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| | |-+  Where to find "real" transmitters (and antennas) for FM and AM.
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Author Topic: Where to find "real" transmitters (and antennas) for FM and AM.  (Read 30121 times)
RFBurns

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« Reply #15 on: September 04, 2010, 09:57:26 AM »

Has anyone used the HLLY transmitters?  Very cheep (5W ~$100, 20W ~$200) but I would be interested to hear if anyone can report on the quality.

These transmitters show up on ebay every now and again, or can be bought direct from http://www.hllyelectronics.com


Make sure you use a low-pass filter - I'm not sure units that cheap have them.  Make sure they do, otherwise you can get one to add between the transmitter and antenna.



The HLLY units (also labeled as CZH-##) do in fact have an internal output filters (3 pole) on all of the models. It is located behind the heat sink near the internal fan connector. They are properly tuned from the factory to cover the entire FM band, but they can be peaked to a specific frequency to improve their performance by simply separating the coil windings or compressing them or combination.

A spec-an is highly recommended to properly adjust these or any other filter.


RFB
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FTL_Ian
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« Reply #16 on: September 04, 2010, 12:48:07 PM »

I am surprised to find that out.  Welcome to the forum and thanks for the expertise. 

For the record, here is HLLY's official response to my question about which of their transmitters have low-pass filters:

http://www.hllyelectronics.com/forums/index.php?action=vthread&forum=1&topic=346
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TX-30S, TX-01S, HLLY 20W Fm transmitter all have good low-pass filters!
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RFBurns

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« Reply #17 on: September 04, 2010, 09:48:05 PM »

Thank you for the welcome. Smile

Thats great they actually provided info! The "CZH" units, I had to practically claw and fight for information. 2 months after purchasing the CZH-5 and CZH-20, the HLLY units started showing up on ebay. Curiosity got the best of me because the HLLY units appeared to be identical to the CZH units...as far as the case styles and front pannel controls.

So I bought 2 of the HLLY units, same power levels of 1/5 watt selectable unit and the 20w unit. Once they arrived I opened them up and put them side by side to the CZH units.

Identical boards in both brands. Some of their lower power units wont have any filtering, but its advisable to buy one or home brew a filter for those.

RFB
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« Reply #18 on: October 09, 2010, 10:01:04 PM »

Our new station in Ohio is using a TX from http://fmuser.com/
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RFBurns

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« Reply #19 on: October 21, 2010, 11:22:35 AM »

Our new station in Ohio is using a TX from http://fmuser.com/


As you can see on the FMuser site, there is a CZH unit (black case) pictured with the silver units.

These units can be set to operate in two power modes. 1.5w and 5w (typical 7w). These can also be set so that if the power goes out and returns, you dont have to re-set your operating frequency. Simply program the unit's upper and lower frequency range to your operating freq.

1. Hold power button on while plugging the power source into the power jack.

2. Display will show either an "L" or an "H". L for low power, H for high power. Use the + or - keys to set, push the power button to go to the next setup sequence...frequency range.

3. The unit will start at its upper frequency setting from the factory. *NOTE: These units CAN transmit well above 108 Mhz and well below 88 Mhz so be careful!! Set the unit's upper frequency limit, then push the power button to go to the low frequency limit.

4. Set the low frequency limit and push the power button. The unit will store the settings and power off.

During these setup stages, the unit will not be transmitting, however it is always safe to attach a dummy load to the output when going into the setup/power modes.

They are great little units with excellent performance for the price.


RFB
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« Reply #20 on: November 23, 2010, 10:45:19 PM »

Wow, useful tip!   Cool
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« Reply #21 on: January 25, 2011, 03:54:49 AM »

Wow, useful tip!   Cool

The later models of the 15 and 20 watt units can also be set for low and high power. These two units are really great for driving large power amplifiers.

I used one as a temporary exciter to drive a Harris FM-25 transmitter. The Harris FM-25 is a 25Kw power amp cabinet that only needs about 15 watts to make full power on the lower third of the band.

The station is KMLD 94.5 in Casper Wy.
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« Reply #22 on: July 21, 2011, 08:59:20 PM »

free radio berkely is bad news. heads up.
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« Reply #23 on: August 06, 2011, 11:31:57 PM »

Wow, useful tip!   Cool

The later models of the 15 and 20 watt units can also be set for low and high power. These two units are really great for driving large power amplifiers.

I used one as a temporary exciter to drive a Harris FM-25 transmitter. The Harris FM-25 is a 25Kw power amp cabinet that only needs about 15 watts to make full power on the lower third of the band.

The station is KMLD 94.5 in Casper Wy.
Do they have remote control I/O for muting, APC, failsafe and such?
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« Reply #24 on: February 18, 2014, 01:40:31 AM »

You'd have to be mad to buy that package.  Just get the transmitter and 5/8 wave.  All you need then is the appropriate length of cable, plus your audio source.


Yes,can't agree with u more. One transmitter ,and cable and antenna make it a complete broadcasting system.
For 10W FM professional transmitter ,i recommend as below for your choice:
http://www.hcfmtv.com/professional-fm-transmitter/
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« Reply #25 on: February 25, 2014, 01:16:16 AM »

You'd have to be mad to buy that package.  Just get the transmitter and 5/8 wave.  All you need then is the appropriate length of cable, plus your audio source.


Yes,can't agree with u more. One transmitter ,and cable and antenna make it a complete broadcasting system.
For 10W FM professional transmitter ,i recommend as below for your choice:
http://www.hcfmtv.com/professional-fm-transmitter/


the link i recommend is from factory direct sale, with low price.
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