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Re: Crystals For GE MASTR II
John Lloyd
W8CQ,
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Ray is right, ICM will do the calculations for you, but if you want high side injection for the Receiver you need to specify it. VHF TX Crystal calculations are: Crystal Freq =Operating Freq/12 VHF RX Crystal Calculations are Crystal Freq=(Operating Freq - 11.2 Mhz)/9 UHF Tx Crystal calculations are: Crystal Freq=Operating Freq/36 UHF Rx Crystal calculations are: Crystal Freq=(Operating Freq - 11.2Mhz ) / 27 John Lloyd, K7JL Utah VHF Society Ray J. Vaughan wrote: From: "Ray J. Vaughan" <ray@...> |
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Re: Crystals For GE MASTR II
John Hackman
The CORRECT way to calculate the crystal frequency for any radio is to let International or whichever crystal supplier you are using do it. Any crystal manufacturer worth dealing with will do so, and will stand behind their calculations. Who will guarantee the accuracy of MY calculation? So I leave it to International.
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The sole exception to this rule is for really strange applications, like converting a standard Micor UHF mobile into a repeater with high-side receive. ......John WB4VVA ----- Original Message -----
From: Jeff Weinberg W8CQ To: Repeater Builder Sent: Thursday, April 15, 1999 9:31 PM Subject: [Repeater-builder] Crystals For GE MASTR II Hello All, I have a simple question (I think), but it may not have a simple answer. Recently I have acquired a GE MASTR II UHF radio for my repeater. I have seen 2 or 3 different ways to calculate the crystal frequency for this radio. This is a "painted handle" version of the radio. The one that DOES NOT have a tripler. What is the correct method for calculating TX/RX crystal frequencies for this radio? Thanks in advance, Jeff Weinberg W8CQ w8cq@... |
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Re: antenna question
John Lloyd
Kurt,
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Have you checked out the Feedline for Loss and or Damage. I would measure your transmitter power going into your feedline next to the transmitter and then climb the tower to the antenna and insert the wattmeter between the feedline and antenna and measure the power output from the transmitter. This will be your feedline loss. I would also check reflected power coming back from the antenna. This would be a good starting point. John Lloyd, K7JL Utah VHF Society Kurt Bleich wrote: From: Kurt Bleich <kurt_bleich@...> |
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Re: ge master II VHF to 220Mhhz
John Lloyd
Look at the page:
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for 220 modifications John Lloyd, K7JL KF4TNP wrote: From: KF4TNP <Bug1@...> |
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Re: FS: Micor low split mobile
John Lloyd
How much?
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Are they 132-151 Mhz? John Lloyd, K7JL Jsimmons wrote: From: "Jsimmons" <auburn@...> |
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Re: antenna question
Todd Ellis
I would also look to see what else was on the tower with the VHF fire stuff.
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More likely than not, you might find a nearby paging transmitter belching 250W into a high gain antenna on the same tower. It could almost completely desense a receiver just a few megahertz away. In short, there's a lot of system concerns the "professionals" have to consider besides the antenna. Even if, like Frank Lynch's comments the other day, the antenna has a narrow vertical lobe, at 5 miles there should be a significant enough lobe to hear the base station. Any obstructions between the portable and the tower site?? Todd Ellis -----Original Message-----
From: Kurt Bleich <kurt_bleich@...> To: repeater-builder@... <repeater-builder@...> Date: Friday, April 16, 1999 11:22 AM Subject: [Repeater-builder] antenna question From: Kurt Bleich <kurt_bleich@...>I have just put one up on 440. Our fire rpt is all new equipment thatsupposedly has been checked out by different companies all saying everything is okay.It is hard to believe there isn't something wrong somewhere because with themiles out. I was just wondering if the exposed dipole antenna, since they seem to |
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Re: FS: Micor low split mobile
Bill Anderson WA9BA
The radio clubs I service Micor repeaters for may be interested. Please send
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a quote for them, we may need 4 or more depending on price. Bill Anderson WA9BA Jsimmons wrote: From: "Jsimmons" <auburn@...> |
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Aerotron-Repco Systems, Inc.
pvs4@xxxxxxx.xxx
Hello:
Has anyone used any equipment, i.e. Exciters or Receivers from ARS, Aerotron-Repco Systems, Inc. I am seeking to build a repeater and am thinking about using their equipment. Looking for honest opinion on the quality of this equipment. Thank You Lindsay Hodgdon |
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New list - 220 MHz
Todd Ellis
For those interested, this new group shares information regarding 220 MHz
narrowband commercial (repeat, COMMERCIAL) two-way radio systems. This would include information about system components, technical issues, site coordination, and more. Note - yes, this is the spectrum that was taken from the ham band. Flames about that matter won't be allowed or tolerated; what's done is done. What IS interesting is the amount of engineering and effort that is needed to implement the new narrowband technologies in this small slice of spectrum as dictated by the FCC. It's completely different from FM!! If you're interested in this and/or wish to contribute your thoughts on various technical matters, we'd appreciate hearing from you. Todd Ellis, N2XL Operations Manager, Telecommunications Division Booth & Associates, Inc. 1011 Schaub Drive Raleigh, NC 27606 Tel: (919) 851-8770 Fax: (919) 859-5918 E-mail: ellistr@... |
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Re: antennas???
KF4TNP
the comet GP-6 works great no a whole lot og gain and for high elevations it
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works great do to the low gain so it covers with in your 30 miles radius just great on VHF and UHF but the comet GP-6 is a dual band antenna and it is two piece not three and about i think it was 8 foot i have had good luck with the OTHERS also but until they acted like a rain gauge i had to give them up or fix them David Peterson wrote: From: David Peterson <DPeterson@...> |
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Re: exposed dipole question
Todd Ellis
Your fire station sites may be completely different from your 2m sites. The
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antenna contribution itself is not likely to be the single issue, but height above ground (AGL), ground elevation (MSL), output power, receiver sensitivity, transmission and duplexer/filter losses all cumulatively contribute to the propagation effect. The antenna is but one element. If you were to compare apples to apples, you could change out the values for the specific elements and do some comparisons. I have some prediction software that takes all of that into account and even spits out a coverage area contour prediction which can be overlayed on top of the station being compared. But then again, we get paid megabucks to do this stuff commercially! Hope this helps you some. Todd Ellis, N2XL Raleigh, NC -----Original Message-----
From: Kurt Bleich <kurt_bleich@...> To: repeater-builder@... <repeater-builder@...> Date: Friday, April 16, 1999 8:59 AM Subject: [Repeater-builder] exposed dipole question From: Kurt Bleich <kurt_bleich@...>now I have a question. We have a VHF repeater for our fire depts in our county.deaf. Would any characteristic of these exposed dipole antennas affect rx? This |
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Re: antennas???
David Peterson
Hi there,
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I have good success with a diamond X500H this is the HEAVY Duty version of the X500. I know that there is other options out there. But for what it is worth that is my 2 cents. Dave KD4POG -----Original Message-----
From: dcarpenter@... [mailto:dcarpenter@...] Sent: Wednesday, April 14, 1999 4:12 PM To: Repeater-builder@... Subject: [Repeater-builder] antennas??? From: dcarpenter@... Can someone suggest a gud dual band antenna to use fer a uhf and vhf repeater system. I've used a cushcraft 270-b (?) and now using a hustler fiberglass. Both work OK but wondered if anybody could suggest something better without costing several hundred dollars.... tnx ki5fw ------------------------------------------------------------------------ Jansport Daytripper the perfect pack for short spring and summer excursions*Key clip keeps keys handy*Front organizer pocket*Weighs1lb* Capacity 2200 cu in! Members Pay $34.00*Free Shipping in US ------------------------------------------------------------------------ This list is sponsored by the owners and users of "RBTIP" |
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Re: Shortening Db-212 style antennas..
David Peterson
Gary,
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check the spacing between the dipoles. Measure the spacing, and then calc. the spacing for the frequency that you are using. Dave -----Original Message-----
From: w7ntf@... [mailto:w7ntf@...] Sent: Thursday, April 15, 1999 6:18 PM To: Repeater-builder@... Subject: [Repeater-builder] Re: Shortening Db-212 style antennas.. From: w7ntf@... Hi Tedd, I read your message with interest. I have a similar situation. I was given a beautiful shiny UHF exposed dipole array with 8 dipoles... four on one side of the mast and four more 180 degrees out... The problem is that the system is cut for the low end of the UHF spectrum, in the 420 mhz range. It does work as is with an acceptable reflected power, however the efficiency is real poor. I am wondering if it is possible to shorten things somehow in order to push the center freq into the FM portion of the UHF ham band? I suspect that it is possible to do so, but would proceed with caution, as we may indeed get the resonant freq moved up into the ham band by tweaking the physical length of each element, but do not forget that the phasing harness is not going to easily be adjusted. That would probably drag the efficiency of the re-tuned dipoles down some, as well as produce uncontrollable effects on the radiation pattern, gain, etc... I would be very pleased to hear what others think. Good luck in your quest.... 73, de Gary, W7NTF ------------------------------------------------------------------------ Have you visited the new ONElist home page lately? ONElist: The Leading e-mail list and community service on the Internet! ------------------------------------------------------------------------ This list is sponsored by the owners and users of "RBTIP" |
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