Ramsey FM25 and FM25B

uses BA1404 Stereo IC,

25B uses BH1415F Stereo IC and i beleive updated finals.

Ramsey 25 also was strappable for 1 watt of rf power.

Give me a bit of time and i will dig out an old pdf that shows where the jumper goes, not that it's legal or important. Also, my personal favorite out of the two is the FM 25, it had much better sound quality and I feel the pre-emphasis wasn't as harsh as the FM 25 B.

I wish i still had the FM 25, i am still running the FM 25 B which at max power does close to 25 miliwatts, mine runs at 1 mW into a dipole pinned to the wall above my desk.
Both seemed to be well filtered too so no spurious emmissions that i could detect.

Both nice rigs, i just like the FM 25 a bit better.

Good luck and hopefully i can dig up that schematic for you Tim.

is strappable for 70mW not 1W your thinking of the FM35B which had a 1 watt version and the FM100B which also had a 1 Watt Version

none of the FM25's would do 1 Watt.

Maybe mine was special? lol

At any rate, here is the pdf. manual for the FM 25 a
and the FM25 b
 Another difference between the two, the 25 a not only relied on dip switches to change frequencies, it also had a button which locked it on frequency while the 25 b , you usually just have to set the frequency on the dip switches and allow the transmitter to lock, i have always had to turn it off and back on again to get the pll to lock.

I have had the 25 B for almost 10 years now, very reliable.

Barry of BBR World Wide

"Challout. Shoolenge?"

Before you know it, we will have to use words like transmisser or sender.. geeez lol

when i get a chance they will be added to the classic hits part 15 forum library

started out with an FM10 in HS the i've had the 25, 25a, 25b over the years. i'd like some more FM 25's to throw on my service monitor to see if they actually output 25mW, i have my doubts they do though. 

Back a few years ago, my family and I lived in London,Ky we were running Rock 95 Seven which later moved to 105.3. A friend had a Ramsey PM50 (i think that's right)  digital power meter.

We put that on the Ramsey 25 B between the transmitter and antenna, 18 mW was the best it would do as far as power goes. That was after carefully tuning it up following the instructions in the manual.

The antenna was a clone of the Ramsey TM-100, a folded dipole that probably has 0 dB gain, the 25 B rf output control was turned up to maximum and reading showed 18 miliwatts.

I think the lowest reading was zero, if i recall correctly, the meter would not show anything below a few mW's. I marked the board right next to the variable control at 2 mW for future reference using a sharpie marker.

At full power into that dipole at 12 feet above the ground, Rock 105 three could cover 1/4 mile in most directions, more if you were directly line of sight with that antenna and much less if you were directly North of my house due to the hills blocking the signal.

With 2 mW we barely covered the mobile home park and apartment complex, building penetration was limited to 200 feet give or take.

Barry of BBR WorldWide

Tim, I don't know what the specifics are on your FM25, but it would be interesting to test it adjusted to its lowest power level - it might have more of a chance of being legal.

I wonder why Ramsey had to pack up and leave? Their stuff was a lot of fun and reasonably priced. Then again, lots of companies seem to lose their vision, owners get tired of running them and want to do something else.

At least I haven't heard of them selling the name to someone else, that nearly always is a disaster, or at least a shadow of the former company, when new owners don't know what to do with the specialty that was created.

I can think of many big companies, like Kodak, General Electric, Jensen. Then there are LPB, Panaxis, Heathkit, others that have melted away somehow.....

Good to see the manuals, I wonder why there are no schematics in them?

Too many hassles from the Dudley Do-Right crowd and complaining about certification. It's better to pack up then they get in trouble because of the Dudley Do-Right folks.

There should be a cartoon and we could call it captain 15:239.   the cartoon character would have antennae sticking out the cartoon character would have antennas sticking out of his head and then the back of his head would be a big meter.  when a person is over a flashing red light goes off and Captain 15 - 39 would holler out by hooker by crook you're going to jail.

Because its so bad to follow the rules.

Would also love to know in actual field tests, if you can do this, how much signal strength you would need at 3 meters to get a reading of 100uV/M@30meters(Canada's BETS-1) to know really how much more signal strength we are allowed here. I think there would be some interest in this.

Mark

... how much signal strength you would need at 3 meters to get a reading of 100uV/M@30meters(Canada's BETS-1) to know really how much more signal strength we are allowed here. ...

Below is a NEC4.2 calculation of this, for the conditions stated there.

The fields vary as functions of the horizontal distance from the transmit antenna, height above the earth, the frequency, and earth conductivity along the path.

They also vary based on reflections/obstructions from other than the surface of the earth.  In this calculation, those were assumed to have zero effect.

The r-f power needed at the feedpoint of the transmit antenna to produce these fields is less than one microwatt.

That power level is actually talked about right in the Bets rules.