdag 29 maart 2006 4:31

 Aan: yak-list(at)matronics.com

 Onderwerp: RE: Re: Antenna impedance (was: HT Leads)  

Mark, as a fellow ham W7COX the idea of a pigtail to adapt improved coax to the existing avionics in a classic aircraft is a great idea but isn’t there a clearly known Db loss with the addition of a male and female connector to complete the task?  

John Cox  

From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Bitterlich GS11 Mark G

 Sent: Tuesday, March 28, 2006 5:55 PM

 To: yak-list(at)matronics.com

 Subject: RE: Re: Antenna impedance (was: HT Leads)  

Brian Lloyd wrote: 

 >Heck, if you want real performance you might want to look at LMR-195.    

Mark Bitterlich Replies: 

 Aw heck, let's go with Inch and 5/8 Heliax where the connectors alone cost $250 ... each!  And, let's use a nitrogen/air dielectric so we can REALLY get that velocity factor up there!   (When are you going to suggest a balanced line?)    

 	  Quote: 	
		  And I am certain that we have gone way beyond what anyone else cares 

 >about.    

Yes, obviously we both know a fair amount about coaxial transmission lines.  It is also obvious that we are both ham radio operators.  I wonder how many more are out there?    

Mark 

 WA3JPY

dsavarese(at)elmore.rr.co
Guest

Posted: Wed Mar 29, 2006 5:12 am Post subject: Antenna impedance (was: HT Leads)

Sounds to me like Mark's suggestion of replacing the antenna,  (which I completely agree with), with a off-the-shelf VHF antenna would not  only resolve the radio problem, but would also shut down this thread. -)   Personally, I like the KISS method of resolving problems.

 Dennis

  

 [quote]   ---

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Wed Mar 29, 2006 6:34 am Post subject: Antenna impedance (was: HT Leads)

Hans Oortman wrote:

 	  Quote: 	
		   OhOh, the worst breed there is,…..Yak pilot AND ham……


	


Wow, that makes at least four of us! The radios in our airplanes had 

better work perfectly, eh? We need some kind of joke about Yak-ing in 

the air and Yak-ing on the air.



English is such a silly language. 



 	  Quote: 	
		   Hans

 

 Yak pilot AND ham

 

 Pa3arw


	




-- 

Brian Lloyd, WB6RQN (extra)

brian-yak at lloyd dot com

+1.916.367.2131 (voice)

+1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Wed Mar 29, 2006 6:37 am Post subject: Antenna impedance (was: HT Leads)

A. Dennis Savarese wrote:

 	  Quote: 	
		   Sounds to me like Mark's suggestion of replacing the antenna, (which I 

 completely agree with), with a off-the-shelf VHF antenna would not only 

 resolve the radio problem, but would also shut down this thread. -)  

 Personally, I like the KISS method of resolving problems.


	


Mounting a new antenna strikes me as a more complex solution than just 

crafting an adapter cable on the bench. It would take me about 5 minutes 

to create the adapter cable and more than that to remove the old antenna 

and install a new one. (Actually, it would take longer than 5 minutes 

because the soldering iron would have to warm up.)



While perhaps less of an issue for people with Yak-52s, there may be 

some who want to maintain the lines of their CJ6A by using the stock 

Chinese antenna. This certainly applies to them too.



-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

BitterlichMG(at)cherrypoi
Guest

Posted: Wed Mar 29, 2006 3:42 pm Post subject: Antenna impedance (was: HT Leads)

--

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