KPA500/Kat500 Cables - PL-259 Question

[James Bennett]

The UPS guy is set to deliver my KAT500 and KPA500 later this afternoon. In the mean time, I've been getting "stuff" ready for the blessed event. Some of that stuff means preparing coax jumpers to run from the K3 to the KPA500 and from the KPA500 to the KAT500. From the KAT500 I may go to my 4:1 balun directly to my doublet or through a 4-position coax switch - undecided there. Anyway, many knowledgeable folks have stated, either on this reflector or on their own web sites, that it's a good idea to stick with known manufacturers of coax and connectors, such as Belden, Amphenol, The Wireman, DXE, etc.

Well, I just got a bunch of PL-259 connectors from that last-mentioned vendor and noticed that they had no brand name on them. Plus, the vendor's web site doesn't say that they are "Amphenol" brand, but that they ARE silver plated and teflon insulated. Comparing these connectors with some other silver / teflon connectors in my parts drawer, I notice a difference in the center conductor. On the DXE PL-259's, the center pin is 100% surrounded with what apparently is the white teflon insulation. On the ones in my bin, there is a small silver-looking "ring" around that center pin, approximately 1 mm wide, and then teflon as the remainder of the insulation. The only other difference between these two types of connectors is that the DXE-supplied PL-259's have a much more coarse "finger grip" area than my other ones.

So, the question is - with neither of them having any brand name on them, should one feel comfortable using either of them? How can you tell if a PL-259 is "crap", other than a lack of teflon insulation and silver plating?

Jim / W6JHB

Folsom, CA (anxiously waiting for Mr. UPS)
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[Fred Smith-2]

The DXE PL-259's are indeed good connectors I use it with their 400MAX coax
and have ran up to 3kw into a dummy load using them no problems. I have used
LMR-400 for years and now use only DXE coax and mostly there connectors.

Fred/N0AZZ

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Jim Bennett
Sent: Friday, November 08, 2013 4:56 PM
To: Elecraft Reflector Reflector
Subject: [Elecraft] KPA500/Kat500 Cables - PL-259 Question

The UPS guy is set to deliver my KAT500 and KPA500 later this afternoon. In
the mean time, I've been getting "stuff" ready for the blessed event. Some
of that stuff means preparing coax jumpers to run from the K3 to the KPA500
and from the KPA500 to the KAT500. From the KAT500 I may go to my 4:1 balun
directly to my doublet or through a 4-position coax switch - undecided
there. Anyway, many knowledgeable folks have stated, either on this
reflector or on their own web sites, that it's a good idea to stick with
known manufacturers of coax and connectors, such as Belden, Amphenol, The
Wireman, DXE, etc.

Well, I just got a bunch of PL-259 connectors from that last-mentioned
vendor and noticed that they had no brand name on them. Plus, the vendor's
web site doesn't say that they are "Amphenol" brand, but that they ARE
silver plated and teflon insulated. Comparing these connectors with some
other silver / teflon connectors in my parts drawer, I notice a difference
in the center conductor. On the DXE PL-259's, the center pin is 100%
surrounded with what apparently is the white teflon insulation. On the ones
in my bin, there is a small silver-looking "ring" around that center pin,
approximately 1 mm wide, and then teflon as the remainder of the insulation.
The only other difference between these two types of connectors is that the
DXE-supplied PL-259's have a much more coarse "finger grip" area than my
other ones.

So, the question is - with neither of them having any brand name on them,
should one feel comfortable using either of them? How can you tell if a
PL-259 is "crap", other than a lack of teflon insulation and silver plating?

Jim / W6JHB

Folsom, CA (anxiously waiting for Mr. UPS)
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[Vic Rosenthal]

Jim,

In my experience, there are quite acceptable unbranded connectors out there. The problem
is, you don't know what you are getting, as you do when you buy Amphenols. But I would
expect that DXE checks out what they buy and they are probably OK.

Problems with junk PL-259's are insulation that melts when you solder the connector,
threads that don't fit other connectors, center pins that loosen up, plating that doesn't
take solder (this is really nice when it happens in the field or on a roof or tower) --
all things that you will notice when you install them.

Sockets are another story because you can't tell about the durability of the contact
material at installation time!

On 11/8/2013 2:55 PM, Jim Bennett wrote:

> The UPS guy is set to deliver my KAT500 and KPA500 later this afternoon. In the mean
> time, I've been getting "stuff" ready for the blessed event. Some of that stuff means
> preparing coax jumpers to run from the K3 to the KPA500 and from the KPA500 to the
> KAT500. From the KAT500 I may go to my 4:1 balun directly to my doublet or through a
> 4-position coax switch - undecided there. Anyway, many knowledgeable folks have stated,
> either on this reflector or on their own web sites, that it's a good idea to stick with
> known manufacturers of coax and connectors, such as Belden, Amphenol, The Wireman, DXE,
> etc.
>
> Well, I just got a bunch of PL-259 connectors from that last-mentioned vendor and
> noticed that they had no brand name on them. Plus, the vendor's web site doesn't say
> that they are "Amphenol" brand, but that they ARE silver plated and teflon insulated.
> Comparing these connectors with some other silver / teflon connectors in my parts
> drawer, I notice a difference in the center conductor. On the DXE PL-259's, the center
> pin is 100% surrounded with what apparently is the white teflon insulation. On the ones
> in my bin, there is a small silver-looking "ring" around that center pin, approximately
> 1 mm wide, and then teflon as the remainder of the insulation. The only other
> difference between these two types of connectors is that the DXE-supplied PL-259's have
> a much more coarse "finger grip" area than my other ones.
>
> So, the question is - with neither of them having any brand name on them, should one
> feel comfortable using either of them? How can you tell if a PL-259 is "crap", other
> than a lack of teflon insulation and silver plating?
>
> Jim / W6JHB
>
> Folsom, CA (anxiously waiting for Mr. UPS)

--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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[Don Wilhelm-4]

I have heard from reliable sources that DXE had some problems with their
PL-259 crimping process over the past 6 months or so.  They have taken
steps to correct it, but if you have purchased pre-assembled cables from
them, be aware that they may be a problem.

The symptoms are that the receive signal goes down in strength after a
few minutes.  A transmit will "fix it", but after a few minutes, RX
signal strength drops again.   If you have similar behavior, check the
DXE assembled cables for good low resistance to the shield at both ends.

73,
Don W3FPR

On 11/8/2013 6:23 PM, Fred Smith wrote:
> The DXE PL-259's are indeed good connectors I use it with their 400MAX coax
> and have ran up to 3kw into a dummy load using them no problems. I have used
> LMR-400 for years and now use only DXE coax and mostly there connectors.
>
> Fred/N0AZZ
>

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[Don Wilhelm-4]

I also use coax seal on my PL-259 connectors outdoors, and it is good
stuff.  Like Ron says, the connectors remain looking just like new when
the coax seal is removed.
However, wrap the connector with electrical tape before putting on the
coax seal.  If you fail to heed that advice, you will be 'picking at'
the remnants of the coax seal that adhere to every part of the connector
- it sticks tight.

73,
Don W3FPR

On 11/8/2013 6:54 PM, Ron D'Eau Claire wrote:

> And, while I agree that the more expensive Type N connectors provide
> superior strength and weather resistance outdoors, I don't bother with them.
> Even on ships, the lowly no-name brand PL-259 offers superb performance when
> encased in inexpensive "coax-seal" - a putty like material that one simply
> molds around the connector and coax. After two or three years exposed to
> heavy salt spray at sea and corrosive stack gasses (some antennas are up
> near the top of the ship's funnel), cutting away the coax seal reveals a
> connector that looks like the day it was installed.
>
> 73 Ron AC7AC
>

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[Edward R Cole]

In my professional work before I retired in 2009, I used N-connectors
as much as possible.  Some commercial VHF marine radios and the CB
radios (required on our boats) had UHF connectors so I bought
Amphenol PL-259's for them.  I bought antennas that had N connectors.

Sealing on boats I used a combination of Scotch-70 (gray annealing
tape) covered either by heat shrink or scotch-33+ black
tape.  Scotch-70 cost $30 per roll so probably too expensive for hams
but it cut easily with a knife and never stuck onto the connector
like coax seal.  For tower lines (typically Heliax hardline) the
connectors were supplied with heat shrink that had sealant goo inside.

For my ham tower work I had added a coating of Scotch-Kote over
heat-shrink or Scotch-33+ which never has failed sealing.  For awhile
I was using Scotch-88 but 33+ has more stretch and better adhesive in
cold climates.

73, Ed - KL7UW
http://www.kl7uw.com
[hidden email]
"Kits made by KL7UW"

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