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Hello! RM Italy KL 503 HD vs 505v thoughts?

Best amp choice for Andrew's CB base station

  • KL 503 HD

    Votes: 2 40.0%

  • KL 505v

    Votes: 0 0.0%

  • Other

    Votes: 3 60.0%

  • None/Don't amp

    Votes: 0 0.0%
  • Total voters
    5
  • Poll closed .
arudlang

arudlang

Member
Dec 7, 2021
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Hi all!

I have been reading information all over the internet, trying to make a decision. I just got into 11 meter/CB radio via my brother and I'm probably on my way to exploring a ham license at some point in the future, but for the moment staying in the CB world trying to keep things simple and costs down for this new hobby.

My brother gave me an old Hy-Gain CLR-2 antenna which I mounted on my roof and paired with a Uniden 980SSB (and a cheap Astatic SWR/power meter). This setup is receiving well, I hear a lot of good skip but of course tend to get buried by everyone else if I try to call out. I have some local contacts but they are at the fringes of my range and I am in the static level for most of them since I don't have an amp yet.

I would like to be heard better both locally and on DX, so I was thinking about throwing an amp into the mix.

I was going to send off for an RM Italy KL 503, probably the HD version to avoid needing to open up my radio and reduce the 3 watt dead key, but in reading on this site and others I have seen advice to consider stepping up to the 505v instead.

I noticed the 505v has a much broader range of 3-30MHz vs the 25-30MHZ range of the 503. I assume the wider range would give better odds that this amp will be useful to me in future ham endeavors but I don't really know.

I have read, and re-read this thread about 10 times now
https://www.worldwidedx.com/threads/rm-kl503-ssb-compatibility.262260/

And I think if I happen to receive a 505v with the 11m block I could be comfortable snipping C1 and L4 to eliminate that issue. I'm a bit of a hack but not a total novice to electronics.

From there my only other concern with the 505v would be whether I am overdriving it with 3-3.5 watts of deadkey. My 980SSB is not overly powerful and bone stock, I don't really want to open it up although I could probably manage to lower the DK if I had to. Thats where the 503 HD was appealing, looked like it could handle whatever out of my stock radio just plug and go.

So I'm trying to figure out where to go from here. Both those amps look like they would come out just under the limit of what my CLR-2 antenna should handle and I would not be running wide open, but I would like to have that ability to bump up 50-100 watts to be clearer to my local contacts and maybe upwards of 200 for DX days.

I've ruled out any amps bigger than this because 1) cost is going to get me in trouble with my wife, and 2) I don't want to have to get a new antenna for a while, this one only handles upwards of 300 watts before the base is likely to go out, from what I understand.

Should I spend the extra money for the 505v to have more flexibility with what to use it with down the road? Or will the 3-25MHz range not really be useful and save the money to go with the 503? Would the 505v sound/work better?

Appreciate any opinions. Kinda hoping @Handy Andy will chime in as he seems highly knowledgeable in his other posts I have read. I'm trying to figure it all out constantly researching but its like drinking from a fire hose.

By the way, either amp I will add the 27/586 low pass filter. I don't want to be making huge a mess on the airwaves. It's another cost though and I think a certain lady around the house here is going to about croak if I tell her I want to buy a $340 amp (plus the $42 filter). I'm going to get hit with the "CB was supposed to be the cheap radio hobby!" which... it is but I think I could personally justify the price jump from the 503 HD to the 505v if I had good enough reasons to. Hoping that's where you guys can set me straight. Either way this amp is going to cost way more than the rest of the money I have into this base station so far which is not going to be popular around here. I was originally looking at the KL 203P but I really want to be able to vary the power a little more than just on/off and it seems like I might as well run up against the upper end of what my antenna can handle, otherwise I'll just be buying another amp down the road and sitting with a 203P on the shelf...

Even if there are no replies thanks for all the great info you all have shard on this site! Learning a lot.
 
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https://pa0fri.home.xs4all.nl/Lineairs/Frinear400/frinear400eng.htm

Now before you go all "it's too hard/complicated/expensive/dangerous/TOOBS!/am I going to have to sacrifice a kitten ...

This is about the minimal tube amplifier. The EL/PL 509/519 are still available, their amerikanski cousin the 6KG6A , not so much.

The construction is not that difficult and the circuit well thought out. As compact as it is it could be placed in a slightly larger box.

https://qrpblog.com/
This amateur may yet be selling in semi kit form. If you get serious I have a Kalafornication Konnection for the LDMOS devices.

If you price out the $$/watt including the 50v switching brick(s), or linear supplies it starts looking like a real bargain.

The entry level ceramic slug is the 4CX250B. Other than the power supply which is lethal , the rf deck is easy. Select an established 50MHZ project and re-do the tank as 27MHZ .
Admittedly this is a somewhat advanced project but assistance with the tank circuit and bias (if not swamped input and grid drive) is available here.

The SB-220 and other established platforms converted to 11m.
Good luck, YMMV, some hacks are better than others, nature abhors a vacuum, High current smells like barbecue, high voltage smells like chicken, unplug the dryer. tune and load, space heater, your voice coming out of your neighbors refrigerator, real amplifiers set fire to antennas, can you hear me now ?
 
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kopcicle said:
https://pa0fri.home.xs4all.nl/Lineairs/Frinear400/frinear400eng.htm

Now before you go all "it's too hard/complicated/expensive/dangerous/TOOBS!/am I going to have to sacrifice a kitten ...
Click to expand...

I hear what you're saying. Building an amp does sound like a fun project. One of my issues with it right now is that I am buried in more partially-started and ready-to-start projects than I could catch up with in an entire year. Heck... I haven't even finished my workbench build I started months ago... got the workbench built and the pegboard hung but still have some wiring to do.

I'm not saying never, but until I at least have a different antenna (or rebuild this one) to handle the wattage I think pay-to-play will be a big enough speed advantage to be worth it this time around.

Skip was rolling pretty good around lunchtime today and a lot of good chatter going on, I can hear it but nobody can (usually) hear me back, I'm looking for a fairly fast and easy fix so I can keep working on my other stuff.

I already am working on a plug-in external scanning mod for my 980SSB. I noticed that I can successfully change channels on the 980SSB using the channel changer buttons on the stock mic off my president bill radio. I am going to probe out the pins for changing channels and program a microcontroller to iterate channels and then listen for a squelch break on each channel by plugging it into the external speaker jack. My custom scanner will pause longer on each active channel, be able to skip specific channels, record and report which channels have been active lately, possibly even record sound bites of what was heard and send my phone an alert, etc. I've already got a set of the 6 pin connectors to put my channel-changing microcontroller inline with the mic. I started this project because I feel like I keep missing potential contacts but I often can't be sitting directly next to my radio all the time. My custom external scanner mod plus the Uniden wireless mic hopefully will help me out with that.
 
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The20poundhammer said:
More money into your antenna system would be more bang for your buck. If your not going to get to around 600 watts or more I would go that route. Also if your thinking about ham stuff get something like an 811 or other comparable tube amp which can be bought used reasonably and handle all the bands.
Click to expand...

My CLR-2 may be old but it seems to work pretty well. Good SWR under 1.5 and I think I can get it a little better this spring when the snow melts and I can get back on the roof again to adjust it a bit more. If I spent that same budget on a new antenna I'd get what... an A99 or a Sirio 827? (assuming all new better coax too and such). I know I am pretty green but its hard to imaging that putting my stock 3.5 watts into slightly better coax into an A99 is going to outreach putting 200-250 watts though existing decent coax into my CLR-2.

I've been able to make a 15+ mile local contact on SSB with the CLR-2 and got one "miracle callback" on Christmas day from Oregon back to me in Minnesota, I think it works pretty good especially when conditions are great, but a lot of the time conditions are not great and I would like to overpower that and still make good local(ish) contacts. I would also like to be able to butt-in at least a little bit when the skip is rolling and everyone is on all at once.

Seems like everybody and their brother has the KL 203 but I can scrimp up enough to step up to the 500 series if it helps the handful of things about my location I can't change. I've already got the antenna pretty high, tip of it is probably 55-60 feet but there are still a few trees a bit higher and I have a big hill to the south that's hard to throw over.
 
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This isn’t directly to your question, but I’ve a half-dozen RM amps. All used in mobile.

The 503HD is not one of them.

But I’m posting about experience with the KL-203 (and 203P). I’ve bought them two (2) at a time for about $115/shipped.

I don’t recall everything about your posts on RadioRef, so just let me add that the 203’s handle heavy use well (with the proviso your diligent reading has given you understanding about amps, and then, RM ITALY Amps), that at this price (starter pack) you can iron out system bugs and have good amps for mobile later on.

I ran my larger amps mobile and decided the benefit didn’t outweigh problems of where to mount in the Kenworth.

Back to the tried & true 203s.

I’ve run a half dozen radios with them, and not paid a lot of attention (close) to JUST how much I’m putting through (low, sure, but . . . .)

Good luck.

.
 
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