[Repeater-Builder] Re: Loss through adaptors:

[Coy Hilton]

BNC connectors are constant impedaqnce connectors so are type Ns but 
UHF (PL259s)are not. Oh, Right angle connectors are the worse for 
loss.
73
AC0Y

--- In Repeater-Builder@yahoogroups.com, "Dave VanHorn" 
<[EMAIL PROTECTED]> wrote:
>
> 
> This one is a bit funny..
> 
> As part of the big project this weekend, I had this UHF amp with 
> output on a pigtail with a BNC male on the end.  I needed to 
connect 
> with the UHF cans about 6 inches and 180 degrees of bend away, but 
> didn't have the bits to make that cable, so I used some adaptors...
> 
> Working backwards from the can:
> N male to PL female.
> PL male PL Male.
> PL right angle.
> PL female to N male.
> N female to PL male.
> PL Right angle.
> PL Female to BNC male.
> BNC female to BNC Female. 
> 
> What seems like pointless conversions in this chain were needed to 
> clear the body of the cans. 
> 
> When testing at full power, this conglomeration of nightmares 
> actually gets warm.  The total loss through them is about 1dB 
though, 
> which brings us back to the question asked last week or so about 
loss 
> in adaptors.. Looks like roughly 0.2dB   
> 
> So, a rule of thumb emerges: Better to have three feet of good 
cable, 
> than one good adaptor.
> 
> 
> Now I've made up a short BNC male to N hardline jumper, and I'm 
ready 
> to go put that in place, but it will still require a BNC female-
> female to make the link.  I'm thinking of wrapping that BNC 
junction 
> in copper tape, because I don't think BNCs are all that "Tight".  
> 
> In the future, I may just pop the covers on the amp and bring the 
> hardlines right to the amp itself, eliminating any connectors.
> 
> Thoughts on my temporary solution?
>








 
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[Repeater-Builder] Re: Loss through adaptors:

[skipp025]

You think the adapter loss is nutty, try different 
kinds of good coax and rigid line to see that it 
also changes things quite a bit. 

For tight spots, consider superflex 1/4 or 3/8 
in hard line.  I actually use the mini 141 rigid 
line for modest power levels. 

Avoid trying to use foam center cables where 
possible. 

cheers, 
skipp  

> "Dave VanHorn" <[EMAIL PROTECTED]> wrote:
> 
> Thoughts on my temporary solution?
>
>
> 
> This one is a bit funny..
> 
> As part of the big project this weekend, I had this UHF amp with 
> output on a pigtail with a BNC male on the end.  I needed to connect 
> with the UHF cans about 6 inches and 180 degrees of bend away, but 
> didn't have the bits to make that cable, so I used some adaptors...
> 
> Working backwards from the can:
> N male to PL female.
> PL male PL Male.
> PL right angle.
> PL female to N male.
> N female to PL male.
> PL Right angle.
> PL Female to BNC male.
> BNC female to BNC Female. 
> 
> What seems like pointless conversions in this chain were needed to 
> clear the body of the cans. 
> 
> When testing at full power, this conglomeration of nightmares 
> actually gets warm.  The total loss through them is about 1dB though, 
> which brings us back to the question asked last week or so about loss 
> in adaptors.. Looks like roughly 0.2dB   
> 
> So, a rule of thumb emerges: Better to have three feet of good cable, 
> than one good adaptor.
> 
> 
> Now I've made up a short BNC male to N hardline jumper, and I'm ready 
> to go put that in place, but it will still require a BNC female-
> female to make the link.  I'm thinking of wrapping that BNC junction 
> in copper tape, because I don't think BNCs are all that "Tight".  
> 
> In the future, I may just pop the covers on the amp and bring the 
> hardlines right to the amp itself, eliminating any connectors.









 
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[Repeater-Builder] Re: Loss through adaptors:

[skipp025]

I lifted the below text from the yahoo rfamplifiers group 
page, posted this last week by my friend Dave. It's right 
on the money. 

http://groups.yahoo.com/group/rfamplifiers/

[paste] 
If you are able to measure the SWR of a coax connection at 
VHF, thenyou've installed a connector wrong. I used an HP 
8510C network analyzer to measure a whole bunch of UHF to N, 
UHF to BNC and so forth, adapters, all stacked on top of 
each other to a foot long, and the lowest frequency where 
I measured anything of concern was at 2 GIGAhertz, where 
the SWR rose to 1.1:1. Yes, I know, amateur radio lore is 
full of the claim that UHF connectors are awful. They are, 
but only if you compare then to BNC and N, which are suitable 
for 10GHz and above. Assembled correctly, a UHF connector is 
invisible below 1GHz.
[end] 

While I agree with Dave, he didn't manage to run into and 
test some of the low cost/dollar right angle adapters 
I've sourced back to being a problem at UHF. 

skipp 







 
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[Repeater-Builder] Re: Loss through adaptors:

[Dave VanHorn]

>  Try to find silver-plated BNC connectors.

As usual, it's a mixed bag.. I have a silver F-F with even an UG number 
on it, but the male connectors are plated, even the one that came with 
the motorola amp..  I also noticed that the daniels gear all runs 
plated connectors, and I haven't seen them skimp on anything.

But, I'm sure that the new version will be a whole lot better than 
what's up there now. 







 
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[Repeater-Builder] Re: Loss through adaptors:

[Dave VanHorn]

> For tight spots, consider superflex 1/4 or 3/8 
> in hard line.  I actually use the mini 141 rigid 
> line for modest power levels. 

FSJ1-50 now in every cable except my adaptor mess (soon to be replaced) 
and the 2M duplexer harness.
 
> Avoid trying to use foam center cables where 
> possible. 

My FJS1-50 is foam, what's the beef with foam?








 
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[Repeater-Builder] Re: Loss through adaptors:

[skipp025]

In sharp bends, the softer center foam conductors 
will migrate from the center over time and with 
modest heat.  Feedline/coax with soft foam centers 
outside in the summer sun is a serious potential 
trouble maker. 

skipp 

>  "Dave VanHorn" <[EMAIL PROTECTED]> wrote:
> > Avoid trying to use foam center cables where 
> > possible. 
> 
> My FJS1-50 is foam, what's the beef with foam?
>








 
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[Repeater-Builder] Re: Loss through adaptors:

[Ian Wells]

 Can you also have problems with desense with  fittings being hand tight  between the diplexer and antenna 
 

Thank You,
Ian Wells,
Kerinvale Comaudio,
www.kerinvalecomaudio.com.au
 





















  




  
  
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[Repeater-Builder] Re: Loss through adaptors:

[Dave VanHorn]

> In sharp bends, the softer center foam conductors 
> will migrate from the center over time and with 
> modest heat.  Feedline/coax with soft foam centers 
> outside in the summer sun is a serious potential 
> trouble maker. 

Define "sharp".  the min bend radius is 1" and none of my outside stuff 
is less than 12".  Indoors I go down to 3"








 
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[Repeater-Builder] Re: Loss through adaptors:

[Coy Hilton]

Gee Skipp, I don't remember having seen any "center foam conductors" 
before, it doesn't seem that it would work very well, especially 
with all of that moving around <;-)

--- In Repeater-Builder@yahoogroups.com, "skipp025" <[EMAIL PROTECTED]> 
wrote:
>
> 
> In sharp bends, the softer center foam conductors 
> will migrate from the center over time and with 
> modest heat.  Feedline/coax with soft foam centers 
> outside in the summer sun is a serious potential 
> trouble maker. 
> 
> skipp 
> 
> >  "Dave VanHorn" <[EMAIL PROTECTED]> wrote:
> > > Avoid trying to use foam center cables where 
> > > possible. 
> > 
> > My FJS1-50 is foam, what's the beef with foam?
> >
>








 
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[Repeater-Builder] Re: Loss through adaptors:

[Ron Wright, Skywarn Coodinator]

Dave,

If you have all these adapters in line feel lucky with only 1 db loss.

Good adapters are sometimes hard to find unless one wants to spend 
some real money.  The Radio Shack and most at hamfest are 
junk...works good on CB I guess.

I've seen barrel connectors with 3 db loss at 150 MHz.

ron



--- In Repeater-Builder@yahoogroups.com, "Dave VanHorn" 
<[EMAIL PROTECTED]> wrote:
>
> 
> This one is a bit funny..
> 
> As part of the big project this weekend, I had this UHF amp with 
> output on a pigtail with a BNC male on the end.  I needed to 
connect 
> with the UHF cans about 6 inches and 180 degrees of bend away, but 
> didn't have the bits to make that cable, so I used some adaptors...
> 
> Working backwards from the can:
> N male to PL female.
> PL male PL Male.
> PL right angle.
> PL female to N male.
> N female to PL male.
> PL Right angle.
> PL Female to BNC male.
> BNC female to BNC Female. 
> 
> What seems like pointless conversions in this chain were needed to 
> clear the body of the cans. 
> 
> When testing at full power, this conglomeration of nightmares 
> actually gets warm.  The total loss through them is about 1dB 
though, 
> which brings us back to the question asked last week or so about 
loss 
> in adaptors.. Looks like roughly 0.2dB   
> 
> So, a rule of thumb emerges: Better to have three feet of good 
cable, 
> than one good adaptor.
> 
> 
> Now I've made up a short BNC male to N hardline jumper, and I'm 
ready 
> to go put that in place, but it will still require a BNC female-
> female to make the link.  I'm thinking of wrapping that BNC 
junction 
> in copper tape, because I don't think BNCs are all that "Tight".  
> 
> In the future, I may just pop the covers on the amp and bring the 
> hardlines right to the amp itself, eliminating any connectors.
> 
> Thoughts on my temporary solution?
>










 
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[Repeater-Builder] Re: Loss through adaptors:

[Dave VanHorn]

--- In Repeater-Builder@yahoogroups.com, "Coy Hilton" <[EMAIL PROTECTED]> 
wrote:
>
> Gee Skipp, I don't remember having seen any "center foam conductors" 
> before, it doesn't seem that it would work very well, especially 
> with all of that moving around <;-)

OH MY GOD!  You're right!!  My center foams are completely gone, and 
they've been replaced by a metallic copper rod!

Could it be aliens?


:)








 
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[Repeater-Builder] Re: Loss through adaptors:

[Dave VanHorn]

> I've seen barrel connectors with 3 db loss at 150 MHz.

I'd replace the word "barrel" with the word "Broken"...









 
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[Repeater-Builder] Re: Loss through adaptors:

[Dave VanHorn]

> 1.  Use only Mil-spec RG-400/U or RG-214/U cable for jumpers and
> interconnecting cables, 

Well, being a ham, I'm using the FSJ1-50 because it's nicely flexible 
(way better than the LMR-400) and I have a ton of it on hand. 

> 3.  Use only crimped connectors with silver-plated brass bodies,
> gold-plated contacts, and Teflon dielectric.

I had to compromise here a bit too, some are plated connectors, and 
all of them are soldered. I did the soldering, and I'll stand behind 
it.  I'd use all silver connectors if I was having any luck finding 
them.

> There are no BNC or UHF connectors; 
Well, I have a power amp that came with BNC, and my VHF cans are UHF 
connectors.. What's a fella to do..?


  I have never heard of any repeater system that was significantly
> improved by replacing RG-214/U with 3/8" hardline, Superflex, or 

No, I'd agree there. I don't have any 214 on hand, nor connectors to 
use it with. I did have connectors that worked nicely with the FSJ1-
50.  Once you have "enough" shielding, any extra is overkill.









 
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[Repeater-Builder] Re: Loss through adaptors:

[nj902]

--- In Repeater-Builder@yahoogroups.com, "skipp025" <[EMAIL PROTECTED]> wrote:
"I lifted the below text from the yahoo rfamplifiers group page,
posted this last week by my friend Dave. It's right on the money. 
 
http://groups.yahoo.com/group/rfamplifiers/
 
 [paste] 
If you are able to measure the SWR of a coax connection at VHF, then
you've installed a connector wrong. I used an HP 8510C network
analyzer to measure a whole bunch of UHF to N, UHF to BNC and so
forth, adapters, all stacked on top of each other to a foot long, and
the lowest frequency where I measured anything of concern was at 2
GIGAhertz, where the SWR rose to 1.1:1. Yes, I know, amateur radio
lore is full of the claim that UHF connectors are awful. They are, but
only if you compare then to BNC and N, which are suitable for 10GHz
and above. Assembled correctly, a UHF connector is invisible below 1GHz.
 [end] 


I hope nobody is buying into this BS.

Connector and adapter mis-match and loss issues are hardly "amateur
radio lore"

RF manufacturers and instrumentation companies have stressed this for
years - justifiably.

It's easy to verify if you have access to instrumentation.  Just out
of curiosity I decided to run a couple of tests.  

When you measure a device for SWR you are actually measuring return
loss.  You can do this on a network analyzer or with a spectrum
analyzer and tracking generator plus a signal separation device such
as a return loss bridge or directional coupler.  

I decided to try both instruments and compare the results.  You first
calibrate the measurement setup with precision components from your
cal kit [e.g. Agilent 85032B].  The critical component is a precision
50 ohm load.  With a good bridge or coupler you should be able to
measure a return loss of 40 dB  or greater [equivalent to an SWR or
1.02:1]

Normally your instrument test ports will be type N although some
instruments have APC-7 test ports. Your cal kit should match the test
ports.  

I started with a full 2-port cal of the VNA and a normalization of the
Spectrum analyzer.  My reference load did measure as expected.

The next step is to "insert" the device under test.  In this case we
are interested in looking at a UHF connector.  Obviously, since the
instrument is type N, we have to use adapters.  Just out of curiosity,
I decided to compare two pairs of adapters.  First an NF-NF mated to
an NM-NM. [UG-57B/U and UG-29B/U] This created an "insertable" device.
 These are "standard" adapters as opposed to "precision" components
and as expected, there was some degradation of the return loss
measurement.

I then compared this to two other adapters, NM to UHF-F and UHF-M to
NF [UG-146/U and UG-83/U], again creating an "insertable device"  This
pair has just a single UHF male to female junction and results in a
significant decrease in return loss [i.e. increase in SWR.]

I also tried inserting an 90 degree UHF adapter [UG-646/U] in line
between the UG146/U and the UG83/U which resulted in further
[significant] return loss degradation.

I measured several sets of these parts and the results were not only
consistent from part to part but generally match within a few tenths
of a dB between the VNA and the spectrum analyzer.  I always like to
see comparable results from two significantly different instrument
setups - it confirms your thought process and results.

Results at: 150 MHz, 450 MHz, 900 MHz

NM-NF adapters: 
[VNA]: 36 dB, 35 dB, 31 dB
[SA/TG] 37 dB, 35.7 dB, 30 dB

N-UHF + UHF-N adapters:
[VNA]: 26 dB, 16.5 dB, 11.4 dB
[SA/TG]: 23.6 dB, 17.2 dB, 11.5 dB

N-UHF + UHF 90 + UHF-N
[VNA]: 20.2 dB, 12.03 dB, 9.3 dB
[SA/TG]: 21.6 DB, 11.9 dB, 9.1 dB

Now just for reference, a return loss of 11 dB would be equivalent to
an SWR of 1.785 : 1 [ONE UHF junction @ 900 MHz] and a return loss of
17 dB would be an SWR of 1.329 : 1 [@ 450 MHz]

UHF connectors "invisible" below a gigahertz??? Hardly.


Also - someone asked about the 90 degree N fitting at 900 MHz so I
tested a few of those.  That's easy because being M on one side and F
on the other, it is inherently "insertable"

The round kind [UG-27A/U] averaged return loss of 22 dB. The square
ones[UG-27D/U] are better at 27 dB [1.094 : 1 SWR]








 
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[Repeater-Builder] Re: Loss through adaptors

[tony dinkel]

I have to agree on all points.  In my limited travels, I have seen a lot of 
questionable plating and dielectric materials showing up on all sorts of RF 
equipment.  If its black with silver underneath, I would rather dig it out 
of the junk box and use it rather than going to an electronics store and 
taking pot luck.  It took me a while to warm up to RF Specialties after 
having been raised on products like Dage, Sealectro, Omni Spectra, Kings and 
a bunch more I can't remember.

On a related issue...I was on assignment at the MJ trial in central ca 
recently.  I needed to build a short UHF duplex link from my live truck to 
our rented space in the coffee shop which housed our ISDN, codecs, etc.  I 
reached into the place that should have held my spare base station antenna 
for such things and nothing.  Where the hell was it?  Makes a good case for 
not cleaning out the truck any more.

So with the intent of building a quick quarter wave UHF ground plane, I made 
a quick run up to the only "real" electronics store (that I knew of) in 
Santa Maria.  I ask for a type N female 4 hole connector.  The guy behind 
the counter had to find somebody who knew what that was, then that guy had 
to find somebody to find them.  15 minutes later I ended up paying 9.99 a 
piece for 4 (all they had or ever will) ug-22 like, no name, no numbers 
connectors and was happy to get them.  The plating looked cheap but the 
dielectric looked like teflon...silly me.

So off to my $150 a night room at the airport Raddison and my soldering 
iron.  Needless to say, as soon as my soldering iron hit the solder pot in 
the center, the dielectric started to give way.  It was not teflon, it was 
some unknown thermo-polymer with a very low melting point!  I would have 
been better off grinding up some corn flakes and graham crackers, mixing 
that with superglue and machining my own.  Well, I got through it.  Luckily 
my hop was short and if I had any duplex noise, it was covered up.

My point is watch out for cheap dielectric materials!  They can end up 
costing you a lot more than you paid for them in performance.

td
wb6mie
Yes, I saw MJ and he looks creepier in person than he does on TV!


>
>This topic interests me, not just because I personally abhor adaptors in 
>any
>repeater system, but also because I see that others are equally passionate
>about certain cables.
>
>After spending many years troubleshooting repeater systems cobbled together
>by my friends and colleagues, most of which were replete with every
>connector series known to Mankind- and which used many adapters to mate
>between series- I became aware that the most troublesome repeaters had the
>largest number of adapters.
>
>When I began to design my own repeater systems, I vowed to abide by three
>simple rules:
>1.  Use only Mil-spec RG-400/U or RG-214/U cable for jumpers and
>interconnecting cables, and
>2.  Make up these cables with the correct connectors on each end, using the
>specified tools, and
>3.  Use only crimped connectors with silver-plated brass bodies, 
>gold-plated
>contacts, and Teflon dielectric.






 
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[Repeater-Builder] Re: Loss through adaptors:

[skipp025]

You are right, it was a typo... 

"the softer center foam, conductors will migrate 
from the center over time". 

Just so we are clear...  the center conductor 
will try to migrate through the foam in sharp 
bends toward the outside conductor. 

skipp


 "Coy Hilton" <[EMAIL PROTECTED]> wrote:
>
> Gee Skipp, I don't remember having seen any "center foam conductors" 
> before, it doesn't seem that it would work very well, especially 
> with all of that moving around <;-)
> 
> --- In Repeater-Builder@yahoogroups.com, "skipp025" <[EMAIL PROTECTED]> 
> wrote:
> >
> > 
> > In sharp bends, the softer center foam conductors 
> > will migrate from the center over time and with 
> > modest heat.  Feedline/coax with soft foam centers 
> > outside in the summer sun is a serious potential 
> > trouble maker. 
> > 
> > skipp 
> > 
> > >  "Dave VanHorn" <[EMAIL PROTECTED]> wrote:
> > > > Avoid trying to use foam center cables where 
> > > > possible. 
> > > 
> > > My FJS1-50 is foam, what's the beef with foam?
> > >
> >
>








 
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[Repeater-Builder] Re: Loss through adaptors:

[Dave VanHorn]

> Results at: 150 MHz, 450 MHz, 900 MHz
> 
> NM-NF adapters: 
> [VNA]: 36 dB, 35 dB, 31 dB
> [SA/TG] 37 dB, 35.7 dB, 30 dB
> 
> N-UHF + UHF-N adapters:
> [VNA]: 26 dB, 16.5 dB, 11.4 dB
> [SA/TG]: 23.6 dB, 17.2 dB, 11.5 dB
> 
> N-UHF + UHF 90 + UHF-N
> [VNA]: 20.2 dB, 12.03 dB, 9.3 dB
> [SA/TG]: 21.6 DB, 11.9 dB, 9.1 dB
> 
> Now just for reference, a return loss of 11 dB would be equivalent 
to
> an SWR of 1.785 : 1 [ONE UHF junction @ 900 MHz] and a return loss 
of
> 17 dB would be an SWR of 1.329 : 1 [@ 450 MHz]


Ok, now what's the actual loss at those levels?
I'm thinking that my intuitive rule of thumb may even be a bit light..
"Better 3' of cable than one adaptor."








 
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[Repeater-Builder] Re: Loss through adaptors

[Dave VanHorn]

> It was not teflon, it was 
> some unknown thermo-polymer with a very low melting point!  

Yeah, I've hit these too.. They look like silver plated, and the 
dielectric is a little pink-ish like teflon.  
Icky. 










 
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[Repeater-Builder] Re: Loss through adaptors:

[skipp025]

I sent a copy of your text examples back to Dave, and 
he replied with the following:  

[paste]

He did not indicate whether he validated his
calibration of the VNA, but the results suggst that
the calibration was performed correctly.  The SA/TG
equipment should be discarded; if there's a
disagreement between VNA results and SA/TG results,
one would always discard the SA/TG results, because an
SA/TG is not vector corrected.

His statement that the precision 50 ohm load is the
most important piece is not correct.  The most
important bit of the calibration kit is that it's been
characterized in a lab that's traceable to NIST, and
the measured data for that calibration kit has been
loaded into the network analyzer.  There is an
erroneous assumption that when one connects the
precision 50 ohm load and pushes "cal", the analyzer
measures the load, assumes it's 50 ohms, and applies a
mathematical correction to itself.  That's not really
how it works.  Instead, you first enter the
calibration kit's coefficients into the VNA (usually
by loading a file from a floppy disk that came with
the kit), then you attach the 50 ohm load and press
"cal".  The analyzer measures the load, then refers
back to the calibration file and corrects itself so
that it will measure that load as it was measured by a
traceable analyzer at a lab.  The load could actually
be 60, 70, 80 or whatever ohms, as long as it has been
accurately characterized, and the data entered into
the VNA.

However, the 85032 loads are good enough that at the
low frequencies we're discussing, it's close enough to
50 ohms that if he doesn't bother loading the cal
coefficients, he's probably not measurably in error. 
As I said, his measurements suggest that his cal
routine was adequate.  Getting fussy about having the
exact cal coefficients in the instrument is only worth
bothering with if you want to make return loss
measurements of devices better than 40dB or above
several GHz.

The values he measured are consistent with some old
and some poorly-assembled connectors that I have
measured.  RF connectors are not intended to be used
and re-used more than a few hundred times; in the
instrumentation industry we think of them as
"dispoables" and keep a budget item for their
replacement.

The characteristics of RF connectors varies a lot by
how well they're manufactured.  I have seen no
correlation whatsoever between price and measured
performance.  The stack of adapters that I measured
some years ago was simply gathered.  I cleaned them
before measurement, and I discarded the type N
connectors which had "fingered" ground connections
that did not appear tight, as those are a well-known
trouble spot.  I'm not sure why anybody built type N
male connectors like that, as it's a lousy way to do
things.

Adapters in particular, take a lot of abuse.

It's good to measure these things.  If you don't, then
you have no idea whether you're using a good connector
or a bad one.

D

> "nj902" <[EMAIL PROTECTED]> wrote:
>
> I hope nobody is buying into this BS.
> 
> Connector and adapter mis-match and loss issues are hardly "amateur
> radio lore"
> 
> RF manufacturers and instrumentation companies have stressed this for
> years - justifiably.
> 
> It's easy to verify if you have access to instrumentation.  Just out
> of curiosity I decided to run a couple of tests.  
> 
> When you measure a device for SWR you are actually measuring return
> loss.  You can do this on a network analyzer or with a spectrum
> analyzer and tracking generator plus a signal separation device such
> as a return loss bridge or directional coupler.  
> 
> I decided to try both instruments and compare the results.  You first
> calibrate the measurement setup with precision components from your
> cal kit [e.g. Agilent 85032B].  The critical component is a precision
> 50 ohm load.  With a good bridge or coupler you should be able to
> measure a return loss of 40 dB  or greater [equivalent to an SWR or
> 1.02:1]
> 
> Normally your instrument test ports will be type N although some
> instruments have APC-7 test ports. Your cal kit should match the test
> ports.  
> 
> I started with a full 2-port cal of the VNA and a normalization of the
> Spectrum analyzer.  My reference load did measure as expected.
> 
> The next step is to "insert" the device under test.  In this case we
> are interested in looking at a UHF connector.  Obviously, since the
> instrument is type N, we have to use adapters.  Just out of curiosity,
> I decided to compare two pairs of adapters.  First an NF-NF mated to
> an NM-NM. [UG-57B/U and UG-29B/U] This created an "insertable" device.
>  These are "standard" adapters as opposed to "precision" components
> and as expected, there was some degradation of the return loss
> measurement.
> 
> I then compared this to two other adapters, NM to UHF-F and UHF-M to
> NF [UG-146/U and UG-83/U], again creating an "insertable device"  This
> pair has just a single UHF male to female junction and results in 

[Repeater-Builder] Re: Loss through adaptors:

[Laryn Lohman]

> 
> I've seen barrel connectors with 3 db loss at 150 MHz.
> 
> ron
> 

What are they using, wet toilet paper for dielectric?

Laryn K8TVZ







 
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[Repeater-Builder] Re: Loss through adaptors:

[skipp025]

Keep in mind the early brown connector insulator is 
hydroscopic, so yes... it might act like wet toilet 
paper. 
skipp 

> "Laryn Lohman" <[EMAIL PROTECTED]> wrote:
> What are they using, wet toilet paper for dielectric?
> Laryn K8TVZ
>
> > I've seen barrel connectors with 3 db loss at 150 MHz. 
> > ron
> >







 
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[Repeater-Builder] Re: Loss through adaptors:

[Dave VanHorn]

I think the biggest problem that we face is that our adaptors tend to 
not have a pedigree.  I have some that I know were from Radio Shack, 
some that I bought at hamfests in boxes of "stuff", some with real 
pedigrees (amphenol, in the bag) and some that are precision test 
equipment in their own right.

If cost were no object, we would do the whole thing in hardline and 
GPC-7 connectors and be done with it, right?  :)

Someone mentioned before, an elbow or tee that used a SPRING to make 
the connection..  Boy, I would love to put that on my SA and see the 
plot!  Probably works nicely at some frequencies, and insanely badly 
at others. 

I ended up having to put at least one right angle in every radio 
connection. The daniels gear uses front panel N connnectors, and 
there's no way I could close the cabinet door without RA connectors. 
I couldn't find anything RA in N, so I used a single RA adaptor on 
each of the four lines.  Not sure who makes them. Markings are "CQA" 
or "CGA" and "UG-27/U"  Definitely silver plated.








 
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[Repeater-Builder] Re: Loss through adaptors:

[Dave VanHorn]

--- In Repeater-Builder@yahoogroups.com, "Eric Lemmon" <[EMAIL PROTECTED]> 
wrote:
>
> Dave,
> 
> Tessco carries right-angle N connectors from several manufacturers.  
Go
> here:
> 
> http://www.tessco.com/products/displayProducts.do?
groupId=410&subgroupId=30
> 
> and look at pages 3 and 4.  Another manufacturer of right-angle N 
connectors
> is Delta.

Yes, but do they work with FSJ1-50?








 
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[Repeater-Builder] Re: Loss through adaptors:

[Dave VanHorn]

--- In Repeater-Builder@yahoogroups.com, "Mike Perryman" <[EMAIL PROTECTED]> 
wrote:
>
> I found them on the Tessco website...  here is the link..
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Re: [Repeater-Builder] Re: Loss through adaptors:

[Jay Urish]

Yea, I use the heck out of LMR-400UF.. Please enlighton me!


Dave VanHorn wrote:
>>For tight spots, consider superflex 1/4 or 3/8 
>>in hard line.  I actually use the mini 141 rigid 
>>line for modest power levels. 
> 
> 
> FSJ1-50 now in every cable except my adaptor mess (soon to be replaced) 
> and the 2M duplexer harness.
>  
> 
>>Avoid trying to use foam center cables where 
>>possible. 
> 
> 
> My FJS1-50 is foam, what's the beef with foam?
> 


-- 
Jay Urish W5GM
DCARA President ARRL Life Member
TXFCA President ERS Vice-Prez
Denton County ARRL VEC
N5ERS VP/Trustee

Monitoring 1292.30Ghz PL-100.0  441.375 PL-88.5 and 444.850 PL-88.5




 
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RE: [Repeater-Builder] Re: Loss through adaptors:

[Eric Lemmon]

This topic interests me, not just because I personally abhor adaptors in any
repeater system, but also because I see that others are equally passionate
about certain cables.

After spending many years troubleshooting repeater systems cobbled together
by my friends and colleagues, most of which were replete with every
connector series known to Mankind- and which used many adapters to mate
between series- I became aware that the most troublesome repeaters had the
largest number of adapters.

When I began to design my own repeater systems, I vowed to abide by three
simple rules:
1.  Use only Mil-spec RG-400/U or RG-214/U cable for jumpers and
interconnecting cables, and
2.  Make up these cables with the correct connectors on each end, using the
specified tools, and
3.  Use only crimped connectors with silver-plated brass bodies, gold-plated
contacts, and Teflon dielectric.

None of my systems have adaptors or "barrel" connectors, since the cables
are made up to fit the job.  There are no BNC or UHF connectors; except for
very unusual situations, all connectors are Type N with a few mini-UHF
needed to mate with a particular radio.  It would not occur to me to use an
adapter to mate a male N connector to a UHF female connector- I would have a
premium UHF male connector on that end of the cable!  Of course, this only
is an issue with older radios and duplexers; the modern counterparts have
female N connectors.

I guess the bottom line here is that almost all double-shielded and 100%
shielded cable will perform superbly in a repeater system, if properly
installed.  I have never heard of any repeater system that was significantly
improved by replacing RG-214/U with 3/8" hardline, Superflex, or any other
trendy cable- unless the original installation was flawed.  We should all be
ready to accept that a flawed installation does not condemn a cable brand or
type.  In my personal opinion, the use of adapters in place of the exactly
correct connectors leads to a flawed installation.  YMMV!

73, Eric Lemmon WB6FLY


-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jay Urish
Sent: Monday, January 30, 2006 7:04 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Re: Loss through adaptors:

Yea, I use the heck out of LMR-400UF.. Please enlighton me!


Dave VanHorn wrote:
>>For tight spots, consider superflex 1/4 or 3/8 
>>in hard line.  I actually use the mini 141 rigid 
>>line for modest power levels. 
> 
> 
> FSJ1-50 now in every cable except my adaptor mess (soon to be replaced) 
> and the 2M duplexer harness.
>  
> 
>>Avoid trying to use foam center cables where 
>>possible. 
> 
> 
> My FJS1-50 is foam, what's the beef with foam?
> 


-- 
Jay Urish W5GM
DCARA President ARRL Life Member
TXFCA President ERS Vice-Prez
Denton County ARRL VEC
N5ERS VP/Trustee

Monitoring 1292.30Ghz PL-100.0  441.375 PL-88.5 and 444.850 PL-88.5




 
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RE: [Repeater-Builder] Re: Loss through adaptors:

[Rod Lane]

The EIA and TIA both have a spec that virtually all cable manufacturers hold
to.  The static minimum bend radius of any cable that meets their spec is
10XD or ten times the diameter of the outer jacket.  Under pulling load that
radius doubles to 20XD.  The individual manufacturer will state the maximum
pulling force.  I've never had any problems if I adhere to that spec.  And I
deal with all sorts of cabling from heliax to precision HD video coax.  

Rod Lane, N1FNE
Senior Systems Engineer
ESPN Systems Engineering

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Dave VanHorn
Sent: Monday, January 30, 2006 8:02 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Loss through adaptors:


> In sharp bends, the softer center foam conductors 
> will migrate from the center over time and with 
> modest heat.  Feedline/coax with soft foam centers 
> outside in the summer sun is a serious potential 
> trouble maker. 

Define "sharp".  the min bend radius is 1" and none of my outside stuff 
is less than 12".  Indoors I go down to 3"








 
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Re: [Repeater-Builder] Re: Loss through adaptors:

[Q]

I have issues with crimp-on connectors. I have seen too many of them 
pull apart when used as pigtails to tower mounted antennas.I have also 
seen the braid break right at the crimp. Blame it on improper crimping 
or the human element or whatever,but I will use the clamp style 
connectors. I seem to be able to get more consistent results and better 
mechanical strength. I agree with all the other points and will add 
proper weatherproofing to outside connections with vapor wrap and Scotch 
tape topped off with Scotchkote. 28 years with a large RCC taught me 
what works and what doesnt,lessons learned the hard way are not soon 
forgotten!   73,Lee,N3APP

Eric Lemmon wrote:

>This topic interests me, not just because I personally abhor adaptors in any
>repeater system, but also because I see that others are equally passionate
>about certain cables.
>
>After spending many years troubleshooting repeater systems cobbled together
>by my friends and colleagues, most of which were replete with every
>connector series known to Mankind- and which used many adapters to mate
>between series- I became aware that the most troublesome repeaters had the
>largest number of adapters.
>
>When I began to design my own repeater systems, I vowed to abide by three
>simple rules:
>1.  Use only Mil-spec RG-400/U or RG-214/U cable for jumpers and
>interconnecting cables, and
>2.  Make up these cables with the correct connectors on each end, using the
>specified tools, and
>3.  Use only crimped connectors with silver-plated brass bodies, gold-plated
>contacts, and Teflon dielectric.
>
>None of my systems have adaptors or "barrel" connectors, since the cables
>are made up to fit the job.  There are no BNC or UHF connectors; except for
>very unusual situations, all connectors are Type N with a few mini-UHF
>needed to mate with a particular radio.  It would not occur to me to use an
>adapter to mate a male N connector to a UHF female connector- I would have a
>premium UHF male connector on that end of the cable!  Of course, this only
>is an issue with older radios and duplexers; the modern counterparts have
>female N connectors.
>
>I guess the bottom line here is that almost all double-shielded and 100%
>shielded cable will perform superbly in a repeater system, if properly
>installed.  I have never heard of any repeater system that was significantly
>improved by replacing RG-214/U with 3/8" hardline, Superflex, or any other
>trendy cable- unless the original installation was flawed.  We should all be
>ready to accept that a flawed installation does not condemn a cable brand or
>type.  In my personal opinion, the use of adapters in place of the exactly
>correct connectors leads to a flawed installation.  YMMV!
>
>73, Eric Lemmon WB6FLY
>
>
>-Original Message-
>From: Repeater-Builder@yahoogroups.com
>[mailto:[EMAIL PROTECTED] On Behalf Of Jay Urish
>Sent: Monday, January 30, 2006 7:04 PM
>To: Repeater-Builder@yahoogroups.com
>Subject: Re: [Repeater-Builder] Re: Loss through adaptors:
>
>Yea, I use the heck out of LMR-400UF.. Please enlighton me!
>
>
>Dave VanHorn wrote:
>  
>
>>>For tight spots, consider superflex 1/4 or 3/8 
>>>in hard line.  I actually use the mini 141 rigid 
>>>line for modest power levels. 
>>>  
>>>
>>FSJ1-50 now in every cable except my adaptor mess (soon to be replaced) 
>>and the 2M duplexer harness.
>> 
>>
>>
>>
>>>Avoid trying to use foam center cables where 
>>>possible. 
>>>  
>>>
>>My FJS1-50 is foam, what's the beef with foam?
>>
>>
>>
>
>
>  
>




 
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Re: [Repeater-Builder] Re: Loss through adaptors:

[Q]

Nice test results! Confirms my beliefs! Would be nice to have a list of 
the worst/best connectors
for those not fortunate enough to have the proper test equipment.
Would make a good pocket guide when hamfesting!!!  73,Lee

nj902 wrote:

>--- In Repeater-Builder@yahoogroups.com, "skipp025" <[EMAIL PROTECTED]> wrote:
>"I lifted the below text from the yahoo rfamplifiers group page,
>posted this last week by my friend Dave. It's right on the money. 
> 
>http://groups.yahoo.com/group/rfamplifiers/
> 
> [paste] 
>If you are able to measure the SWR of a coax connection at VHF, then
>you've installed a connector wrong. I used an HP 8510C network
>analyzer to measure a whole bunch of UHF to N, UHF to BNC and so
>forth, adapters, all stacked on top of each other to a foot long, and
>the lowest frequency where I measured anything of concern was at 2
>GIGAhertz, where the SWR rose to 1.1:1. Yes, I know, amateur radio
>lore is full of the claim that UHF connectors are awful. They are, but
>only if you compare then to BNC and N, which are suitable for 10GHz
>and above. Assembled correctly, a UHF connector is invisible below 1GHz.
> [end] 
>
>
>I hope nobody is buying into this BS.
>
>Connector and adapter mis-match and loss issues are hardly "amateur
>radio lore"
>
>RF manufacturers and instrumentation companies have stressed this for
>years - justifiably.
>
>It's easy to verify if you have access to instrumentation.  Just out
>of curiosity I decided to run a couple of tests.  
>
>When you measure a device for SWR you are actually measuring return
>loss.  You can do this on a network analyzer or with a spectrum
>analyzer and tracking generator plus a signal separation device such
>as a return loss bridge or directional coupler.  
>
>I decided to try both instruments and compare the results.  You first
>calibrate the measurement setup with precision components from your
>cal kit [e.g. Agilent 85032B].  The critical component is a precision
>50 ohm load.  With a good bridge or coupler you should be able to
>measure a return loss of 40 dB  or greater [equivalent to an SWR or
>1.02:1]
>
>Normally your instrument test ports will be type N although some
>instruments have APC-7 test ports. Your cal kit should match the test
>ports.  
>
>I started with a full 2-port cal of the VNA and a normalization of the
>Spectrum analyzer.  My reference load did measure as expected.
>
>The next step is to "insert" the device under test.  In this case we
>are interested in looking at a UHF connector.  Obviously, since the
>instrument is type N, we have to use adapters.  Just out of curiosity,
>I decided to compare two pairs of adapters.  First an NF-NF mated to
>an NM-NM. [UG-57B/U and UG-29B/U] This created an "insertable" device.
> These are "standard" adapters as opposed to "precision" components
>and as expected, there was some degradation of the return loss
>measurement.
>
>I then compared this to two other adapters, NM to UHF-F and UHF-M to
>NF [UG-146/U and UG-83/U], again creating an "insertable device"  This
>pair has just a single UHF male to female junction and results in a
>significant decrease in return loss [i.e. increase in SWR.]
>
>I also tried inserting an 90 degree UHF adapter [UG-646/U] in line
>between the UG146/U and the UG83/U which resulted in further
>[significant] return loss degradation.
>
>I measured several sets of these parts and the results were not only
>consistent from part to part but generally match within a few tenths
>of a dB between the VNA and the spectrum analyzer.  I always like to
>see comparable results from two significantly different instrument
>setups - it confirms your thought process and results.
>
>Results at: 150 MHz, 450 MHz, 900 MHz
>
>NM-NF adapters: 
>[VNA]: 36 dB, 35 dB, 31 dB
>[SA/TG] 37 dB, 35.7 dB, 30 dB
>
>N-UHF + UHF-N adapters:
>[VNA]: 26 dB, 16.5 dB, 11.4 dB
>[SA/TG]: 23.6 dB, 17.2 dB, 11.5 dB
>
>N-UHF + UHF 90 + UHF-N
>[VNA]: 20.2 dB, 12.03 dB, 9.3 dB
>[SA/TG]: 21.6 DB, 11.9 dB, 9.1 dB
>
>Now just for reference, a return loss of 11 dB would be equivalent to
>an SWR of 1.785 : 1 [ONE UHF junction @ 900 MHz] and a return loss of
>17 dB would be an SWR of 1.329 : 1 [@ 450 MHz]
>
>UHF connectors "invisible" below a gigahertz??? Hardly.
>
>
>Also - someone asked about the 90 degree N fitting at 900 MHz so I
>tested a few of those.  That's easy because being M on one side and F
>on the other, it is inherently "insertable"
>
>The round kind [UG-27A/U] averaged return loss of 22 dB. The square
>ones[UG-27D/U] are better at 27 dB [1.094 : 1 SWR]
>
>
>
>
>
>
>
>
>
>  
>




 
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Re: [Repeater-Builder] Re: Loss through adaptors:

[Jim B.]

nj902 wrote:

> Connector and adapter mis-match and loss issues are hardly "amateur
> radio lore"
> 
> RF manufacturers and instrumentation companies have stressed this for
> years - justifiably.

BTW, I am told Motorola derated 'N' connectors a few years ago. They are 
not putting 'N' connectors on any path that carries tranmit power (not 
sure how much) above 800 Mhz. They are using 7/16" DIN for 800/900Mhz 
transmitters of late.

I do know that 250W at 931 Mhz through an 'N' connector gets warm to the 
touch.
-- 
Jim Barbour
WD8CHL





 
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Re: [Repeater-Builder] Re: Loss through adaptors:

[Bob Dengler]

At 1/31/2006 04:56 AM, you wrote:
>Nice test results! Confirms my beliefs! Would be nice to have a list of
>the worst/best connectors
>for those not fortunate enough to have the proper test equipment.
>Would make a good pocket guide when hamfesting!!!  73,Lee
> >
> >N-UHF + UHF-N adapters:
> >[VNA]: 26 dB, 16.5 dB, 11.4 dB
> >[SA/TG]: 23.6 dB, 17.2 dB, 11.5 dB
> >

I measured some N-UHF pairs a while back & found quite a variation in 
return loss.  The best ones had Teflon dielectric in the UHF side & had a 
R.L. of > 20 dB.  The worst one had brown dielectric.

Bob NO6B






 
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Re: [Repeater-Builder] Re: Loss through adaptors

[Bob Dengler]

At 1/31/2006 11:04 AM, you wrote:
> > It was not teflon, it was
> > some unknown thermo-polymer with a very low melting point!
>
>Yeah, I've hit these too.. They look like silver plated, and the
>dielectric is a little pink-ish like teflon.
>Icky.

Me three.  PL-259 connector I bought at the Rochester Hamfest.  Melted so 
badly that it was completely unusable.  Sure looked like Teflon when I 
bought it.

Bob NO6B






 
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RE: [Repeater-Builder] Re: Loss through adaptors:

[Eric Lemmon]

Dave,

Tessco carries right-angle N connectors from several manufacturers.  Go
here:

http://www.tessco.com/products/displayProducts.do?groupId=410&subgroupId=30

and look at pages 3 and 4.  Another manufacturer of right-angle N connectors
is Delta.

73, Eric Lemmon WB6FLY


-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Dave VanHorn
Sent: Thursday, February 02, 2006 12:16 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Loss through adaptors:


I think the biggest problem that we face is that our adaptors tend to 
not have a pedigree.  I have some that I know were from Radio Shack, 
some that I bought at hamfests in boxes of "stuff", some with real 
pedigrees (amphenol, in the bag) and some that are precision test 
equipment in their own right.

If cost were no object, we would do the whole thing in hardline and 
GPC-7 connectors and be done with it, right?  :)

Someone mentioned before, an elbow or tee that used a SPRING to make 
the connection..  Boy, I would love to put that on my SA and see the 
plot!  Probably works nicely at some frequencies, and insanely badly 
at others. 

I ended up having to put at least one right angle in every radio 
connection. The daniels gear uses front panel N connnectors, and 
there's no way I could close the cabinet door without RA connectors. 
I couldn't find anything RA in N, so I used a single RA adaptor on 
each of the four lines.  Not sure who makes them. Markings are "CQA" 
or "CGA" and "UG-27/U"  Definitely silver plated.








 
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Re: [Repeater-Builder] Re: Loss through adaptors:

[Glenn Little WB4UIV]

Lists some of the military codes to indicate who made an item.

73
Glenn
WB4UIV



At 03:15 PM 02/02/06, you wrote:

>I think the biggest problem that we face is that our adaptors tend to
>not have a pedigree.  I have some that I know were from Radio Shack,
>some that I bought at hamfests in boxes of "stuff", some with real
>pedigrees (amphenol, in the bag) and some that are precision test
>equipment in their own right.
>
>If cost were no object, we would do the whole thing in hardline and
>GPC-7 connectors and be done with it, right?  :)
>
>Someone mentioned before, an elbow or tee that used a SPRING to make
>the connection..  Boy, I would love to put that on my SA and see the
>plot!  Probably works nicely at some frequencies, and insanely badly
>at others.
>
>I ended up having to put at least one right angle in every radio
>connection. The daniels gear uses front panel N connnectors, and
>there's no way I could close the cabinet door without RA connectors.
>I couldn't find anything RA in N, so I used a single RA adaptor on
>each of the four lines.  Not sure who makes them. Markings are "CQA"
>or "CGA" and "UG-27/U"  Definitely silver plated.
>
>
>
>
>
>
>
>
>
>Yahoo! Groups Links
>
>
>
>






 
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RE: [Repeater-Builder] Re: Loss through adaptors:

[Mike Perryman]

Dave,
About 2 yrs ago I picked up several Type-N right angle connectors made by
Andrew from an eBay auction.  I will look when I get home this evening to
see if I have any left so I can get the part number for you.  The connectors
were made specifically for FSJ1-50.

 73
Mike Perryman
www.k5jmp.us


-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] Behalf Of Dave VanHorn
Sent: Friday, February 03, 2006 12:06 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Loss through adaptors:


--- In Repeater-Builder@yahoogroups.com, "Eric Lemmon" <[EMAIL PROTECTED]>
wrote:
>
> Dave,
>
> Tessco carries right-angle N connectors from several manufacturers.
Go
> here:
>
> http://www.tessco.com/products/displayProducts.do?
groupId=410&subgroupId=30
>
> and look at pages 3 and 4.  Another manufacturer of right-angle N
connectors
> is Delta.

Yes, but do they work with FSJ1-50?









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RE: [Repeater-Builder] Re: Loss through adaptors:

[Mike Perryman]

I found them on the Tessco website...  here is the link..
<http://www.tessco.com/products/displayProductInfo.do?sku=417130&eventPage=1
>

 73
Mike Perryman
www.k5jmp.us




-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] Behalf Of Mike Perryman
Sent: Friday, February 03, 2006 2:04 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Re: Loss through adaptors:


Dave,
About 2 yrs ago I picked up several Type-N right angle connectors made by
Andrew from an eBay auction.  I will look when I get home this evening to
see if I have any left so I can get the part number for you.  The connectors
were made specifically for FSJ1-50.

 73
Mike Perryman
www.k5jmp.us


-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] Behalf Of Dave VanHorn
Sent: Friday, February 03, 2006 12:06 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Loss through adaptors:


--- In Repeater-Builder@yahoogroups.com, "Eric Lemmon" <[EMAIL PROTECTED]>
wrote:
>
> Dave,
>
> Tessco carries right-angle N connectors from several manufacturers.
Go
> here:
>
> http://www.tessco.com/products/displayProducts.do?
groupId=410&subgroupId=30
>
> and look at pages 3 and 4.  Another manufacturer of right-angle N
connectors
> is Delta.

Yes, but do they work with FSJ1-50?









Yahoo! Groups Links












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