[Amps] UHF Connectors

[Roger (K8RI)]

On 11/11/2013 2:02 PM, Jim Brown wrote:
> On 11/11/2013 10:37 AM, Fuqua, Bill L wrote:
>> Isn't "UHF Connector" an oxymoron?


>
> The name dates from the '30s or early '40s.  No question that there's a
> small discontinuity due to the Zo of the connector, but it certainly
> doesn't matter below 50 MHz, and at higher frequencies is often swamped
> by line loss.
>

I have on average 10 connectors in line from the amp to the antennas. 
228 feet. With UHF type the additive loss is so small as measured on the 
VNA it's insignificant through 10 meters and only a slightky bit more on 
50 MHZ  I haven't checked 2-meters.

As the arrays for 144 and 440 are not going back up and the only VHF/UHF 
antennas will be Diamond duoband verticals Loss isn't much of a concern.
I leave the VNAs connected through a Delta-2 switch, so every tune up 
van have the characteristic traces overlain to see any differences. The 
sensitivity is good enough to see the effects of the wind on the 
antennas and trees.

After using a 4170C for about a year I added a second one to the second 
station.  They sure are different than the old MFJ.

73

Roger (K8RI)


> Several years ago, I made up a dozen or so lengths of coax for a DX trip
> using very low loss cable that I'd bought at a great price, surplus from
> a telecom bankruptcy -- construction much like LMR400, except #10 solid
> copper for the center, excellent braid/foil shield.  As a test, when I
> was finished, I connected them all in series, about 1,200 ft, and
> measured with HP generator and HP spectrum analyzer up to about 500 MHz.
> I had about 23 83-1SPs and 11 or 12 barrels in line. The loss at 500 MHz
> was less than the published spec for the cable. Loss was measured by
> substitution (that is, differencing a short direct connection between
> generator analyzer with the cable under test) at all of the test
> frequencies.
>
> 73, Jim K9YC
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