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Siltronix fs-301 meter questions
- Thread starter Eldorado828
- Start date
It is not a true peak reading meter. The Siltronix FS-600a was but this one does not have power or battery which is required for a active peak reading meter. I liked that Siltronix series as they have nice big displays but those are OLD meters now (vintage) so be aware of that. Some meters will say "PEP" but unless they have an active powered circuit it won't be true PEP.
That being said, one of my favorite unpowered meters of all time is the radio shack 21-534. They are surprising accurate in the lower scales and usually fairly inexpensive although I see them for $50 now on eBay (I used to find them for $20). When tested against a PEP meter I find they are usually about 10%-20% low on the 200 watt and 2000 watt scale for peak but almost right on with the 20 watt scale. I have two of these that must be 20-30 years old and they still work like new. They are very light and portable so great for mobile testing or field day type work. SWR function on these is very good.
I was thinking the other day it might be helpful to make a list of currently available peak reading meters (not vintage ones), perhaps other people can add to the list as well and we can create a new bookmarked post. Might also be handy for people to add their ratings/reviews of each
Telepost lp-100a
Telepost lp-500
Telepost lp-700
Bird 43P
Daiwa cn-901HP / HP3
Palstar PM2000A / AM
Ameritron AWM-30B/30BX
MFJ-815D
MFJ 826B
Coaxial Dynamics 83000 series
MFJ 868B
That being said, one of my favorite unpowered meters of all time is the radio shack 21-534. They are surprising accurate in the lower scales and usually fairly inexpensive although I see them for $50 now on eBay (I used to find them for $20). When tested against a PEP meter I find they are usually about 10%-20% low on the 200 watt and 2000 watt scale for peak but almost right on with the 20 watt scale. I have two of these that must be 20-30 years old and they still work like new. They are very light and portable so great for mobile testing or field day type work. SWR function on these is very good.
I was thinking the other day it might be helpful to make a list of currently available peak reading meters (not vintage ones), perhaps other people can add to the list as well and we can create a new bookmarked post. Might also be handy for people to add their ratings/reviews of each
Telepost lp-100a
Telepost lp-500
Telepost lp-700
Bird 43P
Daiwa cn-901HP / HP3
Palstar PM2000A / AM
Ameritron AWM-30B/30BX
MFJ-815D
MFJ 826B
Coaxial Dynamics 83000 series
MFJ 868B
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I understand that it may not be a true peak meter but was wondering if it was peak or average nonetheless. Thank you for your reply
It's a good idea on getting the current true peak meter available as not all of us want to drop the coin for a bird meter.
I have the cn-901 but it's a little generous on the readings so it's in line with one of the station radios. Looking for something to go in the test bench that can be fairly accurate when working on my own projects.
It's a good idea on getting the current true peak meter available as not all of us want to drop the coin for a bird meter.
I have the cn-901 but it's a little generous on the readings so it's in line with one of the station radios. Looking for something to go in the test bench that can be fairly accurate when working on my own projects.
If it doesn't have a AVG / PEP switch then it's definitely an AVG ONLY meter. If it's not an active PEP circuit but has a PEP switch you can expect that it won't hold as well and may not be as accurate for PEP.
You also may want to run a low pass filter between the radio and meter if your active meter is reading higher than you think it should be.
All that being said, some of the active peak meters can be just as inaccurate as any other meter. I honestly don't trust any meter to be "completely accurate" unless I happened to watch the factory technician calibrate it in front of me
I've tried a lot of them and many of them seemed to return numbers that were higher than they should have been. For example the palstar are fairly well thought of but the brand new one I tested was off and I had to send it back to be re-calibrated. Afterwards it was fine but I've had this experience with other brand new meters that were supposed to be "quality meters".I think we all have to accept that for $150-$350 you're not guaranteed accuracy - you might happen to get it, you might not.
I am interested to try out the Telepost series as I've heard good things about their accuracy but of course they cost a lot more coin.
Those Siltronix FS-600a and the Yaesu version are pretty good old peak meters though, if I happened to see one under $75 I'd probably take a risk and buy it. I like the meter display on those - so many of the newer meters don't have a good display for low power increments.
I like the look of the MFJ Big Meter but never bought one because I just wasn't sure I'd trust the readings.
I guess the question is - how much accuracy do you need? My biggest need is in the low power scale. Under 20 watts I want accuracy within 0.25-0.5 watts if possible but of course most of the time I don't need a peak meter for what I'm doing in that scale anyways.
On a 200 watt scale I don't really care if it's off by 10-20 watts.
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Which is something most people fail to understand and instead think Bird is the final answer in accuracy.
Error of +/- 8% at 100 watts means it could show 92 and that would be still within spec right?
Or 920 when doing 1000?
If that's true then I imagine a 43P that's 15 years old and hasn't been recently calibrated might be even further off the mark.
Would a digital meter such as a Telepost be less likely to show error over time because it isn't relying on a mechnical meter movement?
Or 920 when doing 1000?
If that's true then I imagine a 43P that's 15 years old and hasn't been recently calibrated might be even further off the mark.
Would a digital meter such as a Telepost be less likely to show error over time because it isn't relying on a mechnical meter movement?
According to this guy it is the "Gold Standard"
https://reno.craigslist.org/ele/d/silver-springs-bird-model-43-wattmeter/7330920278.html
The 30 uA meter is pretty stable, until it's been dropped too many times. Or too far.
Dirty secret of many Bird elements (slugs) is a trimpot hiding inside. In all fairness, some elements contain only 1 percent resistors for calibration. But a lot of them contain a trimpot. Pry off the ID plate and you'll probably see one. Or maybe a hole the size of a skinny screwdriver blade with a trimpot behind it.
Nothing is forever.
73
Dirty secret of many Bird elements (slugs) is a trimpot hiding inside. In all fairness, some elements contain only 1 percent resistors for calibration. But a lot of them contain a trimpot. Pry off the ID plate and you'll probably see one. Or maybe a hole the size of a skinny screwdriver blade with a trimpot behind it.
Nothing is forever.
73
And ideally the slugs you use should be calibrated to the meter they are used in for best accuracy.
Anyone that does not understand all the facts can make any claims. Make no mistake, Bird meters are indeed very well made, however the accuracy is no better than many other meters of decent manufacturer. The huge advantage is that they are stable and will maintain accuracy as long as they are calibrated, which is another great feature. Simply being able to calibrate them is a huge bonus. Also the fact that the RF pick ups are individual slugs means that the standard accuracy can be maintained over an extremely wide bandwidth.
I've been testing the Daiwa 901HP for a couple of weeks and I'm really liking the size and rubber feet that keep it from moving around. PEP hold is nice but damn it can take a long time for the needle to drop back.