[time-nuts] Can a Symmetricom 58532A antenna and ham radio transmitters coexist?

Bruce Lane kyrrin at bluefeathertech.com
Thu Apr 14 23:58:36 EDT 2016


	I have multiple GPS antennas, an HF ground plane and a long wire. I
typically run no more than 100W on HF, but am capable of pushing to 500.
All the antennas are within 30-40 feet of each other.

	Personally, I've never had an interference problem between any of them.
I use LMR240DB (Direct Burial) for the GPS runs, and LMR400DB for the
HF's. Yes, the filling goo can be a hassle, but at least it is easily
removed with the citrusy-smelling solvent (darned if I can remember the
name of the stuff at the moment). The extra water protection and UV
resistance are well worth it, at least to me.

	If you're really paranoid, rdr-electronics on Ebay has lots of NIB
High-Rejection rated GPS timing antennas, made by PCTel/MaxRad for
Lucent. They are expressly designed for use in high-RF environments and
contain extra filtering.

	The item number would be 231898765036, going for $30 + shipping last I
looked. The manufacturer part number is GPS-TMG-HR-26NCM, Lucent P/N
KS24019-L112D, ComCode 849143987. The collar takes a 1.5 inch mast.

	No connection with rdr on my part, other than being a very happy
customer of theirs for the last several years.

	Keep the peace(es).


On 14-Apr-16 02:01, Pete Stephenson wrote:
> Hi all,
> 
> I recently acquired a pair of Symmetricom 58532A antennas and so far
> they work great with my setup (antenna --> Symmetricom 58535A splitter
> --> [1] Thunderbolt and [2] other receivers that I swap out
> occasionally).
> 
> I'm also an amateur radio operator and am looking to mount the 58532A
> on a roof-mounted mast to get better coverage (right now it's outside
> a window). Would the presence of nearby (either on the mast or within
> 20m of the mast) HF (3.5-30MHz) , VHF (~145MHz), and UHF (~430MHz)
> transmitters cause any issues? My transmit power is typically around
> 5-20W on HF with peaks up to 100W and 1-5W on VHF/UHF. The HF antenna
> is a simple wire dipole, not a high-gain directional antenna.
> 
> Naturally, I'd like to avoid damaging my GPS antenna or any of the
> downstream devices.
> 
> Since the 58532A is currently mounted relatively close to the
> splitter, I'm using LMR100A coax (it's lossy, but the short lengths
> mean it's not an issue; the window mount makes the thinness of the
> cable important) but for the longer run from the mast I'd used LMR240
> or LMR400 as needed. I use the same type of cable for the HF radio.
> Those cables are well-shielded (braid-on-foil) with >90dB shielding
> attenuation, so I don't think signal leakage from or ingress into the
> cables will be a big deal.
> 
> The datasheet for the 58532A specifies the out-of-band signal
> attenuation is around 60dB at +/- 50MHz.
> 
> Many thanks in advance for the help.
> 
> Cheers!
> -Pete
> 

-- 
---
Bruce Lane, ARS KC7GR
http://www.bluefeathertech.com
kyrrin (at) bluefeathertech dot com
"Quando Omni Flunkus Moritati" (Red Green)


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