10-4 it's not in concrete yet so I can still modify and will consider your suggestion as well. Hopefully tomorrow I can have a little time with it.
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Palomar RFX95HD
- Thread starter grimace
- Start date
Good deal Eldorado!
Ive honestly never measured the current across this resistor so i can't say for sure what is needed there.
everyone just uses 2 or 3 watt resistors there instead of measuring lol.
if you are concerned or the 1/4 watt resistor is getting hot when in TX, then you can parallel some other 1/4 watt resistors together in order to make a 1/2, 3/4, or 1 watt resistor etc.
four 150 ohm 1/4 watt resistors will give you around 37 ohms and will handle 1 watt.
there is no difference on the scope or in performance between the "add a fixed resistor to the bottom of the board" and the "use a tIP120 and a pot to provide a variable deadkey" versions of the mod.
I like to use the TIP120 method and mount a trimmer resistor inside the radio.
that way it can be set for wherever you want it but you don't have to worry about accidentally moving it by turning the wrong knob on the front of the radio.
LC
Ive honestly never measured the current across this resistor so i can't say for sure what is needed there.
everyone just uses 2 or 3 watt resistors there instead of measuring lol.
if you are concerned or the 1/4 watt resistor is getting hot when in TX, then you can parallel some other 1/4 watt resistors together in order to make a 1/2, 3/4, or 1 watt resistor etc.
four 150 ohm 1/4 watt resistors will give you around 37 ohms and will handle 1 watt.
there is no difference on the scope or in performance between the "add a fixed resistor to the bottom of the board" and the "use a tIP120 and a pot to provide a variable deadkey" versions of the mod.
I like to use the TIP120 method and mount a trimmer resistor inside the radio.
that way it can be set for wherever you want it but you don't have to worry about accidentally moving it by turning the wrong knob on the front of the radio.
LC
Well looking through the pile of pulls I found some half watt resistors which is what Bell's had used so it should be sufficient. The pulled stash saves the day.
After adjusting the modulation to where audio sounds good with no crunch I ended up with about 3.5 watt dk, 18 pep amp off. Amp on about 14 watt dk and will spike 100 before the limiter tames it to about 85-95 with voice peaks. Audio through headphones with monitor radio sounds pretty dog gone nice. I like it!
Thank you gentlemen one more time, I'll call it a success.
sure thing!
If you're looking to play a bit further with this, you can try replacing C71 with a 47uF cap, and see how that affects the AMC clamping.
And if you want to go even further, you can try strapping a 1K resistor across C71.
(you can play with this value a bit)
these mods change the timing of the AMC circuit and will allow you to tailor things a bit for your own radio and voice.
LC
If you're looking to play a bit further with this, you can try replacing C71 with a 47uF cap, and see how that affects the AMC clamping.
And if you want to go even further, you can try strapping a 1K resistor across C71.
(you can play with this value a bit)
these mods change the timing of the AMC circuit and will allow you to tailor things a bit for your own radio and voice.
LC
Thank you sir, I'll take those into consideration. I'm always up for more learning.
I won't have time until next weekend or so but will report back when the time comes.
A guy gave me a Cobra 29 Ltd Classic with the RFX95 installed. Which uses the Dim Switch as the on/off switch. And when I turn the RFX95 on, my Dosy shows 40 watts but all I hear is static. I switch the RFX95 off and the radio works just fine. So now, I can at least tell if the "radio guy" followed the installation instructions correctly......? He also threw in a cap/resistor "swing kit" . Stock carrier is at 2.5 watts. Carrier with the RFX95 on is 4.7 watts.
Thank you for taking the time to post the instructions.
Jimbo
Well worth every penny you paid, so far.
It sounds as if the RFX isn't amplifying the radio's transmit signal, but instead is oscillating. The signal the RFX is creating just sounds like static in the other radio.
If you have already installed the RFX with no problem at least five or six times by now you should have no trouble identifying any boo-boos in this radio's install.
And if this is the first one you have seen, your starting point will be the instructions to install it. A close step-by-step comparison from the instructions to this radio may reveal whatever it is that wasn't done quite right.
Or you could remove the RFX and restore the radio to stock.
Just sounds for all the world like an installation fault.
73
I wish they would go back to the old DX-100 and offer a unit with a bipolar. It is not as if HG does not exist and sell bipolars.
My first amp was a DX-100 on the back of an RCI2950 in 1991.
It is bad enough I have to have radio's with non-rf mosfets in them the last thing I want is a bolt on with another non-rf mosfet.
The only people that want these are people that either are unable to save up for something better due to a lack of impulse control and shops that want the cheapest amp they can purchase to sell to those with no impulse control!
These units are about as durable as 95lbs females attempting to become Navy Seals! It is almost as big of a waste of money as lighting a cheap cigar with a $50 bill! Better hope your antenna system is PERFECT!
My first amp was a DX-100 on the back of an RCI2950 in 1991.
It is bad enough I have to have radio's with non-rf mosfets in them the last thing I want is a bolt on with another non-rf mosfet.
The only people that want these are people that either are unable to save up for something better due to a lack of impulse control and shops that want the cheapest amp they can purchase to sell to those with no impulse control!
These units are about as durable as 95lbs females attempting to become Navy Seals! It is almost as big of a waste of money as lighting a cheap cigar with a $50 bill! Better hope your antenna system is PERFECT!
Yep. I like my transistors like I like my mental health, bipolar!
These units are quite durable, I have installed about 4 cases of them on drivers radios and have only had 1 unit come back with a blown fet. I finally put one on a road king 5640 for myself last week and I am very pleased with how that setup drives my 4x hg2879c amp.
In the second half of this video does a durability test on a longhorn N6 which uses the same erf-9530 mosfets as the rfx-95 :
Also the only mosfets I have had blow up while talking are "Real Rf Mosfets" The infamous fqp-13n10 has failed me with explosive results.
I've installed several 95hd's, very resilient. You can run them hot enough to drop the power completely out, let them cool down for 15 minutes or so and they'll bounce right back. Haven't heard of any shooting their wad due to swr as of yet on these 95's. I have a local that got his so hot, the standby circuit shot. The radio won't transmit with the amp off, but works great with the amp on, and still produces 110w PEP with the original 9530. Unhook the amp completely and put the radio back stock, then the radio will transmit barefoot no problem.
Now on to the older rfx75 and high SWR, lol...
The old school Stryker killer Galaxy DX-949 w/RFX75 I own has had the dummy load unhooked mistakenly for 20 to 30 minutes one time before I even realized it was unhooked. Believe it or not, the radio still produced 120w PEP without any issues whatsoever with all the original parts and original 7530. It's still kicking these 955's in the rear. I've had plenty of outrageous offers for this radio, I always tell them "No, it'll be destroyed along with the truck when I pass away", lol.
Remember, RFX75 amps are supposed to do only 70 to 80 watts PEP, but mine does 120w PEP. No mods to the radio at all, not even extra channels or strapped clarifier. The only issue with my rfx75 is when looking at it on a spectrum analyzer, there are 2 extra spikes on other frequencies other than the fundamental spike on frequency. Those other 2 spikes are less than half as tall as the fundamental spike.
Like I always say, "Old school is always better".
Now on to the older rfx75 and high SWR, lol...
The old school Stryker killer Galaxy DX-949 w/RFX75 I own has had the dummy load unhooked mistakenly for 20 to 30 minutes one time before I even realized it was unhooked. Believe it or not, the radio still produced 120w PEP without any issues whatsoever with all the original parts and original 7530. It's still kicking these 955's in the rear. I've had plenty of outrageous offers for this radio, I always tell them "No, it'll be destroyed along with the truck when I pass away", lol.
Remember, RFX75 amps are supposed to do only 70 to 80 watts PEP, but mine does 120w PEP. No mods to the radio at all, not even extra channels or strapped clarifier. The only issue with my rfx75 is when looking at it on a spectrum analyzer, there are 2 extra spikes on other frequencies other than the fundamental spike on frequency. Those other 2 spikes are less than half as tall as the fundamental spike.
Like I always say, "Old school is always better".
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