HP-1: Very interesting (HP-2 Actually)

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NWI_Scanner_Guy

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Hmmmm, experienced a very interesting / unusual occurrence today with my HP-2. It may have been going on for a few days, but today is the first time I really noticed it.

After selling my 536HP that I used at my kitchen table and replacing it with my HP-2, I began experiencing intermod problems with the HP-2 at the table. Tried my 436HP there, and didn't experience the problem, so I decided to do a swap; left the 436 at the table and put the HP-2 bedside.

For some reason, the HP-2 seems to eat through batteries, whether I'm using rechargables or alkaline batteries. Since I use my laptop for Kindle reading in bed, I decided to run a USB cord from the computer to the radio. While it worked okay for the most part, the cord kept getting in the way. After giving it some thought, I hooked up a 10,000mAh external battery (the type used to charge cellphones and tablets) to power the scanner. All seemed to be working fine...until this evening.

Had the HP-2 on, but not hearing much, while I was doing a little light cleaning near my bed when I accidentally hit the battery and knocked it off of the night stand. The radio stayed on the table, but the USB cable came out of the battery end and was dangling off the side of the table, still attached to the radio.. All of a sudden it seemed that the scanner came to life. I figured it was a sudden "flurry" of activity and didn't give it anymore thought. Picked up the battery and reconnected it to the scanner and it went silent. Not totally silent, but I wasn't hearing as much as when the battery was disconnected. Seeing that I was curious, I disconnected the battery and once again, the HP-2 roared to life. As a further test, I decided to connect the scanner back to my laptop to see what the result would be, and when I did, there was no change in reception. It was "hearing" everything it was when it was just running on the internal batteries. So, just to see if the 'problem' was the external battery, I once again hooked it up to the radio and suddenly it got very quiet.

So now I'm wondering why the external battery would cause a reduction of what the HP-2 was picking up. The battery has two outputs, a 1.0 amp output and a 2.1 amp output. Experienced the reduction on both of them. Also thought it might have something to do with the external battery trying to charge the internal batteries, but once again, experienced the reduction whether the batteries were charging or not.

Has anyone else tried using an external battery and experienced the same problem? Anyone have any ideas why something like this would happen? If so, I'd love to hear your thoughts. Thanks in advance.

:)
 

W8RMH

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The cable may have been acting like an antenna / ground plane through the ground circuit. I have found that if I keep the display level as low as possible the batteries last a lot longer. I just keep it on the USB when at home and keep a spare set of externally charged batteries handy. I'm still getting about 8 hours on a set of batteries.
 

hiegtx

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Another random thought:
I would guess that the external battery pack has a voltage regulator circuit, to take whatever the battery has, and cut it down to the regulated 5v USB standard. If so, that could be generating RF interference, carried through the USB cable into the scanner. Might be interesting to see what comes up if you use the Close Call (or Signal Sweeper for the GRE's) of one of your other scanners and try them with the squelch all the off, at the tip of the USB cord. Maybe nothing, or maybe too weak for CC or SS.
 

dkf435

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A lot of these USB supplies and batteries have some real noise making switching dc-dc circuits., This is part of the reason I power my scanners with a Astron RS-35M linear supply and use remote antennas with multicouplers to get the noise down and antennas in the clear.

This is also the reason I have great opposition to the idea of a GPS inside the HomePatrol radios as a lot of the noise I have mobile is either coming from the dash cluster or the GPS/NAV radio

David Kb7uns
 

mancow

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dkf435 is right, they have switching DC - DC converters that are noisy. I have encountered several that will eliminate reception like a jammer.
 

phask

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FWIW - I have one that SEEMS to work - but now I need to re-compare. It's one of the larger ones via Amazon. I keep it in the car just in case. I tried it on everything when I got it. It powered my -2 for a couple days and I never noticed an issue.

I usually have 2 or 3 running with overlaps to compare and not miss something. I usually have a few ferrite beads on the power/usb cable too.


This one.
Amazon.com: RAVPower® Element 10400mAh External Battery USB Portable Charger (Dual USB Outputs, Ultra Compact Design), Travel Charger for iPhone 6,iPhone 6 plus,iPhone 5, 5S, 5C, 4S, 4, iPad Air, 4, 3, 2, Mini 2 (Apple adapters not included); Samsung



dkf435 is right, they have switching DC - DC converters that are noisy. I have encountered several that will eliminate reception like a jammer.
 

NWI_Scanner_Guy

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Thanks everyone for your replies. I appreciate the information.

Thought I had a surefire way to power the radio for an extended period of time. Guess I'll just have to keep a few sets of AA batteries charged at all times.

:)
 
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