[TowerTalk] PL259 Insertion Loss?

[Bill Aycock]

Jim--
The accuracy numbers always quoted for Birds has always bothered me. The 
accuracy numbers are a combination of "Cover your A**" and laziness. The 
real problem usually is repeatability, not accuracy.  Most comparisons 
are just that, comparisons with one set of instruments. The use of a 
single instrument for multiple measurements with careful constancy of 
non-critical items can give far more realistic answers.
I, personally, did a multi-connecter comparison using UHF parts. I 
hooked up a long string of UHF jumpers and barrel connecters with 
"Push-on" fittings at each end. My "Instruments were only the Watt 
meters most hams have. I don't remember how many joints were involved, 
but was every spare jumper I had and all the Barrels in the junk box. 
There was no attempt to get great accuracy, but I did try for 
repeatability and replication.
With this setup, I could measure no significant losses. I am convinced 
(I convinced myself) that the "UHF connector loss" is a myth, right up 
there with that myth about the superiority of N-type at HF.

Bill--W4BSG


On 1/14/2012 11:32 AM, Jim W7RY wrote:
> That's hardly believable. How was it measured? a Bird wattmeter accuracy is
> only +- 5%. A network analyzer or a TDR in return loss mode (Bird SA-6000 or
> Anritsu equivalent) would be required to measure this accurately.
>
> Not to mention, the number of 75 Ohm adapters in the string shown.
>
>
>
> 73
> Jim W7RY
>
>
> --------------------------------------------------
> From: "Steve Hunt"<steve at karinya.net>
> Sent: Saturday, January 14, 2012 9:15 AM
> To:<towertalk at contesting.com>
> Subject: Re: [TowerTalk] PL259 Insertion Loss?
>
>> Not a direct answer to your question, but from Dan's (N3OX) web site:
>>
>> http://n3ox.net/files/23_adapters_28400kHz.jpg
>>
>> 23 connectors/adaptors including UHF types, 0.08dB loss on 10m
>>
>> 73,
>> Steve G3TXQ
>>
>>
>>
>>
>> On 14/01/2012 16:59, Tony wrote:
>>> All,
>>>
>>> I've always assumed that UHF connectors had negligible insertion loss
>>> below 30MHz, but I recently spotted a couple of quotes on the web that
>>> put losses between 0.3 and 0.5db @ 30Mhz. If that were the case, the
>>> cumulative effect of a typical installation with 6 to 8 connectors would
>>> not be so negligible, especially on 10 and 12 meters.
>>>
>>> I was wondering if anyone has done any tests of their own or if they
>>> know of a reliable source on the web for this kind of data? Another
>>> thing that comes to mind is whether there is any additional losses
>>> associated with UHF crimp-on connectors?
>>>
>>> Thanks,
>>>
>>> Tony, K2MO
>>> _______________________________________________
>>>
>>>
>>>
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>>>
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