[TowerTalk] N connector, Re: UHF (PL259) soldered center

[Steve Maki]

On 06/27/18 20:35 PM, Jim Miller wrote:

> Could you layout the typical matrix of connectors from the cell
> antenna down to what remains of the shed at the bottom.?

2G (GSM & TDM) used mostly simple N connector based transmission lines 
with top and bottom N jumpers. Concept of PIM was largely unknown.

3G (CDMA & UMTS) sites typically have diplexers and/or triplexers, top
and bottom, with Bias T's to power TMA's etc., to maximize usage of
limited feedline counts. Lots of connectors (almost always 7-16 DIN),
lots of potential for PIM issues. Fortunately 3G was not as fussy about
PIM as 4G turned out to be.

> I heard somewhere that there was a general move afoot to eliminate
> the fire hoses running up the towers in favor of fiber and put the transmitter
> and receiver electronics at the top.

4G (LTE) started out using the traditional 3G model (ground mounted RF
gear), but it quickly became clear that moving the RF to the tower top
was the way to go. So we're running power & fiber up towers, and 
gradually retiring the big hardlines. In fact there was a brief period 
when we were installing antennas with the radios built in. But that has 
fallen out of favor already, for various reasons.

> If true that would seem to put 7-16 on the way out along with all the
> big hard lines.

On cell sites the 7-16 connector is a fine connector for the short 
jumpers between the radio and antenna. The only problem is the size - 
because some antennas and some radios are now coming with 8-12 RF ports 
each. It's hard to weatherproof connectors that are only nanometers 
apart. But...the cell industry is not the only market for high 
performance connectors. I'm pretty sure that 7-16 DIN, 4.3-10 DIN, N, 
and UHF will all be available for a long time.

-Steve K8LX


>> I haven't looked, but I'm guessing that neither of the *mini* DIN
>> series have much to choose from as far as connectors for 3/8"
>> braided coax (RG213, LMR400, etc). They were developed to be the
>> next generation connector for the Remote Radio Head to Antenna
>> jumper interface, which is 1/2" corrugated hardline 99% of the
>> time. The availability scenario will improve as time goes on, but
>> I'd bet on the 4.3-10 to be the survivor.
>> 
>> Whereas 7-16 DIN has gained enough market share to be available
>> for almost all cables, and will be for the foreseeable future.

>>> The 4.1-9.5 has been around for 15 years at least, and is the
>>> one properly called mini-DIN. The 4.3-10 is much more recent, and
>>> was developed specifically with ultra low PIM in mind, plus high
>>> density jack fields. The 4.3-10 is what all new cell equipment is
>>> and will be using, especially as we move into 5G.
>>> 
>>> Either series though is a big upgrade to the N in mechanical
>>> robustness.