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SL7550 Portable poor RF output

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jerryray

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I have a XPR7550 and can get a decent -95 signal from a local repeater.
When I try the same repeater with brand new SL7550, can't hit the repeater, once it keyed, and that was a one time.

Are these sl units that bad. I understand it's 2 watts, so 3db lower power, fake antenna -6db. Still should hit the repeater.

Perhaps this antenna is really bad.

Do they make a slightly longer (resonant antenna)?

TIA
 

KG4INW

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How far away is the repeater? We've found they work fine when nearby repeaters (as to be expected) but will not work nearly as well for distance/simplex that the 6550s and 7550s will. I do not believe they have better antennas available.
 
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jerryray

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Yes the is the 438-470 version, Repeater is 10 miles on the Empire state building at 1100ft
The signal on my XPR7550 is full scale. I hit the repeater on low power signal is -87.

SO there seems to be a 20db difference.

Perhaps this radio is bad.
 

TampaTyron

Beep Boop, Beep Boop
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low power output (2w vs. 4w) and a negative gain stubby antenna are your differences..... I have only seen a 6-8db difference in RX though. If you couple that rx difference with the -3db of the transmit power, you have almost 10db loss in the tx path.....TT
 

N4KVE

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Many of the users on our system using XPR7550's & 6550's have no problem using the repeater, but those who use the SL7550 are constantly having problems holding the repeater, unless they are real close. It's definitely not good as a primary radio, but fine as a 2nd, or 3rd radio unless you can see the repeater.
 
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jerryray

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What's I find very strange is by holding the antenna, the signal is better on RX&TX.

I have never observed that on a UHF radio.
 

Firebuff880

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If you can find someone with an Aeroflex auto tune for MOTOTRBO, I would suggest having the radio run through the process. I have seen it make huge differences.

Also, might check with the repeaters owner and see what the receive RSSI threshold is set to and if it might be adjusted to be more sensitive / less quieting.

The (other) RSSI Threshold ~ DJ0WH
 
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jerryray

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I can't even see any RSSI indication from the Manhattan repeater. When I hold the Antenna I get 2 bars.
The SL7550 has full signal strength.

My dealer has shipped me his demo radio. I will clone my code plug to his radio and compare them.
 
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jerryray

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Would that antenna work on an SL7550?

The stock antenna is special design held in with 2 screws.
 

Firebuff880

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I am confused -- The title of this is "SL7550 Portable poor RF output" but seeing the repeater and displaying an RSSI Level is receive not transmit (output).

An while I have seen all sorts of issues with transmit due to the 2-watt nature of the SL-7550 reaching a repeater, I can't say I have honestly seen an issue with the repeater reaching the SL-7550.

Have you checked the programing to be sure you are on the right freqs and settings ?

===========================

PS: If you want another, more traditional antenna, the part number is XPR-7550 :)
 
J

jerryray

Guest
OK, thanks. I should have said poor transmit and receive compared to my XPR7550

I have a repeater 1-2 miles away at 350 feet. I cannot reliably get in.

Someone must make a better antenna that fists this radio.
 

Mars_P25

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Also, might check with the repeaters owner and see what the receive RSSI threshold is set to and if it might be adjusted to be more sensitive / less quieting.

The (other) RSSI Threshold ~ DJ0WH
The RSSI threshold has nothing to do with "squelching out" weak incoming (digital) signals to the repeater. That setting is intended to inhibit the repeater TX should any other signals be received on the output which are stronger than the defined value.

It's also called "FCC Type 1 compliance". You can Google the term for a better explanation.

Setting this value too low (weak) will cause audio holes in IPSC/Capacity Plus/Connect Plus systems.
 

Firebuff880

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Someone must make a better antenna that fists this radio.

Nope, the radio is designed for in building discrete executive use. I don't believe anyone has a replacement antenna, as it's a very special unique design. One of the reasons it's also a UHF only radio.

===================
 

JRayfield

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Springfield, MO
No, there is no antenna available that will work with this radio.

It sounds to me like there's a problem with either the SL7550 or your repeater. I don't know what kind of terrain you're in, but I would expect an SL7550 to work much better than that, into a repeater that high and only that small distance away.

John Rayfield, Jr.
Rayfield Communications

OK, thanks. I should have said poor transmit and receive compared to my XPR7550

I have a repeater 1-2 miles away at 350 feet. I cannot reliably get in.

Someone must make a better antenna that fists this radio.
 

cmdrwill

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So Cali
I googled this antenna, are you saying this antenna will go on a SL7550?

Seems the SL7550 has something much different for an antenna. I have not been able to verify what is on the 7550. Someone said "held on by two screws", so the EXC450SF would not work.

Maybe they need to FIX the repeater. '"Only 1-2 miles away at 350 feet. I cannot reliably get in."
Some so-called radio fixers use crappy antennas on repeaters..
 

SCPD

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Hard to get in

Seems the SL7550 has something much different for an antenna. I have not been able to verify what is on the 7550. Someone said "held on by two screws", so the EXC450SF would not work.

Maybe they need to FIX the repeater. '"Only 1-2 miles away at 350 feet. I cannot reliably get in."
Some so-called radio fixers use crappy antennas on repeaters..

Well, there's a few factors I didn't see mentioned in the OP.
Is he in a aluminum sided house, or workplace with metal sheeting, etc?

And the XPR's getting in better than the SL is a no-brainer. The antenna on the SL is a dummy load. What is it, maybe 2" long? I'm certain the OP had no intention of using it primarily for ham radio when he bought it, he just wants to see if it will work the ham bands also.

Like others have said, the radio was designed with working a building. Hotel, casino, business etc. Not designed to talk 2 miles away. I'm sure many people do have good luck working repeaters miles away based upon conditions, elevation, etc. But it really shouldn't be a surprise, with that radio, if you can't.
 
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