SWR Meter

[perrybucsdad]

I just picked up the Yaesu FT-8900 radio yesterday which has four bands on it (10M, 6M, 2M, and 70cm). I only have my general license so I won't be using the 10M (FM on the 8900) anytime just yet, and 6M is really quiet in my neck of the woods, but when I was researching antenna's for this unit, I see Diamond has a 4 band antenna out there for it that requires some tuning. I didn't get that antenna as I have a 2M/70cm antenna that works just fine, but should I be concerned with my SWR in the 2M and 70cm bands? One person told me there is nothing I could do about it even if it was off, but others say that may not be the case.

Anyhow, I was looking at SWR meters this past lunch break, and I'm all confused on if I need one, and which kind should I get. When I read the reviews on eHam, they are all over the place as to quality. Some say go with dual needle meters as they are the easiest to use, others say stick with a single needle design.

Can anyone help educate this new ham on what I should be looking at and if I should even be concerned.

Thanks,

[n9mxq]

Yes, SWR matters everywhere. Any antenna can be tuned, some are just trickier than others.

I have a Diamond SX-1100 single needle that I use. But it's all in what you like. Find a meter that covers the bands you'll use, get to know it well, and you'll be fine. Check your antenna at installation, and every year or so after and you'll keep your finals happy and healthy.

[perrybucsdad]

Thanks. Why do some of them allow you to calibrate them (single needle designs) while others don't need to be calibrated (double needle)? Is this because the double needle measures both forward and reflected at the same time so there is no need to calibrate?

[LtDoc]

Those double-needle meters are a forward reading and reverse reading watt meters. Where the two needles cross is the scale for SWR. It's just another way of doing it using two meters instead of one. The only 'calibration' required for them is making sure you are on the right wattage scale.
The circuit is very simple, the biggest difference is in that one meter or two thingy. You can do exactly the same thing just using two watt metters but hooking one of them up backwards. Good is big readings on the forward meter and none on the backwards meter. Then you get to do the calculations to figure the SWR.
- 'Doc

[Robinsmark]

John: I use the BIRD 43 wattmeter. I have worked for several 2 way radio shops and they use the BIRD 43.
I have 2 of them now and they are used daily. The are pricey but reliable, and I believe what they say before I would believe what some other wattmeter says. Just my own prejudice!

[N5TWB]

Originally Posted by perrybucsdad

I just picked up the Yaesu FT-8900 radio yesterday which has four bands on it (10M, 6M, 2M, and 70cm). I only have my general license so I won't be using the 10M (FM on the 8900) anytime just yet, and 6M is really quiet in my neck of the woods, but when I was researching antenna's for this unit, I see Diamond has a 4 band antenna out there for it that requires some tuning. I didn't get that antenna as I have a 2M/70cm antenna that works just fine, but should I be concerned with my SWR in the 2M and 70cm bands? One person told me there is nothing I could do about it even if it was off, but others say that may not be the case.

Anyhow, I was looking at SWR meters this past lunch break, and I'm all confused on if I need one, and which kind should I get. When I read the reviews on eHam, they are all over the place as to quality. Some say go with dual needle meters as they are the easiest to use, others say stick with a single needle design.

Can anyone help educate this new ham on what I should be looking at and if I should even be concerned.

Thanks,

Most dual-band antennas do not need tuning but there's nothing wrong with checking it out with a meter to run some experiments to learn about the antenna and the proper use of the meter. That's what ham radio is all about: learning. Initially, you should just slide the antenna up or down within its base sleeve to observe the effect on the match. Since it's a dual-band, you'll need to observe the effect in both bands to analyze whether making a permanent change will achieve a desirable result.

Why not use the 10 meter FM portion of your new radio? Your General Class privileges cover that. I understand if there are no repeaters in your areas but propagation on that band can be interesting. Again, experimentation and learning are central themes of ham radio. For many, that's where the pleasure is.

[perrybucsdad]

Thanks everyone for the comments. I'll head over to the store and see what I can find today. I know the two meter designs by Diamond are a little less expensive than the single meter designs. Not sure why that is the case, but we'll see what they have. I'd love to be able to afford a Bird unit, but that's above my budget at this point. Maybe when I can afford the nice HF all mode base station I'll pick one up.

Originally Posted by N5TWB

Why not use the 10 meter FM portion of your new radio? Your General Class privileges cover that. I understand if there are no repeaters in your areas but propagation on that band can be interesting. Again, experimentation and learning are central themes of ham radio. For many, that's where the pleasure is.

N5TWB, I don't have a general class license yet, just a Technicians.... Tech's can only use 28.3 - 28.5 in SSB Voice AM only, so I'm out of luck for the time being. I'd love to get on it and play around with it but I will have to wait a month or two while I study up.

[perrybucsdad]

Well, I picked up the Diamond SX400 this morning, and if I did everything correctly, it looks like my SWR is about 1.8 or 2.0 to 1. That seems a little high for a manufactured antenna and my rig. I'll double check it later. This also was only on one frequency (430.000). I wish I could find a good Youtube Video on how to use this. THere are a bunch of CB videos, but I would prefer to find someone who is a HAM who has one. I'll keep looking but if you know of one that is instructional, please let me know.

Also, am I correct in my understand that to find the resonant frequency of an antenna, I want to take measurements along an entire frequency band? Meaning, if I want to find the resonant frequency for the 70c band, I would take readings from 420.00 mHz - 450 mHz and then find the lowest reading in those to identify the resonant frequency for my antenna on that band? Or, is there a different way to do it?

73's

[n4yek]

Originally Posted by perrybucsdad

N5TWB, I don't have a general class license yet, just a Technicians....

That's not what you said in your first post, that's why he asked. I was going to ask you but he beat me to it.

Here is what you wrote in post #1

Originally Posted by perrybucsdad

I only have my general license so I won't be using the 10M (FM on the 8900) anytime just yet......

[perrybucsdad]

Originally Posted by n4yek

That's not what you said in your first post, that's why he asked. I was going to ask you but he beat me to it.

Here is what you wrote in post #1

Oops... sorry about that. I must have been dreaming about my general. Only a lowly Tech here. I can see why there was the mix up.

[N5TWB]

Originally Posted by perrybucsdad

Well, I picked up the Diamond SX400 this morning, and if I did everything correctly, it looks like my SWR is about 1.8 or 2.0 to 1. That seems a little high for a manufactured antenna and my rig. I'll double check it later. This also was only on one frequency (430.000). I wish I could find a good Youtube Video on how to use this. THere are a bunch of CB videos, but I would prefer to find someone who is a HAM who has one. I'll keep looking but if you know of one that is instructional, please let me know.

Also, am I correct in my understand that to find the resonant frequency of an antenna, I want to take measurements along an entire frequency band? Meaning, if I want to find the resonant frequency for the 70c band, I would take readings from 420.00 mHz - 450 mHz and then find the lowest reading in those to identify the resonant frequency for my antenna on that band? Or, is there a different way to do it?

73's

I'd recommend checking your antenna with the radio set for 445.000 for the UHF portion and 146.000 for the VHF. Those frequencies are right in the middle of those bands and should better represent where the antenna is likely set by the manufacturer. Now, if you have a group of repeaters you plan to operate in your area that have inputs that are significantly different from the center of the band, then recalculate a nearby frequency that would center you in that cluster of inputs and check it again. Experiment as previously described with the rod higher or lower in the base sleeve. If you follow this process, you're likely to find your SWR to be acceptable.

There's a better tool for doing what you describe in the second paragraph. It can be done with an SWR meter but it's more easily done with an antenna analyzer. MFJ makes several versions but they are not cheap. If you belong to a club, you might inquire if the club has one for use by members or if a member is willing to come out to assist with an analyzer he owns.

You might also want to refer to your study materials on the subject of the VHF and especially the UHF band plans. You're overthinking this trying to get your radio and antenna to be happy from 420-450 when the band plan puts the activity mostly 440-450.

[perrybucsdad]

Thanks N5TWB... yes, I over think everything, and I'm sure a simpler approach is what I really should do. I recall seeing a chart someplace that someone had done that graphed their SWR over many frequencies on a band to find their resonant frequency. I presumed they did this by just checking the SWR at all those frequencies. I'm joining a club and have a few Elmers who I can connect with in town who might be able to lend a hand with the antenna analyzer.

Dumb question on the SWR meter as the directions don't really say. Each time I change frequency to check the SWR, should I re-calibrate? I don't think it would hurt in doing so, but is in necessary (wish I would have found that dual needle SWR meter to simplify the process).

Thanks for your help..... 73's

[N5TWB]

Yes, recalibrate when changing frequencies on a single needle meter.

The chart you saw could have been created by several methods that have varying levels of accuracy, ease, and prices. Good luck on working with an Elmer to assist your development in the hobby.

[Ed_Seedhouse]

Originally Posted by N5TWB

Why not use the 10 meter FM portion of your new radio? Your General Class privileges cover that. I understand if there are no repeaters in your areas but propagation on that band can be interesting.

Why not indeed?

Last couple of days 10 has been pretty lively. I am currently (15:20 Pacific Standard time.) listening to a ham in Texas (K5GVP) talking to JA3ETE in Japan. My QTH is the south end of Vancouver Island and I can hear the K5 is hitting S5 and I hear the odd word from the ham in Japan. Propagation to JA land might well pick up as dusk approaches. Antenna is a random wire about 40 foot long.

If I had a transmitter I'd definitely be giving it a try.

[perrybucsdad]

You sure you are listening to 10M FM Ed and not 10M SSB? I don't think too many people even use 10M FM but I could be wrong. I know I have not heard any traffic in my neck of the woods.

As far as transmitting on 10M FM, I will have to wait to do that as I only have my Tech and I can't transmit in FM on any part of the 10M band. Just a small portion of 10M SSB.

[Ed_Seedhouse]

Originally Posted by perrybucsdad

You sure you are listening to 10M FM Ed and not 10M SSB?

I don't believe I mentioned FM. I was listening to SSB signals at around 28.400.

[perrybucsdad]

Not that it matters Ed, but in the above discussion the radio I have is an FM only. If I had a HF rig with SSB, I would be listening to that all day as I'm sure there are tons of great QSO's going on. Unfortunately, the FM portion of 10M not so much.

[gewecke]

Originally Posted by perrybucsdad

Oops... sorry about that. I must have been dreaming about my general. Only a lowly Tech here. I can see why there was the mix up.

There's nothing wrong with being a tech, as long as it offers the privileges and bands you want.
Personally, I'm all good because I have no use for h.f. ( horrible frequencies)
Vhf/ uhf requires a lot less rf out and physically smaller antennas which are more efficient.

73,
n9zas