Need help with VHF transmitter kit

[mndflmr]

Hello all,
Recently I purchased a low-power VHF transmitter kit from Ramsey.
After building this kit, I have discovered that it will not work for
my purpose. I am trying to transmit audio and video about 20 feet from
a satellite receiver to my bedroom. The power output from the
transmitter is so low that the picture quality is very poor. I am a
novice and I am hoping the experts that use these newsgroups can help
me. I will post a link to the Ramsey kit manual. Will some of you
guys please take a look at this manual, and suggest some simple
(hopefully) methods to increase the power of this transmitter? There
is no chance of interference with the neighbors, as my nearest
neighbor is far away. Any help would be greatly appreciated. If you
want to email the response, please send it to [email protected]

Here is the link to the kit manual:
http://www.ramseyelectronics.com/downloads/manuals/TV6.pdf


Thanks for any help

Joe

 

[COLIN LAMB]

The transmitter would necessarily comply with the FCC rules. Modifying it
to increase power is illegal.

If it does not transmit the distance represented, then either the
construction is wrong or the specifications are wrong.

Colin K7FM

 

[Tim Wescott]

Hello all,
Recently I purchased a low-power VHF transmitter kit from Ramsey.
After building this kit, I have discovered that it will not work for
my purpose. I am trying to transmit audio and video about 20 feet from
a satellite receiver to my bedroom. The power output from the
transmitter is so low that the picture quality is very poor. I am a
novice and I am hoping the experts that use these newsgroups can help
me. I will post a link to the Ramsey kit manual. Will some of you
guys please take a look at this manual, and suggest some simple
(hopefully) methods to increase the power of this transmitter? There
is no chance of interference with the neighbors, as my nearest
neighbor is far away. Any help would be greatly appreciated. If you
want to email the response, please send it to [email protected]

Here is the link to the kit manual:
http://www.ramseyelectronics.com/downloads/manuals/TV6.pdf


Thanks for any help

Joe

The best and least expensive way at this point is probably to use better
antennas on each end. What are you using now?

 

[Robert Baer]

The best and least expensive way at this point is probably to use better
antennas on each end. What are you using now?

Ten milliwatts is more than enough for a measly 20 feet, and i am
sure the kit puts out more than that.
Match (tune) the antennas at both ends for starters, orient them to
point at each other is the next step, and have a decent (sensitive)
receiver.
I only had a matched antenna at the (sensitive) receiver, and got
about 100 or so feet at 10mW.

 

[Frank Raffaeli]

Hello all,
Recently I purchased a low-power VHF transmitter kit from Ramsey.
After building this kit, I have discovered that it will not work for
my purpose. I am trying to transmit audio and video about 20 feet from
a satellite receiver to my bedroom. The power output from the
transmitter is so low that the picture quality is very poor. I am a
novice and I am hoping the experts that use these newsgroups can help
me. I will post a link to the Ramsey kit manual. Will some of you
guys please take a look at this manual, and suggest some simple
(hopefully) methods to increase the power of this transmitter? There
is no chance of interference with the neighbors, as my nearest
neighbor is far away. Any help would be greatly appreciated. If you
want to email the response, please send it to [email protected]

Here is the link to the kit manual:
http://www.ramseyelectronics.com/downloads/manuals/TV6.pdf

Something is broken. Either at the transmitter or receiver. A
mis-matched antenna couldn't possibly account for a poor quality
picture at 20 feet. I presume this transmitter is designed to transmit
a signal via antenna to source and not over transmission line. Here
are some probable causes:

1) The transmitter output stage is broken.
2) The receiver is not working (see how well it picks up other
stations).
3) The antenna at either end is disconnected.
4) There is Radio-frequency interference (RFI) such as from a
computer.

Frank Raffaeli
http://www.aomwireless.com/

 

[Rich Grise]

Its my guess that the Transmitter has insufficient bandwidth and power
for that broad of a signal.
one must not forget the amount of band space a single channel takes.

Did the OP go through the alignment procedure? Did the OP bother with
antennas at all?

Did either of you read the kit doc?

Thanks,
Rich

 

[mndflmr]

Thanks for all the hints. I have messed around with different receive
antennas and I have finally gotten a usable picture. It kind of
surprised me that I had to go through so much trouble at such a short
distance. I am afraid I will never understand RF. At any rate, now
my problem is with the audio (yes I have fiddled with all the
adjustments in the transmitter). I cannot get the POPPING out of the
audio. I phoned Ramsey and was told to exchange the 270 pf cap for a
220 pf cap. This cap is mounted on the underside of the board (see
board drawing on the PDF). Well I will give this a try. I still
wouldn't mind upping the power somewhat. I know there are
resstrictions by I have no neighbors nearby. For some reason the
schematic drawing is missing on the PDF. I do have the schematic that
came with the instructions. Not that it does me a lot of good with my
limited knowledge! Anyway, thanks everyone for the input.

Joe

 

[Jamie]

Something is broken. Either at the transmitter or receiver. A
mis-matched antenna couldn't possibly account for a poor quality
picture at 20 feet. I presume this transmitter is designed to transmit
a signal via antenna to source and not over transmission line. Here
are some probable causes:

1) The transmitter output stage is broken.
2) The receiver is not working (see how well it picks up other
stations).
3) The antenna at either end is disconnected.
4) There is Radio-frequency interference (RFI) such as from a
computer.

Frank Raffaeli

Its my guess that the Transmitter has insufficient bandwidth and power
for that broad of a signal.
one must not forget the amount of band space a single channel takes.

 

[Steve Nosko]

Ten milliwatts is more than enough for a measly 20 feet, and i am
sure the kit puts out more than that.
Match (tune) the antennas at both ends for starters, orient them to
point at each other is the next step, and have a decent (sensitive)
receiver.
I only had a matched antenna at the (sensitive) receiver, and got
about 100 or so feet at 10mW.

I concurr. That transistor has the capability of putting out one watt,
though I don't think the circuit is designed to do that much. Even so, if
it is putting out even 100 miliwatts, that should get you several hundred
feet...with decent antennas. Once you are sure the circuit is operating
properly, work on the antennas . I did a TV transmitter of about 10 mw and
a really short whip antenna and got 20 feet no problem. Stuck it onto the
top of my camcorder and walked around the house. This was with the TV
"transmitter" from my 1970's "Pong" game and one of those broad band MMIC
amps...50 ohms in/out and a 18 inch whip above the camera. It was actually
in a Bud box with a home-made bracket that slipped into the light shoe. Had
to be a crummy antenna.
[/QUOTE]

 

[Frank Raffaeli]

Did the OP go through the alignment procedure? Did the OP bother with
antennas at all?

Did either of you read the kit doc?

Thanks,
Rich

I didn't read the kit doc until just now. Not trivial for a beginner
to construct. Looks like fun, though. There are a lot of missteps in
the assembly / test procedure that could cause a "fuzzy" picture.
There are some useful hints for debugging though. Maybe there would be
a market for a better kit ...

I wonder if this transmitter complies with Part 15 regs?

Frank Raffaeli
http://www.aomwireless.com/

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

Hello all,
Recently I purchased a low-power VHF transmitter kit from Ramsey.
After building this kit, I have discovered that it will not work for
my purpose. I am trying to transmit audio and video about 20 feet from
a satellite receiver to my bedroom. The power output from the
transmitter is so low that the picture quality is very poor. I am a
novice and I am hoping the experts that use these newsgroups can help
me. I will post a link to the Ramsey kit manual. Will some of you
guys please take a look at this manual, and suggest some simple
(hopefully) methods to increase the power of this transmitter? There
is no chance of interference with the neighbors, as my nearest
neighbor is far away. Any help would be greatly appreciated. If you
want to email the response, please send it to [email protected]

Here is the link to the kit manual:
http://www.ramseyelectronics.com/downloads/manuals/TV6.pdf

Ramsey purposefully left out the schematic page in this URL. Thanks for
nothing!

I would try better antennas before hacking the TV6.

BTW, you are shamefully crossposting to too many newsgroups!
Novice = flamebait!

 

[Bob Haberkost]

Ramsey purposefully left out the schematic page in this URL. Thanks for
nothing!

The circuit is simple enough that a schematic isn't all that necessary. At the same
time, I can see that there's very little that can be done to boost the signal, short
of adding components. This would be, if investigated by the FCC's enforcement of
unlicensed radiators (in excess of Part 15 regs) evidence that the user was in
violation of the "intentional radiator" limits under Part 15.

I would try better antennas before hacking the TV6.

The manual goes to some length to describe the expected coverage area for this
device. I'm with you that Joe has some issue with antennas (and again, please note
that putting an antenna with gain would suggest that the user is intentionally
violation Part 15). Is there a set-top antenna being used? Is the feedline from the
transmitter unit undamaged, and properly connected? Is there a balun being used to
match the 75-ohm output to a 300-ohm folded dipole?

BTW, you are shamefully crossposting to too many newsgroups!

I show the list of only 5 groups....not excessive, but more than I usually see
without it being tagged (and glommed) as spam.

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

[snip]

I show the list of only 5 groups....not excessive, but more than I usually see
without it being tagged (and glommed) as spam.

That's after I deleted a half dozen newsgroups. I wouldn't be surprised
if some of the others chewed him out thoroughly for wasting their time.

 

[Winfield Hill]

...
It's possible mndflmr's problem is misadjusted pots R3 and R7.