NEED halp on the Ramsey FM100B

A web search will yield the assembly manual for this but you probably already have it. A look at the PCB parts layout drawing on page 35 shows that the base and collector of Q6 are connected by the copper trace which runs under the body of Q6 which may need to be cut if Q6 is installed. It is a bit hard to see since there is a black mark on the drawing at this point but it looks like the C65-L6 junction is connected to HS1. You can check for continuity with an ohmmeter.

Probably the best way to get an answer would be to call Ramsey Tech Support and ask them.

Neil

What Radio8Z wrote sounds to me like the right answer to the question and explains how the output of the 100B is wired.

And I would expect that if you attach your antenna and get a signal at the expected distance, it also proves that the output is functioning properly because the antenna will only work if RF is present at the output.

Hi Radio8Z and Carl

I found the jumper on the circuit board and it did ohm out. Now another question

and you guys know I mainly do AM transmitions over the years and I thought

that playing around with the FM might be fun. This transmitter claims to go down

to 5 microwatts to 25mw.

What is the best way of measuring the 250uV at 3 meters ?

Or some trick I can use to be close to that output ?

Finding a field strength meter that can measure that low of a signal at 3 meter or

say 10ft from the antenna is not a easy device to find.

So how do you guys test for correct radiated power from the antenna.

Thanks

Bear in mind that the FCC limit is based on field strength and not output power on FM. Therefore, concentrate on the field strength and ignore the power specs.

The only means available to me has been to set the transmitter by adjusting the whip antenna length to get a range of about 200 feet on a portable radio (it will be more, maybe 600 feet, on a car radio).

If all you want to do, such as I do here, is cover the house then adjust the transmitter to do just that. If you want to broadcast to neighbors then go for the 200 foot setting.

Neil

The output of the FM100 is internally adjustable, I believe.  But even 5 microwatts probably will get you more than 200 feet.  However, as stated, you can use the internal telescoping whip antenna and you should be able to adjust it to take you down to the 200 feet (i.e., shorten it to deliberately create a mismatch).

The FM100 is a good transmitter - it doesn't compare in quality to the MS-100 but it still sounds great.

Sorry I made a mistake on the Ramsey Transimitter.

It the FM100B model. Boy does this thing have a large amount of audio circuits and

mixing circuits. It also has the Auto Duck to cut out microphone audio.

Anyways Wow I knew the MS100 and MS100S were really good transmitters.

With over night shipping the transmitter only ran me $303.53.

Shipping was close to $64.00 of it.

Now I remember dacade made the MS-100 and the MS100S anyways

I think they quoted me with shippingng around $505 for the MS-100 which

is mono and the MS100S which is stereo for Around $550 plus shipping.

Anyways one good thing about them you know they output the max power

of 250uv @ 3 meters. Also they are FCC certified. That one that scares me running this transmitter since you really have to guess at the the radiated power.

I wish there was a piece of test equipment to measure it. I might have been

better to spend a few hundred dollars more and know the transmitter is putting out

the correct field strength,.,

I wish a company would just put out a tool for us to measure the field strength since

the FCC does say we can design and build our own transmitters. That is in the FCC

rules and the problems there is even if we design a transmitter it very hard

to measure the field strength. I thought about using a Oscilloscope since it could

see down to less than 250uv. My guess would be to hook a half wave dipole

antenna up to the Oscilloscope and see what signal strength it shows at 3 meters.

There alot of O-scopes that go above 100 mhz in frequency,and they can

measure down into the microvolts range.

Not sure if this is the best way to measure a field strength but it is one way of doing it.

Thanks

Simple....U6 the GAL-5 is actually the final output that puts 25 MW to the antenna.

With the 100B EX or getting the add on kit for the extra power the GAL 5 now is just the driver and the power transistor is now the final further amplifying the GAL-5 output.

• Be careful of the GAL-5...any static from your finger touching the antenna will blow it! It's very fragile!
• A  good idea to get extras online
• Don't know why these black dots appeared and the text took on this format, and can't be bothered to try to fix it!!!

Mark

Hi Mark

Thanks for the info on GAL 5. I will make sure I buy some extra ones.

Also very suseptable to high SWR

Dear Sir

    Does the GAL 5 go out easy to a high SWR,or is the transmitter having

a higher output impedance than 50 ohms. ???

Anyways I thought about the MS-100 transmitter,but it appearance is not as

nice as the Ramsey transmitter.

I was wrong about the MS-100S the stereo version is selling for $595.00

right now. So is it worth it. I know that I will be getting a Range Master

for the AM broadcasting,so I can get some good coverage.

Now If you took the MS-100 transmitter and placed it into a PVC type box

and mounted it at the top of a tower ,would this increase it range sinde it would still

maintain it 250 UV@ 3 meters. I just know FM radio is line of sight and the

higher the antenna the further the coverage. would the MS-100 get more

coverage it I get it really high mounted in a box on a tower ???

It sound like the Ramsey FM100B is not a good transmitter by what I am

hearing.

Thanks

Yes, you can put an MS-100 in a weatherproof box and get it high up - it works very well.  I did it on Bowen Island, put it on a rooftop of a building which was at the top of a hill overlooking my intended coverage area - line of sight with no obstructions works amazingly with Part 15 FM.  I fed audio and power to the transmitter with CAT-5 cable (about a 75 foot run).  It ran that way for several years, 24/7, with no issues - the Decade is built like a tank, with quality components.

I've also owned and experimented with an FM-100B.  Aside from the legality issues (it's much easier to get it to conform to the slightly lax'er Canadian regulations than the U.S. ones), it's simply not as high a quality a transmitter.  Plus it's much larger and heavier, making it more difficult to fit inside a weatherproof enclosure.

You can also look at the Ramsey FM-30b which is same 25 MW power as the basic 100B but much smaller and lighter but uses the GAL-5 so you have the same problem of blowing it easily.

You can also take a look at the ACC-100 from Progressive Concepts which is built and small with NO surface mounts...all discrete components, made in US and has good filtering on board so little hum even with any power supply AC or DC. Fcc certified as comes right out of box with number. Output transister is easily obtainable anywhere 2N-5109. Great audio and I am using. Same price as Ramsey FM 30B but certified.

There is a provision for power increase with manual.

And NO I'm not one of their sales people!

Mark

I do have one more question. Is there any good way to test for the 250uv@3meters

that is required by the FCC or anyway to at least get into the ball park of that

power level.

Thanks

Sean,

If you re-read this thread you will find some suggestions.

Neil